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1994-02-06
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Interrupt List, part 4 of 10
This compilation is Copyright (c) 1989,1990,1991,1992,1993,1994 Ralf Brown
--------D-2142-------------------------------
INT 21 - DOS 2+ - "LSEEK" - SET CURRENT FILE POSITION
AH = 42h
AL = origin of move
00h start of file
01h current file position
02h end of file
BX = file handle
CX:DX = offset from origin of new file position
Return: CF clear if successful
DX:AX = new file position in bytes from start of file
CF set on error
AX = error code (01h,06h) (see AH=59h)
Notes: for origins 01h and 02h, the pointer may be positioned before the
start of the file; no error is returned in that case, but subsequent
attempts at I/O will produce errors
if the new position is beyond the current end of file, the file will
be extended by the next write (see AH=40h)
BUG: using this method to grow a file from zero bytes to a very large size
can corrupt the FAT in some versions of DOS; the file should first
be grown from zero to one byte and then to the desired large size
SeeAlso: AH=24h,INT 2F/AX=1228h
--------v-214203-----------------------------
INT 21 - VIRUS - "Shake" - INSTALLATION CHECK
AX = 4203h
Return: AX = 1234h if resident
SeeAlso: AX=3DFFh,AX=4243h
--------v-214243-----------------------------
INT 21 - VIRUS - "Invader" - INSTALLATION CHECK
AX = 4243h
Return: AX = 5678h if resident
SeeAlso: AX=4203h,AX=4B04h
--------D-214300-----------------------------
INT 21 - DOS 2+ - GET FILE ATTRIBUTES
AX = 4300h
DS:DX -> ASCIZ filename
Return: CF clear if successful
CX = file attributes (see AX=4301h)
AX = CX (DR-DOS 5.0)
CF set on error
AX = error code (01h,02h,03h,05h) (see AH=59h)
Notes: under the FlashTek X-32 DOS extender, the filename pointer is in DS:EDX
under DR-DOS 3.41 and 5.0, attempts to change the subdirectory bit are
simply ignored without an error
SeeAlso: AX=4301h,AX=4310h,AH=71h,AH=B6h,INT 2F/AX=110Fh
--------D-214301-----------------------------
INT 21 - DOS 2+ - "CHMOD" - SET FILE ATTRIBUTES
AX = 4301h
CX = new file attributes (see below)
DS:DX -> ASCIZ filename
Return: CF clear if successful
AX destroyed
CF set on error
AX = error code (01h,02h,03h,05h) (see AH=59h)
Notes: will not change volume label or directory attribute bits, but will
change the other attribute bits of a directory (the directory
bit must be cleared to successfully change the other attributes of a
directory, but the directory will not be changed to a normal file as
a result)
MS-DOS 4.01 reportedly closes the file if it is currently open
for security reasons, the Novell NetWare execute-only bit can never
be cleared; the file must be deleted and recreated
under the FlashTek X-32 DOS extender, the filename pointer is in DS:EDX
DOS 5.0 SHARE will close the file if it is currently open in sharing-
compatibility mode, otherwise a sharing violation critical error is
generated if the file is currently open
SeeAlso: AX=4300h,AX=4311h,AH=71h,INT 2F/AX=110Eh
Bitfields for file attributes:
bit 7 shareable (Novell NetWare)
bit 6 unused
bit 5 archive
bit 4 directory
bit 3 volume label
execute-only (Novell NetWare)
bit 2 system
bit 1 hidden
bit 0 read-only
--------D-214302-----------------------------
INT 21 - DOS 7 (Chicago) - GET VOLUME INFORMATION
AX = 4302h
details not yet available
SeeAlso: AH=71h,AH=72h
--------O-214302-----------------------------
INT 21 - DR-DOS 3.41+ internal - GET ACCESS RIGHTS
AX = 4302h
DS:DX -> ASCIZ pathname
Return: CF clear if successful
CX = access rights (see below)
AX = CX (DR-DOS 5.0)
CF set on error
AX = error code
Desc: Determine which operations the calling program may perform on a
specified file without being required to provide a password.
Notes: this protection scheme has been coordinated on all current Digital
Research/Novell operating systems (DR-DOS 3.41+, DRMDOS 5.x, and
FlexOS 2+)
this function is documented in DR-DOS 6.0 and corresponds to the
"Get/Set File Attributes" function, subfunction 2, documented in
Concurrent DOS.
only FlexOS actually uses the "execution" bits; DR-DOS 3.41+ treats
them as "read" bits.
DR-DOS 3.41-5.x only use bits 0-3. Only DR-DOS 6.0 using a
DRMDOS 5.x security system allowing for users and groups uses bits
4-11.
SeeAlso: AX=4303h
Bitfields for access rights:
bit 0 owner delete requires password
bit 1 owner execution requires password (FlexOS)
bit 2 owner write requires password
bit 3 owner read requires password
bit 4 group delete requires password
bit 5 group execution requires password (FlexOS)
bit 6 group write requires password
bit 7 group read requires password
bit 8 world delete requires password
bit 9 world execution requires password (FlexOS)
bit 10 world write requires password
bit 11 world read requires password
--------O-214303-----------------------------
INT 21 - DR-DOS 3.41+ internal - SET ACCESS RIGHTS AND PASSWORD
AX = 4303h
CX = access rights
bits 11-0: access rights (see AX=4302h"DR-DOS")
bit 15: new password is to be set
DS:DX -> ASCIZ pathname
[DTA] = new password if CX bit 15 is set (blank-padded to 8 characters)
Return: CF clear if successful
CF set on error
AX = error code
Notes: if the file is already protected, the old password must be added after
the pathname, separated by a ";"
this function is documented in DR-DOS 6.0 and corresponds to the
"Get/Set File Attributes" function, subfunction 3, documented in
Concurrent DOS.
SeeAlso: AH=0Fh,AH=17h,AX=4302h"DR-DOS",AX=4305h,AX=4454h
--------O-214304-----------------------------
INT 21 U - DR-DOS 5.0-6.0 internal - GET ENCRYPTED PASSWORD
AX = 4304h
DS:DX -> ASCIZ filename
???
Return: CF clear if successful
CX = AX = 0000h if no password assigned to file
CF set on error
AX = error code (see AH=59h)
Note: this function is only supported by DR-DOS 5.0 and 6.0 and DRMDOS 5.1
SeeAlso: AX=4303h,AX=4305h
--------O-214305-----------------------------
INT 21 U - DR-DOS 5.0-6.0 internal - SET EXTENDED FILE ATTRIBUTES
AX = 4305h
DS:DX -> ASCIZ filename
???
Return: CF clear if successful
CF set on error
AX = error code (see AH=59h)
Desc: this function allows the extended attributes, and optionally the
encrypted password, of a file to be set.
Note: this function is only supported by DR-DOS 5.0 and 6.0 and DRMDOS 5.1
SeeAlso: AX=4304h,AX=4311h
--------O-214306-----------------------------
INT 21 - DR-DOS 6.0 - GET FILE OWNER
AX = 4306h
DS:DX -> ASCIZ filename
Return: CF clear if successful
AX = CX = value set with AX=4307h
CF set on error
AX = error code (see AH=59h)
SeeAlso: AX=4307h
--------O-214307-----------------------------
INT 21 - DR-DOS 6.0 - SET FILE OWNER
AX = 4307h
CX = ??? (owner identification number?)
DS:DX -> ASCIZ filename
Return: CF clear if successful
CF set on error
AX = error code (see AH=59h)
SeeAlso: AX=4306h
--------N-214310-----------------------------
INT 21 - Banyan VINES 2.1+ - GET EXTENDED FILE ATTRIBUTES
AX = 4310h
DS:DX -> ASCIZ filename
Return: CF clear if successful
CH = attributes (see AX=4311h)
CF set on error
AX = error code (01h,02h,03h,05h) (see AH=59h)
Note: the filename may be a directory but must be on a VINES file service
SeeAlso: AX=4300h,AX=4311h,AH=B6h,INT 2F/AX=110Fh
--------N-214311-----------------------------
INT 21 - Banyan VINES 2.1+ - SET EXTENDED FILE ATTRIBUTES
AX = 4311h
CH = new attributes
bit 7: unused
bit 6: shareable
bit 5: execute-only
bits 4-0: unused
DS:DX -> ASCIZ filename
Return: CF clear if successful
CF set on error
AX = error code (01h,02h,03h,05h) (see AH=59h)
Note: the filename may be a directory but must be on a VINES file service
SeeAlso: AX=4301h,AX=4305h,AX=4310h,INT 2F/AX=110Eh
--------O-214380-----------------------------
INT 21 - Novell DOS 7 - UNDELETE PENDING DELETE FILE
AX = 4380h
???
Return: ???
SeeAlso: AH=41h,AX=4381h
--------O-214381-----------------------------
INT 21 - Novell DOS 7 - PURGE PENDING DELETE FILE
AX = 4381h
???
Return: ???
SeeAlso: AH=41h,AX=4380h
--------D-214400-----------------------------
INT 21 - DOS 2+ - IOCTL - GET DEVICE INFORMATION
AX = 4400h
BX = handle
Return: CF clear if successful
DX = device information word (see below)
AX destroyed
CF set on error
AX = error code (01h,05h,06h) (see AH=59h)
Notes: value in DH corresponds to high byte of device driver's attribute word
if handle refers to a character device
Novell NetWare reportedly does not return a drive number in bits 5-0
for a disk file
SeeAlso: AX=4401h,INT 2F/AX=122Bh
Bitfields for device information word:
character device
bit 14: device driver can process IOCTL requests (see AX=4402h)
bit 13: output until busy supported
bit 11: driver supports OPEN/CLOSE calls
bit 7: set (indicates device)
bit 6: EOF on input
bit 5: raw (binary) mode
bit 4: device is special (uses INT 29)
bit 3: clock device
bit 2: NUL device
bit 1: standard output
bit 0: standard input
disk file
bit 15: file is remote (DOS 3+)
bit 14: don't set file date/time on closing (DOS 3+)
bit 11: media not removable
bit 8: (DOS 4 only) generate INT 24 if no disk space on write or read past
end of file
bit 7: clear (indicates file)
bit 6: file has not been written
bits 5-0: drive number (0 = A:)
--------D-214401-----------------------------
INT 21 - DOS 2+ - IOCTL - SET DEVICE INFORMATION
AX = 4401h
BX = handle (must refer to character device)
DX = device information word (see AX=4400h)
(DH must be zero)
Return: CF clear if successful
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
SeeAlso: AX=4400h,INT 2F/AX=122Bh
--------D-214402-----------------------------
INT 21 - DOS 2+ - IOCTL - READ FROM CHARACTER DEVICE CONTROL CHANNEL
AX = 4402h
BX = file handle referencing character device
CX = number of bytes to read
DS:DX -> buffer
Return: CF clear if successful
AX = number of bytes actually read
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
Note: format of data is driver-specific (see below for some specific cases)
SeeAlso: AX=4400h,AX=4403h,AX=4404h,INT 2F/AX=122Bh
--------N-214402-----------------------------
INT 21 - Network Driver Interface Specification (NDIS) 2.0.1 - PROTOCOL MANAGER
AX = 4402h
BX = file handle for device "PROTMAN$"
CX = 000Eh (size of request block)
DS:DX -> request block (see below)
Return: CF clear if successful
AX = number of bytes actually read
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
SeeAlso: AX=4402h"FTPSOFT"
Format of request block for GetProtocolManagerInfo:
Offset Size Description
00h WORD 01h
02h WORD returned status (see below)
04h DWORD returned pointer to structure representing parsed user config
08h DWORD unused
0Ch WORD returned BCD version of NDIS on which Protocol Manager is based
Format of request block for RegisterModule:
Offset Size Description
00h WORD 02h
02h WORD returned status (see below)
04h DWORD pointer to module's common characteristics table (see below)
08h DWORD pointer to list of modules to which the module is to be bound
0Ch WORD unused
Format of request block for BindAndStart:
Offset Size Description
00h WORD 03h
02h WORD returned status (see below)
04h DWORD caller's virtual address in FailingModules structure
08h DWORD unused
0Ch WORD unused
Format of request block for GetProtocolManagerLinkage:
Offset Size Description
00h WORD 04h
02h WORD returned status (see below)
04h DWORD returned dispatch point
08h DWORD unused
0Ch WORD returned protocol manager DS
Note: the dispatch point may be called as follows instead of using this IOCTL
STACK: WORD protocol manager DS
DWORD pointer to request block
Return: AX = returned status
STACK popped
Format of request block for GetProtocolIniPath:
Offset Size Description
00h WORD 05h
02h WORD returned status (see below)
04h DWORD pointer to a buffer for the ASCIZ pathname of PROTOCOL.INI
08h DWORD unused
0Ch WORD buffer length
Format of request block for RegisterProtocolManagerInfo:
Offset Size Description
00h WORD 06h
02h WORD returned status (see below)
04h DWORD pointer to structure containing parsed user config file
08h DWORD unused
0Ch WORD length of structure
Format of request block for InitAndRegister:
Offset Size Description
00h WORD 07h
02h WORD returned status (see below)
04h DWORD unused
08h DWORD poitner to ASCIZ name of the module to be prebind initialized
0Ch WORD unused
Format of request block for UnbindAndStop:
Offset Size Description
00h WORD 08h
02h WORD returned status (see below)
04h DWORD failing modules as for BindAndStart
08h DWORD if not 0000h:0000h, pointer to ASCIZ name of module to unbind
if 0000h:0000h, terminate a set of previously dynamically
bound protocol modules
0Ch WORD unused
Format of request block for BindStatus:
Offset Size Description
00h WORD 09h
02h WORD returned status (see below)
04h DWORD must be 0000h:0000h
on return, points to root tree
08h DWORD 0000h:0000h
0Ch WORD unused under DOS
Format of request block for RegisterStatus:
Offset Size Description
00h WORD 0Ah
02h WORD returned status (0000h, 0008h, 002Ch) (see below)
04h DWORD 0000h:0000h
08h DWORD pointer to 16-byte ASCIZ module name
0Ch WORD 0000h
Note: not supported by the 10NET v5.0 PROTMAN$ driver
Values for status code:
0000h success
0001h wait for release--protocol has retained control of the data buffer
0002h request queued
0003h frame not recognized
0004h frame rejected
0005h frame should be forwarded
0006h out of resource
0007h invalid parameter
0008h invalid function
0009h not supported
000Ah hardware error
000Bh transmit error
000Ch unrecognized destination
000Dh buffer too small
0020h already started
0021h binding incomplete
0022h driver not initialized
0023h hardware not found
0024h hardware failure
0025h configuration failure
0026h interrupt conflict
0027h MAC incompatible
0028h initialization failed
0029h no binding
002Ah network may be disconnected
002Bh incompatible OS version
002Ch already registered
002Dh path not found
002Eh insufficient memory
002Fh info not found
00FFh general failure
F000h-FFFFh reserved for vendor-specific codes, treated as general failure
Format of common characteristics table:
Offset Size Description
00h WORD size of table in bytes
02h BYTE NDIS major version
03h BYTE NDIS minor version
04h WORD reserved
06h BYTE module major version
07h BYTE module minor version
08h DWORD module function flag bits
bit 0: binding at upper boundary supported
bit 1: binding at lower boundary supported
bit 2: dynamically bound
bits 3-31 reserved, must be 0
0Ch 16 BYTEs ASCIZ module name
1Ch BYTE upper boundary protocol level (see below)
1Dh BYTE upper boundary interface type
for MACs: 1 = MAC
for data links and transports: to be defined
for session: 1 = NCB
any level: 0 = private (ISV-defined)
1Eh BYTE lower boundary protocol level (see below)
1Fh BYTE lower boundary interface type
same as offset 1Dh
20h WORD module ID filled in by protocol manager
22h WORD module DS
24h DWORD system request entry point
28h DWORD pointer to service-specific characteristics
0000h:0000h if none
2Ch DWORD pointer to service-specific status, or 0000h:0000h if none
30h DWORD pointer to upper dispatch table (see below)
0000h:0000h if none
34h DWORD pointer to lower dispatch table (see below)
0000h:0000h if none
38h 2 DWORDs reserved, must be 0
Note: for compatibility with NDIS 1.x.x, a major version of 00h is
interpreted as 01h
Values for boundary protocol level:
00h physical
01h Media Access Control
02h Data link
03h network
04h transport
05h session
FFh not specified
Format of dispatch table:
Offset Size Description
00h DWORD -> common characteristics table (see above)
04h 4 BYTEs ???
08h DWORD -> ??? function (called with 12 bytes of stack arguments)
0Ch DWORD -> ??? function (called with 10 bytes of stack arguments)
10h DWORD -> ??? function (called with 16 bytes of stack arguments)
14h DWORD -> ??? function (called with 4 bytes of stack arguments)
18h DWORD -> ??? function (called with 18 bytes of stack arguments)
1Ch DWORD -> ??? function (called with 12 bytes of stack arguments)
Format of MAC Service-Specific Characteristics Table:
Offset Size Description
00h WORD length of table in bytes
02h 16 BYTEs ASCIZ MAC type name, "802.3", "802.4", "802.5", "802.6", "DIX",
"DIX+802.3", "APPLETALK", "ARCNET", "FDDI", "SDLC", "BSC",
"HDLC", or "ISDN"
12h WORD length of station addresses in bytes
14h 16 BYTEs permanent station address
24h 16 BYTEs current station address
34h DWORD current functional adapter address (00000000h if none)
38h DWORD pointer to multicast address list
3Ch DWORD link speed in bits/sec
40h DWORD service flags (see below)
44h WORD maximum frame size which may be both sent and received
46h DWORD total transmit buffer capacity in bytes
4Ah WORD transmit buffer allocation block size in bytes
4Ch DWORD total receive buffer capacity in bytes
50h WORD receive buffer allocation block size in bytes
52h 3 BYTEs IEEE vendor code
55h BYTE vendor adapter code
56h DWORD pointer to ASCIZ vendor adapter description
5Ah WORD IRQ used by adapter
5Ch WORD transmit queue depth
5Eh WORD maximum supported number of data blocks in buffer descriptors
60h N BYTEs vendor-specific info
Bitfields for service flags:
bit 0 supports broadcast
bit 1 supports multicast
bit 2 supports functional/group addressing
bit 3 supports promiscuous mode
bit 4 station address software settable
bit 5 statistics always current
bit 6 supports InitiateDiagnostics
bit 7 supports loopback
bit 8 MAC does primarily ReceiveChain indications instead of ReceiveLookahead
indications
bit 9 supports IBM source routing
bit 10 supports MAC reset
bit 11 supports Open/Close adapter
bit 12 supports interrupt request
bit 13 supports source routing bridge
bit 14 supports GDT virtual addresses (OS/2 version)
bit 15 multiple TransferDatas allowed durign a single indication
bit 16 MAC normally sets FrameSize = 0 in ReceiveLookahead
bit 17-31 reserved, must be 0
Format of NetBIOS Service-Specific Characteristics Table
Offset Size Description
00h WORD length of table in bytes
02h 16 BYTEs ASCIZ type name of NetBIOS module
12h WORD NetBIOS module code
14h N BYTEs vendor-specific info
Format of MAC Service-Specific Status Table:
Offset Size Description
00h WORD length of table in bytes
02h DWORD seconds since 0:00 1/1/70 when diagnostics last run
(FFFFFFFFh = never)
06h DWORD MAC status bits (see below)
0Ah WORD current packet filter flags
bit 0: directed/multicast or group/functional
bit 1: broadcast
bit 2: promiscuous
bit 3: all source routing
bits 4-15: reserved, must be zero
0Ch DWORD pointer to media-specific status table or 0000h:0000h
10h DWORD seconds past 0:00 1/1/70 of last ClearStatistics
14h DWORD total frames received (FFFFFFFFh = not counted)
18h DWORD frames with CRC error (FFFFFFFFh = not counted)
1Ch DWORD total bytes received (FFFFFFFFh = not counted)
20h DWORD frames discarded--no buffer space (FFFFFFFFh = not counted)
24h DWORD multicast frames received (FFFFFFFFh = not counted)
28h DWORD broadcast frames received (FFFFFFFFh = not counted)
2Ch DWORD frames with errors (FFFFFFFFh = not counted)
30h DWORD overly large frames (FFFFFFFFh = not counted)
34h DWORD frames less than minimum size (FFFFFFFFh = not counted)
38h DWORD multicast bytes received (FFFFFFFFh = not counted)
3Ch DWORD broadcast bytes received (FFFFFFFFh = not counted)
40h DWORD frames discarded--hardware error (FFFFFFFFh = not counted)
44h DWORD total frames transmitted (FFFFFFFFh = not counted)
48h DWORD total bytes transmitted (FFFFFFFFh = not counted)
4Ch DWORD multicast frames transmitted (FFFFFFFFh = not counted)
50h DWORD broadcast frames transmitted (FFFFFFFFh = not counted)
54h DWORD broadcast bytes transmitted (FFFFFFFFh = not counted)
58h DWORD multicast bytes transmitted (FFFFFFFFh = not counted)
5Ch DWORD frames not transmitted--timeout (FFFFFFFFh = not counted)
60h DWORD frames not transmitted--hardware error (FFFFFFFFh = not countd)
64h N BYTEs vendor-specific info
Bitfields for MAC status bits:
bits 0-2 operational status
000 hardware not installed
001 hardware failed startup diagnostics
010 hardware configuration problem
011 hardware fault
100 operating marginally due to soft faults
101 reserved
110 reserved
111 hardware fully operational
bit 3 MAC bound
bit 4 MAC open
bit 5 diagnostics in progress
bits 6-31 reserved
--------I-214402-----------------------------
INT 21 U - IBM SYSTEM 36/38 WORKSTATION EMULATION - VDI.SYS - GET ???
AX = 4402h
BX = handle for character device "GDMS"
CX = number of bytes to read (>= 4)
DS:DX -> buffer (see below)
Return: CF set on error
AX = error code (see AH=59h)
CF clear if successful
AX = number of bytes read
Format of returned data:
Offset Size Description
00h 4 BYTEs ???
04h DWORD pointer to ???
08h 4 BYTEs ???
--------m-214402-----------------------------
INT 21 U - LASTBYTE.SYS v1.19 - IOCTL - GET ??? TABLE
AX = 4402h
BX = handle for device "LA$TBYTE"
CX = 0004h
DS:DX -> DWORD to hold address of 39-byte table of ???
Return: CF set on error
AX = error code (see AH=59h)
CF clear if successful
AX = number of bytes read
Program: LASTBYTE.SYS is part of the shareware "The Last Byte" memory
management package by Key Software Products
SeeAlso: AX=4402h"HIGHUMM"
--------m-214402-----------------------------
INT 21 - HIGHUMM.SYS v1.17+ - IOCTL - GET API ADDRESS
AX = 4402h
BX = handle for device "KSP$UMM"
CX = 0004h
DS:DX -> DWORD to hold entry point
Return: CF set on error
AX = error code (see AH=59h)
CF clear if successful
AX = number of bytes read
Program: HIGHUMM.SYS is part of the shareware "The Last Byte" memory management
package by Key Software Products
SeeAlso: AX=4402h"LASTBYTE"
Call HIGHUMM.SYS entry point with:
AH = 00h allocate UMB (same as XMS function 10h) (see INT 2F/AX=4310h)
DX = size in paragraphs
Return: BX = segment number (if successful)
DX = size of requested block/size of largest block
AH = 01h deallocate UMB (same as XMS func 11h) (see INT 2F/AX=4310h)
DX = segment number of UMB
AH = 02h request a bank-switched memory block
DX = size in paragraphs
Return: BX = segment number (if successful)
DX = size of requested block/size of largest block
AH = 03h release a bank-switched memory block
DX = segment number
AH = 04h transfer data to/from high memory
DS:SI -> source
ES:DI -> destination
CX = length in bytes
Note: enables bank-switched memory, does the copy, then disables
bank-switched memory
AH = 05h get a word from bank-switched memory
ES:DI -> word to read
Return: DX = word
AH = 06h put a word to bank-switched memory
ES:DI -> word to write
DX = word
AH = 07h put a byte to bank-switched memory
ES:DI -> byte to write
DL = byte
AH = 08h enable bank-switched memory
DS:SI -> 6-byte status save area
AH = 09h disable bank-switched memory
DS:SI -> 6-byte save area from enable call (AH=08h)
AH = 0Ah assign name to UMB or high bank-switched block
DX = segment number
DS:SI -> 8-byte blank-padded name
AH = 0Bh locate UMB block by name
DS:SI -> 8-byte blank-padded name
Return: BX = segment number (if successful)
DX = size of block
AH = 0Ch locate bank-switched block by name
DS:SI -> 8-byte blank-padded name
Return: BX = segment number (if successful)
DX = size of block
Return: AX = status code
0001h successful
0000h failed
BL = error code
80h not implemented
B0h insufficient memory, smaller block available
B1h insufficient memory, no blocks available
B2h invalid segment number
Note: only functions 00h and 01h are always available; the remaining
functions are only enabled if the proper commandline switch is given
--------c-214402-----------------------------
INT 21 - SMARTDRV.SYS v3.x only - IOCTL - GET CACHE STATUS
AX = 4402h
BX = file handle for device "SMARTAAR"
CX = number of bytes to read (min 28h)
DS:DX -> buffer for status record (see below)
Return: CF clear if successful
AX = number of bytes actually read
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
SeeAlso: AX=4403h"SMARTDRV",INT 2F/AX=4A10h/BX=0000h
Format of SMARTDRV status record:
Offset Size Description
00h BYTE write-through flag (always 01h)
01h BYTE writes should be buffered (always 00h)
02h BYTE cache enabled if 01h
03h BYTE driver type (01h extended memory, 02h expanded)
04h WORD clock ticks between cache flushes (currently unused)
06h BYTE cache contains locked tracks if nonzero
07h BYTE flush cache on INT 19 reboot if nonzero
08h BYTE cache full track writes if nonzero
09h BYTE double buffering (for VDS) state (00h off, 01h on, 02h dynamic)
0Ah DWORD original INT 13 vector
0Eh BYTE minor version number
0Fh BYTE major version number
10h WORD unused
12h WORD sectors read \
14h WORD sectors already in cache > may be scaled rather than
16h WORD sectors already in track buffer / absolute counts
18h BYTE cache hit rate in percent
19h BYTE track buffer hit rate in percent
1Ah WORD total tracks in cache
1Ch WORD number of tracks in use
1Eh WORD number of locked tracks
20h WORD number of dirty tracks
22h WORD current cache size in 16K pages
24h WORD original (maximum) cache size in 16K pages
26h WORD minimum cache size in 16K pages
28h DWORD pointer to byte flag to increment for locking cache contents
--------d-214402-----------------------------
INT 21 - CD-ROM device driver - IOCTL INPUT
AX = 4402h
BX = file handle referencing character device for CD-ROM driver
CX = number of bytes to read
DS:DX -> control block (see below)
Return: CF clear if successful
AX = number of bytes actually read
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
Note: the data returned depends on the first byte of the control block; the
remainder of the control block is filled by the driver
SeeAlso: AX=4403h"CD-ROM",INT 2F/AX=0802h
Values for data being requested:
00h device driver header address
01h drive head location
02h reserved
03h error statistics
04h audio channel info
05h raw drive bytes (uninterpreted and device-specific)
06h device status
07h sector size
08h volume size
09h media change status
0Ah audio disk info
0Bh audio track info
0Ch audio Q-Channel info
0Dh audio sub-channel info
0Eh UPC code
Format of control block:
Offset Size Description
00h BYTE data being requested (see above)
---function 00h---
01h DWORD device driver header address (see also AH=52h)
---function 01h---
01h BYTE addressing mode
00h HSG
01h Red Book
02h DWORD current location of drive's head
logical sector number in HSG mode
frame/second/minute/unused in Red Book mode
(HSG sector = minute * 4500 + second * 75 + frame - 150)
---function 03h---
01h N BYTEs undefined as of 5 Aug 88 specification
---function 04h---
01h BYTE input channel (0-3) for output channel 0
02h BYTE volume for output channel 0
03h BYTE input channel (0-3) for output channel 1
04h BYTE volume for output channel 1
05h BYTE input channel (0-3) for output channel 2
06h BYTE volume for output channel 2
07h BYTE input channel (0-3) for output channel 3
08h BYTE volume for output channel 3
Notes: output channels 0 and 1 are left and right, 2 and 3 are left prime and
right prime; a volume of 00h is off
the default setting is for each input channel to be assigned to the
same-numbered output channel at full (FFh) volume
---function 05h---
01h BYTE number of bytes read
02h 128 BYTEs buffer for drive bytes
---function 06h---
01h DWORD device parameters (see below)
---function 07h---
01h BYTE read mode
00h cooked
01h raw
02h WORD sector size in bytes
---function 08h---
01h DWORD volume size in sectors
---function 09h---
01h BYTE media change status
00h don't know
01h media unchanged
FFh media has been changed
---function 0Ah---
01h BYTE lowest audio track number
02h BYTE highest audio track number
03h DWORD start address of lead-out track (Red Book format)
--function 0Bh---
01h BYTE track number (set by caller)
02h DWORD starting point of track (Red Book format)
06h BYTE track control info
bits 15,14,12: track type (notice: bits not contiguous!)
000 two audio channels, no pre-emphasis
001 two audio channels with pre-emphasis
010 data track
100 four audio channels, no pre-emphasis
101 four audio channels with pre-emphasis
other reserved
bit 13: digital copy permitted
---function 0Ch---
01h BYTE CONTROL and ADR byte (as received from drive)
02h BYTE track number
03h BYTE point or index
04h BYTE minute \
05h BYTE second > running time within track
06h BYTE frame /
07h BYTE zero
08h BYTE "AMIN" or "PMIN" \
09h BYTE "ASEC" or "PSEC" > running time on disk
0Ah BYTE "AFRAME" or "PFRAME" /
---function 0Dh---
01h DWORD starting frame address (Red Book format)
05h DWORD transfer address
09h DWORD number of sectors to read
Note: copies 96 bytes of sub-channel info per sector into buffer
---function 0Eh---
01h BYTE CONTROL and ADR byte
02h 7 BYTEs UPC/EAN code (13 BCD digits,low-order nybble of last byte is 0)
09h BYTE zero
0Ah BYTE "AFRAME"
Bitfields for device parameters:
bit 0 door open
bit 1 door unlocked
bit 2 supports raw reading in addition to cooked
bit 3 writable
bit 4 can play audio/video tracks
bit 5 supports interleaving
bit 6 reserved
bit 7 supports prefetch requests
bit 8 supports audio channel control
bit 9 supports Red Book addressing in addition to HSG
bit 10 audio is playing
--------m-214402-----------------------------
INT 21 - Quarterdeck - QEMM-386 v5+ - GET API ENTRY POINT
AX = 4402h
BX = file handle for device "QEMM386$"
CX = 0004h
DS:DX -> DWORD buffer for API entry point
Return: CF clear if successful
buffer filled (see INT 67/AH=3Fh for entry point parameters)
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
Note: Quarterdeck recently (June 1993) documented this function, but the
documentation incorrectly states that it is only available for
QEMM 6+
SeeAlso: AX=4402h"HOOKROM",INT 2F/AX=D201h/BX=5145h,INT 67/AH=3Fh
--------Q-214402-----------------------------
INT 21 U - Quarterdeck - HOOKROM.SYS - GET HOOKED VECTOR TABLE
AX = 4402h
BX = file handle for device "HOOKROM$"
CX = 0004h
DS:DX -> DWORD buffer for address of hooked vector table (see below)
Return: CF clear if successful
DS:DX buffer filled
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
SeeAlso: AX=4402h/SF=01h
Format of hooked vector table entry:
Offset Size Description
00h 5 BYTEs FAR jump to actual interrupt handler
(end of table if first byte is not EAh)
05h BYTE interrupt vector number
--------d-214402-----------------------------
INT 21 - Advanced SCSI Programming Interface (ASPI) - INTERFACE
AX = 4402h
BX = file handle for device "SCSIMGR$"
CX = 0004h or 0005h (see notes)
DS:DX -> buffer for result (see below), set to zeros before call
Return: CF clear if successful
AX = 0004h or 0005h (see notes)
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
Note: the variant of the call requesting five bytes is an UNDOCUMENTED
extension supported by Adaptec's ASPI2DOS.SYS, ASPI4DOS.SYS, and
ASPI7DOS.SYS; if made of a host manager which does not support the
variant, only four bytes will be returned. If the variant is
supported, Adaptec's WINASPI.DLL assumes that the host manager is
an "advanced" one which operates in either real or protected mode
(and thus does not require a DPMI INT 31/AX=0301h call to be invoked
from protected mode). Support of the five-byte variant also appears
to imply that an advanced ASPI host manager uses no temporary storage
space except the SRB and the stack, and that it is fully reentrant.
if called with a standard request for four bytes, even Adaptec's
advanced drivers return only the requested four bytes containing the
ASPI entry point address
the function address is called with the address of a SCSI Request
Block on the stack and the caller must clean up the stack
SeeAlso: AX=440Ch"ASPITAPE",INT 11/AH=FFh"WD7000"
Format of IOCTL result:
Offset Size Description
00h DWORD function address
04h BYTE number of SCSI host adapters supported by host manager
Format of SCSI Request Block (64 bytes):
Offset Size Description
00h BYTE request number
00h "HA_INQ" host adapter inquiry
01h "GET_TYPE" get device type
02h "EXEC_SIO" execute SCSI I/O
03h "ABORT_SRB" abort SRB
04h "RESET_DEV" reset SCSI device
05h "SET_HAPRMS" set host adapter parameters
01h BYTE request status
00h not done yet
02h aborted
04h SCSI I/O error
80h invalid
81h no adapter
82h no device attached
else status
02h BYTE host adapter ID
03h BYTE request flags
bit 3: ???
04h DWORD reserved
---request 00h---
08h BYTE (returned) number of host adapters
09h BYTE (returned) target adapter ID
0Ah 16 BYTEs (returned) manager ID
1Ah 16 BYTEs (returned) adapter ID
2Ah 16 BYTEs (returned) parameters
---request 01h---
08h BYTE target ID
09h BYTE logical unit number
0Ah BYTE (returned) device type
01h streamer
---request 02h---
08h BYTE target ID
09h BYTE logical unit number
0Ah DWORD data allocation length
0Eh BYTE sense allocation length
0Fh DWORD data buffer pointer
13h DWORD next request pointer (for linking)
17h BYTE CDB length
18h BYTE (returned) host adapter status
11h select timeout
12h data overrun
13h bus error
14h bus failure
19h BYTE (returned) target status
02h sense data stored in SRB
08h target busy
18h reservation error
1Ah DWORD post routine address
1Eh WORD real mode Post DS
20h DWORD SRB pointer
24h WORD reserved
26h DWORD SRB physical address
2Ah 22 BYTEs SCSIMGR$ workspace
40h N BYTEs CCB (20-24 bytes)
---request 04h---
08h BYTE target ID
09h BYTE logical unit number
0Ah 14 BYTEs reserved
18h BYTE (returned) host adapter status (see above)
19h BYTE (returned) target status (see above)
1Ah DWORD post routine address
1Eh 34 BYTEs workspace
Format of CCB:
Offset Size Description
00h BYTE command code
01h rewind
05h get block size limits
08h read
0Ah write
10h write file marks
11h SCSI Space (set position?)
12h SCSI Inquire
19h erase
1Bh load/unload media
01h BYTE flags
bits 4-0: vary by function
bits 7-5: logical unit number
02h BYTE "adr_1"
03h BYTE "adr_0"
04h BYTE length
05h BYTE control
...
06h/0Ah 14 BYTEs buffer for sense data
--------m-214402-----------------------------
INT 21 U - Qualitas 386MAX v6.00+ - IOCTL INPUT - GET STATE
AX = 4402h
BX = file handle for device "386MAX$$"
CX = number of bytes to read
DS:DX -> BYTE 03h followed by 386MAX state buffer (see below)
Return: CF clear if successful
buffer at DS:DX+1 filled
AX = number of bytes actually copied
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
Notes: if the value given in CX is less than the size of the state record
(5Ah for v6.01, 66h for v7.00), only a partial state record will be
returned
the state is 40h bytes for 386MAX (actually ASTEMM) v2.20 ("386MAX$$"
did not exist yet, use "QMMXXXX0" and then "EMMXXXX0" instead) and
56h bytes for v5.11.
to invoke 386MAX API functions, push DX onto the stack, load DX with
the word at offset 25h in the returned state, load all other
registers as needed for the desired function, and execute an
OUT DX,AL or OUT DX,AX; DX will be set to the pushed value on return
if it is not otherwise modified by the API function. For safety,
in case a function is not supported or 386MAX is not present, SP
should be saved and restored around the API call.
Windows 3.1 Standard mode, LAN Manager, and Windows for Workgroups all
use the 386MAX API; LAN Manager and Windows for Workgroups reportedly
make some calls incorrectly
SeeAlso: AX=4403h/SF=03h"386MAX",INT 67/AH=3Fh
Format of 386MAX v6.01+ state:
Offset Size Description
-1 BYTE (call) 03h
00h 6 BYTEs signature "386MAX"
06h 4 BYTEs version string "N;NN" (i.e. "6;01" for v6.01)
0Ah WORD segment of low-memory portion of 386MAX.SYS
0Ch 2 BYTEs ???
0Eh WORD segment of ??? memory block or 0000h
10h WORD bit flags 1 (see below)
12h WORD (v6.01) starting address of video memory in KB
(v7.00) low memory size in bytes
14h 2 BYTEs ???
16h WORD total high DOS memory in KB
18h 2 BYTEs ???
1Ah WORD available shared memory in KB
1Ch WORD KBytes extended memory used by 386MAX
1Eh 2 BYTEs ???
20h WORD total extended memory in KB
22h WORD IO port to write (OUT DX,AL) to invoke 386MAX INT 15 functions
24h WORD IO port to write (OUT DX,AL) to invoke 386MAX API functions
26h WORD ??? (depends on DOS version)
28h 2 BYTEs ???
2Ah DWORD machine type (see below)
2Eh WORD ???
30h WORD ???
32h WORD system configuration flags (see below)
34h WORD debugging flags 1 (see below)
36h WORD debugging flags 2 (see below)
38h 2 BYTEs ???
3Ah WORD segment of first MCB in high memory chain???
3Ch WORD feature flags 1 (see below)
3Eh WORD feature flags 2 (see below)
40h WORD feature flags 3 (see below)
42h WORD segment of first 386MAX control block??? (see below)
44h WORD amount of memory to report available on INT 15/AH=88h
46h 4 BYTEs ???
4Ah WORD number of K at start of address space swapped with fast
extended memory (SWAP= parameter)
4Ch 2 BYTEs ???
4Eh WORD ???
50h WORD debugging flags 3 (see below)
52h DWORD old INT 21h
56h DWORD pointer to 386MAX's EMS (INT 67h) handler
---386MAX v7.00---
5Ah DWORD KB of extended memory managed by 386MAX
5Eh DWORD bytes of extended memory (EXT= parameter)
62h 4 BYTEs ???
Bitfields for bit flags 1:
bit 1 ???
bit 2 ???
bit 3 ??? (cleared by calling INT 67 functions)
bit 4 high RAM present???
bit 5 386MAX in AUTO mode
bit 6 386MAX enabled
bit 7 386MAX is providing EMS services
bit 8 ???
bit 9 A20 enabled??? (see INT 15/AX=2402h)
bit 10 Weitek support enabled
bit 11 ???
bit 12 ???
bit 13 QPMS has been used
bit 14 ???
bit 15 ???
Bitfields for system configuration flags:
bit 1 ROM compressed???
bit 3 ???
bit 5 386MAX loaded into high memory
bit 6 Microchannel bus
bit 7 Weitek math coprocessor detected
bit 11 PC/XT (thus only single 8259 interrupt controller present, DMA only
in 1st megabyte, etc)
bit 13 LMLTOP= specified
bit 15 ???
Bitfields for debugging flags 1:
bit 0 DEBUG=LED
bit 1 DEBUG=X67
bit 2 DEBUG=INV
bit 3 DEBUG=EMSPTED
bit 4 DEBUG=JMP
bit 5 DEBUG=CALL
bit 6 DEBUG=HLT
bit 7 DEBUG=PMR
bit 8 DEBUG=CR3
bit 9 DEBUG=CAPS or DEBUG=INT
bit 10 DEBUG=RC
bit 11 DEBUG=ROM
bit 12 DEBUG=XM
bit 13 DEBUG=SOR
bit 14 DEBUG=XR
bit 15 DEBUG=EMSERR
Bitfields for debugging flags 2:
bit 0 DEBUG=ROMSWAP
bit 1 DEBUG=UNSHADOWROM
bit 2 DEBUG=COMPROM
bit 3 DEBUG=DPMIPHYS
bit 4 DEBUG=ALLROM
bit 5 DEBUG=VMS
bit 6 DEBUG=XMS
bit 7 DEBUG=I06
bit 8 DEBUG=VCPI
bit 9 DEBUG=XDMA
bit 10 DEBUG=X09
bit 13 DEBUG=I67
bit 14 DEBUG=EVM
bit 15 DEBUG=EMSSAVE or DEBUG=VDS
Bitfields for debugging flags 3:
bit 10 DEBUG=EPM
bit 12 DEBUG=ABIOS
bit 13 DEBUG=XMSPTED
bit 14 DEBUG=TIME
bit 15 DEBUG=SCRUB
Bitfields for feature flags 1:
bit 1 Weitek present
bit 2 no DPMI services
bit 3 NODMA
bit 4 TERSE
bit 5 NOROM
bit 6 NOPARITY
bit 8 NOFLEX (IGNOREFLEXFRAME)
bit 11 don't create UMBs
bit 12 don't backfill below video memory (NOLOW)
bit 13 FRAME= specified
bit 14 EXT= specified
bit 15 NOEMS, allow prior expanded memory manager to provide EMS
Bitfields for feature flags 2:
bit 0 UNSHIFT specified (FORCEA20 disabled)
bit 1 NOXRAM
bit 2 NOSCSI specified
bit 3 SCREEN specified
bit 4 enabled EISADMA
bit 5 slow DMA
bit 6 RESETKEYB specified
bit 7 ???
bit 9 TOP384
bit 11 NOWARMBOOT
bit 12 USE= specified
bit 13 ROM= specified
Bitfields for feature flags 3:
bit 0 Windows3 support enabled
bit 1 SHADOWROM
bit 2 don't compress ROM (NOCOMPROM)
bit 3 ??? (related to PRGREG=)
bit 4 ??? (related to PRGREG=)
bit 5 SHADOWRAM
bit 6 DOS4 specified
bit 7 NOLOADHIGH
bit 8 NOPULSE
bit 11 FORCEA20
bit 12 DMA buffer enabled
bit 13 NOSCRUB
bit 15 NOFRAME
Bitfields for machine type:
bit 12 Amstrad
bit 13 Epson
bit 14 Zenith Data Systems
bit 15 "ASEM"
bit 16 NEC
bit 17 "HPRS" model codes 69h and 6Ah
bit 18 Dell
bit 19 "CA"
bit 20 ITT (Xtra Business Systems/Alcatel)
bit 21 Toshiba 5100
bit 22 Olivetti
bit 23 Quadram Quad386 (BIOS model FEh, submodel A6h)
bit 24 Tandy???
bit 25 AST 386
bit 26 INBOARD, ??? version
bit 27 INBOARD, ??? version
bit 28 INBOARD, ??? version
bit 29 "HPRS"
bit 30 Compaq 386
bit 31 JET386
Format of 386MAX control block:
Offset Size Description
00h WORD segment of next block (FFFFh if last)
02h WORD segment of previous block (FFFFh if first)
04h 12 BYTEs filename
10h WORD resident size in paragraphs
12h WORD environment size???
14h WORD real prsent environment size + 1 (0000h if ENVSAVE used)
16h 2 BYTEs ???
18h DWORD initial size or SIZE=n in 386LOAD commandline
1Ch DWORD SIZE=-1 ???
20h DWORD SIZE= ???
24h BYTE PRGREG= if specified, else FFh
25h BYTE ENVREG= if specified, else FFh
26h BYTE FlexFrame (00h not present, 01h present)
27h 3 BYTEs ???
2Ah BYTE GROUP= or 00h if not present
2Bh BYTE ???
2Ch WORD PSP
Format of high memory info record:
Offset Size Description
00h WORD segment address of memory region
02h WORD size of memory region in paragraphs
04h BYTE type or flags???
00h if locked out
02h if EMS page frame
04h if high RAM
42h if ROM
05h BYTE ???
Format of ROM shadowing record:
Offset Size Description
00h WORD segment of ROM???
02h WORD segment of ROM???
04h 2 BYTEs ???
06h WORD size of shadowed ROM in paragraphs
08h 4 BYTEs ???
Values for memory type:
00h unused by EMS
01h DOS
04h page frame overlapping ROM???
80h high memory
84h page frame???
87h video ROM???
Note: the type may be 00h (unused) if the 16K page is split among different
uses (such as ROM and high RAM)
Call 386MAX API (via OUT DX,AL) with:
STACK: WORD value for DX
AH = 01h get high memory information
ES:DI -> buffer for array of high memory info records
(see above)
Return: CX = number of records placed in buffer
AH = 02h get shadowed ROM info???
ES:DI -> buffer for array of ROM shadowing records (see above)
Return: CX = number of records placed in buffer
AH = 03h get 386MAX state
ES:DI -> 90-byte buffer for state (see above)
Return: AH = 00h (successful)
buffer filled
Note: unlike INT 21/AX=4402h"386MAX", this function omits
the first byte specifying the state buffer version
AH = 04h get memory types???
ES:DI -> buffer for memory type info (array of bytes, one per
16K page) (see above)
Return: CX = number of bytes placed in buffer
AH = 05h get ???
AL = A20 control (00h enable A20 first, 01h leave unchanged)
CX = number of 4K pages to report (0000h for default)
SI = first K to report (rounded down to 4K page)
ES:DI -> buffer for returned info on ???
Return: CX = number of 4K pages reported on
???
AH = 06h get memory speed info
ES:DI -> buffer for memory speed records (see below)
Return: AH = 00h (successful)
CX = number of bytes placed in buffer
Note: this function can take over a second to execute
AH = 07h ???
DX = EMS handle (on stack)
???
Return: ???
AH = 08h "EMM2_GOREAL" check whether possible to disable 386MAX
AL = ??? (00h or nonzero)
Return: AH = status (00h OK, A4h not possible at this time)
Note: if AL=00h, this function always returns success
AH = 09h toggle Bit Flags 1 flags
BX = bitmask of bit flags 1's flags to toggle (see above)
Return: AH = 00h (successful)
Note: enables A20 first
AH = 0Ah toggle system configuration flags
BX = bitmask of system configuration flags to toggle
(see above)
Return: AH = 00h (successful)
Notes: enabled A20 first
does ??? if bit 3 on after specified bits are toggled
AH = 0Bh toggle debugging flags 1
BX = bitmask of debugging flags 1's bits to toggle (see above)
Return: AH = 00h (successful)
Note: enables A20 first
AH = 0Ch toggle feature flags 3
BX = bitmask of feature flags 3's bits to toggle (see above)
Return: AH = 00h (successful)
Note: enables A20 first
AH = 0Dh specify 386MAX high-memory location
BX = segment address of high-memory real-mode portion of 386MAX
CX = current segment of real-mode stub???
Return: AH = status (00h successful)
???
AH = 0Eh CRT controller register virtualization
AL = subfunction
00h allow access to CRTC I/O ports 03B4h/03B5h, 03D4h/03D5h
01h trap accesses to CRTC I/O ports
AH = 0Fh reboot system
Return: never
AH = 11h get high memory information
ES:DI -> 96-byte buffer for high memory info
Return: AH = 00h (successful)
ES:DI buffer filled
Notes: each byte in buffer contains bit flags for a 4K page in
the A000h-FFFFh region
bit 0: ???
bit 1: physical address same as linear address
bit 2: EMS page frame
bit 6: ???
this function can take over a second to execute,
because it also tests the memory
AH = 12h ???
AL = subfunction
00h ???
01h ???
???
Return: AH = 00h (successful) if AL=00h or 01h
AH = 8Fh otherwise
AH = 13h page protection???
AL = subfunction
00h set all ??? 4K pages to read-only???
01h set all ??? 4K pages to read-write???
???
Return: AH = 00h (successful) if AL=00h or 01h
AH = 8Fh otherwise
AH = 14h ???
ES:DI -> 54-byte buffer for ???
Return: AH = 00h if successful
AH = A4h on error
AH = 15h ???
???
Return: ???
AH = 16h get 386MAX memory usage screen
ES:DI -> buffer for memory info display
CX = size of buffer in bytes
Return: ES:DI buffer filled with '$'-terminated string (if
large enough to hold entire usage screen)
Note: the screen is 0303h bytes in v7.00
AH = 17h Windows 3 startup/termination
AL = subfunction
00h Windows3 initializing
DX (on stack) = Windows startup flags
DI = Windows version number (major in upper byte)
ES:BX = 0000h:0000h
DS:SI = 0000h:0000h
Return: CX = 0000h if OK for Windows to load
<> 0 if Windows should not load
ES:BX -> startup info structure
DS:SI -> Virtual86 mode enable/disable callback
01h Windows3 terminating
ES:BX -> ???
DX (on stack) = Windows exit flags
Return: ???
AH = 18h QPMS (Qualitas Protected Memory Services)
AL = subfunction
00h get QPMS configuration
Return: BX = starting segment of QPMS memory window
CX = number of 4K pages reserved for QPMS???
DX = number of 4K pages in QPMS window???
01h map QPMS memory page???
BX = 4K page number within memory reserved for QPMS???
CL = 4K page number within QPMS memory window???
02h mark all QPMS memory read-only
03h mark all QPMS memory read-write
Return: AH = status (00h,8Ah,8Bh,8Fh)
AH = 19h get linear address for physical address
EDX = physical address (low word on stack)
Return: AH = status
00h successful
EDX = linear address at which physical address
may be accessed
8Bh physical address currently not addressable
Note: enables A20 first
AH = 1Ah set page table entry???
EDX = new page table entry??? (low word on stack)
ESI = linear address of page???
Return: AH = status (00h,8Bh)
Note: enables A20 first
AH = 1Bh get ???
Return: AH = status
BX = ???
CX = ???
EDX = physical address of ???
AH = 1Ch get original interrupt vector
AL = interrupt vector (00h-7Fh)
Return: AH = 00h (successful)
EDX = original vector before 386MAX loaded (segment in
high word, offset in low word)
Note: no range checking is performed; requests for INTs 80h-
FFh will return random values
AH = 1Dh display string???
SI = ???
Return: AH = 00h (successful)
???
AH = 1Eh get memory info
ES:DI -> memory info (see below)
Return: ???
AH = 1Fh get DPMI host information
Return: AX = 0000h if successful
BX = DPMI flags (see INT 31/AX=0400h)
CL = CPU type (02h = 80286, 03h = 80386, etc.)
DX = DPMI ver supported (DH=major, DL=2-digit minor)
SI = ???
ES???:DI -> ???
Note: NOP if NODPMI switch specified
AH = 20h (v7.00) ???
AL = ???
Return: EDX = ??? for ??? AL
AH = 21h (v7.00) STACKS support
AL = 00h get STACKS parameters
Return: BX = ???
CX = number of stacks for hardware interrupts
DX = size of each stack in bytes
SI = ???
DI = ???
AL = 01h set ??? "EMM2_DSTKS"
EBX = ???
ECX = ???
DS = ???
AL = 02h ???
BL = ??? (00h-03h)
???
AH = 22h (v7.00)
AL = 00h ???
AL = nonzero ???
???
AH = 23h (v7.00) ???
AL = 00h set ???
???
AL = 01h ???
???
AL = 02h get ???
CX = size of buffer
ES:DI -> buffer for ???
Return: CX = number of bytes actually returned
AL = 03h set ???
ES:DI -> buffer containing ASCIZ ???
AL = 04h get ???
ES:DI -> buffer for ASCIZ ???
AH = 24h (v7.00) ???
AL = 00h get ???
Return: BX = current state of ??? (0/1)
AL = 01h set ???
BX = new state of ??? (0/1)
AL = other ???
AH = 25h (v7.00) ???
AH = 26h (v7.00) ???
Return: BX = ???
CX = ???
AH = 27h (v7.00) ???
AL = 00h get ???
Return: BX = ???
AL = 01h ???
BX = ???
ES??? = ???
AL = 02h ???
???
AL = 03h ???
CX = ???
DX = ???
ES??? = ???
Return: ???
AH = 28h (v7.00) get ???
Return: CX = ???
DX = ???
AH = 29h (v7.00) get ???
Return: AX = ???
AH = 40h-5Dh EMS services (see INT 67/AH=40h etc)
AH = DEh VCPI services (see INT 67/AX=DE00h etc)
Return: AH = status (as for EMS INT 67 calls)
00h successful
80h internal error
81h hardware malfunction
83h invalid handle
84h undefined function
8Ah invalid logical page nuber
8Bh illegal physical page number
8Fh undefined subfunction
A4h access denied
etc.
STACK popped (value placed in DX if no specific return value for DX)
Format of memory speed record:
Offset Size Description
00h DWORD page table entry for 4K page
04h WORD number of microticks (840ns units) required for REP LODSD of
entire 4K page
Format of memory info [array]:
Offset Size Description
00h DWORD ???
04h DWORD ???
08h 2 BYTEs ???
0Ah BYTE type??? (03h = conventional???)
0Bh BYTE ???
--------V-214402-----------------------------
INT 21 - PGS1600.DEV - IOCTL - GET CONFIGURATION INFO
AX = 4402h
BX = file handle for device "PGS1600$"
CX = 0018h (size of buffer)
DS:DX -> configuration buffer (see below)
Return: CF clear if successful
buffer filled
AX = number of bytes actually copied
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
Program: PGS1600.DEV is a device driver for the Cornerstone Technology PG1600
display adapter, which provides a 1600x1200 monochrome display as
well as one of two emulations, MDA or CGA.
SeeAlso: AX=4403h"PGS1600"
Format of configuration information:
Offset Size Description
00h WORD version (high byte = major, low byte = minor)
02h WORD board initialisation mode
04h WORD board I/O address
03D0h CGA emulation
03B0h MDA emulation
0390h no emulation
0350h no emulation, alternate
06h WORD emulation buffer segment
B800h CGA emulation
B000h MDA emulation
0000h no emulation
08h WORD PG1600 graphics buffer segment
0Ah WORD number of bytes between consecutive graphic rows
0Ch WORD horizontal pixel size
0Eh WORD vertical pixel size
10h WORD horizontal dots per inch
12h WORD vertical dots per inch
14h WORD graphics buffer bits per pixel
16h WORD monitor bits per pixel
--------N-214402-----------------------------
INT 21 - PC/TCP IPCUST.SYS - RESET CONFIGURATION DATA READ POINTER
AX = 4402h
BX = file handle referencing device "$IPCUST"
CX, DS:DX ignored
Return: CF clear if successful
AX destroyed
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
Notes: there are a total of 378h bytes of configuration data for IPCUST.SYS
version 2.05. If less than the entire data is read or written,
the next read/write continues where the previous one ended; this
call and AX=4403h both reset the location at which the next
operation starts to zero
v2.1+ uses a new configuration method, but allows the installation
of IPCUST.SYS for backward compatibility with other software which
must read the PC/TCP configuration
SeeAlso: AH=3Fh"IPCUST",AH=40h"IPCUST",AX=4403h"IPCUST"
--------N-214402-----------------------------
INT 21 - WORKGRP.SYS - GET API ENTRY POINT
AX = 4402h
BX = file handle for device "NET$HLP$"
CX = 0008h
DS:DX -> buffer for entry point record
Return: CF clear if successful
AX = number of bytes actually read
CF set on error
AX = error code
Program: WORKGRP.SYS is the portion of Microsoft's Workgroup Connection which
permits communication with PCs running Windows for Workgroups or
LAN Manager
SeeAlso: AH=3Fh"WORKGRP.SYS"
Format of entry point record:
Offset Size Description
00h WORD 3633h \ signature???
02h WORD EF6Fh /
04h DWORD address of entry point
Note: first four bytes of buffer must be 6Fh E9h 33h 36h on entry when using
IOCTL rather than READ to get the entry point record
Call WORKGRP entry point with:
STACK: WORD function number (0000h-0009h)
Return: STACK unchanged
Call WORKGRP function 00h with:
STACK: WORD 0000h (function "get ???")
Return: DX:AX -> data table
Call WORKGRP function 01h with:
STACK: WORD 0001h (function "hook ???")
Return: STACK: DWORD pointer to ???
WORD 0001h (function number)
Call WORKGRP function 02h with:
STACK: WORD 0002h (function "unhook ???")
???
Return: ???
Call WORKGRP function 03h with:
STACK: WORD 0003h (function "reenable printer port")
WORD LPT port number
Return: ???
Call WORKGRP function 04h with:
STACK: WORD 0004h (function "disable printer port")
WORD LPT port number
Return: ???
Call WORKGRP function 05h with:
STACK: WORD 0005h (function "???")
???
Return: ???
Call WORKGRP function 06h with:
STACK: WORD 0006h (function "???")
Return: STACK unchanged
AX = 0000h
DX = 0000h
Call WORKGRP functions 07h-09h with:
STACK: WORD 0007h-0009h (NOP functions)
Return: STACK unchanged
AX = 0001h
DX = 0000h
--------N-214402-----------------------------
INT 21 - 10NET v5.0 - 10BEUI.DOS - API
AX = 4402h
BX = file handle referencing device "10BEUI$"
DS:DX -> parameter record (see below)
CX ignored
Return: CF clear if successful
AX destroyed
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
SeeAlso: AX=4402h"10MEMMGR",INT 6F/AH=00h"10NET"
Format of parameter record:
Offset Size Description
00h WORD 000Ah (function number???)
02h WORD ???
04h DWORD pointer to buffer for ???
08h 4 BYTEs ???
0Ch WORD transfer size
--------N-214402-----------------------------
INT 21 - 10NET v5.0 - 10MEMMGR.SYS - API
AX = 4402h
BX = file handle referencing device "MEMMGR0$"
DS:DX -> 6-byte buffer for interface info (see below)
CX ignored
Return: CF clear if successful
AX destroyed
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
SeeAlso: AX=4402h"10BEUI",INT 6F/AH=00h"10NET"
Format of interface info:
Offset Size Description
00h DWORD address of entry point (see below)
04h WORD version (0500h for v5.00)
Call entry point with:
AL = 01h ???
BX = ???
Return: CF clear if successful
CF set on error
AX = error code
AL = 02h ???
???
AL = 03h ???
???
AL = 04h set/restore memory allocation strategy
BX = subfunction
0000h set strategy
0001h restore strategy
Return: CF clear if successful
CF set on error (if function disabled)
various registers destroyed
AL = other
Return: CF set
AX = 0000h
BL = 01h
--------m-214402SF00-------------------------
INT 21 U - Memory Managers - GET API ENTRY POINT
AX = 4402h subfn 00h
BX = file handle for device "EMMXXXX0"
CX = 0006h (size of buffer in bytes)
DS:DX -> buffer for API entry point record (see below)
first byte must be 00h on entry
Return: CF clear if successful
buffer filled (see INT 67/AH=3Fh function 1B00h)
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
Notes: this function is supported by Microsoft EMM386.EXE v4.45+ and
CEMM v5.10+, and is intended for use by MS Windows as it starts up
if no other program has hooked INT 67, an alternate installation
check for CEMM is testing for the string
"COMPAQ EXPANDED MEMORY MANAGER 386" at offset 14h in the INT 67
handler's segment; if present, the word at offset 12h contains the
offset of the API entry point
SeeAlso: AX=4402h/SF=01h,AX=4402h/SF=02h,AX=4402h"EMM386",INT 67/AH=3Fh
Format of API entry point record:
Offset Size Description
00h WORD ??? (0022h for CEMM 5.11, 0025h for MS EMM386 v4.45)
02h DWORD manager's private API entry point (see below,INT 67/AX=FFA5h)
Call CEMM v5.10+ entry point with:
AH = 00h get memory manager's state
Return: AH = state
bit 0: turned OFF
bit 1: AUTO mode enabled
AH = 01h set memory manager's state
AL = new state (00h ON, 01h OFF, 02h AUTO)
Return: CF clear if successful
CF set on error
AH = 02h Weitek coprocessor support
AL = subfunction
00h get Weitek support state
Return: AL = status
bit 0: Weitek coprocessor is present
bit 1: Weitek support is enabled
01h turn on Weitek support
02h turn off Weitek support
Return: CF clear if successful
CF set on error
AH = error code (01h invalid subfunc, 02h no Weitek)
AH = 05h get statistics
???
AH > 06h
Return: CF set
AH = 01h (invalid function)
Notes: AH=03h,04h,06h are NOPs which return CF clear, presumably for backwards
compatibility with earlier versions of CEMM
in v5.11, AH=05h merely prints an error message (using INT 21/AH=09h)
stating that a different version of CEMM is installed and it is
therefore not possible to display the statistics
--------m-214402SF01-------------------------
INT 21 U - Memory Managers - GET EMM IMPORT STRUCTURE ADDRESS
AX = 4402h subfn 01h
BX = file handle for device "EMMXXXX0"
CX = 0006h (size of buffer in bytes)
DS:DX -> buffer for EMM import structure record (see below)
first byte must be 01h on entry
Return: CF clear if successful
buffer filled (see INT 67/AH=3Fh function 1B00h)
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
Notes: this function is supported by Microsoft EMM386.EXE v4.45+,
QEMM-386 v6+, and CEMM v5.10+, and is intended for use by MS Windows
as it starts up
for QEMM-386, this call always returns an error if Windows3 support
has been disabled with the NW3 switch
SeeAlso: AX=4402h/SF=00h,AX=4402h"EMM386",INT 2F/AX=D201h/BX=5145h
SeeAlso: INT 67/AH=3Fh
Format of EMM import structure record:
Offset Size Description
00h DWORD physical address of EMM import structure
04h BYTE EMM import structure major version
05h BYTE EMM import structure minor version
--------m-214402SF02-------------------------
INT 21 U - Memory Managers - GET MEMORY MANAGER VERSION
AX = 4402h subfn 02h
BX = file handle for device "EMMXXXX0"
CX = 0002h (size of buffer in bytes)
DS:DX -> buffer for memory manager version (see below)
first byte must be 02h on entry
Return: CF clear if successful
buffer filled
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
Note: this function is supported by Microsoft EMM386.EXE v4.45+ and
CEMM v5.10+, and is intended for use by MS Windows as it starts up
SeeAlso: AX=4402h/SF=00h,AX=4402h"EMM386",INT 67/AH=3Fh
Format of memory manager version:
Offset Size Description
00h BYTE major version
01h BYTE minor version (binary)
--------m-214402-----------------------------
INT 21 U - Microsoft EMM386.EXE v4.45 - GET MEMORY MANAGER INFORMATION
AX = 4402h
BX = file handle for device "EMMXXXX0"
CX = size of buffer in bytes (varies, see below)
DS:DX -> buffer for returned data (see below)
first byte must be set on entry to indicate desired data
Return: CF clear if successful
buffer filled
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
Notes: an error is returned if the number of bytes to be read does not match
the number of bytes returned for the specified data item
this function is part of the interface which allows MS Windows to
cooperate with memory managers
SeeAlso: AX=4402h/SF=00h,AX=4402h/SF=01h,AX=4402h/SF=02h,INT 67/AX=FFA5h
Format of data buffer:
Offset Size Description
00h BYTE (call) function
03h get ???
04h get ???
---function 03h---
00h WORD ???
02h WORD ???
---function 04h---
00h WORD segment of UMB containing EMM386 code/data
02h WORD number of paragraphs of EMM386 code/data in UMB
04h WORD ???
--------V-214402-----------------------------
INT 21 - Compaq AG1024.SYS - RGDI - GET DRIVER LOCATION
AX = 4402h
BX = file handle for device "$$$$RGDI"
CX = 0006h (size of returned data)
DS:DX -> location record (see below)
Return: CF clear if successful
buffer filled
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
Program: AG1024.SYS is a device driver for the Advanced Graphics 1024 adapter
SeeAlso: AX=4403h"RGDI"
Format of location record:
Offset Size Description
00h WORD signature 55AAh
02h WORD segment of ???
04h WORD segment of device driver's code
--------N-214402-----------------------------
INT 21 - FTPSOFT.DOS v3.1 - GET ???
AX = 4402h
BX = file handle for device "FTPSOFT$"
CX = size of buffer
DS:DX -> buffer for data (see below)
Return: CF clear if successful
buffer filled
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
Program: FTPSOFT.DOS is a device driver for Protocol Manager support from
FTP Software, Inc.
SeeAlso: AH=3Fh"PC/TCP",AX=4402h"NDIS"
Format of data:
Offset Size Description
00h WORD (call) BA98h (if different, no data returned)
02h DWORD -> NDIS common characteristics table (see AX=4402h"NDIS")
06h DWORD (call) -> new dispatch table (see AX=4402h"NDIS")
0Ah DWORD -> 28-byte buffer for ??? data
0Eh DWORD ???
12h DWORD -> FAR function to reset dispatch jump table to defaults
16h BYTE ???
Note: the addresses in the new dispatch table are copied into an internal
jump table which may be reset by calling the function pointed at by
offset 12h
--------n-214402-----------------------------
INT 21 U - PenDOS PENDEV.SYS - GET ENTRY POINTS
AX = 4402h
BX = file handle for device "$$PENDOS" or "$$PD_REG"
CX = size of buffer (4 for $$PENDOS and a 4,8,12, or 16 for $$PD_REG)
DS:DX -> buffer for entry point record (see below)
Return: CF clear if successful
buffer filled
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
Program: A limited version of PenDOS by Communication Intelligence Corporation,
which provides pen capability to keyboard-based programs, is bundled
with IBM DOS 6.1
SeeAlso: AX=4403h"PENDEV.SYS"
Format of entry point record:
Offset Size Description
00h DWORD -> array of jumps
04h WORD offset of function to retrieve entry point
06h 2 BYTEs signature "Pe"
08h WORD offset of function to set entry point
0Ah 2 BYTEs signature "nD"
0Ch WORD offset of function to clear entry point
0Eh WORD signature "OS"
Call function to retrieve entry point with:
AX = index of entry point (0-9)
Return: CF clear if successful
DX:AX -> desired entry point
CF set on error (AX out of range)
Call function to set entry point with:
AX = index of entry point (0-9)
DX:SI -> new handler
Return: CF clear if successful
CF set on error (AX out of range)
Call function to clear entry point with:
AX = index of entry point (0-9)
Return: CF clear if successful
CF set on error (AX out of range)
Note: resets the jump at the specified entry point to its default target,
which simply returns
--------N-214402-----------------------------
INT 21 U - LAN Manager - TCPDRV.DOS - API
AX = 4402h
BX = file handle referencing device "TCPDRV$"
CX = 0019h
DS:DX -> buffer containing request block
Return: CF clear if successful
buffer filled
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
Program: TCPDRV.DOS is the low-level device driver supporting LAN Manager's
TCP/IP protocol stack
Format of request block:
Offset Size Description
00h BYTE (call) function number
00h initialize ???
06h get ???
07h get ???
01h BYTE (call) 00h
(return) error code if error, unchanged if successful
02h WORD signature 4354h ('CT')
---function 00h---
04h DWORD (call) pointer to ??? FAR function
function is called with ES:BX -> device driver request used to
invoke this function
08h 4 BYTEs ???
0Ch DWORD (call) pointer to ??? record, WORD at offset 22h is read
10h DWORD (return) -> ??? buffer if 0000h:0000h on call
---function 06h---
04h 4 BYTEs ???
08h DWORD (return) pointer to ???
---function 07h---
04h DWORD (return) pointer to ??? record
--------y-214402-----------------------------
INT 21 U - PC Tools 9 CPRLOW.EXE - GET CODE AND DATA ADDRESSES
AX = 4402h
BX = file handle referencing device "RECLOWLD"
DS:DX -> buffer for address list (see below)
CX ignored
Return: CF clear if successful
buffer filled
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
Format of address list:
Offset Size Description
00h WORD segment of CPRLOW code
02h WORD offset in code segment of ??? entry point
(switches into protected mode)
04h WORD offset in code segment of jump array (see below)
06h WORD segment of copy of interrupt vector table at CPRLOW load time
Note: neither the entry point nor the jump array is valid until after a
CPR /LOAD, because CPR.EXE installs the code into CPRLOW at runtime.
Format of jump array:
Offset Size Description
00h 3 BYTEs initialize CPRLOW interrupt hooks
03h 3 BYTEs reset timers and enable CPR (hotkey enable)
06h 3 BYTEs disable CPR (hotkey disable)
09h 3 BYTEs clear ??? flag, hotkey disable, and ???
0Ch 3 BYTEs initialize delay loop counter (destroys AX,BX,CX,DX)
0Fh 3 BYTEs disable CPR completely (commandline /DISABLE)
12h 3 BYTEs enable ??? if CPR enabled by both cmdline and hotkey
15h 3 BYTEs enable CPR (commandline /ENABLE)
--------D-214403-----------------------------
INT 21 - DOS 2+ - IOCTL - WRITE TO CHARACTER DEVICE CONTROL CHANNEL
AX = 4403h
BX = file handle referencing character device
CX = number of bytes to write
DS:DX -> data to write
Return: CF clear if successful
AX = number of bytes actually written
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
Notes: format of data is driver-specific (see below for some specific cases)
if the file handle refers to "4DOSSTAK", the 4DOS (v2.x-3.03)
KEYSTACK.SYS driver will push the specified characters on the
keyboard stack; similarly for "NDOSSTAK", the NDOS KEYSTACK.SYS
driver will push the characters onto the keyboard stack
SeeAlso: AX=4400h,AX=4402h,AX=4405h,INT 2F/AX=122Bh,INT 2F/AX=D44Dh
SeeAlso: INT 2F/AX=D44Fh
--------c-214403-----------------------------
INT 21 - SMARTDRV.SYS v3.x only - IOCTL - CACHE CONTROL
AX = 4403h
BX = handle for device "SMARTAAR"
CX = number of bytes to write
DS:DX -> SMARTDRV control block (see below)
Return: CF clear if successful
AX = number of bytes actually written
= 0000h if control block too small for given command
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
SeeAlso: AX=4402h"SMARTDRV",INT 2F/AX=4A10h/BX=0000h
Format of SMARTDRV control block:
Offset Size Description
00h BYTE function code
00h flush cache
01h flush and discard cache
02h disable caching (flushes and discards cache first)
03h enable caching
04h control write caching
05h set flushing tick count
06h lock cache contents
07h unlock cache contents
08h set flush-on-reboot flag
09h unused
0Ah control full-track caching
0Bh reduce cache size
0Ch increase cache size
0Dh set INT 13 chain address
---function 04h---
01h BYTE write caching control action
00h turn off write-through
01h turn on write-through
02h turn off write buffering (also flushes cache)
03h turn on write buffering (also flushes cache)
---function 05h---
01h WORD number of timer ticks between cache flushes
---function 08h---
01h BYTE new flush-on-reboot flag (00h off, 01h on)
---function 0Ah---
01h BYTE full-track writes are
00h not cached
01h cached
---functions 0Bh,0Ch---
01h WORD number of 16K pages by which to increase/reduce cache size
---function 0Dh---
01h DWORD new address to which to chain on INT 13
Note: the previous address is not preserved
--------d-214403-----------------------------
INT 21 - CD-ROM device driver - IOCTL OUTPUT
AX = 4403h
BX = file handle referencing character device for CD-ROM driver
CX = number of bytes to write
DS:DX -> control block (see below)
Return: CF clear if successful
AX = number of bytes actually written
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
SeeAlso: AX=4402h"CD-ROM",INT 2F/AX=0802h
Format of control block:
Offset Size Description
00h BYTE function code
00h eject disk
01h lock/unlock door
02h reset drive
03h control audio channel
04h write device control string
05h close tray
---functions 00h,02h,05h---
no further fields
---function 01h---
01h BYTE lock function
00h unlock door
01h lock door
---function 03h---
01h BYTE input channel (0-3) for output channel 0
02h BYTE volume for output channel 0
03h BYTE input channel (0-3) for output channel 1
04h BYTE volume for output channel 1
05h BYTE input channel (0-3) for output channel 2
06h BYTE volume for output channel 2
07h BYTE input channel (0-3) for output channel 3
08h BYTE volume for output channel 3
Note: output channels 0 and 1 are left and right, 2 and 3 are left prime and
right prime; a volume of 00h is off
---function 04h---
01h N BYTEs bytes to send directly to the CD-ROM drive without
interpretation
--------d-214403-----------------------------
INT 21 - Brian Antoine Seagate ST-01 SCSI.SYS - IOCTL - EXECUTE COMMANDS
AX = 4403h
BX = handle for device "SCSITAPE"
CX = number of bytes to write
DS:DX -> SCSITAPE control block (see below)
Return: CF clear if successful
AX = number of bytes actually written
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
SeeAlso: AX=4405h"ST-01",INT 78/AH=10h
Format of SCSITAPE control block:
Offset Size Description
00h WORD command type
'F' Format (argument 1 = interleave, argument 2 = format type)
'E' Erase
'R' Rewind
'L' Load
'N' No Load
'S' Space (argument 1 = count, argument 2 = type)
'M' File Mark (argument 1 = count)
'A' Reassign
02h WORD argument 1
04h WORD argument 2
06h WORD segment of command buffer
08h WORD offset of command buffer
0Ah WORD length of command buffer
--------E-214403-----------------------------
INT 21 U - AI Architects - OS/x86??? - API
AX = 4403h
BX = handle for device "AIA_OS"
CX = number of bytes to write (ignored)
DS:DX -> 12-byte buffer, first byte is command:
81h installation check
82h get API entry point
84h uninstall
Return: CF clear if successful
AX = number of bytes actually written
CF set on error
AX = error code (01h,05h,06h,0Ch,0Dh) (see AH=59h)
Notes: these functions are only available if the DOS extender was loaded as a
device driver in CONFIG.SYS
called by TKERNEL (a licensed version of AI Architects/Ergo OS/x86)
SeeAlso: INT 2F/AX=FBA1h/BX=0081h,INT 2F/AX=FBA1h/BX=0082h
Index: installation check;OS/x86|entry point;OS/x86|uninstall;OS/x86
Format of buffer on return:
Offset Size Description
00h 4 BYTEs signature "IABH"
---if func 81h---
(no additional fields)
---if func 82h---
04h DWORD pointer to API entry point (see INT 2F/AX=FBA1h/BX=0082h)
---if func 84h---
04h WORD success indicator
06h WORD segment of ???
08h WORD segment of ??? memory block to free if nonzero
0Ah WORD segment of ??? memory block to free if nonzero
--------V-214403-----------------------------
INT 21 - PGS1600.DEV - IOCTL - SET CONFIGURATION???
AX = 4403h
BX = file handle for device "PGS1600$"
CX = 0018h (size of buffer)
DS:DX -> configuration buffer (see AX=4402h"PGS1600")
Return: CF clear if successful
AX = number of bytes actually written
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
Program: PGS1600.DEV is a device driver for the Cornerstone Technology PG1600
display adapter, which provides a 1600x1200 monochrome display as
well as one of two emulations, MDA or CGA.
SeeAlso: AX=4402h"PGS1600"
--------N-214403-----------------------------
INT 21 - PC/TCP IPCUST.SYS - RESET CONFIGURATION DATA READ POINTER
AX = 4403h
BX = file handle referencing device "$IPCUST"
CX, DS:DX ignored
Return: CF clear if successful
AX destroyed
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
Notes: there are a total of 378h bytes of configuration data for IPCUST.SYS
version 2.05. If less than the entire data is read or written,
the next read/write continues where the previous one ended; this
call and AX=4402h both reset the location at which the next
operation starts to zero
v2.1+ uses a new configuration method, but allows the installation
of IPCUST.SYS for backward compatibility with other software which
must read the PC/TCP configuration
SeeAlso: AH=3Fh"IPCUST",AH=40h"IPCUST",AX=4402h"IPCUST"
--------V-214403-----------------------------
INT 21 - Compaq AG1024.SYS - CPQ_MGES - IOCTL OUTPUT
AX = 4403h
BX = file handle referencing device "CPQ_MGES"
DS:DX -> request packet (see below)
CX ignored
Return: CF clear if successful
AX destroyed
data buffer filled (if applicable)
first word of request packet set to number of bytes of data
available (amount returned is smaller of this and requested
amount)
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
Program: AG1024.SYS is a device driver for the Advanced Graphics 1024 adapter
SeeAlso: AX=4403h"RGDI"
Format of request packet:
Offset Size Description
00h WORD function
0000h get ??? (26h bytes)
0001h get ??? (36h bytes)
0002h set ??? (same as returned by function 0001h)
0003h get ??? (6 bytes)
0004h get ???
0005h get ???
0006h get ??? (10h bytes)
0007h set ??? (same as returned by function 0006h)
---functions 00h-03h,06h,07h---
02h WORD size of data buffer
04h DWORD -> buffer for function's data
---functions 04h,05h---
02h WORD ???
04h WORD size of data buffer
06h DWORD -> buffer to receive data
--------V-214403-----------------------------
INT 21 - Compaq AG1024.SYS - RGDI - IOCTL OUTPUT
AX = 4403h
BX = file handle referencing device "$$$$RGDI"
DS:DX -> request packet (see below)
CX ignored
Return: CF clear if successful
AX destroyed
data buffer filled (if applicable)
first word of request packet set to number of bytes of data
available (amount returned is smaller of this and requested
amount)
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
Program: AG1024.SYS is a device driver for the Advanced Graphics 1024 adapter
SeeAlso: AX=4402h"RGDI",AX=4403h"CPQ_MGES"
Format of request packet:
Offset Size Description
00h WORD function
0000h get entry points
0001h get ???
02h DWORD address of buffer for returned data
--------m-214403SF01-------------------------
INT 21 U - Qualitas 386MAX v6.01+ - TURN 386MAX OFF
AX = 4403h subfn 01h
BX = handle for device "386MAX$$"
DS:DX -> BYTE 01h
CX ignored
Return: DS:DX -> BYTE status (00h = successful)
CF clear if successful
AX destroyed
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
Note: this function will fail if any EMS or UMBs are in use
SeeAlso: AX=4403h/SF=02h,AX=4403h/SF=03h,AX=4403h/SF=05h
--------m-214403SF02-------------------------
INT 21 U - Qualitas 386MAX v6.01+ - TURN 386MAX ON
AX = 4403h subfn 02h
BX = handle for device "386MAX$$"
DS:DX -> BYTE 02h
CX ignored
Return: DS:DX -> BYTE status (00h = successful)
CF clear if successful
AX destroyed
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
SeeAlso: AX=4403h/SF=01h,AX=4403h/SF=03h,AX=4403h/SF=05h
--------m-214403SF03-------------------------
INT 21 U - Qualitas 386MAX v6.01+ - SET STATE
AX = 4403h subfn 03h
BX = handle for device "386MAX$$"
CX = number of bytes to copy (up to size of state buffer)
DS:DX -> BYTE 03h followed by state buffer (see AX=4402h"386MAX")
Return: CF clear if successful
AX = number of bytes actually written
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
Note: the first byte of the buffer must be either 01h, 02h, or 03h
(specifying the version of the state record) and the buffer must
contain CX bytes AFTER the initial byte
SeeAlso: AX=4402h"386MAX"
--------m-214403SF05-------------------------
INT 21 U - Qualitas 386MAX v7.00+ - LIMIT AUTOMATIC ACTIVATION TO STD EMS CALLS
AX = 4403h subfn 05h
BX = handle for device "386MAX$$"
DS:DX -> BYTE 05h
CX ignored
Return: CF clear if successful
AX destroyed
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
Desc: specifies that 386MAX will only shift from AUTO to ON mode on standard
EMS calls INT 67/AH=40h-5Dh
SeeAlso: AX=4403h/SF=02h,AX=4403h/SF=03h,AX=4403h/SF=06h
--------m-214403SF06-------------------------
INT 21 U - Qualitas 386MAX v7.00+ - ALLOW AUTOMATIC ACTIVATION ON ANY INT 67
AX = 4403h subfn 06h
BX = handle for device "386MAX$$"
DS:DX -> BYTE 06h
CX ignored
Return: CF clear if successful
AX destroyed
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
Desc: specified that 386MAX should shift from AUTO to ON mode on any INT 67
call other than INT 67/AH=3Fh
SeeAlso: AX=4403h/SF=01h,AX=4403h/SF=03h,AX=4403h/SF=05h
--------n-214403-----------------------------
INT 21 U - PenDOS PENDEV.SYS - ???
AX = 4403h
BX = file handle for device "$$PENDOS" or "$$PD_REG"
CX = size of buffer
DS:DX -> buffer containing ???
Return: CF clear if successful
buffer filled
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
Program: A limited version of PenDOS by Communication Intelligence Corporation,
which provides pen capability to keyboard-based programs, is bundled
with IBM DOS 6.1
Note: this call sets the WORD at offset 1Ah into the device driver request
header used to call the driver to 0000h.
SeeAlso: AX=4402h"PENDEV.SYS"
--------D-214404-----------------------------
INT 21 - DOS 2+ - IOCTL - READ FROM BLOCK DEVICE CONTROL CHANNEL
AX = 4404h
BL = drive number (00h = default, 01h = A:, etc.)
CX = number of bytes to read
DS:DX -> buffer
Return: CF clear if successful
AX = number of bytes actually read
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
Note: format of data is driver-specific
SeeAlso: AX=4402h,AX=4405h,INT 2F/AX=122Bh
--------d-214404-----------------------------
INT 21 - Stacker - GET DEVICE DRIVER ADDRESS AND SET VOLUME NUMBER
AX = 4404h
BL = drive number (00h = default, 01h = A:, etc.)
CX = 0004h
DS:DX -> DWORD buffer to receive device driver address
Note: In addition to returning the address of the Stacker device driver,
this call also sets the volume number at offset 3Eh in the device
driver (see INT 25/AX=CDCDh)
SeeAlso: INT 25/AX=CDCDh
--------d-214404-----------------------------
INT 21 - Stacker - GET STACVOL FILE SECTORS
AX = 4404h
BL = drive number (0 is current drive)
CX = byte count (i.e., 200h = 1 sector)
DS:DX -> buffer (see below)
Return: Data Buffer contains the number of sectors requested from the
STACVOL physical file for the drive specified.
Format of stacker buffer:
Offset Size Description
00h WORD 01CDh
02h WORD sector count
04h DWORD number of starting sector
08h DWORD far pointer to Data Buffer
--------d-214404-----------------------------
INT 21 - DUBLDISK.SYS v2.6 - GET INFO
AX = 4404h
BL = drive number of DoubleDisk drive (00h = default, 01h = A:, etc.)
CX = number of bytes (000Ah-0014h, call ignored otherwise)
DS:DX -> data record (see below)
Return: CF clear if successful
AX = number of bytes read
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
Program: DUBLDISK.SYS is the device driver portion of DoubleDisk, a disk
expander by Vertisoft Systems, Inc.
Note: the installation check consists of scanning memory for the signature
"FAT 2.6 byte:", which is immediately followed by a data table
SeeAlso: AX=440Dh
Index: installation check;DUBLDISK.SYS
Format of data record:
Offset Size Description
00h WORD (call) signature 4444h
02h BYTE (call) function
00h ???
01h ???
---function 00h---
02h BYTE (return) ???
03h BYTE (return) ???
---function 01h---
02h WORD (return) 4444h
04h WORD allocation unit size???
06h WORD ???
08h WORD ???
0Ah BYTE ???
Format of signature data table:
Offset Size Description
00h 5 BYTEs ???
05h BYTE first drive number
06h BYTE number of drives
07h ???
--------d-214404-----------------------------
INT 21 - DBLSPACE.BIN - IOCTL - FLUSH OR INVALIDATE INTERNAL CACHES
AX = 4404h
BL = drive number (00h = default, 01h = A:, etc)
CX = 000Ah (size of DSPACKET structure)
DS:DX -> DSPACKET structure (see below)
Return: CF clear if IOCTL successful -- check DSPACKET for actual status
AX = number of bytes actually transferred
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
SeeAlso: AX=4405h"DBLSPACE",INT 2F/AX=4A11h/BX=0000h
Format of DSPACKET structure:
Offset Size Description
00h WORD signature 444Dh ("DM")
02h BYTE command code
46h ('F') flush internal caches
49h ('I') flush and invalidate internal caches
03h WORD result code
(return) 4F4Bh ("OK") if successful, else unchanged
05h 5 BYTEs padding
--------d-214404-----------------------------
INT 21 - DBLSPACE.BIN 6.2 - IOCTL - GET ??? FOR SPECIFIED DRIVE
AX = 4404h
BL = drive number (00h = default, 01h = A:, etc)
CX = size of DSPACKET structure (ignored in DOS 6.2)
DS:DX -> DSPACKET structure (see below)
Return: CF clear if IOCTL successful -- check DSPACKET for actual status
AX = number of bytes actually transferred
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
SeeAlso: AX=4405h"DBLSPACE",INT 2F/AX=4A11h/BX=0000h
Format of DSPACKET structure:
Offset Size Description
00h WORD signature 444Dh ("DM")
02h BYTE command code
53h ('S') get ??? for specified drive
03h WORD result code
(return) 4F4Bh ("OK") if successful, else unchanged
05h DWORD (return) pointer to 96-byte ??? data
09h DWORD (return) pointer to ??? data
0Dh 3 BYTEs reserved
--------d-214404-----------------------------
INT 21 U - xDISK v3.31 - CONFIGURE
AX = 4404h
BL = drive number (00h = default, 01h = A:, etc)
CX = 0047h (length of version string)
DS:DX -> 79-byte buffer for version string and ???
DS:0081h = commandline containing new switches for driver
Return: CF clear if successful
AX = number of bytes actually transferred
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
Program: xDISK is a shareware resizeable EMS RAMdisk by FM de Monasterio
SeeAlso: AX=4405h"xDISK",INT 2F/AH=DDh"xDISK"
--------c-214404-----------------------------
INT 21 - COMBI-disk v1.13 - GET DATA RECORD
AX = 4404h
BL = drive number (00h = default, 01h = A:, etc)
CX = (length of data packet)
DS:DX -> buffer for data packet (see below)
Return: CF clear if successful
AX = number of bytes actually transferred
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
Program: COMBI-disk is a shareware combination cache and RAMdisk sharing a
single pool of memory by Vadim V. Vlasov
Note: the installation check consists of scanning the valid drives for one
which returns a correctly-sized data packet with the proper
signature in the first field
SeeAlso: AX=4405h"COMBI"
Index: installation check;COMBI-disk
Format of data packet:
Offset Size Description
00h 6 BYTEs ASCIZ signature "COMBI"
06h WORD version (high byte = major, low = decimal minor version)
08h BYTE current options (see below)
09h BYTE sectors per allocation block
0Ah WORD maximum buffer in KB
0Ch WORD current buffer in KB (less than max if XMS memory being lent)
0Eh WORD total number of allocation blocks
10h WORD current number of allocation blocks
12h WORD number of blocks being used by RAM disk
14h WORD number of blocks being used by cache or unused
16h WORD number of dirty cache blocks
18h WORD number of blocks which could not be written out due to errors
1Ah WORD total number of read requests
1Ch WORD total number of sectors read
1Eh WORD number of BIOS read requests (cache misses)
20h WORD number of sectors read via BIOS (cache misses)
22h WORD total number of write requests
24h WORD total number of sectors written
26h WORD number of BIOS write requests
28h WORD number of sectors written via BIOS
2Ah WORD number of RAM disk read requests
2Ch WORD number of sectors read from RAM disk
2Eh WORD number of RAM disk write requests
30h WORD number of sectors written to RAM disk
--------D-214405-----------------------------
INT 21 - DOS 2+ - IOCTL - WRITE TO BLOCK DEVICE CONTROL CHANNEL
AX = 4405h
BL = drive number (00h = default, 01h = A:, etc)
CX = number of bytes to write
DS:DX -> data to write
Return: CF clear if successful
AX = number of bytes actually written
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
Note: format of data is driver-specific
SeeAlso: AX=4403h,AX=4404h,INT 2F/AX=122Bh
--------d-214405-----------------------------
INT 21 - Brian Antoine Seagate ST-01 SCSI.SYS - IOCTL - EXECUTE COMMANDS
AX = 4405h
BX = drive number (00h = default, 01h = A:, etc)
CX = number of bytes to write
DS:DX -> SCSIDISK control block (see AX=4403h"ST-01")
Return: CF clear if successful
AX = number of bytes actually written
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
SeeAlso: AX=4403h"ST-01"
--------d-214405-----------------------------
INT 21 U - DBLSPACE.BIN - IOCTL - FLUSH OR INVALIDATE INTERNAL CACHES
AX = 4405h
BL = drive number (00h = default, 01h = A:, etc)
CX = 000Ah (size of DSPACKET structure)
DS:DX -> DSPACKET structure (see below)
Return: CF clear if IOCTL successful -- check DSPACKET for actual status
AX = number of bytes actually transferred
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
Note: this call is identical to the documented AX=4404h
SeeAlso: AX=4404h"DBLSPACE",INT 2F/AX=4A11h/BX=0000h
Format of DSPACKET structure:
Offset Size Description
00h WORD signature 444Dh ("DM")
02h BYTE command code
46h ('F') flush internal caches
49h ('I') flush and invalidate internal caches
03h WORD result code
(return) 4F4Bh ("OK") if successful, else unchanged
05h 5 BYTEs padding
--------d-214405-----------------------------
INT 21 U - xDISK v3.31 - ???
AX = 4405h
BL = drive number (00h = default, 01h = A:, etc)
CX = number of bytes to write
DS:DX -> buffer containing version string
???
Return: CF clear if successful
AX = number of bytes actually transferred
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
Program: xDISK is a shareware resizeable EMS RAMdisk by FM de Monasterio
SeeAlso: AX=4404h"xDISK",INT 2F/AH=DDh"xDISK"
--------d-214405-----------------------------
INT 21 - COMBI-disk v1.13 - CONTROL COMBI-disk
AX = 4405h
BL = drive number (00h = default, 01h = A:, etc) for RAM disk
CX = number of bytes to write
DS:DX -> buffer containing command packet (see below)
Return: CF clear if successful
AX = number of bytes actually transferred
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
SeeAlso: AX=4404h"COMBI"
Format of command packet:
Offset Size Description
00h WORD version
02h BYTE command code
80h flush cache
81h change options byte
82h shrink memory
83h expand memory
84h get dirty block information
85h reset write errors
86h reset counters
---command code 81h---
03h BYTE new options byte (see below)
---command code 82h---
03h WORD number of KB to release
---command code 83h---
03h WORD number of KB to expand
---command code 84h---
03h DWORD -> buffer for block info (see below)
---command code 85h---
03h DWORD block ID
---command code 86h---
03h BYTE which counters to reset
bit 0: hard disk read counts
bit 1: hard disk write counts
bit 2: RAM disk read/write counts
Note: multiple commands may be placed in a single packet by stringing
together as many command/argument pairs as desired
Bitfields for options byte:
bit 0 cache off
bit 1 cache frozen
bit 2 write caching enabled
bit 3 delayed writing disabled
bit 5 fix memory allocation (no XMS lending)
bit 6 no 'sector not found' error
Format of block info:
Offset Size Description
00h DWORD block ID
04h BYTE bitmask of valid sectors in block
05h BYTE bitmask of dirty sectors in block
06h BYTE last error returned by BIOS
07h BYTE number of errors
--------D-214406-----------------------------
INT 21 - DOS 2+ - IOCTL - GET INPUT STATUS
AX = 4406h
BX = file handle
Return: CF clear if successful
AL = input status
00h not ready (device) or at EOF (file)
FFh ready
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
Note: files may not register as being at EOF if positioned there by AH=42h
SeeAlso: AX=4407h,INT 2F/AX=122Bh
--------D-214407-----------------------------
INT 21 - DOS 2+ - IOCTL - GET OUTPUT STATUS
AX = 4407h
BX = file handle
Return: CF clear if successful
AL = input status
00h not ready
FFh ready
CF set on error
AX = error code (01h,05h,06h,0Dh) (see AH=59h)
Note: for DOS 2+, files are always ready for output, even if the disk is
full or no media is in the drive
SeeAlso: AX=4406h,INT 2F/AX=122Bh
--------D-214408-----------------------------
INT 21 - DOS 3.0+ - IOCTL - CHECK IF BLOCK DEVICE REMOVABLE
AX = 4408h
BL = drive number (00h = default, 01h = A:, etc)
Return: CF clear if successful
AX = 0000h if removable
= 0001h if fixed
CF set on error
AX = error code (01h,0Fh) (see AH=59h)
SeeAlso: AX=4400h,AX=4409h,INT 2F/AX=122Bh
--------D-214409-----------------------------
INT 21 - DOS 3.1+ - IOCTL - CHECK IF BLOCK DEVICE REMOTE
AX = 4409h
BL = drive number (00h = default, 01h = A:, etc)
Return: CF clear if successful
DX = device attribute word
bit 15: drive is SUBSTituted
bit 12: drive is remote
bit 9: direct I/O not allowed
CF set on error
AX = error code (01h,0Fh) (see AH=59h)
Note: on local drives, DX bits not listed above are the attribute word from
the device driver header (see AH=52h); for remote drives, the other
bits appear to be undefined for DOS versions prior to 5.0 (they are
all cleared in DOS 5+)
SeeAlso: AX=4400h,AX=4408h,AX=440Ah,INT 2F/AX=122Bh
--------D-21440A-----------------------------
INT 21 - DOS 3.1+ - IOCTL - CHECK IF HANDLE IS REMOTE
AX = 440Ah
BX = handle
Return: CF clear if successful
DX = attribute word (as stored in SFT)
bit 15: set if remote
bit 14: date/time not set on close
CF set on error
AX = error code (01h,06h) (see AH=59h)
Notes: if file is remote, Novell Advanced NetWare 2.0 returns the number of
the file server on which the handle is located in CX
DR-DOS 3.41 and 5.0 clear all bits of DX except bit 15
SeeAlso: AX=4400h,AX=4409h,AH=52h,INT 2F/AX=122Bh
--------D-21440B-----------------------------
INT 21 - DOS 3.1+ - IOCTL - SET SHARING RETRY COUNT
AX = 440Bh
CX = pause between retries (default 1)
DX = number of retries (default 3)
Return: CF clear if successful
CF set on error
AX = error code (01h) (see AH=59h)
Notes: delay is dependent on processor speed (value in CX specifies number of
64K-iteration empty loops to execute)
if DX=0000h on entry, the retry count is left unchanged
SeeAlso: AH=52h,INT 2F/AX=1224h,INT 2F/AX=122Bh
--------D-21440C-----------------------------
INT 21 - DOS 3.2+ - IOCTL - GENERIC CHARACTER DEVICE REQUEST
AX = 440Ch
BX = device handle
CH = category code
00h unknown (DOS 3.3+)
01h COMn: (DOS 3.3+)
03h CON (DOS 3.3+)
05h LPTn:
9Eh Media Access Control driver (STARLITE)
00h-7Fh reserved for Microsoft
80h-FFh reserved for OEM/user-defined
CL = function
00h MAC driver Bind (STARLITE)
45h set iteration (retry) count
4Ah select code page
4Ch start code-page preparation
4Dh end code-page preparation
5Fh set display information (DOS 4+)
65h get iteration (retry) count
6Ah query selected code page
6Bh query prepare list
7Fh get display information (DOS 4+)
DS:DX -> parameter block (see below)
SI = parameter to pass to driver (European MS-DOS 4.0, OS/2 comp box)
DI = parameter to pass to driver (European MS-DOS 4.0, OS/2 comp box)
Return: CF set on error
AX = error code (see AH=59h)
CF clear if successful
DS:DX -> iteration count if CL=65h
SI = returned value (European MS-DOS 4.0, OS/2 comp box)
DI = returned value (European MS-DOS 4.0, OS/2 comp box)
Notes: bit assignments for function code in CL:
bit 7: set to ignore if unsupported, clear to return error
bit 6: set if passed to driver, clear if intercepted by DOS
bit 5: set if queries data from device, clear if sends command
bits 4-0: subfunction
DR-DOS 3.41 and 5.0 return error code 16h on CL=45h,65h if the device
does not support a retry counter
SeeAlso: AX=440Dh,INT 2F/AX=0802h,INT 2F/AX=122Bh,INT 2F/AX=14FFh
SeeAlso: INT 2F/AX=1A01h
Format of parameter block for function 00h:
Offset Size Description
00h 8 BYTEs ASCIZ signature "STARMAC"
08h WORD version
0Ah WORD flags
bit 0: media requires connect or listen request before use
bit 1: network is a LAN (broadcast/multicast supported)
bit 2: point-to-point network
0Ch WORD handle for use with MAC driver's private interface (filled in
by MAC driver)
0Eh WORD context
10h WORD approximate speed in KB/sec (filled in by MAC driver)
12h WORD approximate cost in cents per hour (filled in by MAC driver)
14h WORD maximum packet size in bytes (filled in by MAC driver)
16h WORD addressing format (filled in by MAC driver)
0000h general addressing
0001h Ethernet addressing
0002h Token Ring addressing
0003h Token Bus addressing
18h DWORD Send entry point (filled in by MAC driver)
1Ch DWORD RegisterEventHandler entry point (filled in by MAC driver)
20h DWORD SetPacketFilter entry point (filled in by MAC driver)
24h DWORD UnBind entry point (filled in by MAC driver)
Format of parameter block for function 45h:
Offset Size Description
00h WORD number of times output is attempted before driver assumes
device is busy
Format of parameter block for functions 4Ah and 6Ah:
Offset Size Description
00h WORD length of data
02h WORD code page ID
04h 2N BYTEs DCBS (double byte character set) lead byte range
start/end for each of N ranges (DOS 4.0)
WORD 0000h end of data (DOS 4.0)
Format of parameter block for function 4Ch:
Offset Size Description
00h WORD flags
DISPLAY.SYS = 0000h
PRINTER.SYS bit 0 clear to prepare downloaded font, set to
prepare cartridge selection
02h WORD length of remainder of parameter block
04h WORD number of code pages following
06h N WORDs code page 1,...,N
Format of parameter block for function 4Dh:
Offset Size Description
00h WORD length of data
02h WORD code page ID
Format of parameter block for functions 5Fh and 7Fh:
Offset Size Description
00h BYTE level (0 for DOS 4.x-6.0)
01h BYTE reserved (0)
02h WORD length of following data (14)
04h WORD control flags
bit 0 set for blink, clear for intensity
bits 1 to 15 reserved
06h BYTE mode type (1=text, 2=graphics)
07h BYTE reserved (0)
08h WORD colors
0 = monochrome
else N bits per pixel
0Ah WORD pixel columns
0Ch WORD pixel rows
0Eh WORD character columns
10h WORD character rows
Format of parameter block for function 6Bh:
Offset Size Description
00h WORD length of following data
02h WORD number of hardware code pages
04h N WORDs hardware code pages 1,...,N
WORD number of prepared code pages
N WORDs prepared code pages 1,...,N
--------d-21440C-----------------------------
INT 21 - Greg Shenaut ASPITAPE.SYS - INTERFACE
AX = 440Ch
BX = device handle
CH = category code
07h tape (ASPITAPE.SYS)
CL = function
01h "mtop" - perform tape operation
02h "mtget" - get tape status
03h ignore end-of-tape errors
04h enable end-of-tape errors
DS:DX -> parameter block (see below)
Return: CF set on error
AX = error code (see AH=59h)
CF clear if successful
DS:DX -> data block
Notes: This device driver is a simple DOS interface to the Adaptec Advanced
SCSI Programming Interface (ASPI). It provides the following device
names as access to the SCSI tape, 'RMTx' (rewind on close) and
'NRMTx' (NO rewind on close) where x can go from 0 to 3. There may
also be the following names 'MTx' and 'NMTx' which default to 1024
byte blocks. The names may also have a '$' appended to try and make
them unique from file names of 'RMT0' etc.
once opend these devices must be put into RAW mode
SeeAlso: AX=4402h"ASPI"
Format of mtop parameter block:
Offset Size Description
00h WORD operation code
00h "MTWEOF" - write an end-of-file record
01h "MTFSF" - forward space file
02h "MTBSF" - backward space file
03h "MTFSR" - forward space record
04h "MTBSR" - backward space record
05h "MTREW" - rewind
06h "MTOFFL" - rewind and unload
07h "MTNOP" - perform TEST UNIT READY
02h DWORD repetition count
Format of mtget parameter block:
Offset Size Description
00h BYTE ASPI host ID
01h BYTE SCSI target ID
02h BYTE SCSI logical unit number
03h BYTE device parameters
bit 0: drive must use fixed-block read and write
bit 7: drive is an ASPI device
04h BYTE current device state (see below)
05h BYTE unit number within driver
06h WORD fixed block blocksize
08h BYTE last SCSI status
09h BYTE last SCSI sense key
0Ah WORD last SCSI opcode (packed)
bits 0-7: SCSI operation (SCSI packet byte 0)
bits 8-10: SCSI flags (SCSI packet byte 1)
bits 11-12: ASPI "Direction Bits" (ASPI SRB byte 3)
0Ch WORD residual bytes from SCSI opcode
Bitfields for current device state:
bit 0 device currently opened in buffered mode
bit 1 drive currently opened in nonbuffered mode
bit 2 rewind drive on last close
bit 3 drive has been written on
bit 4 drive has been read from
bit 5 next read will return 0 bytes
bit 6 EOM will resemble EOF
bit 7 drive may be busy rewinding
--------D-21440D-----------------------------
INT 21 - DOS 3.2+ - IOCTL - GENERIC BLOCK DEVICE REQUEST
AX = 440Dh
BL = drive number (00h=default,01h=A:,etc)
CH = category code
08h disk drive
00h-7Fh reserved for Microsoft
80h-FFh reserved for OEM/user-defined
CL = minor code (function) (see below)
DS:DX -> (DOS) parameter block (see below)
SI:DI -> (OS/2 comp box) parameter block (see below)
Return: CF set on error
AX = error code (01h,02h) (see AH=59h)
CF clear if successful
DS:DX -> data block if CL=60h or CL=61h
Notes: DOS 4.01 seems to ignore the high byte of the number of directory
entries in the BPB for diskettes.
functions 46h and 66h undocumented in DOS 4.x, documented for DOS 5+
the DUBLDISK.SYS v2.6 driver only supports minor codes 60h and 67h
DR-DOS 3.41-6.0 only support minor codes 40h-42h and 60h-62h; all
other minor codes return error code 16h
SeeAlso: AX=440Ch,AH=69h,INT 2F/AX=0802h,INT 2F/AX=122Bh
Values for minor code:
00h (OS/2) \ used to lock/unlock a drive
01h (OS/2) /
40h set device parameters
41h write logical device track
42h format and verify logical device track
46h (DOS 4+) set volume serial number (see also AH=69h)
47h (DOS 4+) set access flag
50h (PCMCIA) attribute memory write
51h (PCMCIA) common memory write
52h (PCMCIA) force media change
53h (PCMCIA) erase drive
54h (PCMCIA) erase media
56h (PCMCIA) set erase status callback
57h (PCMCIA) append Card Information Structure (CIS) tuple
58h (PCMCIA) erase CIS tuples
60h get device parameters
61h read logical device track
62h verify logical device track
66h (DOS 4+) get volume serial number (see also AH=69h)
67h (DOS 4+) get access flag
68h (DOS 5+) sense media type
70h (PCMCIA) attribute memory read
73h (PCMCIA) get memory media information
76h (PCMCIA) get erase status callback
77h (PCMCIA) get first Card Information Structure (CIS) tuple
78h (PCMCIA) get next CIS tuple
Format of parameter block for functions 40h, 60h:
Offset Size Description
00h BYTE special functions
bit 0 set if function to use current BPB, clear if Device
BIOS Parameter Block field contains new default BPB
bit 1 set if function to use track layout fields only
must be clear if CL=60h
bit 2 set if all sectors in track same size (should be set)
bits 3-7 reserved
01h BYTE device type (see below)
02h WORD device attributes
bit 0 set if nonremovable medium
bit 1 set if door lock ("changeline") supported
bits 2-15 reserved
04h WORD number of cylinders
06h BYTE media type
for 1.2M drive
00h 1.2M disk (default)
01h 320K/360K disk
F8h for DUBLDISK.SYS v2.6 expanded drives
always 00h for other drive types
07h 31 BYTEs device BPB (see AH=53h), bytes after BPB offset 1Eh omitted
---function 40h only---
26h WORD number of sectors per track (start of track layout field)
max 63
28h N word pairs: number,size of each sector in track
Values for device type:
00h 320K/360K disk
01h 1.2M disk
02h 720K disk
03h single-density 8-inch disk
04h double-density 8-inch disk
05h fixed disk
06h tape drive
07h (DOS 3.3+) other type of block device, normally 1.44M floppy
08h read/write optical disk
09h (DOS 5+) 2.88M floppy
Format of parameter block for functions 41h, 61h:
Offset Size Description
00h BYTE special functions (reserved, must be zero)
01h WORD number of disk head
03h WORD number of disk cylinder
05h WORD number of first sector to read/write
07h WORD number of sectors
09h DWORD transfer address
Format of parameter block for function 42h:
Offset Size Description
00h BYTE reserved, must be zero (DOS <3.2)
bit 0=0: format/verify track
1: format status call (DOS 3.2+), don't actually format
bits 1-7 reserved, must be zero
value on return (DOS 3.3+):
00h specified tracks, sectors/track supported by BIOS
01h function not supported by BIOS
02h specified tracks, sectors/track not allowed for drive
03h no disk in drive
01h WORD number of disk head
03h WORD number of disk cylinder
Format of parameter block for function 62h:
Offset Size Description
00h BYTE reserved, must be zero (DOS <3.2)
bit 0=0: verify single track
1: verify multiple tracks
bits 1-7 reserved, must be zero
value on return (DOS 3.3+):
00h specified tracks, sectors/track supported by BIOS
01h function not supported by BIOS
02h specified tracks, sectors/track not allowed for drive
03h no disk in drive
01h WORD number of disk head
03h WORD number of disk cylinder
05h WORD number of tracks to verify (equivalent to 255 or fewer sectors)
Format of parameter block for functions 46h, 66h:
Offset Size Description
00h WORD (call) info level (should be 0000h)
02h DWORD disk serial number (binary)
06h 11 BYTEs volume label or "NO NAME "
11h 8 BYTEs filesystem type "FAT12 " or "FAT16 " (CL=66h only)
Format of parameter block for functions 47h, 67h:
Offset Size Description
00h BYTE special-function field (must be zero)
01h BYTE disk-access flag, nonzero if access allowed by driver
Format of parameter block for function52h:
00h BYTE (call) unused???
(return) 00h if flast/ATA drive but no card inserted
unchanged otherwise
Note: the absense of a flash card should be tested by checking the DOS error
code rather than the returned byte
Format of parameter block for function 68h:
Offset Size Description
00h BYTE 01h for default media type, 00h for any other media type
(see also INT 13/AH=20h)
01h BYTE 02h for 720K, 07h for 1.44M, 09h for 2.88M
--------D-21440E-----------------------------
INT 21 - DOS 3.2+ - IOCTL - GET LOGICAL DRIVE MAP
AX = 440Eh
BL = drive number (00h=default,01h=A:,etc)
Return: CF set on error
AX = error code (01h,0Fh) (see AH=59h)
CF clear if successful
AL = 00h block device has only one logical drive assigned
1..26 the last letter used to reference the drive (1=A:,etc)
Note: DR-DOS 3.41-5.0 DRIVER.SYS does not support drive mapping and thus
always returns AL=00h
SeeAlso: AX=440Fh,INT 2F/AX=122Bh
--------D-21440F-----------------------------
INT 21 - DOS 3.2+ - IOCTL - SET LOGICAL DRIVE MAP
AX = 440Fh
BL = physical drive number (00h=default,01h=A:,etc))
Return: CF set on error
AX = error code (01h,0Fh) (see AH=59h)
CF clear if successful
drive now responds to next logical drive number
Notes: maps logical drives to physical drives, similar to DOS's treatment of
a single physical floppy drive as both A: and B:
DR-DOS 3.41-5.0 DRIVER.SYS does not support drive mapping and thus
always returns an error on this function
SeeAlso: AX=440Eh,INT 2F/AX=122Bh
--------D-214410-----------------------------
INT 21 - DOS 5+ - IOCTL - QUERY GENERIC IOCTL CAPABILITY (HANDLE)
AX = 4410h
BX = handle for device
CH = category code (see AX=440Ch)
CL = function code
Return: CF clear if successful
AX = 0000h specified IOCTL function is supported
CF set on error
AL = 01h IOCTL capability not available
Note: a program which wishes to use Generic IOCTL calls beyond those in the
standard DOS 3.2 set may use this call first to see whether a
particular call is supported
SeeAlso: AX=440Ch,AX=440Dh,AX=4411h
--------d-214410BXFFFF-----------------------
INT 21 U - NewSpace - ENABLE DRIVER
AX = 4410h
BX = FFFFh
Program: NewSpace is a TSR by Isogon Corporation which automatically compresses
all files as they are written and decompresses them as they are read
Note: compressed files are not accessible unless the driver is enabled
SeeAlso: AX=4411h/BX=FFFFh
--------D-214411-----------------------------
INT 21 - DOS 5+ - IOCTL - QUERY GENERIC IOCTL CAPABILITY (DRIVE)
AX = 4411h
BL = drive number
CH = category code (see AX=440Dh)
CL = function code
Return: CF clear if successful
AX = 0000h specified IOCTL function is supported
CF set on error
AL = 01h IOCTL capability not available
Note: a program which wishes to use Generic IOCTL calls beyond those in the
standard DOS 3.2 set may use this call first to see whether a
particular call is supported
SeeAlso: AX=440Ch,AX=440Dh,AX=4410h
--------d-214411BXFFFF-----------------------
INT 21 U - NewSpace - DISABLE DRIVER
AX = 4411h
BX = FFFFh
Program: NewSpace is a TSR by Isogon Corporation which automatically compresses
all files as they are written and decompresses them as they are read
Note: compressed files are not accessible unless the driver is enabled
SeeAlso: AX=4410h/BX=FFFFh
--------O-214412-----------------------------
INT 21 - DR-DOS 5+ - DETERMINE DOS TYPE
AX = 4412h
CF set
Return: CF set if not DR-DOS
AX = error code (see AH=59h)
CF clear if DR-DOS
DX = AX = version code (see AX=4452h)
Note: this obsolete call which will not be supported in future versions of
DR-DOS is identical to AX=4452h
SeeAlso: AX=4452h
--------d-214412BXFFFF-----------------------
INT 21 U - NewSpace - INSTALLATION CHECK???
AX = 4412h
BX = FFFFh
Return: AX = PSP segment of NewRes (resident driver for NewSpace)
BX:DX -> ???
CX = ???
SeeAlso: AX=4411h/BX=FFFFh
--------d-214413BXFFFF-----------------------
INT 21 U - NewSpace - GET ???
AX = 4413h
BX = FFFFh
Return: AX = code segment of NewRes (resident driver for NewSpace)
BX = offset of ???
SeeAlso: AX=4412h/BX=FFFFh
--------O-214414-----------------------------
INT 21 U - DR-DOS 5.0 - SET GLOBAL PASSWORD
AX = 4414h
DS:DX -> password string (blank-padded to 8 characters)
Desc: Specify the master password for accessing files.
Note: this obsolete call which will not be supported in future versions of
DR-DOS is identical to AX=4452h
SeeAlso: AX=4454h
--------d-214414BXFFFF-----------------------
INT 21 U - NewSpace - DEBUGGING DUMP
AX = 4414h
BX = FFFFh
Return: debugging dump written to X:\NEWSPACE.SMP
SeeAlso: AX=4413h/BX=FFFFh,AX=44FFh/BX=FFFFh
--------O-2144-------------------------------
INT 21 U - DR-DOS 5.0 - HISTORY BUFFER, SHARE, AND HILOAD CONTROL
AH = 44h
AL = 16h to 18h
Note: these obsolete subfunctions (which will not be supported in future
versions of DR-DOS) are identical to AX=4456h through 4458h
SeeAlso: AX=4456h,AX=4457h,AX=4458h
--------O-214451-----------------------------
INT 21 - Concurrent DOS v3.2+ - INSTALLATION CHECK
AX = 4451h
Return: CF set if not Concurrent DOS
AX = error code (see AH=59h)
CF clear if successful
AH = single-user/multiuser nature
10h single-user
AL = operating system version ID (see AX=4452h)
14h multiuser
AL = operating system version ID (see below)
Notes: as of Concurrent DOS/XM 5.0 (possibly earlier), the version is stored
in the environment variable VER
use this function if you are looking for multiuser capabilities,
AX=4452h for single-user
this function should never return the single-user values
SeeAlso: AX=4452h,AX=4459h
Values for operating system version ID:
32h Concurrent PC DOS 3.2
41h Concurrent DOS 4.1
50h Concurrent DOS/XM 5.0 or Concurrent DOS/386 1.1
60h Concurrent DOS/XM 6.0 or Concurrent DOS/386 2.0
62h Concurrent DOS/XM 6.2 or Concurrent DOS/386 3.0
66h DR Multiuser DOS 5.1
67h Concurrent DOS 5.1
--------O-214452-----------------------------
INT 21 - DR-DOS 3.41+ - DETERMINE DOS TYPE/GET DR-DOS VERSION
AX = 4452h ("DR")
CF set
Return: CF set if not DR-DOS
AX = error code (see AH=59h)
CF clear if DR-DOS
DX = AX = version code
AH = single-user/multiuser nature
10h single-user
AL = operating system version ID (see below)
14h multiuser
AL = operating system version ID (see AX=4451h)
Notes: the DR-DOS version is stored in the environment variable VER
use this function if looking for single-user capabilities, AX=4451h
if looking for multiuser; this call should never return multiuser
values
SeeAlso: AX=4412h,AX=4451h,AX=4459h
Values for operating system version ID:
60h DOS Plus
63h DR-DOS 3.41
64h DR-DOS 3.42
65h DR-DOS 5.00
67h DR-DOS 6.00
70h PalmDOS
71h DR-DOS 6.0 March 1993 "business update"
72h Novell DOS 7.0
--------O-214454-----------------------------
INT 21 U - DR-DOS 3.41+ - SET GLOBAL PASSWORD
AX = 4454h
DS:DX -> password string (blank-padded to 8 characters)
Desc: Specify the master password for accessing files.
SeeAlso: AX=4303h,AX=4414h
--------O-214456-----------------------------
INT 21 U - DR-DOS 5.0+ - HISTORY BUFFER CONTROL
AX = 4456h
DL = flag
bit 0: 1 = COMMAND.COM history buffers
0 = set to application
Return: AL = ??? (20h if DL bit 0 set, A0h if clear (DR-DOS 6.0))
Note: This was seen called by COMMAND.COM of DR-DOS 6.0
--------O-214457-----------------------------
INT 21 U - DR-DOS 5.0+ - SHARE/HILOAD CONTROL
AX = 4457h
DH = subfunction
00h enable/disable SHARE
DL = 00h disable
= 01h enable
else Return: AX = ???
01h get HILOAD status
Return: AX = status
0000h off
0001h on
02h set HILOAD status
DL = new state (00h off, 01h on)
Return: AX = ???
other
Return: AX = ???
Note: This was seen called by COMMAND.COM of DR-DOS 6.0
SeeAlso: AX=4457h/DX=FFFFh
--------O-214457DXFFFF-----------------------
INT 21 U - DR-DOS 6.0 - GET SHARE STATUS
AX = 4457h
DX = FFFFh
Return: AX = SHARE status
SeeAlso: INT 2F/AX=1000h
--------O-214458-----------------------------
INT 21 U - DR-DOS 5.0+ internal - GET POINTER TO INTERNAL VARIABLE TABLE
AX = 4458h
Return: ES:BX -> internal variable table (see below)
AX = ??? (0B50h for DR-DOS 5.0, 0A56h for DR-DOS 6.0)
SeeAlso: AX=4452h
Format of internal variable table:
Offset Size Description
00h WORD ???
02h WORD segment of ???
04h 7 BYTEs ???
0Bh WORD KB of extended memory at startup
0Dh BYTE number of far jump entry points
0Eh WORD segment containing far jumps to DR-DOS entry points (see below)
10h WORD (only if kernel loaded in HMA) offset in HMA of first free HMA
memory block (see below) or 0000h if none; segment is FFFFh
12h WORD pointer to segment of environment variables set in CONFIG,
or 0000h if already used
---DR-DOS 6.0---
14h WORD (only if kernel loaded in HMA) offset in HMA of first used HMA
memory block (see below) or 0000h if none; segment is FFFFh
Note: the segment used for the DR-DOS 6.0 CONFIG environment variables
(excluding COMSPEC, VER and OS) is only useful for programs/drivers
called from CONFIG.SYS. The word is set to zero later when the area
is copied to the COMMAND.COM environment space. This allows
CONFIG.SYS to pass information to AUTOEXEC.BAT.
Format of kernel entry jump table for DR-DOS 5.0-6.0:
Offset Size Description
00h 5 BYTEs far jump to kernel entry point for CP/M CALL 5
05h 5 BYTEs far jump to kernel entry point for INT 20
0Ah 5 BYTEs far jump to kernel entry point for INT 21
0Fh 5 BYTEs far jump to kernel entry point for INT 22 (RETF)
14h 5 BYTEs far jump to kernel entry point for INT 23 (RETF)
19h 5 BYTEs far jump to kernel entry point for INT 24
1Eh 5 BYTEs far jump to kernel entry point for INT 25
23h 5 BYTEs far jump to kernel entry point for INT 26
28h 5 BYTEs far jump to kernel entry point for INT 27
2Dh 5 BYTEs far jump to kernel entry point for INT 28
32h 5 BYTEs far jump to kernel entry point for INT 2A (IRET)
37h 5 BYTEs far jump to kernel entry point for INT 2B (IRET)
3Ch 5 BYTEs far jump to kernel entry point for INT 2C (IRET)
41h 5 BYTEs far jump to kernel entry point for INT 2D (IRET)
46h 5 BYTEs far jump to kernel entry point for INT 2E (IRET)
4Bh 5 BYTEs far jump to kernel entry point for INT 2F
Notes: all of these entry points are indirected through this jump table
to allow the kernel to be relocated into high memory while leaving
the actual entry addresses in low memory for maximum compatibility
some of these entry points (22h,23h,24h,2Eh,2Fh) are replaced as soon
as COMMAND.COM is loaded, and return immediately to the caller, some
returning an error code (the original handler for INT 2F returns
AL=03h [fail]).
Format of HMA Memory Block (DR-DOS 6.0 kernel loaded in HMA):
Offset Size Description
00h WORD offset of next HMA Memory Block (0000h if last block)
02h WORD size of this block in bytes (at least 10h)
04h BYTE type of HMA Memory Block (interpreted by MEM)
00h system
01h KEYB
02h NLSFUNC
03h SHARE
04h TaskMAX
05h COMMAND
05h var TSR (or system) code and data. DR-DOS TSR's, such as KEYB,
hooks interrupts using segment FFFEh instead FFFFh.
--------O-214459-----------------------------
INT 21 - DR MultiUser DOS 5.0 - API
AX = 4459h
CL = function (see INT E0"CP/M")
DS,DX = parameters
Notes: DR-DOS 5.0 returns CF set and AX=0001h
this API is also available on INT E0
SeeAlso: AX=4452h,INT E0"CP/M"
--------N-2144E0-----------------------------
INT 21 U - Sun PC-NFS - API???
AX = 44E0h
DS:DX -> ???
SS:BP -> stack frame (see below)
Return: ???
Note: this function is also supported by Beame&Whiteside's BWPCNFS shim; the
description presented here was derived from that shim
Format of stack frame:
Offset Size Description
00h WORD -> previous stack frame
02h DWORD return address
--------d-2144FFBXFFFF-----------------------
INT 21 U - NewSpace - ???
AX = 44FFh
BX = FFFFh
DX = ???
Program: NewSpace is a TSR by Isogon Corporation which automatically compresses
all files as they are written and decompresses them as they are read
SeeAlso: AX=4414h/BX=FFFFh
--------D-2145-------------------------------
INT 21 - DOS 2+ - "DUP" - DUPLICATE FILE HANDLE
AH = 45h
BX = file handle
Return: CF clear if successful
AX = new handle
CF set on error
AX = error code (04h,06h) (see AH=59h)
Notes: moving file pointer for either handle will also move it for the other,
because both will refer to the same system file table
for DOS versions prior to 3.3, file writes may be forced to disk by
duplicating the file handle and closing the duplicate
SeeAlso: AH=3Dh,AH=46h
--------D-2146-------------------------------
INT 21 - DOS 2+ - "DUP2", "FORCEDUP" - FORCE DUPLICATE FILE HANDLE
AH = 46h
BX = file handle
CX = file handle to become duplicate of first handle
Return: CF clear if successful
CF set on error
AX = error code (04h,06h) (see AH=59h)
Notes: closes file with handle CX if it is still open
DOS 3.30 hangs if BX=CX on entry
moving file pointer for either handle will also move it for the other,
because both will refer to the same system file table
SeeAlso: AH=3Dh,AH=45h
--------D-2147-------------------------------
INT 21 - DOS 2+ - "CWD" - GET CURRENT DIRECTORY
AH = 47h
DL = drive number (00h = default, 01h = A:, etc)
DS:SI -> 64-byte buffer for ASCIZ pathname
Return: CF clear if successful
AX = 0100h (undocumented)
CF set on error
AX = error code (0Fh) (see AH=59h)
Notes: the returned path does not include a drive or the initial backslash
many Microsoft products for Windows rely on AX being 0100h on success
under the FlashTek X-32 DOS extender, the buffer pointer is in DS:ESI
SeeAlso: AH=19h,AH=3Bh,AH=71h,INT 15/AX=DE25h
--------D-2148-------------------------------
INT 21 - DOS 2+ - ALLOCATE MEMORY
AH = 48h
BX = number of paragraphs to allocate
Return: CF clear if successful
AX = segment of allocated block
CF set on error
AX = error code (07h,08h) (see AH=59h)
BX = size of largest available block
Notes: DOS 2.1-6.0 coalesces free blocks while scanning for a block to
allocate
.COM programs are initially allocated the largest available memory
block, and should free some memory with AH=49h before attempting any
allocations
under the FlashTek X-32 DOS extender, EBX contains a protected-mode
near pointer to the allocated block on a successful return
SeeAlso: AH=49h,AH=4Ah,AH=58h,AH=83h
--------D-2149-------------------------------
INT 21 - DOS 2+ - FREE MEMORY
AH = 49h
ES = segment of block to free
Return: CF clear if successful
CF set on error
AX = error code (07h,09h) (see AH=59h)
Notes: apparently never returns an error 07h, despite official docs; DOS 2.1+
code contains only an error 09h exit
DOS 2.1-6.0 does not coalesce adjacent free blocks when a block is
freed, only when a block is allocated or resized
the code for this function is identical in DOS 2.1-6.0 except for
calls to start/end a critical section in DOS 3+
SeeAlso: AH=48h,AH=4Ah
--------D-214A-------------------------------
INT 21 - DOS 2+ - RESIZE MEMORY BLOCK
AH = 4Ah
BX = new size in paragraphs
ES = segment of block to resize
Return: CF clear if successful
CF set on error
AX = error code (07h,08h,09h) (see AH=59h)
BX = maximum paragraphs available for specified memory block
Notes: under DOS 2.1-6.0, if there is insufficient memory to expand the block
as much as requested, the block will be made as large as possible
DOS 2.1-6.0 coalesces any free blocks immediately following the block
to be resized
SeeAlso: AH=48h,AH=49h,AH=83h
--------D-214B-------------------------------
INT 21 - DOS 2+ - "EXEC" - LOAD AND/OR EXECUTE PROGRAM
AH = 4Bh
AL = type of load
00h load and execute
01h load but do not execute
03h load overlay
04h load and execute in background (European MS-DOS 4.0 only)
"Exec & Go" (see also AH=80h)
DS:DX -> ASCIZ program name (must include extension)
ES:BX -> parameter block (see below)
CX = mode (subfunction 04h only)
0000h child placed in zombie mode after termination
0001h child's return code discarded on termination
Return: CF clear if successful
BX,DX destroyed
if subfunction 01h, process ID set to new program's PSP; get with
INT 21/AH=62h
CF set on error
AX = error code (01h,02h,05h,08h,0Ah,0Bh) (see AH=59h)
Notes: DOS 2.x destroys all registers, including SS:SP
under ROM-based DOS, if no disk path characters (colons or slashes)
are included in the program name, the name is searched for in the
ROM module headers (see below) before searching on disk
for functions 00h and 01h, the calling process must ensure that there
is enough unallocated memory available; if necessary, by releasing
memory with AH=49h or AH=4Ah
for function 01h, the AX value to be passed to the child program is put
on top of the child's stack
for function 03h, DOS assumes that the overlay is being loaded into
memory allocated by the caller
function 01h was undocumented prior to the release of DOS 5.0
some versions (such as DR-DOS 6.0) check the parameters and parameter
block and return an error if an invalid value (such as an offset of
FFFFh) is found
background programs under European MS-DOS 4.0 must use the new
executable format
new executables begin running with the following register values
AX = environment segment
BX = offset of command tail in environment segment
CX = size of automatic data segment (0000h = 64K)
ES,BP = 0000h
DS = automatic data segment
SS:SP = initial stack
the command tail corresponds to an old executable's PSP:0081h and
following, except that the 0Dh is turned into a NUL (00h); new
format executables have no PSP
under the FlashTek X-32 DOS extender, only function 00h is supported
and the pointers are passed in DS:EDX and ES:EBX
DR-DOS 6 always loads .EXE-format programs with no fixups above the
64K mark to avoid the EXEPACK bug
names for the various executable type understood by various
environments:
MZ old-style DOS executable
NE Windows or OS/2 1.x segmented ("new") executable
LE Windows virtual device driver (VxD) linear executable
LX variant of LE used in OS/2 2.x
W3 Windows WIN386.EXE file; a collection of LE files
PE Win32 (Windows NT and Win32s) portable executable based on
Unix COFF
BUGS: DOS 2.00 assumes that DS points at the current program's PSP
Load Overlay (subfunction 03h) loads up to 512 bytes too many if the
file contains additional data after the actual overlay
SeeAlso: AX=4B05h,AH=4Ch,AH=4Dh,AH=64h"OS/2",AH=8Ah,INT 2E
Format of EXEC parameter block for AL=00h,01h,04h:
Offset Size Description
00h WORD segment of environment to copy for child process (copy caller's
environment if 0000h)
02h DWORD pointer to command tail to be copied into child's PSP
06h DWORD pointer to first FCB to be copied into child's PSP
0Ah DWORD pointer to second FCB to be copied into child's PSP
0Eh DWORD (AL=01h) will hold subprogram's initial SS:SP on return
12h DWORD (AL=01h) will hold entry point (CS:IP) on return
Format of EXEC parameter block for AL=03h:
Offset Size Description
00h WORD segment at which to load overlay
02h WORD relocation factor to apply to overlay if in .EXE format
Format of EXEC parameter block for FlashTek X-32:
Offset Size Description
00h PWORD 48-bit far pointer to environment string
06h PWORD 48-bit far pointer to command tail string
Format of .EXE file header:
Offset Size Description
00h 2 BYTEs .EXE signature, either "MZ" or "ZM" (5A4Dh or 4D5Ah)
02h WORD number of bytes in last 512-byte page of executable
04h WORD total number of 512-byte pages in executable (includes any
partial last page)
06h WORD number of relocation entries
08h WORD header size in paragraphs
0Ah WORD minimum paragraphs of memory to allocation in addition to
executable's size
0Ch WORD maximum paragraphs to allocate in addition to executable's size
0Eh WORD initial SS relative to start of executable
10h WORD initial SP
12h WORD checksum (one's complement of sum of all words in executable)
14h DWORD initial CS:IP relative to start of executable
18h WORD offset within header of relocation table
40h or greater for new-format (NE,LE,LX,W3,PE,etc.) executable
1Ah WORD overlay number (normally 0000h = main program)
---new executable---
1Ch 4 BYTEs ???
20h WORD behavior bits
22h 26 BYTEs reserved for additional behavior info
3Ch DWORD offset of new executable (NE,LE,etc) header within disk file,
or 00000000h if plain MZ executable
---Borland TLINK---
1Ch 2 BYTEs ??? (apparently always 01h 00h)
1Eh BYTE signature FBh
1Fh BYTE TLINK version (major in high nybble, minor in low nybble)
20h 2 BYTEs ??? (v2.0 apparently always 72h 6Ah, v3.0+ seems always 6Ah 72h)
---ARJ self-extracting archive---
1Ch 4 BYTEs signature "RJSX" (older versions, new signature is "aRJsfX" in
the first 1000 bytes of the file)
---LZEXE 0.90 compressed executable---
1Ch 4 BYTEs signature "LZ09"
---LZEXE 0.91 compressed executable---
1Ch 4 BYTEs signature "LZ91"
---PKLITE compressed executable---
1Ch BYTE minor version number
1Dh BYTE bits 0-3: major version
bit 4: extra compression
bit 5: huge (multi-segment) file
1Eh 6 BYTEs signature "PKLITE" (followed by copyright message)
---LHarc 1.x self-extracting archive---
1Ch 4 BYTEs unused???
20h 3 BYTEs jump to start of extraction code
23h 2 BYTEs ???
25h 12 BYTEs signature "LHarc's SFX "
---LHA 2.x self-extracting archive---
1Ch 8 BYTEs ???
24h 10 BYTEs signature "LHa's SFX " (v2.10) or "LHA's SFX " (v2.13)
---TopSpeed C 3.0 CRUNCH compressed file---
1Ch DWORD 018A0001h
20h WORD 1565h
---PKARCK 3.5 self-extracting archive---
1Ch DWORD 00020001h
20h WORD 0700h
---BSA (Soviet archiver) self-extracting archive---
1Ch WORD 000Fh
1Eh BYTE A7h
---LARC self-extracting archive---
1Ch 4 BYTEs ???
20h 11 BYTEs "SFX by LARC "
---LH self-extracting archive---
1Ch 8 BYTEs ???
24h 8 BYTEs "LH's SFX "
---other linkers---
1Ch var optional information
---
N N DWORDs relocation items
Notes: if word at offset 02h is 4, it should be treated as 00h, since pre-1.10
versions of the MS linker set it that way
if both minimum and maximum allocation (offset 0Ah/0Ch) are zero, the
program is loaded as high in memory as possible
the maximum allocation is set to FFFFh by default
Format of ROM Module Header:
Offset Size Description
00h 2 BYTEs ROM signature 55h, AAh
02h BYTE size of ROM in 512-byte blocks
03h 3 BYTEs POST initialization entry point (near JMP instruction)
06h ROM Program Name List [array]
Offset Size Description
00h BYTE length of ROM program's name (00h if end of name list)
01h N BYTEs program name
N+1 3 BYTEs program entry point (near JMP instruction)
Format of new executable header:
Offset Size Description
00h 2 BYTEs "NE" (4Eh 45h) signature
02h 2 BYTEs linker version (major, then minor)
04h WORD offset from start of this header to entry table (see below)
06h WORD length of entry table in bytes
08h DWORD file load CRC (0 in Borland's TPW)
0Ch BYTE program flags
bits 0-1 DGROUP type
0 = none
1 = single shared
2 = multiple (unshared)
3 = (null)
bit 2: global initialization
bit 3: protected mode only
bit 4: 8086 instructions
bit 5: 80286 instructions
bit 6: 80386 instructions
bit 7: 80x87 instructions
0Dh BYTE application flags
bits 0-2: application type
001 full screen (not aware of Windows/P.M. API)
010 compatible with Windows/P.M. API
011 uses Windows/P.M. API
bit 3: is a Family Application (OS/2)
bit 5: 0=executable, 1=errors in image
bit 6: non-conforming program (valid stack is not maintained)
bit 7: DLL or driver rather than application
(SS:SP info invalid, CS:IP points at FAR init routine
called with AX=module handle which returns AX=0000h
on failure, AX nonzero on successful initialization)
0Eh WORD auto data segment index
10h WORD initial local heap size
12h WORD initial stack size (added to data seg, 0000h if SS <> DS)
14h DWORD program entry point (CS:IP), "CS" is index into segment table
18h DWORD initial stack pointer (SS:SP), "SS" is segment index
if SS=automatic data segment and SP=0000h, the stack pointer is
set to the top of the automatic data segment, just below the
local heap
1Ch WORD segment count
1Eh WORD module reference count
20h WORD length of nonresident names table in bytes
22h WORD offset from start of this header to segment table (see below)
24h WORD offset from start of this header to resource table
26h WORD offset from start of this header to resident names table
28h WORD offset from start of this header to module reference table
2Ah WORD offset from start of this header to imported names table
(array of counted strings, terminated with a string of length
00h)
2Ch DWORD offset from start of file to nonresident names table
30h WORD count of moveable entry point listed in entry table
32h WORD file alignment size shift count
0 is equivalent to 9 (default 512-byte pages)
34h WORD number of resource table entries
36h BYTE target operating system
00h unknown
01h OS/2
02h Windows
03h European MS-DOS 4.x
04h Windows 386
05h BOSS (Borland Operating System Services)
37h BYTE other EXE flags
bit 0: supports long filenames
bit 1: 2.X protected mode
bit 2: 2.X proportional font
bit 3: gangload area
38h WORD offset to return thunks or start of gangload area
3Ah WORD offset to segment reference thunks or length of gangload area
3Ch WORD minimum code swap area size
3Eh 2 BYTEs expected Windows version (minor version first)
Note: this header is documented in detail in the Windows 3.1 SDK Programmer's
Reference, Vol 4.
Format of Codeview trailer (at end of executable):
Offset Size Description
00h WORD signature 4E42h ('NB')
02h WORD Microsoft debug info version number
04h DWORD Codeview header offset
Format of new executable segment table record:
00h WORD offset in file (shift left by alignment shift to get byte offs)
02h WORD length of image in file (0000h = 64K)
04h WORD segment attributes (see below)
06h WORD number of bytes to allocate for segment (0000h = 64K)
Note: the first segment table entry is entry number 1
Bitfields for segment attributes:
bit 0 data segment rather than code segment
bit 1 unused???
bit 2 real mode
bit 3 iterated
bit 4 movable
bit 5 sharable
bit 6 preloaded rather than demand-loaded
bit 7 execute-only (code) or read-only (data)
bit 8 relocations (directly following code for this segment)
bit 9 debug info present
bits 10,11 80286 DPL bits
bit 12 discardable
bits 13-15 discard priority
Format of new executable entry table item (list):
Offset Size Description
00h BYTE number of entry points (00h if end of entry table list)
01h BYTE segment number (00h if end of entry table list)
02h 3N BYTEs entry records
Offset Size Description
00h BYTE flags
bit 0: exported
bit 1: single data
bits 2-7: unused???
01h WORD offset within segment
Format of new executable relocation data (immediately follows segment image):
Offset Size Description
00h WORD number of relocation items
02h 8N BYTEs relocation items
Offset Size Description
00h BYTE relocation type
00h LOBYTE
02h BASE
03h PTR
05h OFFS
0Bh PTR48
0Dh OFFS32
01h BYTE flags
bit 2: additive
02h WORD offset within segment
04h WORD target address segment
06h WORD target address offset
Format of new executable resource data:
Offset Size Description
00h WORD alignment shift count for resource data
02h N RECORDs resources
Format of resource record:
Offset Size Description
00h WORD type ID
0000h if end of resource records
>= 8000h if integer type
else offset from start of resource table to type string
02h WORD number of resources of this type
04h DWORD reserved for runtime use
08h N Resources (see below)
Note: resource type and name strings are stored immediately following the
resource table, and are not null-terminated
Format of new executable resource entry:
Offset Size Description
00h WORD offset in alignment units from start of file to contents of
the resource data
02h WORD length of resource image in bytes
04h WORD flags
bit 4: moveable
bit 5: shareable
bit 6: preloaded
06h WORD resource ID
>= 8000h if integer resource
else offset from start of resource table to resource string
08h DWORD reserved for runtime use
Notes: resource type and name strings are stored immediately following the
resource table, and are not null-terminated
strings are counted strings, with a string of length 0 indicating the
end of the resource table
Format of new executable module reference table [one bundle of entries]:
Offset Size Description
00h BYTE number of records in this bundle (00h if end of table)
01h BYTE segment indicator
00h unused
FFh movable segment, segment number is in entry
else segment number of fixed segment
02h N RECORDs
Format of segment record
Offset Size Description
00h BYTE flags
bit 0: entry is exported
bit 1: entry uses global (shared) data
bits 7-3: number of parameter words
---fixed segment---
01h WORD offset
---moveable segment---
01h 2 BYTEs INT 3F instruction (CDh 3Fh)
03h BYTE segment number
05h WORD offset
Note: table entries are numbered starting from 1
Format of new executable resident/nonresident name table entry:
Offset Size Description
00h BYTE length of string (00h if end of table)
01h N BYTEs ASCII text of string
N+1 WORD ordinal number (index into entry table)
Notes: the first string in the resident name table is the module name; the
first entry in the nonresident name table is the module description
the strings are case-sensitive; if the executable was linked with
/IGNORECASE, all strings are in uppercase
Format of Linear Executable (enhanced mode executable) header:
Offset Size Description
00h 2 BYTEs "LE" (4Ch 45h) signature (Windows)
"LX" (4Ch 58h) signature (OS/2)
02h BYTE byte order (00h = little-endian, nonzero = big-endian)
03h BYTE word order (00h = little-endian, nonzero = big-endian)
04h DWORD executable format level
08h WORD CPU type (see also INT 15/AH=C9h)
01h Intel 80286 or upwardly compatible
02h Intel 80386 or upwardly compatible
03h Intel 80486 or upwardly compatible
04h Intel Pentium (80586) or upwardly compatible
20h Intel i860 (N10) or compatible
21h Intel "N11" or compatible
40h MIPS Mark I (R2000, R3000) or compatible
41h MIPS Mark II (R6000) or compatible
42h MIPS Mark III (R4000) or compatible
0Ah WORD target operating system
01h OS/2
02h Windows
03h European DOS 4.0
04h Windows 386
0Ch DWORD module version
10h DWORD module type
bit 2: initialization (only for DLLs)
0 = global
1 = per-process
bit 4: no internal fixups in executable image
bit 5: no external fixups in executable image
bits 8,9,10:
0 = unknown
1 = incompatible with PM windowing \
2 = compatible with PM windowing > (only for
3 = uses PM windowing API / programs)
bit 13: module not loadable (only for programs)
bits 17,16,15: module type
000 program
001 library (DLL)
011 protected memory library module
100 physical device driver
110 virtual device driver
bit 30: per-process library termination
(requires valid CS:EIP, can't be set for .EXE)
14h DWORD number of memory pages
18h Initial CS:EIP
DWORD object number
DWORD offset
20h Initial SS:ESP
DWORD object number
DWORD offset
28h DWORD memory page size
2Ch DWORD (Windows LE) bytes on last page
(OS/2 LX) page offset shift count
30h DWORD fixup section size
34h DWORD fixup section checksum
38h DWORD loader section size
3Ch DWORD loader section checksum
40h DWORD offset of object table (see below)
44h DWORD object table entries
48h DWORD object page map table offset
4Ch DWORD object iterate data map offset
50h DWORD resource table offset
54h DWORD resource table entries
58h DWORD resident names table offset
5Ch DWORD entry table offset
60h DWORD module directives table offset
64h DWORD Module Directives entries
68h DWORD Fixup page table offset
6Ch DWORD Fixup record table offset
70h DWORD imported modules name table offset
74h DWORD imported modules count
78h DWORD imported procedures name table offset
7Ch DWORD per-page checksum table offset
80h DWORD data pages offset
84h DWORD preload page count
88h DWORD non-resident names table offset
8Ch DWORD non-resident names table length
90h DWORD non-resident names checksum
94h DWORD automatic data object
98h DWORD debug information offset
9Ch DWORD debug information length
A0h DWORD preload instance pages number
A4h DWORD demand instance pages number
A8h DWORD extra heap allocation
ACh 20 BYTEs reserved
C0h WORD device ID (MS-Windows VxD only)
C2h WORD DDK version (MS-Windows VxD only)
Note: used by EMM386.EXE, QEMM, and Windows 3.0 Enhanced Mode drivers
Format of object table entry:
Offset Size Description
00h DWORD virtual size in bytes
04h DWORD relocation base address
08h DWORD object flags (see below)
0Ch DWORD page map index
10h DWORD page map entries
14h 4 BYTEs reserved??? (apparently always zeros)
Bitfields for object flags:
bit 0 readable
bit 1 writable
bit 2 executable
bit 3 resource
bit 4 discardable
bit 5 shared
bit 6 preloaded
bit 7 invalid
bit 8-9 type
00 normal
01 zero-filled
10 resident
11 resident and contiguous
bit 10 resident and long-lockable
bit 11 reserved
bit 12 16:16 alias required
bit 13 "BIG" (Huge: 32-bit)
bit 14 conforming
bit 15 "OBJECT_I/O_PRIVILEGE_LEVEL"
bits 16-31 reserved
Format of object page map table entry:
Offset Size Description
00h BYTE ??? (usually 00h)
01h WORD (big-endian) index to fixup table
0000h if no relocation info
03h BYTE type (00h hard copy in file, 03h some relocation needed)
Format of resident names table entry:
Offset Size Description
00h BYTE length of name
01h N BYTEs name
N+1 3 BYTEs ???
Format of LE linear executable entry table:
Offset Size Description
00h BYTE number of entries in table
01h 10 BYTEs per entry
Offset Size Description
00h BYTE bit flags
bit 0: non-empty bundle
bit 1: 32-bit entry
01h WORD object number
03h BYTE entry type flags
bit 0: exported
bit 1: uses single data rather than instance
bit 2: reserved
bits 3-7: number of stack parameters
04h DWORD offset of entry point
08h 2 BYTEs ???
Note: empty bundles (bit flags at 00h = 00h) are used to skip unused indices,
and do not contain the remaining nine bytes
Format of LX linear executable entry table [array]:
Offset Size Description
00h BYTE number of bundles following (00h = end of entry table)
01h BYTE bundle type
00h empty
01h 16-bit entry
02h 286 callgate entry
03h 32-bit entry
04h forwarder entry
bit 7 set if additional parameter typing information is present
---bundle type 00h---
no additional fields
---bundle type 01h---
02h WORD object number
04h BYTE entry flags
bit 0: exported
bits 7-3: number of stack parameters
05h WORD offset of entry point in object (shifted by page size shift)
---bundle type 02h---
02h WORD object number
04h BYTE entry flags
bit 0: exported
bits 7-3: number of stack parameters
05h WORD offset of entry point in object
07h WORD reserved for callgate selector (used by loader)
---bundle type 03h---
02h WORD object number
04h BYTE entry flags
bit 0: exported
bits 7-3: number of stack parameters
05h DWORD offset of entry point in object
---bundle type 04h---
02h WORD reserved
04h BYTE forwarder flags
bit 0: import by ordinal
bits 7-1 reserved
05h WORD module ordinal
(forwarder's index into Import Module Name table)
07h DWORD procedure name offset or import ordinal number
Note: all fields after the first two bytes are repeated N times
Bitfields for linear executable fixup type:
bit 7 ordinal is BYTE rather than WORD
bit 6 16-bit rather than 8-bit object number/module ordinal
bit 5 addition with DWORD rather than WORD
bit 4 relocation info has size with new two bytes at end
bit 3 reserved (0)
bit 2 set if add to destination, clear to replace destination
bits 1-0 type
00 internal fixup
01 external fixup, imported by ordinal
10 external fixup, imported by name
11 internal fixup via entry table
Format of linear executable fixup record:
Offset Size Description
00h BYTE type
bits 7-4: modifier (0001 single, 0011 multiple)
bits 3-0: type
0000 byte offset
0010 word segment
0011 16-bit far pointer (DWORD)
0101 16-bit offset
0110 32-bit far pointer (PWORD)
0111 32-bit offset
1000 near call or jump, WORD/DWORD based on seg attrib
01h BYTE linear executable fixup type (see above)
---if single type---
02h WORD offset within page
04h relocation information
---internal fixup---
BYTE object number
---external,ordinal---
BYTE one-based module number in Import Module table
BYTE/WORD ordinal number
WORD/DWORD value to add (only present if modifier bit 4 set)
---external,name---
BYTE one-based module number in Import Module table
WORD offset in Import Procedure names
WORD/DWORD value to add (only present if modifier bit 4 set)
---if multiple type---
02h BYTE number of items
03h var relocation info as for "single" type (see above)
N WORDs offsets of items to relocate
Format of old Phar Lap .EXP file header:
Offset Size Description
00h 2 BYTEs "MP" (4Dh 50h) signature
02h WORD remainder of image size / page size (page size = 512h)
04h WORD size of image in pages
06h WORD number of relocation items
08h WORD header size in paragraphs
0Ah WORD minimum number of extra 4K pages to be allocated at the end
of program, when it is loaded
0Ch WORD maximum number of extra 4K pages to be allocated at the end
of program, when it is loaded
0Eh DWORD initial ESP
12h WORD word checksum of file
14h DWORD initial EIP
18h WORD offset of first relocation item
1Ah WORD overlay number
1Ch WORD ??? (wants to be 1)
Format of new Phar Lap .EXP file header:
Offset Size Description
00h 2 BYTEs signature ("P2" for 286 .EXP executable, "P3" for 386 .EXP)
02h WORD level (01h flat-model file, 02h multisegmented file)
04h WORD header size
06h DWORD file size in bytes
0Ah WORD checksum
0Ch DWORD offset of run-time parameters within file
10h DWORD size of run-time parameters in bytes
14h DWORD offset of relocation table within file
18h DWORD size of relocation table in bytes
1Ch DWORD offset of segment information table within file
20h DWORD size of segment information table in bytes
24h WORD size of segment information table entry in bytes
26h DWORD offset of load image within file
2Ah DWORD size of load image on disk
2Eh DWORD offset of symbol table within file
32h DWORD size of symbol table in bytes
36h DWORD offset of GDT within load image
3Ah DWORD size of GDT in bytes
3Eh DWORD offset of LDT within load image
42h DWORD size of LDT in bytes
46h DWORD offset of IDT within load image
4Ah DWORD size of IDT in bytes
4Eh DWORD offset of TSS within load image
52h DWORD size of TSS in bytes
56h DWORD minimum number of extra bytes to be allocated at end of program
(level 1 executables only)
5Ah DWORD maximum number of extra bytes to be allocated at end of program
(level 1 executables only)
5Eh DWORD base load offset (level 1 executables only)
62h DWORD initial ESP
66h WORD initial SS
68h DWORD initial EIP
6Ch WORD initial CS
6Eh WORD initial LDT
70h WORD initial TSS
72h WORD flags
bit 0: load image is packed
bit 1: 32-bit checksum is present
bits 4-2: type of relocation table
74h DWORD memory requirements for load image
78h DWORD 32-bit checksum (optional)
7Ch DWORD size of stack segment in bytes
80h 256 BYTEs reserved (0)
Format of Phar Lap segment information table entry:
Offset Size Description
00h WORD selector number
02h WORD flags
04h DWORD base offset of selector
08h DWORD minimum number of extra bytes to be allocated to the segment
Format of 386|DOS-Extender run-time parameters:
Offset Size Description
00h 2 BYTEs signature "DX" (44h 58h)
02h WORD minimum number of real-mode params to leave free at run time
04h WORD maximum number of real-mode params to leave free at run time
06h WORD minimum interrupt buffer size in KB
08h WORD maximum interrupt buffer size in KB
0Ah WORD number of interrupt stacks
0Ch WORD size in KB of each interrupt stack
0Eh DWORD offset of byte past end of real-mode code and data
12h WORD size in KB of call buffers
14h WORD flags
bit 0: file is virtual memory manager
bit 1: file is a debugger
16h WORD unprivileged flag (if nonzero, executes at ring 1, 2, or 3)
18h 104 BYTEs reserved (0)
Format of Phar Lap repeat block header:
Offset Size Description
00h WORD byte count
02h BYTE repeat string length
Format of Borland debugging information header (following load image):
Offset Size Description
00h WORD signature 52FBh
02h WORD version ID
04h DWORD size of name pool in bytes
08h WORD number of names in namem pool
0Ah WORD number of type entries
0Ch WORD number of structure members
0Eh WORD number of symbols
10h WORD number of global symbols
12h WORD number of modules
14h WORD number of locals (optional)
16h WORD number of scopes in table
18h WORD number of line-number entries
1Ah WORD number of include files
1Ch WORD number of segment records
1Eh WORD number of segment/file correlations
20h DWORD size of load image after removing uninitialized data and debug
info
24h DWORD debugger hook; pointer into debugged program whose meaning
depends on program flags
28h BYTE program flags
bit 0: case-sensitive link
bit 1: pascal overlay program
29h WORD no longer used
2Bh WORD size of data pool in bytes
2Dh BYTE padding
2Eh WORD size of following header extension (currently 00h, 10h, or 20h)
30h WORD number of classes
32h WORD number of parents
34h WORD number of global classes (currently unused)
36h WORD number of overloads (currently unused)
38h WORD number of scope classes
3Ah WORD number of module classes
3Ch WORD number of coverage offsets
3Eh DWORD offset relative to symbol base of name pool
42h WORD number of browser information records
44h WORD number of optimized symbol records
46h WORD debugging flags
48h 8 BYTEs padding
Note: additional information on the Borland debugging info may be found in
Borland's Open Architecture Handbook
--------U-214B-------------------------------
INT 21 - ELRES v1.0 only - INSTALLATION CHECK
AH = 4Bh
DS:DX = 0000h:0000h
Return: ES:BX -> ELRES history structure (see AH=2Bh/CX=454Ch)
DX = DABEh (signature, DAve BEnnett)
Program: ELRES is an MS-DOS return code (errorlevel) recorder by David H.
Bennett
SeeAlso: AH=2Bh/CX=454Ch
--------v-214B04-----------------------------
INT 21 - VIRUS - "MG", "699"/"Thirteen Minutes" - INSTALLATION CHECK
AX = 4B04h
Return: CF clear if "MG" resident
AX = 044Bh if "699"/"Thirteen Minutes" resident
SeeAlso: AX=4243h,AX=4B21h
--------D-214B05-----------------------------
INT 21 - DOS 5+ - SET EXECUTION STATE
AX = 4B05h
DS:DX -> execution state structure (see below)
Return: CF clear if successful
AX = 0000h
CF set on error
AX = error code (see AH=59h)
Note: used by programs which intercept AX=4B00h to prepare new programs for
execution (including setting the DOS version number). No DOS, BIOS
or other software interrupt may be called after return from this call
before commencement of the child process. If DOS is running in the
HMA, A20 is turned off on return from this call.
SeeAlso: AH=4Bh
Format of execution state structure:
Offset Size Description
00h WORD reserved (00h)
02h WORD type flags
bit 0: program is an .EXE
bit 1: program is an overlay
04h DWORD pointer to ASCIZ name of program file
08h WORD PSP segment of new program
0Ah DWORD starting CS:IP of new program
0Eh DWORD program size including PSP
--------v-214B20-----------------------------
INT 21 - VIRUS - "Holocaust"/"Telefonica" - ???
AX = 4B20h
SeeAlso: AX=4B04h,AX=4B21h
--------v-214B21-----------------------------
INT 21 C - VIRUS - "Holocaust"/"Telefonica" - ???
AX = 4B21h
Note: called at completion of virus installation
SeeAlso: AX=4B04h,AX=4B20h,AX=4B25h
--------v-214B25-----------------------------
INT 21 - VIRUS - "1063"/"Mono" - INSTALLATION CHECK
AX = 4B25h
Return: DI = 1234h if resident
SeeAlso: AX=4B21h,AX=4B40h
--------v-214B40-----------------------------
INT 21 - VIRUS - "Plastique"/"AntiCad" - INSTALLATION CHECK
AX = 4B40h
Return: AX = 5678h if resident
SeeAlso: AX=4B25h,AX=4B41h,AX=4B4Ah
--------v-214B41-----------------------------
INT 21 - VIRUS - "Plastique"/"AntiCad" - ???
AX = 4B41h
???
Return: ???
SeeAlso: AX=4B40h
--------v-214B4A-----------------------------
INT 21 - VIRUS - "Jabberwocky" - INSTALLATION CHECK
AX = 4B4Ah
Return: AL = 57h if resident
SeeAlso: AX=4B40h,AX=4B4Bh
--------v-214B4B-----------------------------
INT 21 - VIRUS - "Horse-2" - INSTALLATION CHECK
AX = 4B4Bh
Return: CF clear if resident
SeeAlso: AX=4B4Ah,AX=4B4Dh
--------v-214B4D-----------------------------
INT 21 - VIRUS - "Murphy-2", "Patricia"/"Smack" - INSTALLATION CHECK
AX = 4B4Dh
Return: CF clear if resident
SeeAlso: AX=4B4Ah,AX=4B50h
--------v-214B50-----------------------------
INT 21 - VIRUS - "Plastique-2576"/"AntiCad-2576" - INSTALLATION CHECK
AX = 4B50h
Return: AX = 1234h if resident
SeeAlso: AX=4B4Dh,AX=4B53h,AX=4B60h
--------v-214B53-----------------------------
INT 21 - VIRUS - "Horse" - INSTALLATION CHECK
AX = 4B53h
Return: CF clear if resident
SeeAlso: AX=4B50h,AX=4B55h
--------v-214B55-----------------------------
INT 21 - VIRUS - "Sparse" - INSTALLATION CHECK
AX = 4B55h
Return: AX = 1231h if resident
SeeAlso: AX=4B53h,AX=4B59h
--------v-214B59-----------------------------
INT 21 - VIRUS - "Murphy-1", "Murphy-4" - INSTALLATION CHECK
AX = 4B59h
Return: CF clear if resident
SeeAlso: AX=4B50h,AX=4B5Eh
--------v-214B5E-----------------------------
INT 21 - VIRUS - "Brothers" - INSTALLATION CHECK
AX = 4B5Eh
Return: CF clear if resident
SeeAlso: AX=4B59h,AX=4B87h
--------v-214B60-----------------------------
INT 21 - VIRUS - "Plastique-2576"/"AntiCad-2576" - ???
AX = 4B60h
???
Return: ???
SeeAlso: AX=4B50h
--------v-214B87-----------------------------
INT 21 - VIRUS - "Shirley" - INSTALLATION CHECK
AX = 4B87h
Return: AX = 6663h if resident
SeeAlso: AX=4B5Eh,AX=4B95h
--------v-214B95-----------------------------
INT 21 - VIRUS - "Zherkov-1882" - INSTALLATION CHECK
AX = 4B95h
Return: AX = 1973h if resident
SeeAlso: AX=4B87h,AX=4BA7h
--------v-214BA7-----------------------------
INT 21 - VIRUS - "1876"/"Dash-em" - INSTALLATION CHECK
AX = 4BA7h
Return: AX = B459h if resident
SeeAlso: AX=4B95h,AX=4BAAh
--------v-214BAA-----------------------------
INT 21 - VIRUS - "Nomenklatura" - INSTALLATION CHECK
AX = 4BAAh
Return: CF clear if resident
SeeAlso: AX=4BA7h,AX=4BAFh
--------v-214BAF-----------------------------
INT 21 - VIRUS - "948"/"Screenplus1", "Magnitogorsk" - INSTALLATION CHECK
AX = 4BAFh
Return: AL = AFh if "Magnitogorsk" resident
AL = FAh if "948"/"Screenplus1" resident
SeeAlso: AX=4BAAh,AX=4BDDh
--------v-214BDD-----------------------------
INT 21 - VIRUS - "Lozinsky"/"Zherkov" - INSTALLATION CHECK
AX = 4BDDh
Return: AX = 1234h
SeeAlso: AX=4BAFh,AX=4BFEh
--------v-214BEE-----------------------------
INT 21 - F-DRIVER.SYS v1.14+ - GRAB INT 21
AX = 4BEEh
Return: AX = 1234h if grab successful
= 2345h if failed (INT 21 grabbed previously)
Notes: F-DRIVER.SYS is part of the F-PROT virus/trojan protection package by
Fridrik Skulason
when called the first time, this function moves the INT 21 monitoring
code from its original location in the INT 21 chain to be the first
thing called by INT 21. This is the mechanism used by F-NET.
SeeAlso: INT 2F/AX=4653h
--------k-214BF0-----------------------------
INT 21 - DIET v1.10+ (Overlay Mode) - INSTALLATION CHECK
AX = 4BF0h
Return: CF clear if installed
AX = 899Dh
Program: DIET is an executable-compression program by Teddy Matsumoto
SeeAlso: AX=37D0h,AX=4BF1h
--------k-214BF1-----------------------------
INT 21 - DIET v1.10+ (Overlay Mode) - EXPAND PROGRAM???
AX = 4BF1h
Return: ???
SeeAlso: AX=37D0h,AX=4BF0h
--------v-214BFE-----------------------------
INT 21 - VIRUS - "Hitchcock", "Dark Avenger-1028", "1193" - INSTALLATION CHECK
AX = 4BFEh
Return: AX = 1234h if "Hitchcock" resident
AX = ABCDh if "1193"/"Copyright" resident
DI = 55BBh if "Dark Avenger-1028" resident
SeeAlso: AX=4BDDh,AX=4BFFh"Justice"
--------v-214BFF-----------------------------
INT 21 - VIRUS - "USSR-707", "Justice", "Europe 92" - INSTALLATION CHECK
AX = 4BFFh
Return: BL = FFh if "USSR-707" resident
DI = 55AAh if "Justice" resident
CF clear if "Europe 92" resident
SeeAlso: AX=4BFEh,AX=4BFFh"Cascade",AX=5252h
--------v-214BFFSI0000-----------------------
INT 21 - VIRUS - "Cascade" - INSTALLATION CHECK
AX = 4BFFh
SI = 0000h
DI = 0000h
Return: DI = 55AAh if installed
SeeAlso: AX=4BFFh"Justice",AX=5252h
--------D-214C-------------------------------
INT 21 - DOS 2+ - "EXIT" - TERMINATE WITH RETURN CODE
AH = 4Ch
AL = return code
Return: never returns
Notes: unless the process is its own parent (see AH=26h, offset 16h in PSP),
all open files are closed and all memory belonging to the process
is freed
all network file locks should be removed before calling this function
SeeAlso: AH=00h,AH=26h,AH=4Bh,AH=4Dh,INT 15/AH=12h/BH=02h,INT 20,INT 22
SeeAlso: INT 60/DI=0601h
----------214C57-----------------------------
INT 21 - Headroom - ???
AX = 4C57h
DS:DX -> target address
Note: jumps to target address instead of terminating program
SeeAlso: AX=5758h
--------D-214D-------------------------------
INT 21 - DOS 2+ - GET RETURN CODE (ERRORLEVEL)
AH = 4Dh
Return: AH = termination type
00h normal (INT 20,INT 21/AH=00h, or INT 21/AH=4Ch)
01h control-C abort
02h critical error abort
03h terminate and stay resident (INT 21/AH=31h or INT 27)
AL = return code
Notes: the word in which DOS stores the return code is cleared after being
read by this function, so the return code can only be retrieved once
COMMAND.COM stores the return code of the last external command it
executed as ERRORLEVEL
this call should not be used if the child was started with AX=4B04h;
use AH=8Ah instead
the following sequence will close a Virtual DOS Machine under OS/2 2.0:
MOV AH,4Dh
INT 21h
HLT
DB 02h,0FDh
This sequence is the only way to close a specific VDM which was
booted from floppy or a disk image.
SeeAlso: AH=4Bh,AH=4Ch,AH=8Ah
--------D-214E-------------------------------
INT 21 - DOS 2+ - "FINDFIRST" - FIND FIRST MATCHING FILE
AH = 4Eh
AL = special flag for use by APPEND (see note below)
CX = file attribute mask (see AX=4301h) (bits 0 and 5 ignored)
0088h (Novell DOS 7) find first deleted file
DS:DX -> ASCIZ file specification (may include path and wildcards)
Return: CF clear if successful
[DTA] = FindFirst data block (see below)
CF set on error
AX = error code (02h,03h,12h) (see AH=59h)
Notes: for search attributes other than 08h, all files with at MOST the
specified combination of hidden, system, and directory attributes
will be returned. Under DOS 2.x, searching for attribute 08h
(volume label) will also return normal files, while under DOS 3+
only the volume label (if any) will be returned.
this call also returns successfully if given the name of a character
device without wildcards. DOS 2.x returns attribute 00h, size 0,
and the current date and time. DOS 3+ returns attribute 40h and the
current date and time.
immediately after an INT 2F/AX=B711h (APPEND return found name), the
name at DS:DX will be overwritten; if AL=00h on entry, the actual
found pathname will be stored, otherwise, the actual found path
will be prepended to the original filespec without a path.
under LANtastic, this call may be used to obtain a list of a server's
shared resources by searching for "\\SERVER\*.*"; a list of printer
resources may be obtained by searching for "\\SERVER\@*.*"
under the FlashTek X-32 DOS extender, the filespec pointer is in DS:EDX
BUGS: under DOS 3.x and 4.x, the second and subsequent calls to this function
with a character device name (no wildcards) and search attributes
which include the volume-label bit (08h) will fail unless there is
an intervening DOS call which implicitly or explicity performs a
directory search without the volume-label bit. Such implicit
searches are performed by CREATE (AH=3Ch), OPEN (AH=3Dh), UNLINK
(AH=41h), and RENAME (AH=56h)
DR-DOS 3.41 and 5.0 return the Directory attribute for the volume label
SeeAlso: AH=11h,AH=4Fh,AX=4301h,AH=71h,INT 2F/AX=111Bh,INT 2F/AX=B711h
Format of FindFirst data block:
Offset Size Description
---PC-DOS 3.10, PC-DOS 4.01, MS-DOS 3.2/3.3/5.0---
00h BYTE drive letter (bits 0-6), remote if bit 7 set
01h 11 BYTEs search template
0Ch BYTE search attributes
---DOS 2.x (and some DOS 3.x???)---
00h BYTE search attributes
01h BYTE drive letter
02h 11 BYTEs search template
---WILDUNIX.COM---
00h 12 BYTEs 15-character wildcard search pattern and drive letter (packed)
0Ch BYTE search attributes
---DOS 2.x and most 3.x---
0Dh WORD entry count within directory
0Fh DWORD pointer to DTA???
13h WORD cluster number of start of parent directory
---PC-DOS 4.01, MS-DOS 3.2/3.3/5.0---
0Dh WORD entry count within directory
0Fh WORD cluster number of start of parent directory
11h 4 BYTEs reserved
---all versions, documented fields---
15h BYTE attribute of file found
16h WORD file time
bits 11-15: hour
bits 5-10: minute
bits 0-4: seconds/2
18h WORD file date
bits 9-15: year-1980
bits 5-8: month
bits 0-4: day
1Ah DWORD file size
1Eh 13 BYTEs ASCIZ filename+extension
--------f-214E-------------------------------
INT 21 - WILDUNIX.COM internal - INSTALLATION CHECK
AH = 4Eh
DS:DX = 0000h:0000h
Return: AH = 99h if installed
Program: WILDUNIX.COM is a resident Unix-style wildcard expander by Steve
Hosgood and Terry Barnaby
--------D-214F-------------------------------
INT 21 - DOS 2+ - "FINDNEXT" - FIND NEXT MATCHING FILE
AH = 4Fh
[DTA] = data block from previous FindFirst or FindNext call
Return: CF clear if successful
CF set on error
AX = error code (12h) (see AH=59h)
Note: under Novell DOS 7, if the FindFirst call (AH=4Eh) had CX=0088h, then
the next matching deleted file will be returned
BUG: DR-DOS 3.41 and 5.0 return the Directory attribute for the volume label
SeeAlso: AH=12h,AH=4Eh,AH=71h,AH=72h
--------D-2150-------------------------------
INT 21 - DOS 2+ internal - SET CURRENT PROCESS ID (SET PSP ADDRESS)
AH = 50h
BX = segment of PSP for new process
Notes: DOS uses the current PSP address to determine which processes own files
and memory; it corresponds to process identifiers used by other OSs
under DOS 2.x, this function cannot be invoked inside an INT 28h
handler without setting the Critical Error flag
under MS-DOS 3+ and DR-DOS 3.41+, this function does not use any of
the DOS-internal stacks and may thus be called at any time, even
during another INT 21h call
some Microsoft applications such as Quick C 2.51 use segments of 0000h
and FFFFh and direct access to the SDA (see AX=5D06h) to test whether
they are running under MS-DOS rather than a compatible OS; although
one should only call this function with valid PSP addresses, any
program hooking it should be prepared to handle invalid addresses
supported by OS/2 compatibility box
this call was undocumented prior to the release of DOS 5.0
SeeAlso: AH=26h,AH=51h,AH=62h
--------D-2151-------------------------------
INT 21 - DOS 2+ internal - GET CURRENT PROCESS ID (GET PSP ADDRESS)
AH = 51h
Return: BX = segment of PSP for current process
Notes: DOS uses the current PSP address to determine which processes own files
and memory; it corresponds to process identifiers used by other OSs
under DOS 2.x, this function cannot be invoked inside an INT 28h
handler without setting the Critical Error flag
under DOS 3+, this function does not use any of the DOS-internal stacks
and may thus be called at any time, even during another INT 21h call
supported by OS/2 compatibility box
identical to the documented AH=62h
this call was undocumented prior to the release of DOS 5.0
SeeAlso: AH=26h,AH=50h,AH=62h
--------D-2152-------------------------------
INT 21 U - DOS 2+ internal - "SYSVARS" - GET LIST OF LISTS
AH = 52h
Return: ES:BX -> DOS list of lists
Notes: partially supported by OS/2 v1.1 compatibility box (however, most
pointers are FFFFh:FFFFh, LASTDRIVE is FFh, and the NUL header "next"
pointer is FFFFh:FFFFh).
on return, ES points at the DOS data segment (see also INT 2F/AX=1203h)
SeeAlso: INT 2F/AX=1203h
Format of List of Lists:
Offset Size Description
-24 WORD (DOS 3.1+) contents of CX from INT 21/AX=5E01h
-22 WORD (DOS ???+) LRU counter for FCB caching
-20 WORD (DOS ???+) LRU counter for FCB opens
-18 DWORD (DOS ???+) address of OEM function handler (see INT 21/AH=F8h)
FFFFh:FFFFh if not installed or not available
-14 WORD (DOS ???+) offset in DOS CS of code to return from INT 21 call
-12 WORD (DOS 3.1+) sharing retry count (see AX=440Bh)
-10 WORD (DOS 3.1+) sharing retry delay (see AX=440Bh)
-8 DWORD (DOS 3+) pointer to current disk buffer
-4 WORD (DOS 3+) pointer in DOS data segment of unread CON input
when CON is read via a handle, DOS reads an entire line,
and returns the requested portion, buffering the rest
for the next read. 0000h indicates no unread input
-2 WORD segment of first memory control block
00h DWORD pointer to first Drive Parameter Block (see AH=32h)
04h DWORD pointer to first System File Table (see below)
08h DWORD pointer to active CLOCK$ device's header (most recently loaded
driver with CLOCK bit set)
0Ch DWORD pointer to active CON device's header (most recently loaded
driver with STDIN bit set)
---DOS 2.x---
10h BYTE number of logical drives in system
11h WORD maximum bytes/block of any block device
13h DWORD pointer to first disk buffer (see below)
17h 18 BYTEs actual NUL device driver header (not a pointer!)
NUL is always the first device on DOS's linked list of device
drivers. (see below)
---DOS 3.0---
10h BYTE number of block devices
11h WORD maximum bytes/block of any block device
13h DWORD pointer to first disk buffer (see below)
17h DWORD pointer to array of current directory structures (see below)
1Bh BYTE value of LASTDRIVE command in CONFIG.SYS (default 5)
1Ch DWORD pointer to STRING= workspace area
20h WORD size of STRING area (the x in STRING=x from CONFIG.SYS)
22h DWORD pointer to FCB table
26h WORD the y in FCBS=x,y from CONFIG.SYS
28h 18 BYTEs actual NUL device driver header (not a pointer!)
NUL is always the first device on DOS's linked list of device
drivers. (see below)
---DOS 3.1-3.3---
10h WORD maximum bytes per sector of any block device
12h DWORD pointer to first disk buffer in buffer chain (see below)
16h DWORD pointer to array of current directory structures (see below)
1Ah DWORD pointer to system FCB tables (see below)
1Eh WORD number of protected FCBs (the y in the CONFIG.SYS FCBS=x,y)
20h BYTE number of block devices installed
21h BYTE number of available drive letters (largest of 5, installed
block devices, and CONFIG.SYS LASTDRIVE=). Also size of
current directory structure array.
22h 18 BYTEs actual NUL device driver header (not a pointer!)
NUL is always the first device on DOS's linked list of device
drivers. (see below)
34h BYTE number of JOIN'ed drives
---DOS 4.x---
10h WORD maximum bytes per sector of any block device
12h DWORD pointer to disk buffer info record (see below)
16h DWORD pointer to array of current directory structures (see below)
1Ah DWORD pointer to system FCB tables (see below)
1Eh WORD number of protected FCBs (the y in the CONFIG.SYS FCBS=x,y)
(always 00h for DOS 5.0)
20h BYTE number of block devices installed
21h BYTE number of available drive letters (largest of 5, installed
block devices, and CONFIG.SYS LASTDRIVE=). Also size of
current directory structure array.
22h 18 BYTEs actual NUL device driver header (not a pointer!)
NUL is always the first device on DOS's linked list of device
drivers. (see below)
34h BYTE number of JOIN'ed drives
35h WORD pointer within IBMDOS code segment to list of special program
names (see below)
(always 0000h for DOS 5.0)
37h DWORD pointer to FAR routine for resident IFS utility functions
(see below)
may be called by any IFS driver which does not wish to
service functions 20h or 24h-28h itself
3Bh DWORD pointer to chain of IFS (installable file system) drivers
3Fh WORD the x in BUFFERS x,y (rounded up to multiple of 30 if in EMS)
41h WORD number of lookahead buffers (the y in BUFFERS x,y)
43h BYTE boot drive (1=A:)
44h BYTE flag: 01h to use DWORD moves (80386+), 00h otherwise
45h WORD extended memory size in KB
---DOS 5.0-6.0---
10h 39 BYTEs as for DOS 4.x (see above)
37h DWORD pointer to SETVER program list or 0000h:0000h
3Bh WORD (DOS=HIGH) offset in DOS CS of function to fix A20 control
when executing special .COM format
3Dh WORD PSP of most-recently EXECed program if DOS in HMA, 0000h if low
3Fh 8 BYTEs as for DOS 4.x (see above)
Format of memory control block (see also below):
Offset Size Description
00h BYTE block type: 5Ah if last block in chain, otherwise 4Dh
01h WORD PSP segment of owner or
0000h if free
0006h if DR-DOS XMS UMB
0007h if DR-DOS excluded upper memory ("hole")
0008h if belongs to DOS
FFFAh if 386MAX UMB control block (see AX=4402h"386MAX")
FFFDh if 386MAX locked-out memory
FFFEh if 386MAX UMB (immediately follows its control block)
FFFFh if 386MAX 6.01 device driver
03h WORD size of memory block in paragraphs
05h 3 BYTEs unused by MS-DOS
(386MAX) if locked-out block, region start/prev region end
---DOS 2.x,3.x---
08h 8 BYTEs unused
---DOS 4+ ---
08h 8 BYTEs ASCII program name if PSP memory block or DR-DOS UMB,
else garbage
null-terminated if less than 8 characters
Notes: the next MCB is at segment (current + size + 1)
under DOS 3.1+, the first memory block is the DOS data segment,
containing installable drivers, buffers, etc. Under DOS 4+ it is
divided into subsegments, each with its own memory control block
(see below), the first of which is at offset 0000h.
for DOS 5+, blocks owned by DOS may have either "SC" or "SD" in bytes
08h and 09h. "SC" is system code or locked-out inter-UMB memory,
"SD" is system data, device drivers, etc.
Some versions of DR-DOS use only seven characters of the program name,
placing a NUL in the eighth byte.
Format of MS-DOS 5+ UMB control block:
Offset Size Description
00h BYTE type: 5Ah if last block in chain, 4Dh otherwise
01h WORD first available paragraph in UMB if control block at start
of UMB, 000Ah if control block at end of UMB
03h WORD length in paragraphs of following UMB or locked-out region
05h 3 BYTEs unused
08h 8 BYTEs block type name: "UMB" if start block, "SM" if end block in UMB
Format of STARLITE (General Software's Embedded DOS) memory control block:
Offset Size Description
00h BYTE block type: 5Ah if last block in chain, otherwise 4Dh
01h WORD PSP segment of owner, 0000h if free, 0008h if belongs to DOS
03h WORD size of memory block in paragraphs
05h BYTE unused
06h WORD segment address of next memory control block (0000h if last)
08h WORD segment address of previous memory control block or 0000h
0Ah 6 BYTEs reserved
Format of DOS 4+ data segment subsegment control blocks:
Offset Size Description
00h BYTE subsegment type (blocks typically appear in this order)
"D" device driver
"E" device driver appendage
"I" IFS (Installable File System) driver
"F" FILES= control block storage area (for FILES>5)
"X" FCBS= control block storage area, if present
"C" BUFFERS EMS workspace area (if BUFFERS /X option used)
"B" BUFFERS= storage area
"L" LASTDRIVE= current directory structure array storage area
"S" STACKS= code and data area, if present (see below)
"T" INSTALL= transient code
01h WORD paragraph of subsegment start (usually the next paragraph)
03h WORD size of subsegment in paragraphs
05h 3 BYTEs unused
08h 8 BYTEs for types "D" and "I", base name of file from which the driver
was loaded (unused for other types)
Format of data at start of STACKS code segment (if present):
Offset Size Description
00h WORD ???
02h WORD number of stacks (the x in STACKS=x,y)
04h WORD size of stack control block array (should be 8*x)
06h WORD size of each stack (the y in STACKS=x,y)
08h DWORD pointer to STACKS data segment
0Ch WORD offset in STACKS data segment of stack control block array
0Eh WORD offset in STACKS data segment of last element of that array
10h WORD offset in STACKS data segment of the entry in that array for
the next stack to be allocated (initially same as value in 0Eh
and works its way down in steps of 8 to the value in 0Ch as
hardware interrupts pre-empt each other)
Note: the STACKS code segment data may, if present, be located as follows:
DOS 3.2: The code segment data is at a paragraph boundary fairly early
in the IBMBIO segment (seen at 0070:0190h)
DOS 3.3: The code segment is at a paragraph boundary in the DOS data
segment, which may be determined by inspecting the segment
pointers of the vectors for those of interrupts 02h, 08h-0Eh,
70h, 72-77h which have not been redirected by device drivers or
TSRs.
DOS 4+ Identified by sub-segment control block type "S" within the DOS
data segment.
SeeAlso: INT B4"STACKMAN"
Format of array elements in STACKS data segment:
Offset Size Description
00h BYTE status: 00h=free, 01h=in use, 03h=corrupted by overflow of
higher stack.
01h BYTE not used
02h WORD previous SP
04h WORD previous SS
06h WORD ptr to word at top of stack (new value for SP). The word at the
top of the stack is preset to point back to this control block.
SHARE.EXE hooks (DOS 3.1-6.00):
(offsets from first system file table--pointed at by ListOfLists+04h)
Offset Size Description
-3Ch DWORD pointer to FAR routine for ???
Note: not called by MS-DOS 3.3, set to 0000h:0000h by
SHARE 3.3+
-38h DWORD pointer to FAR routine called on opening file
on call, internal DOS location points at filename(see AX=5D06h)
Return: CF clear if successful
CF set on error
AX = DOS error code (24h) (see AH=59h)
Note: SHARE directly accesses DOS-internal data to get name of
file just opened
-34h DWORD pointer to FAR routine called on closing file
ES:DI -> system file table
Note: does something to every Record Lock Record for file
-30h DWORD pointer to FAR routine to close all files for given computer
(called by AX=5D03h)
-2Ch DWORD pointer to FAR routine to close all files for given process
(called by AX=5D04h)
-28h DWORD pointer to FAR routine to close file by name
(called by AX=5D02h)
DS:SI -> DOS parameter list (see AX=5D00h)
DPL's DS:DX -> name of file to close
Return: CF clear if successful
CF set on error
AX = DOS error code (03h) (see AH=59h)
-24h DWORD pointer to FAR routine to lock region of file
call with BX = file handle
---DOS 3.x---
CX:DX = starting offset
SI:AX = size
---DOS 4+---
DS:DX -> lock range
DWORD start offset
DWORD size in bytes
Return: CF set on error
AL = DOS error code (21h) (see AH=59h)
Note: not called if file is marked as remote
-20h DWORD pointer to FAR routine to unlock region of file
call with BX = file handle
---DOS 3.x---
CX:DX = starting offset
SI:AX = size
---DOS 4+---
DS:DX -> lock range
DWORD start offset
DWORD size in bytes
Return: CF set on error
AL = DOS error code (21h) (see AH=59h)
Note: not called if file is marked as remote
-1Ch DWORD pointer to FAR routine to check if file region is locked
call with ES:DI -> system file table entry for file
CX = length of region from current position in file
Return: CF set if any portion of region locked
AX = 0021h
-18h DWORD pointer to FAR routine to get open file list entry
(called by AX=5D05h)
call with DS:SI -> DOS parameter list (see AX=5D00h)
DPL's BX = index of sharing record
DPL's CX = index of SFT in SFT chain of sharing rec
Return: CF set on error or not loaded
AX = DOS error code (12h) (see AH=59h)
CF clear if successful
ES:DI -> filename
CX = number of locks owned by specified SFT
BX = network machine number
DX destroyed
-14h DWORD pointer to FAR routine for updating FCB from SFT???
call with DS:SI -> unopened FCB
ES:DI -> system file table entry
Return: BL = C0h???
Note: copies following fields from SFT to FCB:
starting cluster of file 0Bh 1Ah
sharing record offset 33h 1Ch
file attribute 04h 1Eh
-10h DWORD pointer to FAR routine to get first cluster of FCB file ???
call with ES:DI -> system file table entry
DS:SI -> FCB
Return: CF set if SFT closed or sharing record offsets
mismatched
CF clear if successful
BX = starting cluster number from FCB
-0Ch DWORD pointer to FAR routine to close file if duplicate for process
DS:SI -> system file table
Return: AX = number of handle in JFT which already uses SFT
Note: called during open/create of a file
Note: if SFT was opened with inheritance enabled and sharing
mode 111, does something to all other SFTs owned by
same process which have the same file open mode and
sharing record
-08h DWORD pointer to FAR routine for closing file
Note: closes various handles referring to file most-recently
opened
-04h DWORD pointer to FAR routine to update directory info in related SFT
entries
call with ES:DI -> system file table entry for file (see below)
AX = subfunction (apply to each related SFT)
00h: update time stamp (offset 0Dh) and date
stamp (offset 0Fh)
01h: update file size (offset 11h) and starting
cluster (offset 0Bh). Sets last-accessed
cluster fields to start of file if file
never accessed
02h: as function 01h, but last-accessed fields
always changed
03h: do both functions 00h and 02h
Note: follows ptr at offset 2Bh in system file table entries
Note: NOP if opened with no-inherit or via FCB
Notes: most of the above hooks (except -04h, -14h, -18h, and -3Ch) assume
either that SS=DOS DS or SS=DS=DOS DS and directly access
DOS-internal data
sharing hooks are not supported by DR-DOS 5-6; will reportedly be
supported by Novell DOS 7
Format of sharing record:
Offset Size Description
00h BYTE flag
00h free block
01h allocated block
FFh end marker
01h WORD size of block
03h BYTE checksum of pathname (including NUL)
if sum of ASCII values is N, checksum is (N/256 + N%256)
04h WORD offset in SHARE's DS of first Record Lock Record (see below)
06h DWORD pointer to start of system file table chain for file
0Ah WORD unique sequence number
0Ch var ASCIZ full pathname
Note: not supported by DR-DOS SHARE 1.1 and 2.0; will reportedly be
supported by Novell DOS 7
Format of Record Lock Record (SHARE.EXE):
Offset Size Description
00h WORD offset in SHARE's DS of next lock table in list or 0000h
02h DWORD offset in file of start of locked region
06h DWORD offset in file of end of locked region
0Ah DWORD pointer to System File Table entry for this file
0Eh WORD PSP segment of lock's owner
---DOS 5+ ---
10h WORD lock type: (00h lock all, 01h lock writes only)
Format of DOS 2.x system file tables:
Offset Size Description
00h DWORD pointer to next file table (offset FFFFh if last)
04h WORD number of files in this table
06h 28h bytes per file
Offset Size Description
00h BYTE number of file handles referring to this file
01h BYTE file open mode (see AH=3Dh)
02h BYTE file attribute
03h BYTE drive (0 = character device, 1 = A, 2 = B, etc)
04h 11 BYTEs filename in FCB format (no path,no period,blank-padded)
0Fh WORD ???
11h WORD ???
13h DWORD file size???
17h WORD file date in packed format (see AX=5700h)
19h WORD file time in packed format (see AX=5700h)
1Bh BYTE device attribute (see AX=4400h)
---character device---
1Ch DWORD pointer to device driver
---block device---
1Ch WORD starting cluster of file
1Eh WORD relative cluster in file of last cluster accessed
------
20h WORD absolute cluster number of current cluster
22h WORD ???
24h DWORD current file position???
Format of DOS 3.0 system file tables and FCB tables:
Offset Size Description
00h DWORD pointer to next file table (offset FFFFh if last)
04h WORD number of files in this table
06h 38h bytes per file
Offset Size Description
00h-1Eh as for DOS 3.1+ (see below)
1Fh WORD byte offset of directory entry within sector
21h 11 BYTEs filename in FCB format (no path/period, blank-padded)
2Ch DWORD (SHARE.EXE) pointer to previous SFT sharing same file
30h WORD (SHARE.EXE) network machine number which opened file
(Windows Enhanced mode DOSMGR uses the virtual machine
ID as the machine number; see INT 2F/AX=1683h)
32h WORD PSP segment of file's owner (first three entries for
AUX/CON/PRN contain segment of IO.SYS startup code)
34h WORD (SHARE.EXE) offset in SHARE code seg of share record
36h WORD ??? apparently always 0000h
Format of DOS 3.1-3.3x, DR-DOS 5.0-6.0 system file tables and FCB tables:
Offset Size Description
00h DWORD pointer to next file table (offset FFFFh if last)
04h WORD number of files in this table
06h 35h bytes per file
Offset Size Description
00h WORD number of file handles referring to this file
02h WORD file open mode (see AH=3Dh)
bit 15 set if this file opened via FCB
04h BYTE file attribute (see AX=4301h)
05h WORD device info word (see AX=4400h)
bit 15 set if remote file
bit 14 set means do not set file date/time on closing
bit 12 set means don't inherit on EXEC
bits 5-0 drive number for disk files
07h DWORD pointer to device driver header if character device
else pointer to DOS Drive Parameter Block (see AH=32h)
0Bh WORD starting cluster of file
0Dh WORD file time in packed format (see AX=5700h)
not used for character devices in DR-DOS
0Fh WORD file date in packed format (see AX=5700h)
not used for character devices in DR-DOS
11h DWORD file size
---system file table---
15h DWORD current offset in file (may be larger than size of
file; INT 21/AH=42h does not check new position)
---FCB table---
15h WORD counter for last I/O to FCB
17h WORD counter for last open of FCB
(these are separate to determine the times of the
latest I/O and open)
---
19h WORD relative cluster within file of last cluster accessed
1Bh WORD absolute cluster number of last cluster accessed
0000h if file never read or written???
1Dh WORD number of sector containing directory entry
1Fh BYTE number of dir entry within sector (byte offset/32)
20h 11 BYTEs filename in FCB format (no path/period, blank-padded)
2Bh DWORD (SHARE.EXE) pointer to previous SFT sharing same file
2Fh WORD (SHARE.EXE) network machine number which opened file
(Windows Enhanced mode DOSMGR uses the virtual machine
ID as the machine number; see INT 2F/AX=1683h)
31h WORD PSP segment of file's owner (see AH=26h) (first three
entries for AUX/CON/PRN contain segment of IO.SYS
startup code)
33h WORD offset within SHARE.EXE code segment of
sharing record (see above) 0000h = none
Format of DOS 4.0-6.0 system file tables and FCB tables:
Offset Size Description
00h DWORD pointer to next file table (offset FFFFh if last)
04h WORD number of files in this table
06h 3Bh bytes per file
Offset Size Description
00h WORD number of file handles referring to this file
FFFFh if in use but not referenced
02h WORD file open mode (see AH=3Dh)
bit 15 set if this file opened via FCB
04h BYTE file attribute (see AX=4301h)
05h WORD device info word (see also AX=4400h)
bit 15 set if remote file
bit 14 set means do not set file date/time on closing
bit 13 set if named pipe
bit 12 set if no inherit
bit 11 set if network spooler
bit 7 set if device, clear if file (only if local)
bits 6-0 as for AX=4400h
07h DWORD pointer to device driver header if character device
else pointer to DOS Drive Parameter Block (see AH=32h)
or REDIR data
0Bh WORD starting cluster of file (local files only)
0Dh WORD file time in packed format (see AX=5700h)
0Fh WORD file date in packed format (see AX=5700h)
11h DWORD file size
15h DWORD current offset in file (SFT)
LRU counters (FCB table, two WORDs)
---local file---
19h WORD relative cluster within file of last cluster accessed
1Bh DWORD number of sector containing directory entry
1Fh BYTE number of dir entry within sector (byte offset/32)
---network redirector---
19h DWORD pointer to REDIRIFS record
1Dh 3 BYTEs ???
------
20h 11 BYTEs filename in FCB format (no path/period, blank-padded)
2Bh DWORD (SHARE.EXE) pointer to previous SFT sharing same file
2Fh WORD (SHARE.EXE) network machine number which opened file
(Windows Enhanced mode DOSMGR uses the virtual machine
ID as the machine number; see INT 2F/AX=1683h)
31h WORD PSP segment of file's owner (see AH=26h) (first three
entries for AUX/CON/PRN contain segment of IO.SYS
startup code)
33h WORD offset within SHARE.EXE code segment of
sharing record (see above) 0000h = none
35h WORD (local) absolute cluster number of last clustr accessed
(redirector) ???
37h DWORD pointer to IFS driver for file, 0000000h if native DOS
Note: the OS/2 2.0 DOS Boot Session does not properly fill in the filename
field due to incomplete support for SFTs; the OS/2 2.0 DOS Window
does not appear to support SFTs at all
Format of current directory structure (CDS) (array, LASTDRIVE entries):
Offset Size Description
00h 67 BYTEs ASCIZ path in form X:\PATH (local) or \\MACH\PATH (network)
43h WORD drive attributes (see also note below and AX=5F07h)
bit 15: uses network redirector \ invalid if 00, installable
bit 14: physical drive / file system if 11
bit 13: JOIN'ed \ path above is true path that would be
bit 12: SUBST'ed / needed if not under SUBST or JOIN
bit 7: remote drive hidden from redirector's assign-list and
exempt from network connection make/break commands;
set for CD-ROM drives
45h DWORD pointer to Drive Parameter Block for drive (see AH=32h)
---local drives---
49h WORD starting cluster of current directory
0000h = root, FFFFh = never accessed
4Bh WORD ??? seems to be FFFFh always
4Dh WORD ??? seems to be FFFFh always
---network drives---
49h DWORD pointer to redirector or REDIRIFS record, or FFFFh:FFFFh
(DOS 4 only) available for use by IFS driver
4Dh WORD stored user data from INT 21/AX=5F03h
------
4Fh WORD offset in current directory path of backslash corresponding to
root directory for drive
this value specifies how many characters to hide from the
"CHDIR" and "GETDIR" calls; normally set to 2 to hide the
drive letter and colon, SUBST, JOIN, and networks change it
so that only the appropriate portion of the true path is
visible to the user
---DOS 4+ ---
51h BYTE (DOS 4 only, remote drives) device type
04h network drive
52h DWORD pointer to IFS driver (DOS 4) or redirector block (DOS 5+) for
this drive, 00000000h if native DOS
56h WORD available for use by IFS driver
Notes: the path for invalid drives is normally set to X:\, but may be empty
after JOIN x: /D in DR-DOS 5.0 or NET USE x: /D in older LAN versions
normally, only one of bits 13&12 may be set together with bit 14, but
DR-DOS 5.0 uses other combinations for bits 15-12: 0111 JOIN,
0001 SUBST, 0101 ASSIGN (see below)
Format of DR-DOS 5.0-6.0 current directory structure entry (array):
Offset Size Description
00h 67 BYTEs ASCIZ pathname of actual root directory for this logical drive
43h WORD drive attributes
1000h SUBSTed drive
3000h??? JOINed drive
4000h physical drive
5000h ASSIGNed drive
7000h JOINed drive
8000h network drive
45h BYTE physical drive number (0=A:) if this logical drive is valid
46h BYTE ??? apparently flags for JOIN and ASSIGN
47h WORD cluster number of start of parent directory (0000h = root)
49h WORD entry number of current directory in parent directory
4Bh WORD cluster number of start of current directory
4Dh WORD used for media change detection (details not available)
4Fh WORD cluster number of SUBST/JOIN "root" directory
0000h if physical root directory
Format of device driver header:
Offset Size Description
00h DWORD pointer to next driver, offset=FFFFh if last driver
04h WORD device attributes
Character device:
bit 15 set (indicates character device)
bit 14 IOCTL supported (see AH=44h)
bit 13 (DOS 3+) output until busy supported
bit 12 reserved
bit 11 (DOS 3+) OPEN/CLOSE/RemMedia calls supported
bits 10-8 reserved
bit 7 (DOS 5+) Generic IOCTL check call supported (cmd 19h)
(see AX=4410h,AX=4411h)
bit 6 (DOS 3.2+) Generic IOCTL call supported (command 13h)
(see AX=440Ch,AX=440Dh)
bit 5 reserved
bit 4 device is special (use INT 29 "fast console output")
bit 3 device is CLOCK$ (all reads/writes use transfer
record described below)
bit 2 device is NUL
bit 1 device is standard output
bit 0 device is standard input
Block device:
bit 15 clear (indicates block device)
bit 14 IOCTL supported
bit 13 non-IBM format
bit 12 network device (device is remote)
bit 11 (DOS 3+) OPEN/CLOSE/RemMedia calls supported
bit 10 reserved
bit 9 direct I/O not allowed???
(set by DOS 3.3 DRIVER.SYS for "new" drives)
bit 8 ??? set by DOS 3.3 DRIVER.SYS for "new" drives
bit 7 (DOS 5+) Generic IOCTL check call supported (cmd 19h)
(see AX=4410h,AX=4411h)
bit 6 (DOS 3.2+) Generic IOCTL call supported (command 13h)
implies support for commands 17h and 18h
(see AX=440Ch,AX=440Dh,AX=440Eh,AX=440Fh)
bits 5-2 reserved
bit 1 driver supports 32-bit sector addressing (DOS 3.31+)
bit 0 reserved
Note: for European MS-DOS 4.0, bit 11 also indicates that bits
8-6 contain a version code (000 = DOS 3.0,3.1;
001 = DOS 3.2, 010 = European DOS 4.0)
06h WORD device strategy entry point
call with ES:BX -> request header (see INT 2F/AX=0802h)
08h WORD device interrupt entry point
---character device---
0Ah 8 BYTEs blank-padded character device name
---block device---
0Ah BYTE number of subunits (drives) supported by driver
0Bh 7 BYTEs unused
---
12h WORD (CD-ROM driver) reserved, must be 0000h
appears to be another device chain
14h BYTE (CD-ROM driver) drive letter (must initially be 00h)
15h BYTE (CD-ROM driver) number of units
16h 6 BYTEs (CD-ROM driver) signature 'MSCDnn' where 'nn' is version
(currently '00')
Format of CLOCK$ transfer record:
Offset Size Description
00h WORD number of days since 1-Jan-1980
02h BYTE minutes
03h BYTE hours
04h BYTE hundredths of second
05h BYTE seconds
Format of DOS 2.x disk buffer:
Offset Size Description
00h DWORD pointer to next disk buffer, offset = FFFFh if last
least-recently used buffer is first in chain
04h BYTE drive (0=A, 1=B, etc), FFh if not in use
05h 3 BYTEs unused??? (seems always to be 00h 00h 01h)
08h WORD logical sector number
0Ah BYTE number of copies to write (1 for non-FAT sectors)
0Bh BYTE sector offset between copies if multiple copies to be written
0Ch DWORD pointer to DOS Drive Parameter Block (see AH=32h)
10h buffered data
Format of DOS 3.x disk buffer:
Offset Size Description
00h DWORD pointer to next disk buffer, offset = FFFFh if last
least-recently used buffer is first in chain
04h BYTE drive (0=A,1=B, etc), FFh if not in use
05h BYTE buffer flags
bit 7: ???
bit 6: buffer dirty
bit 5: buffer has been referenced
bit 4: ???
bit 3: sector in data area
bit 2: sector in a directory, either root or subdirectory
bit 1: sector in FAT
bit 0: boot sector??? (guess)
06h WORD logical sector number
08h BYTE number of copies to write (1 for non-FAT sectors)
09h BYTE sector offset between copies if multiple copies to be written
0Ah DWORD pointer to DOS Drive Parameter Block (see AH=32h)
0Eh WORD unused??? (almost always 0)
10h buffered data
Format of DOS 4.00 (pre UR 25066) disk buffer info:
Offset Size Description
00h DWORD pointer to array of disk buffer hash chain heads (see below)
04h WORD number of disk buffer hash chains (referred to as NDBCH below)
06h DWORD pointer to lookahead buffer, zero if not present
0Ah WORD number of lookahead sectors, else zero (the y in BUFFERS=x,y)
0Ch BYTE 00h if buffers in EMS (/X), FFh if not
0Dh WORD EMS handle for buffers, zero if not in EMS
0Fh WORD EMS physical page number used for buffers (usually 255)
11h WORD ??? seems always to be 0001h
13h WORD segment of EMS physical page frame
15h WORD ??? seems always to be zero
17h 4 WORDs EMS partial page mapping information???
Format of DOS 4.01 (from UR 25066 Corrctive Services Disk on) disk buffer info:
Offset Size Description
00h DWORD pointer to array of disk buffer hash chain heads (see below)
04h WORD number of disk buffer hash chains (referred to as NDBCH below)
06h DWORD pointer to lookahead buffer, zero if not present
0Ah WORD number of lookahead sectors, else zero (the y in BUFFERS=x,y)
0Ch BYTE 01h, possibly to distinguish from pre-UR 25066 format
0Dh WORD ??? EMS segment for BUFFERS (only with /XD)
0Fh WORD ??? EMS physical page number of EMS seg above (only with /XD)
11h WORD ??? EMS segment for ??? (only with /XD)
13h WORD ??? EMS physical page number of above (only with /XD)
15h BYTE ??? number of EMS page frames present (only with /XD)
16h WORD segment of one-sector workspace buffer allocated in main memory
if BUFFERS/XS or /XD options in effect, possibly to avoid DMA
into EMS
18h WORD EMS handle for buffers, zero if not in EMS
1Ah WORD EMS physical page number used for buffers (usually 255)
1Ch WORD ??? appears always to be 0001h
1Eh WORD segment of EMS physical page frame
20h WORD ??? appears always to be zero
22h BYTE 00h if /XS, 01h if /XD, FFh if BUFFERS not in EMS
Format of DOS 4.x disk buffer hash chain head (array, one entry per chain):
Offset Size Description
00h WORD EMS logical page number in which chain is resident, -1 if not
in EMS
02h DWORD pointer to least recently used buffer header. All buffers on
this chain are in the same segment.
06h BYTE number of dirty buffers on this chain
07h BYTE reserved (00h)
Notes: buffered disk sectors are assigned to chain N where N is the sector's
address modulo NDBCH, 0 <= N <= NDBCH-1
each chain resides completely within one EMS page
this structure is in main memory even if buffers are in EMS
Format of DOS 4.0-6.0 disk buffer:
Offset Size Description
00h WORD forward ptr, offset only, to next least recently used buffer
02h WORD backward ptr, offset only
04h BYTE drive (0=A,1=B, etc) if bit 7 clear
SFT index if bit 7 set
FFh if not in use
05h BYTE buffer flags
bit 7: remote buffer
bit 6: buffer dirty
bit 5: buffer has been referenced (reserved in DOS 5+)
bit 4: search data buffer (only valid if remote buffer)
bit 3: sector in data area
bit 2: sector in a directory, either root or subdirectory
bit 1: sector in FAT
bit 0: reserved
06h DWORD logical sector number (local buffers only)
0Ah BYTE number of copies to write
for FAT sectors, same as number of FATs
for data and directory sectors, usually 1
0Bh WORD offset in sectors between copies to write for FAT sectors
0Dh DWORD pointer to DOS Drive Parameter Block (see AH=32h)
11h WORD size of data in buffer if remote buffer (see flags above)
13h BYTE reserved (padding)
14h buffered data
Note: for DOS 4.x, all buffered sectors which have the same hash value
(computed as the sum of high and low words of the logical sector
number divided by the number of disk buffer chains) are on the same
doubly-linked circular chain; for DOS 5+, only a single circular
chain exists.
the links consist of offset addresses only, the segment being the same
for all buffers in the chain.
Format of DOS 5.0-6.0 disk buffer info:
Offset Size Description
00h DWORD pointer to least-recently-used buffer header (may be in HMA)
(see above)
04h WORD number of dirty disk buffers
06h DWORD pointer to lookahead buffer, zero if not present
0Ah WORD number of lookahead sectors, else zero (the y in BUFFERS=x,y)
0Ch BYTE buffer location
00h base memory, no workspace buffer
01h HMA, workspace buffer in base memory
0Dh DWORD pointer to one-segment workspace buffer in base memory
11h 3 BYTEs unused
14h WORD ???
16h BYTE flag: INT 24 fail while making an I/O status call
17h BYTE temp storage for user memory allocation strategy during EXEC
18h BYTE counter: number of INT 21 calls for which A20 is off
19h BYTE bit flags
bit 0: ???
bit 1: SWITCHES=/W specified in CONFIG.SYS (don't load
WINA20.SYS when MS Windows 3.0 starts)
bit 2: in EXEC state (INT 21/AX=4B05h)
1Ah WORD offset of unpack code start (used only during INT 21/AX=4B05h)
1Ch BYTE bit 0 set iff UMB MCB chain linked to normal MCB chain
1Dh WORD minimum paragraphs of memory required by program being EXECed
1Fh WORD segment of first MCB in upper memory blocks or FFFFh if DOS
memory chain in base 640K only (first UMB MCB usually at 9FFFh,
locking out video memory with a DOS-owned memory block)
21h WORD paragraph from which to start scanning during memory allocation
Format of IFS driver list:
Offset Size Description
00h DWORD pointer to next driver header
04h 8 BYTEs IFS driver name (blank padded), as used by FILESYS command
0Ch 4 BYTEs ???
10h DWORD pointer to IFS utility function entry point (see below)
call with ES:BX -> IFS request (see below)
14h WORD offset in header's segment of driver entry point
???
Call IFS utility function entry point with:
AH = 20h miscellaneous functions
AL = 00h get date
Return: CX = year
DH = month
DL = day
AL = 01h get process ID and computer ID
Return: BX = current PSP segment
DX = active network machine number
AL = 05h get file system info
ES:DI -> 16-byte info buffer
Return: buffer filled
Offset Size Description
00h 2 BYTEs unused
02h WORD number of SFTs (actually counts only
the first two file table arrays)
04h WORD number of FCB table entries
06h WORD number of proctected FCBs
08h 6 BYTEs unused
0Eh WORD largest sector size supported
AL = 06h get machine name
ES:DI -> 18-byte buffer for name
Return: buffer filled with name starting at offset 02h
AL = 08h get sharing retry count
Return: BX = sharing retry count
AL = other
Return: CF set
AH = 21h get redirection state
BH = type (03h disk, 04h printer)
Return: BH = state (00h off, 01h on)
AH = 22h ??? some sort of time calculation
AL = 00h ???
nonzero ???
AH = 23h ??? some sort of time calculation
AH = 24h compare filenames
DS:SI -> first ASCIZ filename
ES:DI -> second ASCIZ filename
Return: ZF set if files are same ignoring case and / vs \
AH = 25h normalize filename
DS:SI -> ASCIZ filename
ES:DI -> buffer for result
Return: filename uppercased, forward slashes changed to backslashes
AH = 26h get DOS stack
Return: DS:SI -> top of stack
CX = size of stack in bytes
AH = 27h increment InDOS flag
AH = 28h decrement InDOS flag
Note: IFS drivers which do not wish to implement functions 20h or 24h-28h may
pass them on to the default handler pointed at by [LoL+37h]
Format of IFS request block:
Offset Size Description
00h WORD total size in bytes of request
02h BYTE class of request
02h ???
03h redirection
04h ???
05h file access
06h convert error code to string
07h ???
03h WORD returned DOS error code
05h BYTE IFS driver exit status
00h success
01h ???
02h ???
03h ???
04h ???
FFh internal failure
06h 16 BYTEs ???
---request class 02h---
16h BYTE function code
04h ???
17h BYTE unused???
18h DWORD pointer to ???
1Ch DWORD pointer to ???
20h 2 BYTEs ???
---request class 03h---
16h BYTE function code
17h BYTE ???
18h DWORD pointer to ???
1Ch DWORD pointer to ???
22h WORD returned ???
24h WORD returned ???
26h WORD returned ???
28h BYTE returned ???
29h BYTE unused???
---request class 04h---
16h DWORD pointer to ???
1Ah DWORD pointer to ???
---request class 05h---
16h BYTE function code
01h flush disk buffers
02h get disk space
03h MKDIR
04h RMDIR
05h CHDIR
06h delete file
07h rename file
08h search directory
09h file open/create
0Ah LSEEK
0Bh read from file
0Ch write to file
0Dh lock region of file
0Eh commit/close file
0Fh get/set file attributes
10h printer control
11h ???
12h process termination
13h ???
---class 05h function 01h---
17h 7 BYTEs ???
1Eh DWORD pointer to ???
22h 4 BYTEs ???
26h BYTE ???
27h BYTE ???
---class 05h function 02h---
17h 7 BYTEs ???
1Eh DWORD pointer to ???
22h 4 BYTEs ???
26h WORD returned total clusters
28h WORD returned sectors per cluster
2Ah WORD returned bytes per sector
2Ch WORD returned available clusters
2Eh BYTE returned ???
2Fh BYTE ???
---class 05h functions 03h,04h,05h---
17h 7 BYTEs ???
1Eh DWORD pointer to ???
22h 4 BYTEs ???
26h DWORD pointer to directory name
---class 05h function 06h---
17h 7 BYTEs ???
1Eh DWORD pointer to ???
22h 4 BYTEs ???
26h WORD attribute mask
28h DWORD pointer to filename
---class 05h function 07h---
17h 7 BYTEs ???
1Eh DWORD pointer to ???
22h 4 BYTEs ???
26h WORD attribute mask
28h DWORD pointer to source filespec
2Ch DWORD pointer to destination filespec
---class 05h function 08h---
17h 7 BYTEs ???
1Eh DWORD pointer to ???
22h 4 BYTEs ???
26h BYTE 00h FINDFIRST
01h FINDNEXT
28h DWORD pointer to FindFirst search data + 01h if FINDNEXT
2Ch WORD search attribute if FINDFIRST
2Eh DWORD pointer to filespec if FINDFIRST
---class 05h function 09h---
17h 7 BYTEs ???
1Eh DWORD pointer to ???
22h DWORD pointer to IFS open file structure (see below)
26h WORD ??? \ together, specify open vs. create, whether or
28h WORD ??? / not to truncate
2Ah 4 BYTEs ???
2Eh DWORD pointer to filename
32h 4 BYTEs ???
36h WORD file attributes on call
returned ???
38h WORD returned ???
---class 05h function 0Ah---
17h 7 BYTEs ???
1Eh DWORD pointer to ???
22h DWORD pointer to IFS open file structure (see below)
26h BYTE seek type (02h = from end)
28h DWORD offset on call
returned new absolute position
---class 05h functions 0Bh,0Ch---
17h 7 BYTEs ???
1Eh DWORD pointer to ???
22h DWORD pointer to IFS open file structure (see below)
28h WORD number of bytes to transfer
returned bytes actually transferred
2Ah DWORD transfer address
---class 05h function 0Dh---
17h 7 BYTEs ???
1Eh DWORD pointer to ???
22h DWORD pointer to IFS open file structure (see below)
26h BYTE file handle???
27h BYTE unused???
28h WORD ???
2Ah WORD ???
2Ch WORD ???
2Eh WORD ???
---class 05h function 0Eh---
17h 7 BYTEs ???
1Eh DWORD pointer to ???
22h DWORD pointer to IFS open file structure (see below)
26h BYTE 00h commit file
01h close file
27h BYTE unused???
---class 05h function 0Fh---
17h 7 BYTEs ???
1Eh DWORD pointer to ???
22h 4 BYTEs ???
26h BYTE 02h GET attributes
03h PUT attributes
27h BYTE unused???
28h 12 BYTEs ???
34h WORD search attributes???
36h DWORD pointer to filename
3Ah WORD (GET) returned ???
3Ch WORD (GET) returned ???
3Eh WORD (GET) returned ???
40h WORD (GET) returned ???
42h WORD (PUT) new attributes
(GET) returned attributes
---class 05h function 10h---
17h 7 BYTEs ???
1Eh DWORD pointer to ???
22h DWORD pointer to IFS open file structure (see below)
26h WORD ???
28h DWORD pointer to ???
2Ch WORD ???
2Eh BYTE ???
2Fh BYTE subfunction
01h get printer setup
03h ???
04h ???
05h ???
06h ???
07h ???
21h set printer setup
---class 05h function 11h---
17h 7 BYTEs ???
1Eh DWORD pointer to ???
22h DWORD pointer to IFS open file structure (see below)
26h BYTE subfunction
27h BYTE unused???
28h WORD ???
2Ah WORD ???
2Ch WORD ???
2Eh BYTE ???
2Fh BYTE ???
---class 05h function 12h---
17h 15 BYTEs unused???
26h WORD PSP segment
28h BYTE type of process termination
29h BYTE unused???
---class 05h function 13h---
17h 15 BYTEs unused???
26h WORD PSP segment
---request class 06h---
16h DWORD returned pointer to string corresponding to error code at 03h
1Ah BYTE returned ???
1Bh BYTE unused
---request class 07h---
16h DWORD pointer to IFS open file structure (see below)
1Ah BYTE ???
1Bh BYTE unused???
Format of IFS open file structure:
Offset Size Description
00h WORD ???
02h WORD device info word
04h WORD file open mode
06h WORD ???
08h WORD file attributes
0Ah WORD owner's network machine number
0Ch WORD owner's PSP segment
0Eh DWORD file size
12h DWORD current offset in file
16h WORD file time
18h WORD file date
1Ah 11 BYTEs filename in FCB format
25h WORD ???
27h WORD hash value of SFT address
(low word of linear address + segment&F000h)
29h 3 WORDs network info from SFT
2Fh WORD ???
Format of one item in DOS 4+ list of special program names:
Offset Size Description
00h BYTE length of name (00h = end of list)
01h N BYTEs name in format name.ext
N 2 BYTEs DOS version to return for program (major,minor)
(see AH=30h,INT 2F/AX=122Fh)
---DOS 4 only---
N+2 BYTE number of times to return fake version number (FFh = always)
Note: if the name of the executable for the program making the DOS "get
version" call matches one of the names in this list, DOS returns the
specified version rather than the true version number
--------v-215252-----------------------------
INT 21 - VIRUS - "516"/"Leapfrog" - INSTALLATION CHECK
AX = 5252h
Return: BX = FFEEh if resident
SeeAlso: AX=4BFFh"Cascade",AX=58CCh
--------D-2153-------------------------------
INT 21 - DOS 2+ internal - TRANSLATE BIOS PARAMETER BLOCK TO DRIVE PARAM BLOCK
AH = 53h
DS:SI -> BIOS Parameter Block (see below)
ES:BP -> buffer for Drive Parameter Block (see AH=32h for format)
Return: ES:BP buffer filled
Note: for DOS 3+, the cluster at which to start searching is set to 0000h
and the number of free clusters is set to FFFFh (unknown)
Format of BIOS Parameter Block:
Offset Size Description
00h WORD number of bytes per sector
02h BYTE number of sectors per cluster
03h WORD number of reserved sectors at start of disk
05h BYTE number of FATs
06h WORD number of entries in root directory
08h WORD total number of sectors
for DOS 4+, set to zero if partition >32M, then set DWORD at
15h to actual number of sectors
0Ah BYTE media ID byte
0Bh WORD number of sectors per FAT
---DOS 3+---
0Dh WORD number of sectors per track
0Fh WORD number of heads
11h DWORD number of hidden sectors
15h 11 BYTEs reserved
---DOS 4+ ---
15h DWORD total number of sectors if word at 08h contains zero
19h 6 BYTEs ???
1Fh WORD number of cylinders
21h BYTE device type
22h WORD device attributes (removable or not, etc)
---DR-DOS 5+ ---
15h DWORD total number of sectors if word at 08h contains zero
19h 6 BYTEs reserved
---European MS-DOS 4.00---
15h DWORD total number of sectors if word at 08h contains zero
(however, this DOS does not actually implement >32M partitions)
--------D-2154-------------------------------
INT 21 - DOS 2+ - GET VERIFY FLAG
AH = 54h
Return: AL = verify flag
00h off
01h on (all disk writes verified after writing)
SeeAlso: AH=2Eh
--------D-2155-------------------------------
INT 21 - DOS 2+ internal - CREATE CHILD PSP
AH = 55h
DX = segment at which to create new PSP
SI = (DOS 3+) value to place in memory size field at DX:[0002h]
Return: CF clear if successful
Notes: creates a "child" PSP rather than making an exact copy of the current
PSP; the new PSP's parent pointer is set to the current PSP and the
reference count for each inherited file is incremented
(DOS 2+) sets current PSP to DX
(DOS 3+) marks "no inherit" file handles as closed in child PSP
SeeAlso: AH=26h,AH=50h
--------D-2156-------------------------------
INT 21 - DOS 2+ - "RENAME" - RENAME FILE
AH = 56h
DS:DX -> ASCIZ filename of existing file (no wildcards, but see below)
ES:DI -> ASCIZ new filename (no wildcards)
CL = attribute mask (server call only, see below)
Return: CF clear if successful
CF set on error
AX = error code (02h,03h,05h,11h) (see AH=59h)
Notes: allows move between directories on same logical volume
does not set the archive attribute (see AX=4300h), which results in
incremental backups not backing up the file under its new name
open files should not be renamed
(DOS 3+) allows renaming of directories
(DOS 3.1+) wildcards are allowed if invoked via AX=5D00h, in which case
error 12h (no more files) is returned on success, and both source and
destination specs must be canonical (as returned by AH=60h).
Wildcards in the destination are replaced by the corresponding char
of each source file being renamed. Under DOS 3.x, the call will fail
if the destination wildcard is *.* or equivalent; under DR-DOS 5.0,
the call will fail if any wildcards are used. When invoked via
AX=5D00h, only those files matching the attribute mask in CL are
renamed.
under the FlashTek X-32 DOS extender, the old-name pointer is in DS:EDX
and the new-name pointer is in ES:EDI (DS must equal ES)
BUG: under DR-DOS 3.41, this function will generate a new directory entry
with the new name (including any wildcards) which can only be removed
with a sector editor when invoked via AX=5D00h
SeeAlso: AH=17h,AX=4301h,AX=5D00h,AH=60h,AH=71h
--------D-215700-----------------------------
INT 21 - DOS 2+ - GET FILE'S DATE AND TIME
AX = 5700h
BX = file handle
Return: CF clear if successful
CX = file's time
bits 15-11: hours (0-23)
10-5: minutes
4-0: seconds/2
DX = file's date
bits 15-9: year - 1980
8-5: month
4-0: day
CF set on error
AX = error code (01h,06h) (see AH=59h)
Note: under DR-DOS 3.41 and 5.0, this function returns 0 (no date/time) for
character devices; MS-DOS returns date and time of opening
SeeAlso: AX=5701h
--------D-215701-----------------------------
INT 21 - DOS 2+ - SET FILE'S DATE AND TIME
AX = 5701h
BX = file handle
CX = new time (see AX=5700h)
DX = new date (see AX=5700h)
Return: CF clear if successful
CF set on error
AX = error code (01h,06h) (see AH=59h)
SeeAlso: AX=5700h
--------D-215702-----------------------------
INT 21 - DOS 4.x only - GET EXTENDED ATTRIBUTES FOR FILE
AX = 5702h
BX = file handle
CX = size of result buffer or 0000h
DS:SI -> EAP list (see below)
ES:DI -> buffer for returned EAV list (see below)
Return: CF clear if successful
CX = size of returned data
CF set on error
AX = error code (see AH=59h)
Desc: get the current value of one or more extended attributes
Notes: if CX=0000h on entry, ES:DI is ignored and no data is actually
returned, only the amount of data which is available
the default DOS 4 behavior is to return a single word of 0000h (no
structures) in the result buffer if CX>=0002h on entry
SeeAlso: AX=5703h,AX=5704h,AH=6Eh,INT 2F/AX=112Dh
Format of EAP (extended attribute properties) list:
Offset Size Description
00h WORD number of EAP structures following
02h var array of EAP structures (see below)
Format of EAP (extended attribute property) structure:
Offset Size Description
00h BYTE attribute type
01h boolean (either 00h or 01h)
02h number (BYTE, WORD, or DWORD)
03h string
04h date stamp
05h time stamp
01h WORD EAP flags (see below)
03h BYTE size of reference string (name)
04h N BYTEs reference string
Bitfields for EAP flags:
bit 12 unchangeable
bit 13 ignore
bit 14 unchangeable
bit 15 used by COMMAND.COM for code page, but not understood by ATTRIB
Format of EAV (extended attribute value) list:
Offset Size Description
00h WORD number of EAV structures following
02h var array of Extended Attribute Value structures
Format of Extended Attribute Value structures:
Offset Size Description
00h 4 BYTEs ???
04h BYTE size of reference string
05h WORD size of value
07h var reference string
var value
--------O-215702-----------------------------
INT 21 - OS/2 v1.1+ Family API - DosQFileInfo
AX = 5702h
BX = file handle
CX = size of buffer for information
DX = level of information
ES:DI -> buffer for information
Return: CF clear if successful
CF set on error
AX = error code
SeeAlso: AX=5702h/BX=FFFFh,AX=5703h"OS/2"
--------O-215702BXFFFF-----------------------
INT 21 - OS/2 v1.1+ Compatibility Box Family API - DosQPathInfo
AX = 5702h
BX = FFFFh
CX = size of buffer for information
DX = level of information (0002h)
DS:SI -> filename
ES:DI -> buffer for information (see below)
Return: CF clear if successful
AL = 00h
CF set on error
AX = error code
SeeAlso: AX=5702h"OS/2",AX=5703h/BX=FFFFh
Format of path information:
Offset Size Description
00h 22 BYTEs ???
16h DWORD extended attribute size (none present if less than 5)
--------D-215703-----------------------------
INT 21 - DOS 4.x only - GET EXTENDED ATTRIBUTE PROPERTIES
AX = 5703h
BX = file handle
CX = size of result buffer or 0000h
ES:DI -> result buffer
Return: CF clear if successful
CX = size of returned data
CF set on error
AX = error code (see AH=59h)
ES:DI -> zero word (DOS 4.0) if CX >= 2 on entry
Desc: get a list of the extended attributes which are defined for the
specified file
Notes: if CX=0000h on entry, ES:DI is ignored and no data is actually
returned, only the amount of data which is available
the default DOS 4 behavior is to return a trivial EAP list consisting
of the single word 0000h (no EAP structures) if CX>=0002h on entry
SeeAlso: AX=5702h,AX=5704h,AH=6Eh,INT 2F/AX=112Dh
--------O-215703-----------------------------
INT 21 - OS/2 v1.1+ Family API - DosSetFileInfo
AX = 5703h
BX = file handle
CX = size of information buffer
DX = level of information
ES:DI -> information buffer
Return: CF clear if successful
CF set on error
AX = error code
SeeAlso: AX=5702h"OS/2",AX=5703h/BX=FFFFh
--------O-215703BXFFFF-----------------------
INT 21 - OS/2 v1.1+ Family API - DosSetPathInfo
AX = 5703h
BX = FFFFh
CX = size of information buffer
DX = level of information
DS:SI -> filename
ES:DI -> information buffer
Return: CF clear if successful
CF set on error
AX = error code
SeeAlso: AX=5702h/BX=FFFFh,AX=5703h"OS/2"
--------D-215704-----------------------------
INT 21 - DOS 4.x only - SET EXTENDED ATTRIBUTES
AX = 5704h
BX = file handle
ES:DI -> EAV list (see AX=5702h)
Return: CF clear if successful
CF set on error
AX = error code (see AH=59h)
Note: the default DOS 4 behavior is to do nothing and return successfully
SeeAlso: AX=5702h,AX=5703h,INT 2F/AX=112Dh
----------215757BX5757-----------------------
INT 21 U - IBM Genie - Resident Manager - INSTALLATION CHECK
AX = 5757h
BX = 5757h
Return: AX = 0000h if installed
BX = ???
DX = ???
DS:SI -> list of 27 DWORD entry point addresses
Program: IBM Genie is a set of utility TSRs by Helix Software
Note: other functions possible if BX <> 5757h, but details not yet available
----------215758-----------------------------
INT 21 U - Headroom - API
AX = 5758h
BL = function
00h ???
01h get Headroom location
Return: CF clear if installed
AX = PSP segment of Headroom TSR
BX = paragraphs of memory used by Headroom
CF set if not (normal DOS return)
Note: this function is also used as an installation check
02h get INT 21 handler
Return: CF clear
ES:BX -> Headroom's INT 21 handler
Note: also sets unknown flag
03h launch application???
DS:SI -> 233-byte application record
Return: ???
04h ???
???
Return: CF clear
05h get swap directory
Return: CF clear
DX:AX -> ASCIZ swap directory name
06h ???
DX = ???
Return: CF clear
07h ???
08h ???
09h get current application
Return: BX = application number
0Ah ???
DX = application number
DS:SI = ???
Return: ???
0Bh ???
0Ch ???
DX = application number
???
Return: ???
0Dh ???
DX = application number
???
Return: ???
0Eh get ???
Return: CF clear
AX = ???
0Fh set ??? flag
10h clear ??? flag
11h find application by name
DS:SI -> ASCIZ application name
Return: CF clear
AX = application number or FFFFh if not loaded
12h ???
DX = application number
Return: CF clear
???
13h ???
Return: CF clear
14h ???
same as function 13h
15h set ???
DX = ???
16h get ???
Return: AX = ??? set by function 15h
17h get ???
Return: BX = ???
CX = ??? (may be pointer in BX:CX)
18h BUG: branches incorrectly due to fencepost error
Program: Headroom is a TSR/task switcher by Helix Software
SeeAlso: AX=4C57h,AX=5757h
--------D-2158-------------------------------
INT 21 - DOS 3+ - GET OR SET MEMORY ALLOCATION STRATEGY
AH = 58h
AL = subfunction
00h get allocation strategy
Return: AX = current strategy
00h low memory first fit
01h low memory best fit
02h low memory last fit
---DOS 5+ ---
40h high memory first fit
41h high memory best fit
42h high memory last fit
80h first fit, try high then low memory
81h best fit, try high then low memory
82h last fit, try high then low memory
01h set allocation strategy
BL = new allocation strategy (see above)
BH = 00h (DOS 5+)
Return: CF clear if successful
CF set on error
AX = error code (01h) (see AH=59h)
Notes: the Set subfunction accepts any value in BL for DOS 3.x and 4.x;
2 or greater means last fit
the Get subfunction returns the last value set
setting an allocation strategy involving high memory does not
automatically link in the UMB memory chain; this must be done
explicitly with AX=5803h in order to actually allocate high memory
a program which changes the allocation strategy should restore it
before terminating
Toshiba MS-DOS 2.11 supports subfunctions 00h and 01h
DR-DOS 3.41 reportedly reverses subfunctions 00h and 01h
SeeAlso: AH=48h,AH=49h,AH=4Ah,INT 2F/AX=4310h,INT 67/AH=3Fh
--------D-2158-------------------------------
INT 21 - DOS 5+ - GET OR SET UMB LINK STATE
AH = 58h
AL = subfunction
02h get UMB link state
Return: AL = 00h UMBs not part of DOS memory chain
= 01h UMBs in DOS memory chain
03h set UMB link state
BX = 0000h remove UMBs from DOS memory chain
= 0001h add UMBs to DOS memory chain
Return: CF clear if successful
CF set on error
AX = error code (01h) (see AH=59h)
Note: a program which changes the UMB link state should restore it before
terminating
--------v-2158CC-----------------------------
INT 21 - VIRUS - "1067"/"Headcrash" - INSTALLATION CHECK
AX = 58CCh
Return: CF clear if resident
SeeAlso: AX=5252h,AX=58DDh,AX=6969h
--------v-2158DD-----------------------------
INT 21 - VIRUS - "1067"/"Headcrash" - GET ORIGINAL INT 21h VECTOR
AX = 58DDh
Return: CX = code segment of virus
ES:BX = old INT 21h vector
SeeAlso: AX=5252h,AX=58CCh,AX=6969h
--------D-2159--BX0000-----------------------
INT 21 - DOS 3+ - GET EXTENDED ERROR INFORMATION
AH = 59h
BX = 0000h
Return: AX = extended error code (see below)
BH = error class (see below)
BL = recommended action (see below)
CH = error locus (see below)
ES:DI may be pointer (see error code list below)
CL, DX, SI, BP, and DS destroyed
Notes: functions available under DOS 2.x map the true DOS 3+ error code into
one supported under DOS 2.x
you should call this function to retrieve the true error code when an
FCB or DOS 2.x call returns an error
under DR-DOS 5.0, this function does not use any of the DOS-internal
stacks and may thus be called at any time
SeeAlso: AH=59h/BX=0001h,AX=5D0Ah,INT 2F/AX=122Dh
Values for extended error code:
00h (0) no error
01h (1) function number invalid
02h (2) file not found
03h (3) path not found
04h (4) too many open files (no handles available)
05h (5) access denied
06h (6) invalid handle
07h (7) memory control block destroyed
08h (8) insufficient memory
09h (9) memory block address invalid
0Ah (10) environment invalid (usually >32K in length)
0Bh (11) format invalid
0Ch (12) access code invalid
0Dh (13) data invalid
0Eh (14) reserved
0Fh (15) invalid drive
10h (16) attempted to remove current directory
11h (17) not same device
12h (18) no more files
---DOS 3+---
13h (19) disk write-protected
14h (20) unknown unit
15h (21) drive not ready
16h (22) unknown command
17h (23) data error (CRC)
18h (24) bad request structure length
19h (25) seek error
1Ah (26) unknown media type (non-DOS disk)
1Bh (27) sector not found
1Ch (28) printer out of paper
1Dh (29) write fault
1Eh (30) read fault
1Fh (31) general failure
20h (32) sharing violation
21h (33) lock violation
22h (34) disk change invalid
ES:DI -> ASCIZ volume label of required disk
23h (35) FCB unavailable
24h (36) sharing buffer overflow
25h (37) (DOS 4+) code page mismatch
26h (38) (DOS 4+) cannot complete file operation (out of input)
27h (39) (DOS 4+) insufficient disk space
28h-31h reserved
32h (50) network request not supported
33h (51) remote computer not listening
34h (52) duplicate name on network
35h (53) network name not found
36h (54) network busy
37h (55) network device no longer exists
38h (56) network BIOS command limit exceeded
39h (57) network adapter hardware error
3Ah (58) incorrect response from network
3Bh (59) unexpected network error
3Ch (60) incompatible remote adapter
3Dh (61) print queue full
3Eh (62) queue not full
3Fh (63) not enough space to print file
40h (64) network name was deleted
41h (65) network: Access denied
42h (66) network device type incorrect
43h (67) network name not found
44h (68) network name limit exceeded
45h (69) network BIOS session limit exceeded
46h (70) temporarily paused
47h (71) network request not accepted
48h (72) network print/disk redirection paused
49h (73) network software not installed
(LANtastic) invalid network version
4Ah (74) unexpected adapter close
(LANtastic) account expired
4Bh (75) (LANtastic) password expired
4Ch (76) (LANtastic) login attempt invalid at this time
4Dh (77) (LANtastic v3+) disk limit exceeded on network node
4Eh (78) (LANtastic v3+) not logged in to network node
4Fh (79) reserved
50h (80) file exists
51h (81) reserved
52h (82) cannot make directory
53h (83) fail on INT 24h
54h (84) (DOS 3.3+) too many redirections
55h (85) (DOS 3.3+) duplicate redirection
56h (86) (DOS 3.3+) invalid password
57h (87) (DOS 3.3+) invalid parameter
58h (88) (DOS 3.3+) network write fault
59h (89) (DOS 4+) function not supported on network
5Ah (90) (DOS 4+) required system component not installed
64h (100) (MSCDEX) unknown error
65h (101) (MSCDEX) not ready
66h (102) (MSCDEX) EMS memory no longer valid
67h (103) (MSCDEX) not High Sierra or ISO-9660 format
68h (104) (MSCDEX) door open
Values for Error Class:
01h out of resource (storage space or I/O channels)
02h temporary situation (file or record lock)
03h authorization (denied access)
04h internal (system software bug)
05h hardware failure
06h system failure (configuration file missing or incorrect)
07h application program error
08h not found
09h bad format
0Ah locked
0Bh media error
0Ch already exists
0Dh unknown
Values for Suggested Action:
01h retry
02h delayed retry
03h prompt user to reenter input
04h abort after cleanup
05h immediate abort
06h ignore
07h retry after user intervention
Values for Error Locus:
01h unknown or not appropriate
02h block device (disk error)
03h network related
04h serial device (timeout)
05h memory related
--------D-2159--BX0001-----------------------
INT 21 - European MS-DOS 4.0 - GET HARD ERROR INFORMATION
AH = 59h
BX = 0001h
Return: ES:DI -> hard error information packet (see below) for most recent
hard (critical) error
SeeAlso: AH=59h/BX=0000h,AH=95h,INT 24
Format of hard error information packet:
Offset Size Description
00h WORD contents of AX at system entry
02h WORD Process ID which encountered error
04h WORD contents of AX at time of error
06h BYTE error type
00h physical I/O error
01h disk change request
02h file sharing violation
03h FCB problem
04h file locking violation
05h bad FAT
06h network detected error
07h BYTE INT 24 error code
08h WORD extended error code (see AH=59h/BX=0000h)
0Ah DWORD pointer to associated device
--------D-215A-------------------------------
INT 21 - DOS 3+ - CREATE TEMPORARY FILE
AH = 5Ah
CX = file attribute (see AX=4301h)
DS:DX -> ASCIZ path ending with a '\' + 13 zero bytes to receive the
generated filename
Return: CF clear if successful
AX = file handle opened for read/write in compatibility mode
DS:DX pathname extended with generated name for temporary file
CF set on error
AX = error code (03h,04h,05h) (see AH=59h)
Desc: creates a file with a unique name which must be explicitly deleted
BUGS: COMPAQ DOS 3.31 hangs if the pathname is at XXXXh:0000h; it apparently
wraps around to the end of the segment
MS-DOS 5.00 revisions A and B and PC-DOS 5.00 revision A reportedly
hang the system if the specified path is the root directory and the
root directory is full (no free directory entries)
Note: under the FlashTek X-32 DOS extender, the path pointer is in DS:EDX
SeeAlso: AH=3Ch,AH=5Bh
--------D-215B-------------------------------
INT 21 - DOS 3+ - CREATE NEW FILE
AH = 5Bh
CX = file attribute (see AX=4301h)
DS:DX -> ASCIZ filename
Return: CF clear if successful
AX = file handle opened for read/write in compatibility mode
CF set on error
AX = error code (03h,04h,05h,50h) (see AH=59h)
Notes: unlike AH=3Ch, this function will fail if the specified file exists
rather than truncating it; this permits its use in creating semaphore
files because it is an atomic "test and set" operation
under the FlashTek X-32 DOS extender, the filename pointer is in DS:EDX
SeeAlso: AH=3Ch,AH=5Ah
--------D-215C-------------------------------
INT 21 - DOS 3+ - "FLOCK" - RECORD LOCKING
AH = 5Ch
AL = subfunction
00h lock region of file
01h unlock region of file
BX = file handle
CX:DX = start offset of region within file
SI:DI = length of region in bytes
Return: CF clear if successful
CF set on error
AX = error code (01h,06h,21h,24h) (see AH=59h)
Notes: error returned unless SHARE or network installed
an unlock call must specify the same region as some prior lock call
locked regions become entirely inaccessible to other processes
duplicate handles created with AH=45h or AH=46h inherit locks, but
handles inherited by child processes (see AH=4Bh) do not
under DR-DOS 3.41 and 5.0, if a process opens a file without the no-
inherit flag and then starts a child, any locks set by the parent
are ignored, and the child will only get an error if it tries to
lock an area previously locked by the parent process
SeeAlso: AX=440Bh,AH=BCh,AH=BEh,INT 2F/AX=110Ah,INT 2F/AX=110Bh
--------D-215D00-----------------------------
INT 21 U - DOS 3.1+ internal - SERVER FUNCTION CALL
AX = 5D00h
DS:DX -> DOS parameter list (see below)
DPL contains all register values for a call to INT 21h
Return: as appropriate for function being called
Notes: does not check AH. Out of range values will crash the system
executes using specified computer ID and process ID
sharing delay loops skipped
a special sharing mode is enabled to handle FCBs opened across network
wildcards are enabled for DELETE (AH=41h) and RENAME (AH=56h) under
MS-DOS; under DR-DOS 3.41, wildcards corrupt the filesystem; and
under DR-DOS 5.0-6.0, the call returns error code 03h due to improper
support for the server function call (see below)
an extra file attribute parameter is enabled for OPEN (AH=3Dh),
DELETE (AH=41h), and RENAME (AH=56h)
functions which take filenames require canonical names (as returned
by AH=60h); this is apparently to prevent multi-hop file forwarding
BUGS: the OS/2 2.0 DOS Boot Session incorrectly maps DOS drive letters,
seemingly ignoring HPFS drives
DR-DOS 5.0-6.0 merely recursively call INT 21 after loading the
registers from the DPL, leading to problems for peer-to-peer
networks
SeeAlso: AH=3Dh,AH=41h,AH=56h,AH=60h
Format of DOS parameter list:
Offset Size Description
00h WORD AX
02h WORD BX
04h WORD CX
06h WORD DX
08h WORD SI
0Ah WORD DI
0Ch WORD DS
0Eh WORD ES
10h WORD reserved (0)
12h WORD computer ID (0 = current system)
14h WORD process ID (PSP segment on specified computer)
Note: under Windows Enhanced mode, the computer ID is normally the virtual
machine ID (see INT 2F/AX=1683h), though this can reportedly be
changed by setting UniqueDOSPSP= in SYSTEM.INI
--------D-215D01-----------------------------
INT 21 U - DOS 3.1+ internal - COMMIT ALL FILES FOR SPECIFIED COMPUTER/PROCESS
AX = 5D01h
DS:DX -> DOS parameter list (see AX=5D00h), only computer ID and
process ID fields used
Return: CF set on error
AX = error code (see AH=59h)
CF clear if successful
Notes: flushes buffers and updates directory entries for each file which has
been written to; if remote file, calls INT 2F/AX=1107h
the computer ID and process ID are stored but ignored under DOS 3.3
not supported by DR-DOS 3.41 and 5.0; returns error code 01h
SeeAlso: AH=0Dh,AH=68h,INT 2F/AX=1107h
--------D-215D02-----------------------------
INT 21 U - DOS 3.1+ internal - SHARE.EXE - CLOSE FILE BY NAME
AX = 5D02h
DS:DX -> DOS parameter list (see AX=5D00h), only fields DX, DS,
computer ID, and process ID used
DPL's DS:DX -> ASCIZ name of file to close
Return: CF set on error
AX = error code (see AH=59h)
CF clear if successful
Notes: error unless SHARE is loaded (calls [SysFileTable-28h]) (see AH=52h)
name must be canonical fully-qualified, such as returned by AH=60h
not supported by DR-DOS 3.41 and 5.0; returns error code 01h
SeeAlso: AX=5D03h,AX=5D04h,AH=3Eh,AH=60h
--------D-215D03-----------------------------
INT 21 U - DOS 3.1+ internal - SHARE.EXE - CLOSE ALL FILES FOR GIVEN COMPUTER
AX = 5D03h
DS:DX -> DOS parameter list (see AX=5D00h), only computer ID used
Return: CF set on error
AX = error code (see AH=59h)
CF clear if successful
Notes: error unless SHARE is loaded (calls [SysFileTable-30h]) (see AH=52h)
not supported by DR-DOS 3.41 and 5.0; returns error code 01h
SeeAlso: AX=5D02h,AX=5D04h
--------D-215D04-----------------------------
INT 21 U - DOS 3.1+ internal - SHARE.EXE - CLOSE ALL FILES FOR GIVEN PROCESS
AX = 5D04h
DS:DX -> DOS parameter list (see AX=5D00h), only computer ID and
process ID fields used
Return: CF set on error
AX = error code (see AH=59h)
CF clear if successful
Notes: error unless SHARE is loaded (calls [SysFileTable-2Ch]) (see AH=52h)
not supported by DR-DOS 3.41 and 5.0; returns error code 01h
SeeAlso: AX=5D02h,AX=5D03h,INT 2F/AX=111Dh
--------D-215D05-----------------------------
INT 21 U - DOS 3.1+ internal - SHARE.EXE - GET OPEN FILE LIST ENTRY
AX = 5D05h
DS:DX -> DOS parameter list (see AX=5D00h)
DPL's BX = index of sharing record (see AH=52h)
DPL's CX = index of SFT in sharing record's SFT list
Return: CF clear if successful
ES:DI -> ASCIZ filename
BX = network machine number of SFT's owner
CX = number of locks held by SFT's owner
CF set if either index out of range
AX = 0012h (no more files)
Notes: error unless SHARE is loaded (calls [SysFileTable-18h]) (see AH=52h)
names are always canonical fully-qualified, such as returned by AH=60h
not supported by DR-DOS 3.41 and 5.0, but does not return an error
SeeAlso: AH=5Ch,AH=60h
--------D-215D06-----------------------------
INT 21 U - DOS 3.0+ internal - GET ADDRESS OF DOS SWAPPABLE DATA AREA
AX = 5D06h
Return: CF set on error
AX = error code (see AH=59h)
CF clear if successful
DS:SI -> nonreentrant data area (includes all three DOS stacks)
(critical error flag is first byte)
CX = size in bytes of area which must be swapped while in DOS
DX = size in bytes of area which must always be swapped
Notes: the Critical Error flag is used in conjunction with the InDOS flag
(see AH=34h) to determine when it is safe to enter DOS from a TSR
setting CritErr flag allows use of functions 50h/51h from INT 28h under
DOS 2.x by forcing use of correct stack
swapping the data area allows reentering DOS unless DOS is in a
critical section delimited by INT 2A/AH=80h and INT 2A/AH=81h,82h
under DOS 4.0, AX=5D0Bh should be used instead of this function
SHARE and other DOS utilities consult the byte at offset 04h in the
DOS data segment (see INT 2F/AX=1203h) to determine the SDA format
in use: 00h = DOS 3.x, 01h = DOS 4.0-6.0, other = error.
DR-DOS 3.41+ supports this function, but the SDA format beyond the
first 18h bytes is completely different from MS-DOS
SeeAlso: AX=5D0Bh,INT 2A/AH=80h,INT 2A/AH=81h,INT 2A/AH=82h
Format of DOS 3.10-3.30 Swappable Data Area:
Offset Size Description
-34 BYTE (DOS 3.10+) printer echo flag (00h off, FFh active)
-31 BYTE (DOS 3.30) current switch character
-28 BYTE (DOS 3.30) incremented on each INT 21/AX=5E01h call
-27 16 BYTEs (DOS 3.30) machine name set by INT 21/AX=5E01h
-11 5 WORDs zero-terminated list of offsets which need to be patched to
enable critical-section calls (see INT 2A/AH=80h)
-1 BYTE unused padding
---start of actual SDA---
00h BYTE critical error flag ("ErrorMode")
01h BYTE InDOS flag (count of active INT 21 calls)
02h BYTE drive on which current critical error occurred, or FFh
(DR-DOS sets to drive number during INT 24, 00h otherwise)
03h BYTE locus of last error
04h WORD extended error code of last error
06h BYTE suggested action for last error
07h BYTE class of last error
08h DWORD ES:DI pointer for last error
0Ch DWORD current DTA
10h WORD current PSP
12h WORD stores SP across an INT 23
14h WORD return code from last process termination (zerod after reading
with AH=4Dh)
16h BYTE current drive
17h BYTE extended break flag
---remainder need only be swapped if in DOS---
18h WORD value of AX on call to INT 21
1Ah WORD PSP segment for sharing/network
1Ch WORD network machine number for sharing/network (0000h = us)
1Eh WORD first usable memory block found when allocating memory
20h WORD best usable memory block found when allocating memory
22h WORD last usable memory block found when allocating memory
24h WORD memory size in paragraphs (used only during initialization)
26h WORD last entry checked during directory search
28h BYTE flag: INT 24 returned Fail
29h BYTE flags: allowable INT 24 actions (passed to INT 24 in AH)
2Ah BYTE directory flag (00h directory, 01h file)
2Bh BYTE flag: FFh if Ctrl-Break termination, 00h otherwise
2Ch BYTE flag: allow embedded blanks in FCB
2Dh BYTE padding (unused)
2Eh BYTE day of month
2Fh BYTE month
30h WORD year - 1980
32h WORD number of days since 1-1-1980
34h BYTE day of week (0 = Sunday)
35h BYTE flag: console swapped during read from device
36h BYTE flag: safe to call INT 28 if nonzero
37h BYTE flag: if nonzero, INT 24 Abort turned into INT 24 Fail
(set only during process termination)
38h 26 BYTEs device driver request header (see INT 2F/AX=0802h)
52h DWORD pointer to device driver entry point (used in calling driver)
56h 22 BYTEs device driver request header for I/O calls
6Ch 14 BYTEs device driver request header for disk status check
7Ah DWORD pointer to device I/O buffer???
7Eh WORD ???
80h WORD ???
82h BYTE type of PSP copy (00h=simple for INT 21/AH=26h, FFh=make child)
83h BYTE padding (unused)
84h 3 BYTEs 24-bit user number (see AH=30h)
87h BYTE OEM number (see AH=30h)
88h WORD offset to error code conversion table for INT 25/INT 26
8Ah 6 BYTEs CLOCK$ transfer record (see AH=52h)
90h BYTE device I/O buffer for single-byte I/O functions
91h BYTE padding??? (unused)
92h 128 BYTEs buffer for filename
112h 128 BYTEs buffer for filename
192h 21 BYTEs findfirst/findnext search data block (see AH=4Eh)
1A7h 32 BYTEs directory entry for found file (see AH=11h)
1C7h 81 BYTEs copy of current directory structure for drive being accessed
218h 11 BYTEs FCB-format filename for device name comparison
223h BYTE terminating NUL for above filename
224h 11 BYTEs wildcard destination specification for rename (FCB format)
22Fh BYTE terminating NUL for above spec
230h BYTE ???
231h WORD destination file/directory starting sector
233h 5 BYTEs ???
238h BYTE extended FCB file attribute
239h BYTE type of FCB (00h regular, FFh extended)
23Ah BYTE directory search attributes
23Bh BYTE file open/access mode
23Ch BYTE file found/delete flag
bit 0: file found
bit 4: file deleted
23Dh BYTE flag: device name found on rename, or file not found
23Eh BYTE splice flag (file name and directory name together)
23Fh BYTE flag indicating how DOS function was invoked
(00h = direct INT 20/INT 21, FFh = server call AX=5D00h)
240h BYTE sector position within cluster
241h BYTE flag: translate sector/cluster (00h no, 01h yes)
242h BYTE flag: 00h if read, 01h if write
243h BYTE current working drive number
244h BYTE cluster factor
245h BYTE flag: cluster split mode
246h BYTE line edit (AH=0Ah) insert mode flag (nonzero = on)
247h BYTE canonicalized filename referred to existing file/dir if FFh
248h BYTE volume ID flag
249h BYTE type of process termination (00h-03h) (see AH=4Dh)
24Ah BYTE file create flag (00h = no)
24Bh BYTE value with which to replace first byte of deleted file's name
(normally E5h, but 00h as described under INT 21/AH=13h)
24Ch DWORD pointer to Drive Parameter Block for critical error invocation
temp: used during process termination
250h DWORD pointer to stack frame containing user registers on INT 21
254h WORD stores SP across INT 24
256h DWORD pointer to DOS Drive Parameter Block for ???
25Ah WORD saving partial cluster number
25Ch WORD temp: sector of work current cluster
25Eh WORD high part of cluster number (only low byte referenced)
260h WORD ??? temp
262h BYTE Media ID byte returned by AH=1Bh,1Ch
263h BYTE padding (unused)
264h DWORD pointer to device header
268h DWORD pointer to current SFT
26Ch DWORD pointer to current directory structure for drive being accessed
270h DWORD pointer to caller's FCB
274h WORD number of SFT to which file being opened will refer
276h WORD temporary storage for file handle
278h DWORD pointer to a JFT entry in process handle table (see AH=26h)
27Ch WORD offset in DOS DS of first filename argument
27Eh WORD offset in DOS DS of second filename argument
280h WORD offset of last component in pathname or FFFFh
282h WORD offset of transfer address to add
284h WORD last relative cluster within file being accessed
286h WORD temp: absolute cluster number being accessed
288h WORD directory sector number
28Ah WORD ??? current cluster number
28Ch WORD ??? current offset in file DIV bytes per sector
28Eh WORD current sector number
290h WORD current byte offset within sector
292h DWORD current offset in file
296h DWORD temp: file byte count
29Ah WORD temp: file byte count
29Ch WORD free file cluster entry
29Eh WORD last file cluster entry
2A0h WORD next file cluster number
2A2h DWORD number of bytes appended to file
2A6h DWORD pointer to current work disk buffer
2AAh DWORD pointer to working SFT
2AEh WORD used by INT 21 dispatcher to store caller's BX
2B0h WORD used by INT 21 dispatcher to store caller's DS
2B2h WORD temporary storage while saving/restoring caller's registers
2B4h DWORD pointer to prev call frame (offset 250h) if INT 21 reentered
also switched to for duration of INT 24
2B8h 21 BYTEs FindFirst search data for source file(s) of a rename operation
(see AH=4Eh)
2CDh 32 BYTEs directory entry for file being renamed (see AH=11h for format)
2EDh 331 BYTEs critical error stack
403h 35 BYTEs scratch SFT
438h 384 BYTEs disk stack (functions greater than 0Ch, INT 25,INT 26)
5B8h 384 BYTEs character I/O stack (functions 01h through 0Ch)
---DOS 3.2,3.3x only---
738h BYTE device driver lookahead flag (usually printer) (see AH=64h)
739h BYTE volume change flag
73Ah BYTE flag: virtual open
73Bh BYTE ???
--------D-215D07-----------------------------
INT 21 U - DOS 3.1+ network - GET REDIRECTED PRINTER MODE
AX = 5D07h
Return: DL = mode
00h redirected output is combined
01h redirected output in separate print jobs
SeeAlso: AX=5D08h,AX=5D09h,INT 2F/AX=1125h
--------D-215D08-----------------------------
INT 21 U - DOS 3.1+ network - SET REDIRECTED PRINTER MODE
AX = 5D08h
DL = mode
00h redirected output is combined
01h redirected output placed in separate jobs, start new print job
now
SeeAlso: AX=5D07h,AX=5D09h,INT 2F/AX=1125h
--------D-215D09-----------------------------
INT 21 U - DOS 3.1+ network - FLUSH REDIRECTED PRINTER OUTPUT
AX = 5D09h
Notes: forces redirected printer output to be printed, and starts a new print
job
this function is also supported by 10Net, which calls it Terminate All
Spool Jobs, and does not flush if in "combine" mode
SeeAlso: AX=5D07h,AX=5D08h,INT 2F/AX=1125h
--------D-215D0A-----------------------------
INT 21 - DOS 3.1+ - SET EXTENDED ERROR INFORMATION
AX = 5D0Ah
DS:DX -> 11-word DOS parameter list (see AX=5D00h)
Return: nothing. next call to AH=59h will return values from fields AX,BX,CX,
DX,DI, and ES in corresponding registers
Notes: documented for DOS 5+, but undocumented in earlier versions
the MS-DOS Programmer's Reference incorrectly states that this call was
introduced in DOS 4, and fails to mention that the ERROR structure
passed to this function is a DOS parameter list.
BUG: DR-DOS 3.41 and 5.0 read the value for ES from the DS field of the DPL;
fortunately, MS-DOS ignores the DS field, allowing a generic routine
which sets both DS and ES fields to the same value
SeeAlso: AH=59h
--------D-215D0B-----------------------------
INT 21 OU - DOS 4.x only internal - GET DOS SWAPPABLE DATA AREAS
AX = 5D0Bh
Return: CF set on error
AX = error code (see AH=59h)
CF clear if successful
DS:SI -> swappable data area list (see below)
Notes: copying and restoring the swappable data areas allows DOS to be
reentered unless it is in a critical section delimited by calls to
INT 2A/AH=80h and INT 2A/AH=81h,82h
SHARE and other DOS utilities consult the byte at offset 04h in the
DOS data segment (see INT 2F/AX=1203h) to determine the SDA format
in use: 00h = DOS 3.x, 01h = DOS 4.0-6.0, other = error.
DOS 5+ use the SDA format listed below, but revert back to the DOS 3.x
call for finding the SDA (see AX=5D06h)
SeeAlso: AX=5D06h,INT 2A/AH=80h,INT 2A/AH=81h,INT 2A/AH=82h,INT 2F/AX=1203h
Format of DOS 4.x swappable data area list:
Offset Size Description
00h WORD count of data areas
02h N BYTEs "count" copies of data area record
Offset Size Description
00h DWORD address
04h WORD length and type
bit 15 set if swap always, clear if swap in DOS
bits 14-0: length in bytes
Format of DOS 4.0-6.0 swappable data area:
Offset Size Description
-34 BYTE printer echo flag (00h off, FFh active)
-31 BYTE current switch character (ignored by DOS 5+)
-28 BYTE incremented on each INT 21/AX=5E01h call
-27 16 BYTEs machine name set by INT 21/AX=5E01h
-11 5 WORDs zero-terminated list of offsets which need to be patched to
enable critical-section calls (see INT 2A/AH=80h)
(all offsets are 0D0Ch, but this list is still present for
DOS 3.x compatibility)
-1 BYTE unused padding
---start of actual SDA---
00h BYTE critical error flag ("ErrorMode")
01h BYTE InDOS flag (count of active INT 21 calls)
02h BYTE drive on which current critical error occurred or FFh
03h BYTE locus of last error
04h WORD extended error code of last error
06h BYTE suggested action for last error
07h BYTE class of last error
08h DWORD ES:DI pointer for last error
0Ch DWORD current DTA
10h WORD current PSP
12h WORD stores SP across an INT 23
14h WORD return code from last process termination (zerod after reading
with AH=4Dh)
16h BYTE current drive
17h BYTE extended break flag
18h BYTE flag: code page switching
19h BYTE flag: copy of previous byte in case of INT 24 Abort
---remainder need only be swapped if in DOS---
1Ah WORD value of AX on call to INT 21
1Ch WORD PSP segment for sharing/network
1Eh WORD network machine number for sharing/network (0000h = us)
20h WORD first usable memory block found when allocating memory
22h WORD best usable memory block found when allocating memory
24h WORD last usable memory block found when allocating memory
26h WORD memory size in paragraphs (used only during initialization)
28h WORD last entry checked during directory search
2Ah BYTE flag: nonzero if INT 24 Fail
2Bh BYTE flags: allowable INT 24 responses (passed to INT 24 in AH)
2Ch BYTE flag: do not set directory if nonzero
2Dh BYTE flag: program aborted by ^C
2Eh BYTE flag: allow embedded blanks in FCB
2Fh BYTE padding (unused)
30h BYTE day of month
31h BYTE month
32h WORD year - 1980
34h WORD number of days since 1-1-1980
36h BYTE day of week (0 = Sunday)
37h BYTE flag: console swapped during read from device
38h BYTE flag: safe to call INT 28 if nonzero
39h BYTE flag: abort currently in progress, turn INT 24 Abort into Fail
3Ah 30 BYTEs device driver request header (see INT 2F/AX=0802h) for
device calls
58h DWORD pointer to device driver entry point (used in calling driver)
5Ch 22 BYTEs device driver request header for I/O calls
72h 14 BYTEs device driver request header for disk status check
80h DWORD pointer to device I/O buffer
84h WORD ???
86h WORD ??? (0)
88h BYTE type of PSP copy (00h=simple for INT 21/AH=26h, FFh=make child)
89h DWORD start offset of file region to lock/unlock
8Dh DWORD length of file region to lock/unlock
91h BYTE padding (unused)
92h 3 BYTEs 24-bit user number (see AH=30h)
95h BYTE OEM number (see AH=30h)
96h 6 BYTEs CLOCK$ transfer record (see AH=52h)
9Ch BYTE device I/O buffer for single-byte I/O functions???
9Dh BYTE padding???
9Eh 128 BYTEs buffer for filename
11Eh 128 BYTEs buffer for filename
19Eh 21 BYTEs findfirst/findnext search data block (see AH=4Eh)
1B3h 32 BYTEs directory entry for found file (see AH=11h)
1D3h 88 BYTEs copy of current directory structure for drive being accessed
22Bh 11 BYTEs FCB-format filename for device name comparison
236h BYTE terminating NUL for above filename
237h 11 BYTEs wildcard destination specification for rename (FCB format)
242h BYTE terminating NUL for above spec
243h BYTE ???
244h WORD ???
246h 5 BYTEs ???
24Bh BYTE extended FCB file attributes
24Ch BYTE type of FCB (00h regular, FFh extended)
24Dh BYTE directory search attributes
24Eh BYTE file open/access mode
24Fh BYTE ??? flag bits
250h BYTE flag: device name found on rename, or file not found
251h BYTE splice flag??? (file name and directory name together)
252h BYTE flag indicating how DOS function was invoked
(00h = direct INT 20/INT 21, FFh = server call AX=5D00h)
253h BYTE ???
254h BYTE ???
255h BYTE ???
256h BYTE ???
257h BYTE ???
258h BYTE ???
259h BYTE ???
25Ah BYTE canonicalized filename referred to existing file/dir if FFh
25Bh BYTE ???
25Ch BYTE type of process termination (00h-03h)
25Dh BYTE ???
25Eh BYTE ???
25Fh BYTE ???
260h DWORD pointer to Drive Parameter Block for critical error invocation
264h DWORD pointer to stack frame containing user registers on INT 21
268h WORD stores SP???
26Ah DWORD pointer to DOS Drive Parameter Block for ???
26Eh WORD segment of disk buffer
270h WORD ???
272h WORD ???
274h WORD ???
276h WORD ???
278h BYTE Media ID byte returned by AH=1Bh,1Ch
279h BYTE ??? (doesn't seem to be referenced)
27Ah DWORD pointer to ???
27Eh DWORD pointer to current SFT
282h DWORD pointer to current directory structure for drive being accessed
286h DWORD pointer to caller's FCB
28Ah WORD SFT index to which file being opened will refer
28Ch WORD temporary storage for file handle
28Eh DWORD pointer to a JFT entry in process handle table (see AH=26h)
292h WORD offset in DOS DS of first filename argument
294h WORD offset in DOS DS of second filename argument
296h WORD ???
298h WORD ???
29Ah WORD ???
29Ch WORD ???
29Eh WORD ???
2A0h WORD ???
2A2h WORD ??? directory cluster number???
2A4h DWORD ???
2A8h DWORD ???
2ACh WORD ???
2AEh DWORD offset in file???
2B2h WORD ???
2B4h WORD bytes in partial sector
2B6h WORD number of sectors
2B8h WORD ???
2BAh WORD ???
2BCh WORD ???
2BEh DWORD number of bytes appended to file
2C2h DWORD pointer to ??? disk buffer
2C6h DWORD pointer to ??? SFT
2CAh WORD used by INT 21 dispatcher to store caller's BX
2CCh WORD used by INT 21 dispatcher to store caller's DS
2CEh WORD temporary storage while saving/restoring caller's registers
2D0h DWORD pointer to prev call frame (offset 264h) if INT 21 reentered
also switched to for duration of INT 24
2D4h WORD open mode/action for INT 21/AX=6C00h
2D6h BYTE ??? (set to 00h by INT 21h dispatcher, 02h when a read is
performed, and 01h or 03h by INT 21/AX=6C00h)
2D7h WORD ??? apparently unused
2D9h DWORD stored ES:DI for AX=6C00h
2DDh WORD extended file open action code (see AX=6C00h)
2DFh WORD extended file open attributes (see AX=6C00h)
2E1h WORD extended file open file mode (see AX=6C00h)
2E3h DWORD pointer to filename to open (see AX=6C00h)
2E7h WORD ???
2E9h WORD ???
2EBh BYTE ???
2ECh WORD stores DS during call to [List-of-Lists + 37h]
2EEh WORD ???
2F0h BYTE ???
2F1h WORD ??? bit flags
2F3h DWORD pointer to user-supplied filename
2F7h DWORD pointer to ???
2FBh WORD stores SS during call to [List-of-Lists + 37h]
2FDh WORD stores SP during call to [List-of-Lists + 37h]
2FFh BYTE flag, nonzero if stack switched in calling [List-of-Lists+37h]
300h 21 BYTEs FindFirst search data for source file(s) of a rename operation
(see AH=4Eh)
315h 32 BYTEs directory entry for file being renamed (see AH=11h)
335h 331 BYTEs critical error stack
480h 384 BYTEs disk stack (functions greater than 0Ch, INT 25,INT 26)
600h 384 BYTEs character I/O stack (functions 01h through 0Ch)
780h BYTE device driver lookahead flag (usually printer) (see AH=64h)
781h BYTE volume change flag
782h BYTE flag: virtual open
783h BYTE ???
784h WORD ???
786h WORD ???
788h WORD ???
78Ah WORD ???
--------D-215E00-----------------------------
INT 21 - DOS 3.1+ network - GET MACHINE NAME
AX = 5E00h
DS:DX -> 16-byte buffer for ASCIZ machine name
Return: CF clear if successful
CH = validity
00h name invalid
nonzero valid
CL = NetBIOS number for machine name
DS:DX buffer filled with blank-paded name
CF set on error
AX = error code (01h) (see AH=59h)
Note: supported by OS/2 v1.3+ compatibility box, PC-NFS
SeeAlso: AX=5E01h
--------N-215E00-----------------------------
INT 21 - 10NET v5.0 - GET MACHINE NAME
AX = 5E00h
Return: CL = redirector's NetBIOS name number
ES:DI -> network node ID
SeeAlso: AX=5E01h"10NET"
--------D-215E01CH00-------------------------
INT 21 - DOS 3.1+ network - SET MACHINE NAME
AX = 5E01h
CH = 00h undefine name (make it invalid)
<> 0 define name
CL = name number
DS:DX -> 15-character blank-padded ASCIZ name
SeeAlso: AX=5E00h
--------N-215E01-----------------------------
INT 21 - 10NET v5.0 - GET LOCAL 10NET CONFIGURATION TABLE
AX = 5E01h
CX = length of buffer
DS:DX -> buffer for 10Net configuration table
SeeAlso: AX=5E00h"10NET",INT 6F/AH=02h,INT 6F/AH=03h
Format of 10Net Configuration Table:
Offset Size Description
00h 8 BYTEs user name
08h 15 BYTEs node ID
17h 3 BYTEs unique portion of Ethernet address
1Ah BYTE Who group number
1Bh WORD services mask (see below)
1Dh DWORD serial number
21h BYTE maximum concurrent users with same serial number allowed on net
22h BYTE chat mask (see below)
23h BYTE internal system bits (see below)
24h 9 BYTEs version number in format MM.mm.xxx
2Dh BYTE flag: 01h if machine is a PS/2
2Eh BYTE flag: 03h if 80386
2Fh BYTE spool termination mode: 01h concatenate, 02h truncate
(see AX=5D09h)
30h WORD autospool timeout in clock ticks
32h WORD monitor timeout in clock ticks
34h WORD unused
36h WORD chat timeout in clock ticks
38h WORD netBIOS session timeout in half-seconds
3Ah WORD datagram send timeout in seconds
3Ch WORD keyboard value for initiating chat mode
3Eh WORD Who timeout in clock ticks
40h BYTE flag: 01h if server should process rom NetBIOS Post return
41h BYTE flag: 01h if FCBs should be recycled
42h 3 BYTEs signature "DBG"
45h BYTE last interrupt (21h or 6Fh)
46h BYTE last INT 21 AH value
47h BYTE last INT 6F AH value
48h WORD last item posted
4Ah WORD last item free-posted
4Ch WORD last item handled by server
4Eh WORD last redirector send NCB
50h WORD last redirector receive NCB
52h 4 BYTEs signature "TABL"
56h WORD offset of datagram buffer table header
58h WORD offset of chat buffer table header
5Ah WORD offset of Raw buffer table header
5Ch WORD offset of Workstation buffer table header
5Eh WORD offset of server receive-any table header
60h WORD offset of Tiny buffer table header
62h WORD offset of zero-length buffer table (NCBs)
64h WORD offset of Rdr (Redirector Mount) table header
66h WORD offset of Ntab (Redirector Session) table header
68h WORD offset of FCB table header
6Ah WORD offset of user file handle table header
6Ch WORD offset of workstation printer RDR extension table header
6Eh WORD offset of server shared device table header
70h WORD offset of server connection table header
72h WORD offset of server login table header
74h WORD offset of server file table header
76h WORD offset of server shared file table header
78h WORD offset of server record lock table header
7Ah WORD offset of remote printer claim table header
7Ch WORD offset of remote printer device table header
7Eh WORD offset of print server mount table header
80h WORD offset of print server sessions table header
82h WORD offset of print server print job structure table header
84h WORD offset of print server pooled device table header
86h WORD size of workstation buffer
88h WORD size of server receive-any buffer
8Ah WORD size of server raw I/O buffer
8Ch 6 BYTEs reserved
92h DWORD pointer to profile pathname
96h BYTE datagram retry count
97h BYTE NetBIOS LAN adapter number
98h 6 BYTEs physical Ethernet address
9Eh BYTE NetBIOS server name number
9Fh BYTE NetBIOS redirector name number
A0h BYTE 10Net interrupt number
A1h BYTE flag: chat is loaded
A2h BYTE flag: INT 6F APIs permanently loaded
A3h BYTE flag: file security present
A4h WORD reserved
A6h BYTE fixed mount bitmask for drives A:-H:
A7h BYTE reserved
A8h WORD 10Net system flags (see below)
AAh BYTE monitor flags (see below)
ABh 5 BYTEs reserved
B0h WORD offset of monitor timer block
B2h WORD offset of server timer block
B4h WORD offset of chat timer block
B6h WORD timer chain
B8h 4 BYTEs signature "TALS"
BCh WORD number of 10Net sends
BEh WORD number of 10Net receives
C0h WORD number of no-buffer conditions
C2h WORD number of dropped posted messages
C4h WORD number of server NCB errors
C6h WORD number of redirector NCB errors
C8h WORD number of datagram send/receive errors
CAh WORD number of dropped Whos
CCh WORD number of dropped submits
CEh WORD number of session aborts
D0h BYTE number of NetBIOS interface-busy errors
D1h BYTE last NetBIOS bad post command
D2h BYTE last NetBIOS bad redirector command
D3h BYTE do send datagram send/receive error command
D4h DWORD -> DOS system parameter table
D8h WORD number of DOS physical drives
DAh WORD offset of DOS PSP field in DOS data segment
DCh WORD offset of in-DOS flag in DOS data segment
DEh WORD DOS data segment
E0h WORD offset of DOS SFT in DOS data segment
E2h WORD offset of number-of-physical-units field in DOS data segment
E4h WORD 10Net code segment
E6h WORD 10Net data segment
E8h WORD 10Net common server segment
EAh WORD 10Net file server segment
ECh WORD 10Net print server segment
EEh WORD 10Net remote printer segment
Note: documentation lists field at offset D0h as a WORD, but all following
offsets are as though it were a BYTE; if it is indeed a WORD, all
offsets after D0h must be increased by one byte
Format of 10Net Table Header:
Offset Size Description
-16 4 BYTEs table identifier
-12 WORD peak number of tables allocated
-10 WORD number of tables currently in use
-8 WORD total number of tables
-6 WORD size of each table
-4 WORD offset of first allocated table
-2 WORD offset of first free table
Bitfields for services mask:
bit 0 workstation
bit 1 file server
bit 2 print queue server
bit 3 de-spool server
Bitfields for chat mask:
bit 0 chat permitted
bit 1 bell enabled
bit 2 chat keyboard initiated
bit 3 in INT 16 handler
bit 4 in Get Input
bit 5 display has timed out
bit 6 chat is idle
Bitfields for internal system bits:
bit 0 submit permitted
bit 1 submit initiated
bit 2 submit executing
bit 3 internal client call/chat/spool/autospool
bit 4 in spool termination
bit 5 print permitted
bit 6 waiting for keyboard input
Bitfields for 10Net System Flags:
bit 0 in NetBIOS
bit 1 processing INT 28
bit 2 is server
bit 3 in net user-DOS function
bit 4 in DOS user-DOS function
bit 5 in net for user non-DOS function
bit 6 in server DOS function
bit 7 in server non-DOS function
bit 8 in terminate
bit 10 in user on server request
bit 13 in DOS for user on server
bit 14 disable critical error handler
Bitfields for Monitor Flags:
bit 0 waiting for monitor response
bit 4 in monitor get-input routine
bit 5 monitor display timeout
bit 6 sensing for escape key
--------D-215E02-----------------------------
INT 21 - DOS 3.1+ network - SET NETWORK PRINTER SETUP STRING
AX = 5E02h
BX = redirection list index (see AX=5F02h)
CX = length of setup string
DS:SI -> setup string
Return: CF clear if successful
CF set on error
AX = error code (01h) (see AH=59h)
Note: also supported by 10NET v5.0
SeeAlso: AX=5E03h,INT 2F/AX=111Fh
--------D-215E03-----------------------------
INT 21 - DOS 3.1+ network - GET NETWORK PRINTER SETUP STRING
AX = 5E03h
BX = redirection list index (see AX=5F02h)
ES:DI -> 64-byte buffer for setup string
Return: CF clear if successful
CX = length of setup string
ES:DI buffer filled
CF set on error
AX = error code (01h) (see AH=59h)
Note: also supported by 10NET v5.0, but 10NET is documented as using DS:SI
instead of ES:DI
SeeAlso: AX=5E02h,INT 2F/AX=111Fh
--------D-215E04-----------------------------
INT 21 - DOS 3.1+ network - SET PRINTER MODE
AX = 5E04h
BX = redirection list index (see AX=5F02h)
DX = mode
bit 0: set if binary, clear if text (tabs expanded to blanks)
Return: CF set on error
AX = error code (see AH=59h)
CF clear if successful
Note: calls INT 2F/AX=111Fh with 5E04h on stack
SeeAlso: AX=5E05h"DOS",INT 2F/AX=111Fh
--------N-215E04-----------------------------
INT 21 - 10NET v5.0 - INITIATE PRINT JOB
AX = 5E04h
BX = zero-based redirection list index (see AX=5F02h)
DS:DX -> extended workstation printer setup structure (see below)
Return: CF clear if successful
CF set on error
AX = error code (see AH=59h)
SeeAlso: AX=5E05h"10NET",AX=5E06h"10NET"
Format of extended workstation printer setup structure:
Offset Size Description
00h BYTE notification flags (see below)
01h BYTE job control mask (see below)
02h WORD days to retain file
04h WORD test print length
06h BYTE number of copies to print
07h BYTE compression algorithm
08h BYTE tab width (00h = don't expand)
09h BYTE initiation type (00h normal, 01h non-spooled)
0Ah 38 BYTEs job start operation notification instructions
30h 32 BYTEs comment for job
50h 64 BYTEs output filename or non-spooled file
Bitfields for notification flags:
bit 0 user at print start
bit 1 operator at start, with reply
bit 2 user at print completion
bit 3 operator at completion, with reply
bit 4 user on queue switch
bit 5 operator on queue switch, with reply
bit 6 user on print error
Bitfields for job control mask:
bit 0 print banner page
bit 1 eject page at end of job
bit 2 mark as "held" (queue but don't print)
bit 3 rush job (queue at top)
bit 4 overwrite file with zeros before deletion
bit 5 hyperspool if possible
--------D-215E05-----------------------------
INT 21 - DOS 3.1+ network - GET PRINTER MODE
AX = 5E05h
BX = redirection list index (see AX=5F02h)
Return: CF set on error
AX = error code (see AH=59h)
CF clear if successful
DX = printer mode (see AX=5E04h)
Note: calls INT 2F/AX=111Fh with 5E05h on stack
SeeAlso: AX=5E04h"DOS",INT 2F/AX=111Fh
--------N-215E05-----------------------------
INT 21 - 10NET v5.0 - TERMINATE PRINT JOB
AX = 5E05h
BX = zero-based redirection list index (see AX=5F02h)
Return: CF clear if successful
CF set on error
AX = error code (see AH=59h)
Note: this call resets the spool termination mode to "truncate"
(see AX=5D08h)
SeeAlso: AX=5E04h"10NET",AX=5E06h
--------N-215E06-----------------------------
INT 21 - 10NET v5.0 - GET/SET 10NET WORKSTATION PRINTER SETUP STRUCTURE
AX = 5E06h
BX = zero-based redirection list index (see AX=5F02h)
CX = operation (06h set, 07h get)
DS:DX -> buffer for setup structure (same as first nine bytes of
workstation printer setup) (see AX=5E04h"10NET")
Return: CF clear if successful
DS:DX buffer updated on get
CF set on error
AX = error code (see AH=59h)
SeeAlso: AX=5E04h"10NET",AX=5E05h"10NET"
--------D-215F00-----------------------------
INT 21 - DOS 3.1+ network - GET REDIRECTION MODE
AX = 5F00h
BL = redirection type
03h printer
04h disk drive
Return: CF set on error
AX = error code (see AH=59h)
CF clear if successful
BH = redirection state
00h off
01h on
Note: calls INT 2F/AX=111Eh with AX on top of the stack
SeeAlso: AX=5F01h,INT 2F/AX=111Eh
--------D-215F01-----------------------------
INT 21 - DOS 3.1+ network - SET REDIRECTION MODE
AX = 5F01h
BL = redirection type
03h printer
04h disk drive
BH = redirection state
00h off
01h on
Return: CF set on error
AX = error code (see AH=59h)
CF clear if successful
Notes: when redirection is off, the local device (if any) rather than the
remote device is used
calls INT 2F/AX=111Eh with AX on top of the stack
SeeAlso: AX=5F00h,INT 2F/AX=111Eh
--------D-215F02-----------------------------
INT 21 - DOS 3.1+ network - GET REDIRECTION LIST ENTRY
AX = 5F02h
BX = zero-based redirection list index
CX = 0000h (LANtastic)
DS:SI -> 16-byte buffer for ASCIZ local device name
ES:DI -> 128-byte buffer for ASCIZ network name
Return: CF clear if successful
BH = device status
00h valid
01h invalid
BL = device type
03h printer
04h disk drive
CX = user data previously set with AX=5F03h
DS:SI and ES:DI buffers filled
DX,BP destroyed
CF set on error
AX = error code (01h,12h) (see AH=59h)
Notes: this function is passed through to INT 2F/AX=111Eh by the DOS kernel
error code 12h is returned if BX is greater than the size of the list
also supported by Banyan VINES, PC-NFS, LANtastic, and 10NET
SeeAlso: AX=5F03h,INT 2F/AX=111Eh
--------D-215F03-----------------------------
INT 21 - DOS 3.1+ network - REDIRECT DEVICE
AX = 5F03h
BL = device type
03h printer
04h disk drive
CX = user data to save
0000h for LANtastic
4E57h ("NW") for NetWare 4.0 requester
DS:SI -> ASCIZ local device name (16 bytes max)
ES:DI -> ASCIZ network name + ASCIZ password (128 bytes max total)
Return: CF clear if successful
CF set on error
AX = error code (01h,03h,05h,08h,0Fh,12h) (see AH=59h)
Notes: if device type is disk drive, DS:SI must point at either a null string
or a string consisting the drive letter followed by a colon; if a
null string, the network attempts to access the destination without
redirecting a local drive
the DOS kernel calls INT 2F/AX=111Eh with AX on top of the stack
also supported by Banyan VINES, LANtastic, and 10NET
SeeAlso: AX=5F02h,AX=5F04h,INT 2F/AX=111Eh
--------D-215F04-----------------------------
INT 21 - DOS 3.1+ network - CANCEL REDIRECTION
AX = 5F04h
DS:SI -> ASCIZ local device name or path
CX = 4E57h ("NW") for NetWare 4.0 requester
Return: CF clear if successful
CF set on error
AX = error code (01h,03h,05h,08h,0Fh,12h) (see AH=59h)
Notes: the DS:SI string must be either a local device name, a drive letter
followed by a colon, or a network directory beginning with two
backslashes
the DOS kernel calls INT 2F/AX=111Eh with AX on top of the stack
also supported by Banyan VINES, LANtastic, and 10NET
SeeAlso: AX=5F03h,INT 2F/AX=111Eh
--------D-215F05-----------------------------
INT 21 - DOS 4+ network - GET EXTENDED REDIRECTION LIST ENTRY
AX = 5F05h
BX = redirection list index
DS:SI -> buffer for ASCIZ source device name
ES:DI -> buffer for destination ASCIZ network path
Return: CF set on error
AX = error code (see AH=59h)
CF clear if successful
AX = server's network process ID handle (10NET)
BH = device status flag (bit 0 clear if valid)
BL = device type (03h if printer, 04h if drive)
CX = stored parameter value (user data) from AX=5F03h
BP = NETBIOS local session number
DS:SI buffer filled
ES:DI buffer filled
Notes: the local session number allows sharing the redirector's session number
if an error is caused on the NETBIOS LSN, the redirector may be unable
to correctly recover from errors
the DOS kernel calls INT 2F/AX=111Eh with AX on top of the stack
supported by DR-DOS 5.0
also supported by 10NET v5.0
SeeAlso: AX=5F06h"Network",INT 2F/AX=111Eh
--------O-215F05-----------------------------
INT 21 - STARLITE architecture - MAP LOCAL DRIVE LETTER TO REMOTE FILE SYSTEM
AX = 5F05h
DL = drive number (0=A:)
DS:SI -> ASCIZ name of the object to map the drive to
Return: CF set on error
AX = error code (see AH=59h)
CF clear if successful
SeeAlso: AX=5F06h"STARLITE"
--------N-215F06-----------------------------
INT 21 U - Network - GET FULL REDIRECTION LIST
AX = 5F06h
???
Return: ???
Notes: similar to AX=5F02h and AX=5F05h, but also returns redirections
excluded from those calls for various reasons
calls INT 2F/AX=111Eh with AX on top of the stack
SeeAlso: AX=5F05h"DOS",INT 2F/AX=111Eh
--------O-215F06-----------------------------
INT 21 - STARLITE architecture - UNMAP DRIVE LETTER
AX = 5F06h
DL = drive to be unmapped (0=A:)
Return: CF set on error
AX = error code (see AH=59h)
CF clear if successful
SeeAlso: AX=5F05h"STARLITE"
--------D-215F07-----------------------------
INT 21 - DOS 5+ - ENABLE DRIVE
AX = 5F07h
DL = drive number (0=A:)
Return: CF clear if successful
CF set on error
AX = error code (0Fh) (see AH=59h)
Note: simply sets the "valid" bit in the drive's CDS
SeeAlso: AH=52h,AX=5F08h"DOS"
--------O-215F07-----------------------------
INT 21 - STARLITE architecture - MAKE NAMED OBJECT AVAILABLE ON NETWORK
AX = 5F07h
DS:SI -> ASCIZ name of object to offer to network
ES:DI -> ASCIZ name under which object will be known on the network
MUST begin with three slashes
Return: CF set on error
AX = error code (see AH=59h)
CF clear if successful
SeeAlso: AX=5F08h"STARLITE"
--------D-215F08-----------------------------
INT 21 - DOS 5+ - DISABLE DRIVE
AX = 5F08h
DL = drive number (0=A:)
Return: CF clear if successful
CF set on error
AX = error code (0Fh) (see AH=59h)
Note: simply clears the "valid" bit in the drive's CDS
SeeAlso: AH=52h,AX=5F07h"DOS"
--------O-215F08-----------------------------
INT 21 - STARLITE architecture - REMOVE GLOBAL NETWORK NAME OF OBJECT
AX = 5F08h
DS:SI -> ASCIZ network name (not local name) of object to unshare
Return: CF set on error
AX = error code (see AH=59h)
CF clear if successful
SeeAlso: AX=5F07h"STARLITE"
--------O-215F09-----------------------------
INT 21 - STARLITE architecture - BIND TO NETWORK DEVICE
AX = 5F09h
DS:DX -> ASCIZ name of the device driver to attach to
Return: CF set on error
AX = error code (see AH=59h)
CF clear if successful
Note: the STARLITE distributed file system can attach to multiple networks
simultaneously
SeeAlso: AX=5F0Ah
--------O-215F0A-----------------------------
INT 21 - STARLITE architecture - DETACH FROM NETWORK DEVICE
AX = 5F0Ah
DS:DX -> ASCIZ name of device driver to detach from
Return: CF set on error
AX = error code (see AH=59h)
CF clear if successful
SeeAlso: AX=5F09h
--------N-215F30-----------------------------
INT 21 U - LAN Manager Enhanced DOS - ???
AX = 5F30h
???
Return: ???
--------N-215F32-----------------------------
INT 21 u - Named Pipes - LOCAL DosQNmPipeInfo
AX = 5F32h
BX = handle
CX = size of _PIPEINFO structure
DX = level (must be 0001h)
DS:SI -> _PIPEINFO structure (see below)
Return: CF clear if successful
_PIPEINFO structure filled in
CF set on error
AX = error code
Note: this function was introduced by LAN Manager but is also supported by
the Novell DOS Named Pipe Extender, Banyan VINES, OS/2 Virtual DOS
Machines, and others
SeeAlso: AX=5F33h,AX=5F34h
Format of _PIPEINFO structure:
Offset Size Description
00h WORD size of outgoing buffer
02h WORD size of incoming buffer
04h BYTE maximum number of instances allowed
05h BYTE current number of instances
06h BYTE length of the name (including terminating NUL)
07h N BYTEs name
--------N-215F33-----------------------------
INT 21 u - Named Pipes - LOCAL DosQNmPHandState
AX = 5F33h
BX = handle
Return: CF clear if successful
AH = pipe mode bit mask (see below)
AL = maximum number of instances
CF set on error
AX = error code
Note: this function was introduced by LAN Manager but is also supported by
the Novell DOS Named Pipe Extender, Banyan VINES, OS/2 Virtual DOS
Machines, and others
SeeAlso: AX=5F32h,AX=5F34h
Bitfields for pipe mode:
bit 7 set if nonblocking, clear if blocking
bit 6 set if server end, clear if client end
bit 2 set if write in message mode, clear if write in byte mode
bit 0 set if read in message mode, clear if read in byte mode
--------N-215F34-----------------------------
INT 21 u - Named Pipes - LOCAL DosSetNmPHandState
AX = 5F34h
BX = handle
CX = pipe mode bit mask
bit 15: set if nonblocking, clear if blocking
bit 8: set if read in message mode, clear if read in byte mode
Return: CF clear if successful
CF set if error
AX = error code
Note: this function was introduced by LAN Manager but is also supported by
the Novell DOS Named Pipe Extender, Banyan VINES, OS/2 Virtual DOS
Machines, and others
SeeAlso: AX=5F32h,AX=5F33h,AX=5F36h
--------N-215F35-----------------------------
INT 21 u - Named Pipes - LOCAL DosPeekNmPipe
AX = 5F35h
BX = handle
CX = buffer length
DS:SI -> buffer
Return: CF clear if successful
CX = bytes read
SI = bytes left in the pipe
DX = bytes left in the current message
DI = pipe status
0001h disconnected
0002h listening
0003h connected
0004h closing
CF set if error
AX = error code
Note: this function was introduced by LAN Manager but is also supported by
the Novell DOS Named Pipe Extender, Banyan VINES, OS/2 Virtual DOS
Machines, and others
SeeAlso: AX=5F38h,AX=5F39h,AX=5F51h
--------N-215F36-----------------------------
INT 21 u - Named Pipes - LOCAL DosTransactNmPipe
AX = 5F36h
BX = handle
CX = in buffer length
DS:SI -> in buffer
DX = out buffer length
ES:DI -> out buffer
Return: CF clear if successful
CX = bytes read
CF set on error
AX = error code
Note: this function was introduced by LAN Manager but is also supported by
the Novell DOS Named Pipe Extender, Banyan VINES, OS/2 Virtual DOS
Machines, and others
SeeAlso: AX=5F34h,AX=5F37h
--------N-215F37-----------------------------
INT 21 u - Named Pipes - DosCallNmPipe
AX = 5F37h
DS:SI -> DosCallNmPipe stack frame (see below)
Return: CF clear if successful
CX = bytes read
CF set on error
AX = error code
Note: this function was introduced by LAN Manager but is also supported by
the Novell DOS Named Pipe Extender, Banyan VINES, OS/2 Virtual DOS
Machines, and others
SeeAlso: AX=5F36h,AX=5F38h
Format of DosCallNmPipe stack frame:
Offset Size Description
00h DWORD timeout
04h DWORD -> bytes read WORD (not used!!)
08h WORD out buffer length
0Ah DWORD address of out buffer
0Eh WORD in buffer length
10h DWORD address of in buffer
14h DWORD address of pipe name
--------N-215F38-----------------------------
INT 21 u - Named Pipes - LOCAL DosWaitNmPipe - AWAIT AVAIL. OF PIPE INSTANCE
AX = 5F38h
DS:DX -> pipe name
BX:CX = timeout value
Return: CF clear if successful
CF set if error
AX = error code
Notes: when a client gets a return code of ERROR_PIPE_BUSY on attempting to
open a pipe, it should issue this call to wait until the pipe
instance becomes available again; on return from this call, the
client must attempt to open the pipe once again
this function was introduced by LAN Manager but is also supported by
the Novell DOS Named Pipe Extender, Banyan VINES, OS/2 Virtual DOS
Machines, and others
SeeAlso: AX=5F37h,AX=5F39h
--------N-215F39-----------------------------
INT 21 U - Named Pipes - LOCAL DosRawReadNmPipe
AX = 5F39h
BX = handle
CX = buffer length
DS:DX -> buffer
Return: CF clear if successful
CX = bytes read
CF set if error
AX = error code
Notes: this function was introduced by LAN Manager but is also supported by
the Novell DOS Named Pipe Extender, Banyan VINES, OS/2 Virtual DOS
Machines, and others
not documented in the LAN Manager Toolkit
SeeAlso: AX=5F35h,AX=5F3Ah,INT 2F/AX=1186h
--------N-215F3A-----------------------------
INT 21 U - Named Pipes - LOCAL DosRawWriteNmPipe
AX = 5F3Ah
BX = handle
CX = buffer length
DS:DX -> buffer
Return: CF clear if successful
CX = bytes written
CF set if error
AX = error code
Notes: this function was introduced by LAN Manager but is also supported by
the Novell DOS Named Pipe Extender, Banyan VINES, OS/2 Virtual DOS
Machines, and others
not documented in the LAN Manager Toolkit
SeeAlso: AX=5F39h,AX=5F3Bh,INT 2F/AX=118Fh
--------N-215F3B-----------------------------
INT 21 u - LAN Manager Enhanced DOS - NetHandleSetInfo
AX = 5F3Bh
BX = handle
CX = handle_info_1 structure length or sizeof DWORD
DI = parameter number to set
0000h all
0001h number of milliseconds
0002h number of characters
DS:DX -> handle_info_1 structure (DI=0000h) (see below)
or DWORD (DI=0001h or 0002h)
SI = level of information (0001h)
Return: CF clear if successful
CX = total bytes available
CF set if error
AX = error code
SeeAlso: AX=5F3Ch
Format of handle_info_1 structure:
Offset Size Description
00h DWORD number of milliseconds which workstation collects data before
it sends the data to the named pipe
04h DWORD number of characters which workstation collects before it
sends the data to the named pipe
--------N-215F3C-----------------------------
INT 21 u - LAN Manager Enhanced DOS - NetHandleGetInfo
AX = 5F3Ch
BX = handle
CX = length of handle_info_1 structure
DS:DX -> handle_info_1 structure (see AX=5F3Bh)
SI = level of information (must be 0001h)
Return: CF clear if successful
CX = total bytes available
CF set if error
AX = error code
SeeAlso: AX=5F3Bh
--------N-215F3D-----------------------------
INT 21 U - LAN Manager Enhanced DOS - WRITE MAILSLOT???
AX = 5F3Dh
???
Return: ???
--------N-215F3E-----------------------------
INT 21 u - LAN Manager Enhanced DOS - LOCAL NetSpecialSMB
AX = 5F3Eh
???
Return: ???
Note: This function is not documented anywhere in the LAN Manager 2.x Toolkit
but was documented in LAN Manager 1.x manuals.
--------N-215F3F-----------------------------
INT 21 U - LAN Manager Enhanced DOS - REMOTE API CALL
AX = 5F3Fh
CX = api number
ES:DI -> data descriptor
ES:SI -> parameter descriptor
ES:DX -> auxiliary descriptor (if DX <> 0)
???
Return: ???
--------N-215F40-----------------------------
INT 21 u - LAN Manager Enhanced DOS - LOCAL NetMessageBufferSend
AX = 5F40h
DS:DX -> NetMessageBufferSend parameter structure (see below)
Return: AX = error code
Format of NetMessageBufferSend parameter structure:
Offset Size Description
00h DWORD -> recipient name (name for specific user, name* for domain
wide name, * for broadcast)
04h DWORD -> buffer
08h WORD length of buffer
--------N-215F41-----------------------------
INT 21 u - LAN Manager Enhanced DOS - LOCAL NetServiceEnum
AX = 5F41h
BL = level of detail (0000h, 0001h or 0002h)
CX = buffer length
ES:DI -> buffer of service_info_0, service_info_1, or service_info_2
(see below)
Return: CF clear if successful
CX = entries read
DX = total available
CF set on error
AX = error code
Format of service_info_0 structure:
Offset Size Description
00h 16 BYTEs name
Format of service_info_1 structure:
Offset Size Description
00h 16 BYTEs name
10h WORD status bitmask (see below)
12h DWORD status code (see below)
(also see Microsoft LAN Manager Programmer's Reference)
16h WORD process id
Format of service_info_2 structure:
Offset Size Description
00h 16 BYTEs name
10h WORD status bitmask (see below)
12h DWORD status code (see below)
16h WORD process id
18h 64 BYTEs text
Bitfields for status bitmask:
bits 0,1 00 uninstall
01 install pending
10 uninstall pending
11 installed
bits 2,3 00 active
01 Continue pending
10 Pause pending
11 paused
bit 4 uninstallable
bit 5 pausable
bit 8 disk redirector paused
bit 9 spooled device redirector paused (printing)
bit 10 communication device redirector paused
Values for status code:
high word
3051 Bad parameter value
3052 A parameter is missing
3053 An unknown parameter was specified
3054 The resource is insufficient
3055 Configuration is faulty
3056 An MS-DOS or MS OS/2 error occured
3057 An internal error occured
3058 An ambiguous parameter name was given
3059 A duplicate parameter exists
3060 The service was terminated by NetSeviceControl when it did not respond
3061 The service program file could not be executed
3062 The subservice failed to start
3063 There is a conflict in the value or use of these parameters
3064 There is a problem with the file
low word
3070 There is insufficient memory
3071 There is insufficeient disk space
3072 Unable to create thread
3073 Unable to create process
3074 A security failure occured
3075 There is bad or missing default path
3076 Network software is not installed
3077 Server software is not installed
3078 The server could not access the UAS database
3079 The action requires user-level security
3080 The log directory is invalid
3081 The LAN group specificed could not be used
3082 The computername is being used as a message alias on another computer
3083 The workstation failed to announce the servername
3084 The user accounts system is not configured properly
--------N-215F42-----------------------------
INT 21 u - LAN Manager Enhanced DOS - LOCAL NetServiceControl
AX = 5F42h
DH = opcode
00h interrogate status
01h pause
02h continue
03h uninstall
DL = argument
01h disk resource
02h print resource
04h communications resource (not implemented for DOS)
ES:BX -> NetServiceControl parameter structure (see below)
Return: CF clear if successful
CF set on error
AX = error code
Format of NetServiceControl parameter structure:
Offset Size Description
00h DWORD -> service name
04h WORD result buffer size
06h DWORD -> result buffer as service_info_2 structure
--------N-215F43-----------------------------
INT 21 u - LAN Manager Enhanced DOS - LOCAL DosPrintJobGetId
AX = 5F43h
BX = handle of remote print job
CX = size of PRIDINFO struture
ES:DI -> PRIDINFO structure (see below)
Return: CF clear if successful
PRIDINFO filled in
CF set on error
AX = error code
Format of PRIDINFO structure:
Offset Size Description
00h WORD job id
02h 16 BYTEs server name
12h 13 BYTEs queue name
1Fh 1 BYTE pad
--------N-215F44-----------------------------
INT 21 u - LAN Manager Enhanced DOS - LOCAL NetWkstaGetInfo
AX = 5F44h
BX = information level (00h, 01h, or 0Ah)
CX = buffer size
ES:DI -> buffer in which to store info
Return: AX = error code
DX = amount of buffer used (or required)
SeeAlso: AX=5F45h,AX=5F49h
--------N-215F45-----------------------------
INT 21 u - LAN Manager Enhanced DOS - LOCAL NetWkstaSetInfo
AX = 5F45h
BX = level (0000h or 0001h)
CX = buffer size
DX = parameter to set
ES:DI -> buffer
Return: CF clear if successful
CF set if error
AX = error code
SeeAlso: AX=5F44h
--------N-215F46-----------------------------
INT 21 u - LAN Manager Enhanced DOS - LOCAL NetUseEnum
AX = 5F46h
BX = level (0000h or 0001h)
CX = size of buffer
ES:DI -> buffer of use_info_0 or use_info_1 structures (see below)
Return: CF clear if successful
CX = entries read
DX = total available entries
CF set if error
AX = error code
SeeAlso: AX=5F47h,AX=5F48h,AX=5F4Ch
Format of use_info_0 structure:
Offset Size Description
00h 9 BYTEs local device name
09h BYTE padding
0Ah DWORD -> remote device name in UNC form \\server\share
Format of use_info_1 structure:
Offset Size Description
00h 9 BYTEs Local device name
09h BYTE padding
0Ah DWORD -> remote device name in UNC form \\server\share
0Eh DWORD -> password
12h WORD ignored
14h WORD use type (-1 wildcard, 0 disk, 1 print, 2 com, 3 ipc)
16h WORD ignored
18h WORD ignored
--------N-215F47-----------------------------
INT 21 u - LAN Manager Enhanced DOS - LOCAL NetUseAdd
AX = 5F47h
BX = level (0001h)
CX = size of use_info_1 structure
ES:DI -> use_info_1 structure (see AX=5F46h)
Return: CF clear on success
CF set on error
AX = error code
SeeAlso: AX=5F46h,AX=5F48h
--------N-215F48-----------------------------
INT 21 u - LAN Manager Enhanced DOS - LOCAL NetUseDel
AX = 5F48h
BX = force level
0000h no force
0001h force
0002h lots of force
ES:DI -> buffer as either the local device name or UNC remote name
Return: CF clear on success
CF set on error
AX = error code
SeeAlso: AX=5F46h,AX=5F48h,AX=5F49h
--------N-215F49-----------------------------
INT 21 u - LAN Manager Enhanced DOS - NetUseGetInfo
AX = 5F49h
DS:DX -> NetUseGetInfo parameter structure
Return: CF clear on success
DX = total available
CF set on error
AX = error code
SeeAlso: AX=5F44h,AX=5F47h
Format of NetUseGetInfo parameter structure:
Offset Size Description
00h DWORD pointer to either the local device name or UNC remote name
04h WORD level of information (0000h or 0001h)
06h DWORD pointer to buffer of use_info_0 or use_info_1 structures
0Ah WORD length of buffer
--------N-215F4A-----------------------------
INT 21 u - LAN Manager Enhanced DOS - LOCAL NetRemoteCopy
AX = 5F4Ah
DS:DX -> NetRemoteCopy parameter structure
Return: CF clear if successful
CF set on error
AX = error code
SeeAlso: AX=5F4Bh
Format of NetRemoteCopy parameter structure:
Offset Size Description
00h DWORD -> source name as UNC
04h DWORD -> destination name as UNC
08h DWORD -> source password
0Ch DWORD -> destination password
10h WORD destination open bitmap
if destination path exists
0000h open fails
0001h file is appended
0002h file is overwritten
if destination path doesn't exist
0000h open fails
0010h file is created
12h WORD copy control bitmap (see below)
14h DWORD -> copy_info buffer
18h WORD length of copy_info buffer
Bitfields for copy control:
bit 0 destination must be a file
bit 1 destination must be a directory
bit 2 destination is opened in ascii mode instead of binary
bit 3 source is opened in ascii mode instead of binary
bit 4 verify all write operations
--------N-215F4B-----------------------------
INT 21 u - LAN Manager Enhanced DOS - LOCAL NetRemoteMove
AX = 5F4Bh
DS:DX -> NetRemoteMove parameter structure
Return: CF clear if successful
CF set on error
AX = error code
SeeAlso: AX=5F4Ah
Format of NetRemoteMove parameter structure:
Offset Size Description
00h DWORD -> source name as UNC
04h DWORD -> destination name as UNC
08h DWORD -> source password
0Ch DWORD -> destination password
10h WORD destination open bitmap
if destination path exists
0000h open fails
0001h file is appended
0002h file is overwritten
if destination path doesn't exist
0000h open fails
0010h file is created
12h WORD move control bitmap
0001h destination must be a file
0002h destination must be a directory
14h DWORD -> move_info buffer
18h WORD length of move_info buffer
--------N-215F4C-----------------------------
INT 21 u - LAN Manager Enhanced DOS - LOCAL NetServerEnum
AX = 5F4Ch
BX = level (0000h or 0001h)
CX = buffer length
ES:DI -> buffer in which to store information
Return: CF clear if successful
ES:DI -> server_info_X structures (depending on level) (see below)
BX = entries read
CX = total entries available
CF set on error
AX = error code
Notes: this function is also supported by the Novell DOS Named Pipe Extender
this function has been obseleted by NetServerEnum2
SeeAlso: AX=5F53h
Format of server_info_0 structure:
Offset Size Description
00h 16 BYTEs name
Format of server_info_1 structure:
Offset Size Description
00h 16 BYTEs name
10h BYTE major version in lower nibble
11h BYTE minor version
12h DWORD server type bitmask (see below)
16h DWORD -> comment string
Bitfields for server type:
bit 0 workstation
bit 1 server
bit 2 SQL server
bit 3 primary domain controller
bit 4 backup domain controller
bit 5 time server
bit 6 Apple File Protocol (AFP) server
bit 7 Novell server
bit 8 Domain Member (v2.1+)
bit 9 Print Queue server (v2.1+)
bit 10 Dialin server (v2.1+)
bit 11 Unix server (v2.1+)
--------N-215F4D-----------------------------
INT 21 u - LAN Manager Enhanced DOS - DosMakeMailslot
AX = 5F4Dh
BX = message size
CX = mailslot size (must be bigger than message size by at least 1)
(minimum 1000h, maximum FFF6h)
(buffer must be 9 bytes bigger than this)
DS:SI -> name
ES:DI -> memory buffer
Return: CF clear if successful
AX = handle
CF set on error
AX = error code
SeeAlso: AX=5F4Eh,AX=5F4Fh,AX=5F50h,AX=5F51h
--------N-215F4E-----------------------------
INT 21 u - LAN Manager Enhanced DOS - DosDeleteMailslot
AX = 5F4Eh
BX = handle
Return: CF clear if successful
ES:DI -> memory to be freed (allocated during DosMakeMailslot)
CF set on error
AX = error code
SeeAlso: AX=5F4Dh,AX=5F4Fh
--------N-215F4F-----------------------------
INT 21 u - LAN Manager Enhanced DOS - DosMailslotInfo
AX = 5F4Fh
BX = handle
Return: CF clear if successful
AX = max message size
BX = mailslot size
CX = next message size
DX = next message priority
SI = number of messages waiting
CF set on error
AX = error code
SeeAlso: AX=5F4Dh,AX=5F4Eh,AX=5F50h
--------N-215F50-----------------------------
INT 21 u - LAN Manager Enhanced DOS - DosReadMailslot
AX = 5F50h
BX = handle
DX:CX = timeout
ES:DI -> buffer
Return: CF clear if successful
AX = bytes read
CX = next item's size
DX = next item's priority
CF set on error
AX = error code
SeeAlso: AX=5F4Dh,AX=5F4Fh,AX=5F51h,AX=5F52h
--------N-215F51-----------------------------
INT 21 u - LAN Manager Enhanced DOS - DosPeekMailslot
AX = 5F51h
BX = handle
ES:DI -> buffer
Return: CF clear if successful
AX = bytes read
CX = next item's size
DX = next item's priority
CF set on error
AX = error code
SeeAlso: AX=5F35h,AX=5F4Fh,AX=5F50h,AX=5F52h
--------N-215F52-----------------------------
INT 21 u - LAN Manager Enhanced DOS - DosWriteMailslot
AX = 5F52h
BX = class
CX = length of buffer
DX = priority
ES:DI -> DosWriteMailslot parameter structure (see below)
DS:SI -> mailslot name
Return: CF clear if successful
CF set on error
AX = error code
SeeAlso: AX=5F4Fh,AX=5F50h,AX=5F51h
Format of DosWriteMailslot parameter structure:
Offset Size Description
00h DWORD timeout
04h DWORD -> buffer
--------N-215F53-----------------------------
INT 21 u - LAN Manager Enhanced DOS - NetServerEnum2
AX = 5F53h
DS:SI -> NetServerEnum2 parameter structure (see below)
Return: CF clear if successful
BX = entries read
CX = total entries available
CF set on error
AX = error code
SeeAlso: AX=5F4Ch
Format of NetServerEnum2 parameter structure:
Offset Size Description
00h WORD level (0000h or 0001h)
02h DWORD -> buffer as array of server_info_??? structures
06h WORD length of buffer
08h DWORD server type bitmask (see below)
0Ch DWORD -> Domain name (may be 0000h:0000h for all local domains)
Bitfields for server type:
bit 0 workstation
bit 1 server
bit 2 SQL server
bit 3 primary domain controller
bit 4 backup domain controller
bit 5 time server
bit 6 Apple File Protocol (AFP) server
bit 7 Novell server
bit 8 Domain Member (v2.1+)
bit 9 Print Queue server (v2.1+)
bit 10 Dialin server (v2.1+)
bit 11 Unix server (v2.1+)
Note: set all bits (FFFFFFFFh) for All Types
Format of server_info_0 structure:
Offset Size Description
00h 16 BYTEs name
Format of server_info_1 structure:
Offset Size Description
00h 16 BYTEs name
10h BYTE major version in lower nibble
11h BYTE minor version
12h DWORD server type (bits 0-11) (see above)
16h DWORD -> comment string
--------N-215F55----------------------------
INT 21 U - LAN Manager Enhanced DOS - KILL ALL CONNECTIONS???
AX = 5F55h
BX = ???
Return: CF clear if successful
CF set on error
AX = error code
--------N-215F80-----------------------------
INT 21 - LANtastic - GET LOGIN ENTRY
AX = 5F80h
BX = login entry index (0-based)
ES:DI -> 16-byte buffer for machine name
Return: CF clear if successful
buffer filled with machine name ("\\" prefix removed)
DL = adapter number (v3+)
CF set on error
AX = error code
Note: the login entry index corresponds to the value BX used in AX=5F83h
SeeAlso: AX=5F83h
--------N-215F81-----------------------------
INT 21 - LANtastic - LOGIN TO SERVER
AX = 5F81h
ES:DI -> ASCIZ login path followed immediately by ASCIZ password
BL = adapter number
FFh try all valid adapters
00h-07h try only specified adapter
Return: CF clear if successful
CF set on error
AX = error code
Notes: login path is of form "\\machine\username"
if no password is used, the string at ES:DI must be terminated with
three NULs for compatibility with LANtastic v3.0.
SeeAlso: AX=5F82h,AX=5F84h
--------N-215F82-----------------------------
INT 21 - LANtastic - LOGOUT FROM SERVER
AX = 5F82h
ES:DI -> ASCIZ server name (in form "\\machine")
Return: CF clear if successful
CF set on error
AX = error code
SeeAlso: AX=5F81h,AX=5F88h,AX=5FCBh
--------N-215F83-----------------------------
INT 21 - LANtastic - GET USERNAME ENTRY
AX = 5F83h
BX = login entry index (0-based)
ES:DI -> 16-byte buffer for username currently logged into
Return: CF clear if successful
DL = adapter number (v3+)
CF set on error
AX = error code
Note: the login entry index corresponds to the value BX used in AX=5F80h
SeeAlso: AX=5F80h
--------N-215F84-----------------------------
INT 21 - LANtastic - GET INACTIVE SERVER ENTRY
AX = 5F84h
BX = server index not currently logged into
ES:DI -> 16-byte buffer for server name which is available for logging
in to ("\\" prefix omitted)
Return: CF clear if successful
DL = adapter number to non-logged in server is on
CF set on error
AX = error code
SeeAlso: AX=5F81h
--------N-215F85-----------------------------
INT 21 - LANtastic - CHANGE PASSWORD
AX = 5F85h
ES:DI -> buffer containing "\\machine\oldpassword" 00h "newpassword"00h
Return: CF clear if successful
CF set on error
AX = error code
Notes: must be logged into the named machine
this function is illegal for group accounts
--------N-215F86-----------------------------
INT 21 - LANtastic - DISABLE ACCOUNT
AX = 5F86h
ES:DI -> ASCIZ machine name and password in form "\\machine\password"
Return: CF clear if successful
CF set on error
AX = error code
Note: must be logged into the named machine and concurrent logins set to 1
by NET_MGR. Requires system manager to re-enable account.
--------N-215F87-----------------------------
INT 21 - LANtastic v3+ - GET ACCOUNT
AX = 5F87h
DS:SI -> 128-byte buffer for account information (see below)
ES:DI -> ASCIZ machine name in form "\\machine"
Return: CF clear if successful
CF set on error
AX = error code
BX destroyed
Note: must be logged into the specified machine
Format of user account structure:
Offset Size Description
00h 16 BYTEs blank-padded username (zero-padded for v4.x)
10h 16 BYTEs reserved (00h)
20h 32 BYTEs user description
40h BYTE privilege bits (see below)
41h BYTE maximum concurrent users
42h 42 BYTEs bit map for disallowed half hours, beginning on Sunday
(bit set if half-hour not an allowed time)
6Ch WORD internal (0002h)
6Eh 2 WORDs last login time
72h 2 WORDs account expiration date (MS-DOS-format year/month:day)
76h 2 WORDs password expiration date (0 = none)
7Ah BYTE number of days to extend password after change (1-31)
00h if no extension required
---v3.x---
7Bh 5 BYTEs reserved
---v4.x---
7Bh BYTE storage for first letter of user name when deleted (first
character is changed to 00h when deleting account)
7Ch BYTE extended privileges
7Dh 3 BYTEs reserved
Bitfields for privilege bits:
bit 7 bypass access control lists
bit 6 bypass queue protection
bit 5 treat as local process
bit 4 bypass mail protection
bit 3 allow audit entry creation
bit 2 system manager
bit 0 user cannot change password
--------N-215F88-----------------------------
INT 21 - LANtastic v4.0+ - LOGOUT FROM ALL SERVERS
AX = 5F88h
Return: CF clear if successful
CF set on error
AX = error code
SeeAlso: AX=5F82h
--------N-215F97-----------------------------
INT 21 - LANtastic - COPY FILE
AX = 5F97h
CX:DX = number of bytes to copy (FFFFFFFFh = entire file)
SI = source file handle
DI = destination file handle
Return: CF clear if successful
DX:AX = number of bytes copied
CF set on error
AX = error code
Note: copy is performed by server
--------N-215F98-----------------------------
INT 21 - LANtastic - SEND UNSOLICITED MESSAGE
AX = 5F98h
DS:SI -> message buffer (see below)
Return: CF clear if successful
CF set on error
AX = error code
Note: v4.1- return no errors
SeeAlso: AX=5F99h
Format of message buffer:
Offset Size Description
00h BYTE reserved
01h BYTE message type
00h general
01h server warning
02h-7Fh reserved
80h-FFh user-defined
02h 16 BYTEs ASCIZ destination machine name
12h 16 BYTEs ASCIZ server name which user must be logged into
22h 16 BYTEs ASCIZ user name
32h 16 BYTEs ASCIZ originating machine name (filled in when received)
42h 80 BYTEs message text
--------N-215F99-----------------------------
INT 21 - LANtastic - GET LAST RECEIVED UNSOLICITED MESSAGE
AX = 5F99h
ES:DI -> messsage buffer (see AX=5F98h for format)
Return: CF clear if successful
CF set on error
AX = error code
SeeAlso: AX=5F98h
--------N-215F9A-----------------------------
INT 21 - LANtastic - GET MESSAGE PROCESSING FLAGS
AX = 5F9Ah
Return: CF clear if successful
DL = bits describing processing for received unsolicited messages
bit 0: beep before message is delivered
bit 1: deliver message to message service
bit 2: pop up message automatically (v3+)
CF set on error
AX = error code
SeeAlso: AX=5F9Bh,AX=5F9Ch,AX=5F9Dh
--------N-215F9B-----------------------------
INT 21 - LANtastic - SET MESSAGE PROCESSING FLAGS
AX = 5F9Bh
DL = bits describing processing for received unsolicited messages
(see AX=5F9Ah)
Return: CF clear if successful
CF set on error
AX = error code
SeeAlso: AX=5F9Ah,AX=5F9Eh
--------N-215F9C-----------------------------
INT 21 - LANtastic v3+ - POP UP LAST RECEIVED MESSAGE
AX = 5F9Ch
CX = time to leave on screen in clock ticks
DH = 0-based screen line on which to place message
Return: CF clear if successful
CF set on error
AX = error code (0Bh)
Notes: the original screen contents are restored when the message is removed
the message will not appear, and an error will be returned, if the
screen is in a graphics mode
SeeAlso: AX=5F9Ah
--------N-215F9D-----------------------------
INT 21 - LANtastic v4.1+ - GET REDIRECTOR CONTROL BITS
AX = 5F9Dh
Return: DL = redirector control bits
bit 7: set to notify on print job completion
SeeAlso: AX=5F9Ah,AX=5F9Eh
--------N-215F9E-----------------------------
INT 21 - LANtastic v4.1+ - SET REDIRECTOR CONTROL BITS
AX = 5F9Eh
DL = redirector control bits (see AX=5F9Dh)
Return: nothing
SeeAlso: AX=5F9Bh,AX=5F9Dh
--------N-215FA0-----------------------------
INT 21 - LANtastic - GET QUEUE ENTRY
AX = 5FA0h
BX = queue entry index (0000h is first entry)
DS:SI -> buffer for queue entry (see below)
ES:DI -> ASCIZ server name in form "\\name"
Return: CF clear if successful
CF set on error
AX = error code
BX = entry index for next queue entry (BX-1 is current index)
SeeAlso: AX=5FA1h,AX=5FA2h
Values for status of entry:
00h empty
01h being updated
02h being held
03h waiting for despool
04h being despooled
05h canceled
06h spooled file could not be accessed
07h destination could not be accessed
08h rush job
Values for type of entry:
00h printer queue file
01h message
02h local file
03h remote file
04h to remote modem
05h batch processor file
Format of queue entry:
Offset Size Description
00h BYTE status of entry (see above)
01h DWORD size of spooled file
05h BYTE type of entry (see above)
06h BYTE output control
bit 6: don't delete (for mail)
bit 5: mail file contains voice mail (v3+)
bit 4: mail message has been read
bit 3: response has been requested for this mail
07h WORD number of copies
09h DWORD sequence number of queue entry
0Dh 48 BYTEs pathname of spooled file
3Dh 16 BYTEs user who spooled file
4Dh 16 BYTEs name of machine from which file was spooled
5Dh WORD date file was spooled (see AX=5700h)
5Fh WORD time file was spooled (see AX=5700h)
61h 17 BYTEs ASCIZ destination device or user name
72h 48 BYTEs comment field
--------N-215FA1-----------------------------
INT 21 - LANtastic - SET QUEUE ENTRY
AX = 5FA1h
BX = handle of opened queue entry
DS:SI -> queue entry (see AX=5FA0h)
Return: CF clear if successful
CF set on error
AX = error code
Notes: the only queue entry fields which may be changed are output control,
number of copies, destination device, and comment
the handle in BX is that from a create or open (INT 21/AH=3Ch,3Dh)
call on the file "\\server\\@MAIL" or "\\server\@name" (for
printer queue entries)
SeeAlso: AX=5FA0h,AX=5FA2h,AX=5FA9h
--------N-215FA2-----------------------------
INT 21 - LANtastic - CONTROL QUEUE
AX = 5FA2h
BL = control command
00h start despooling (privileged)
01h halt despooling (privileged)
02h halt despooling at end of job (privileged)
03h pause despooler at end of job (privileged)
04h print single job (privileged)
05h restart current job (privileged)
06h cancel the current job
07h hold queue entry
08h release a held queue entry
09h make queue entry a rushed job (privileged)
CX:DX = sequence number to control (commands 06h-09h)
DX = physical printer number (commands 00h-05h)
00h-02h LPT1-LPT3
03h,04h COM1,COM2
other all printers
ES:DI -> ASCIZ server name in form "\\machine"
Return: CF clear if successful
CF set on error
AX = error code
--------N-215FA3-----------------------------
INT 21 - LANtastic v3+ - GET PRINTER STATUS
AX = 5FA3h
BX = physical printer number (00h-02h = LPT1-LPT3, 03h-04h = COM1-COM2)
DS:SI -> buffer for printer status (see below)
ES:DI -> ASCIZ server name in form "\\machine"
Return: CF clear if successful
CF set on error
AX = error code
BX = next physical printer number
Note: you must be logged in to the specified server
Format of printer status:
Offset Size Description
00h BYTE printer state
bit 7: printer paused
bits 0-6: 0 printer disabled
1 will stop at end of job
2 print multiple jobs
01h WORD queue index of print job being despooled
FFFFh if not despooling--ignore all following fields
03h WORD actual characters per second being output
05h DWORD number of characters actually output so far
09h DWORD number of bytes read from spooled file so far
0Dh WORD copies remaining to print
--------N-215FA4-----------------------------
INT 21 - LANtastic v3+ - GET STREAM INFO
AX = 5FA4h
BX = 0-based stream index number
DS:SI -> buffer for stream information (see below)
ES:DI -> ASCIZ machine name in form "\\machine"
Return: CF clear if successful
CF set on error
AX = error code
BX = next stream number
SeeAlso: AX=5FA5h
Format of stream information:
Offset Size Description
00h BYTE queueing of jobs for logical printer (0=disabled,other=enabled)
01h 11 BYTEs logical printer resource template (may contain ? wildcards)
--------N-215FA5-----------------------------
INT 21 - LANtastic v3+ - SET STREAM INFO
AX = 5FA5h
BX = 0-based stream index number
DS:SI -> buffer containing stream information (see AX=5FA4h)
ES:DI -> ASCIZ machine name in form "\\machine"
Return: CF clear if successful
CF set on error
AX = error code
SeeAlso: AX=5FA4h
--------N-215FA7-----------------------------
INT 21 - LANtastic - CREATE USER AUDIT ENTRY
AX = 5FA7h
DS:DX -> ASCIZ reason code (max 8 bytes)
DS:SI -> ASCIZ variable reason string (max 128 bytes)
ES:DI -> ASCIZ machine name in form "\\machine"
Return: CF clear if successful
CF set on error
AX = error code
Note: you must be logged in to the specified server and have the "U"
privilege to execute this call
--------N-215FA9-----------------------------
INT 21 - LANtastic v4.1+ - SET EXTENDED QUEUE ENTRY
AX = 5FA9h
BX = handle of opened queue entry
DS:SI -> queue entry (see AX=5FA0h)
Return: CF clear if successful
CF set on error
AX = error code
Note: functions exactly the same as AX=5FA1h except the spooled filename is
also set. This call supports direct despooling.
SeeAlso: AX=5FA1h
--------N-215FB0-----------------------------
INT 21 - LANtastic - GET ACTIVE USER INFORMATION
AX = 5FB0h
BX = server login entry index
DS:SI -> buffer for active user entry (see below)
ES:DI -> ASCIZ machine name in form "\\server"
Return: CF clear if successful
CF set on error
AX = error code
BX = next login index
SeeAlso: AX=5FB2h
Format of active user entry:
Offset Size Description
00h WORD virtual circuit number
02h BYTE login state (see below)
03h BYTE last command issued (see below)
04h 5 BYTEs number of I/O bytes (40-bit unsigned number)
09h 3 BYTEs number of server requests (24-bit unsigned)
0Ch 16 BYTEs name of user who is logged in
1Ch 16 BYTEs name of remote logged in machine
2Ch BYTE extended privileges (v4+???)
bit 0: user cannot change his password
2Dh WORD time left in minutes (0000h = unlimited) (v4+???)
Bitfields for login state:
bit 0 fully logged in
bit 1 remote program load login
bit 2 user has system manager privileges
bit 3 user can create audit entries
bit 4 bypass mail protection
bit 5 treat as local process
bit 6 bypass queue protection
bit 7 bypass access control lists
Values for last command:
00h login
01h process termination
02h open file
03h close file
04h create file
05h create new file
06h create unique file
07h commit data to disk
08h read file
09h write file
0Ah delete file
0Bh set file attributes
0Ch lock byte range
0Dh unlock byte range
0Eh create subdirectory
0Fh remove subdirectory
10h rename file
11h find first matching file
12h find next matching file
13h get disk free space
14h get a queue entry
15h set a queue entry
16h control the queue
17h return login information
18h return link description
19h seek on file
1Ah get server's time
1Bh create audit entry
1Ch open file in multitude of modes
1Dh change password
1Eh disable account
1Fh local server file copy
---v3+---
20h get username from account file
21h translate server's logical path
22h make indirect file
23h get indirect file contents
24h get physical printer status
25h get logical print stream info
26h set logical print stream info
27h get user's account record
---v4+---
28h request server shutdown
29h cancel server shutdown
2Ah stuff server's keyboard
2Bh write then commit data to disk
2Ch set extended queue entry
2Dh terminate user from server
2Eh enable/disable logins
2Fh flush server caches
30h change username
31h get extended queue entry
(same as get queue, but can return named fields blanked)
--------N-215FB1-----------------------------
INT 21 - LANtastic - GET SHARED DIRECTORY INFORMATION
AX = 5FB1h
DS:SI -> 64-byte buffer for link description
ES:DI -> ASCIZ machine and shared directory name in form
"\\machine\shared-resource"
Return: CF clear if successful
CX = access control list privileges for requesting user (see below)
CF set on error
AX = error code
Bitfields for access control list:
bit 4 (I) allow expansion of indirect files
bit 5 (A) allow attribute changing
bit 6 (P) allow physical access to device
bit 7 (E) allow program execution
bit 8 (N) allow file renaming
bit 9 (K) allow directory deletion
bit 10 (D) allow file deletion
bit 11 (L) allow file/directory lookups
bit 12 (M) allow directory creation
bit 13 (C) allow file creation
bit 14 (W) allow open for write and writing
bit 15 (R) allow open for read and reading
--------N-215FB2-----------------------------
INT 21 - LANtastic v3+ - GET USERNAME FROM ACCOUNT FILE
AX = 5FB2h
BX = username entry index (0 for first)
DS:SI -> 16-byte buffer for username
ES:DI -> ASCIZ server name in form "\\machine"
Return: CF clear if successful
CF set on error
AX = error code
BX = next queue entry index
SeeAlso: AX=5FB0h
--------N-215FB3-----------------------------
INT 21 - LANtastic v3+ - TRANSLATE PATH
AX = 5FB3h
DS:SI -> 128-byte buffer for ASCIZ result
ES:DI -> full ASCIZ path, including server name
DX = types of translation to be performed
bit 0: expand last component as indirect file
bit 1: return actual path relative to server's physical disk
Return: CF clear if successful
CF set on error
AX = error code
Note: always expands any indirect files along the path
SeeALso: AX=5FB4h,INT 21/AH=60h
--------N-215FB4-----------------------------
INT 21 - LANtastic v3+ - CREATE INDIRECT FILE
AX = 5FB4h
DS:SI -> 128-byte buffer containing ASCIZ contents of indirect file
ES:DI -> full ASCIZ path of indirect file to create, incl machine name
Return: CF clear if successful
CF set on error
AX = error code
Note: the contents of the indirect file may be any valid server-relative path
SeeAlso: AX=5FB3h,AX=5FB5h
--------N-215FB5-----------------------------
INT 21 - LANtastic v3+ - GET INDIRECT FILE CONTENTS
AX = 5FB5h
DS:SI -> 128-byte buffer for ASCIZ indirect file contents
ES:DI -> full ASCIZ path of indirect file
Return: CF clear if successful
CF set on error
AX = error code
SeeAlso: AX=5FB4h
--------N-215FB6-----------------------------
INT 21 - LANtastic v4.1+ - SET AUTO-LOGIN DEFAULTS
AX = 5FB6h
ES:DI -> pointer to ASCIZ default user name, immediately followed by
ASCIZ password
BL = adapter number to use for default login attempt
FFh try all valid adapters
00h-05h try adapter 0-5 explicitly
Return: CF clear if successful
CF set on error
AX = error code
Notes: call with ES:DI -> two nulls to disable auto-login
SeeAlso: AX=5FB7h
--------N-215FB7-----------------------------
INT 21 - LANtastic v4.1+ - GET AUTO-LOGIN DEFAULTS
AX = 5FB7h
ES:DI -> pointer to 16-byte buffer to store ASCIZ auto-login user name
Return: CF clear if successful
DL = adapter number used for default login attempt
FFh all valid adapters will be tried
00h-05h specified adapter will be tried explicitly
CF set on error
AX = error code
SeeAlso: AX=5F81h,AX=5FB6h
--------N-215FC0-----------------------------
INT 21 - LANtastic - GET TIME FROM SERVER
AX = 5FC0h
DS:SI -> time block (see below)
ES:DI -> ASCIZ server name to get time from
Return: CF clear if successful
CF set on error
AX = error code
SeeAlso: AH=E7h
Format of time block:
Offset Size Description
00h WORD year
02h BYTE day
03h BYTE month
04h BYTE minutes
05h BYTE hour
06h BYTE hundredths of second
07h BYTE second
--------N-215FC8-----------------------------
INT 21 - LANtastic v4.0+ - SCHEDULE SERVER SHUTDOWN
AX = 5FC8h
ES:DI -> ASCIZ server name in form "\\machine"
DS:SI -> ASCIZ reason string (80 characters)
CX = number of minutes until shutdown (0 = immediate)
DX = option flags (see below)
Return: CF clear if successful
CF set on error
AX = error code
SeeAlso: AX=5FC9h
Bitfields for option flags:
bit 0 auto reboot
bit 1 do not notify users
bit 2 halt after shutdown
bit 3 shutdown due to power fail (used by UPS)
bits 4-7 reserved
bits 8-14 user definable
bit 15 reserved
--------N-215FC9-----------------------------
INT 21 - LANtastic v4.0+ - CANCEL SERVER SHUTDOWN
AX = 5FC9h
ES:DI -> ASCIZ server name in form "\\machine"
Return: CF clear if successful
CF set on error
AX = error code
Note: you must have the "S" privilege to use this call
SeeAlso: AX=5FC8h
--------N-215FCA-----------------------------
INT 21 - LANtastic v4.0+ - STUFF SERVER KEYBOARD BUFFER
AX = 5FCAh
ES:DI -> ASCIZ server name in form "\\machine"
DS:SI -> ASCIZ string to stuff (128 bytes)
Return: CF clear if successful
CF set on error
AX = error code
Note: you must have the "S" privilege to use this call
maximum number of characters that can be stuffed is determined by the
server's RUN BUFFER SIZE.
SeeAlso: INT 16/AH=05h
--------N-215FCB-----------------------------
INT 21 - LANtastic v4.1+ - TERMINATE USER
AX = 5FCBh
ES:DI -> ASCIZ server name in form "\\machine"
DS:SI -> blank-padded username. A null char = wildcard.
DS:DX -> blank-padded machine name. A null char = wildcard.
CX = minutes until termination (0 = immediate)
Return: CF clear if successful
CF set on error
AX = error code
Note: you must have the "S" privilege to use this call
you cannot log yourself out using this call
SeeAlso: AX=5F82h
--------N-215FCC-----------------------------
INT 21 - LANtastic v4.1+ - GET/SET SERVER CONTROL BITS
AX = 5FCCh
ES:DI -> ASCIZ server name in form "\\machine"
CX = bit values (value of bits you want to set) (see below)
DX = bit mask (bits you are interested in, 0 = get only) (see below)
Return: CF clear if successful
CX = control bits after call
bit 0: disable logins
CF set on error
AX = error code
Note: you must have the "S" privilege to SET, anyone can GET.
--------N-215FCD-----------------------------
INT 21 - LANtastic v4.1+ - FLUSH SERVER CACHES
AX = 5FCDh
ES:DI -> ASCIZ server name in form "\\machine"
Return: CF clear if successful
CF set on error
AX = error code
Note: you must have the "S" privilege to use this call.
--------N-215FD0-----------------------------
INT 21 - LANtastic - GET REDIRECTED PRINTER TIMEOUT
AX = 5FD0h
Return: CF clear if successful
CX = redirected printer timeout in clock ticks of 55ms
0000h if timeout disabled
CF set on error
AX = error code
SeeAlso: AX=5FD1h
--------N-215FD1-----------------------------
INT 21 - LANtastic - SET REDIRECTED PRINTER TIMEOUT
AX = 5FD1h
CX = printer timeout in clock ticks of 55ms, 0000h to disable timeouts
Return: CF clear if successful
CF set on error
AX = error code
SeeAlso: AX=5FD0h
--------N-215FE0-----------------------------
INT 21 C - LANtastic - GET DOS SERVICE VECTOR
AX = 5FE0h
Return: CF clear if successful
ES:BX -> current FAR service routine
CF set on error
AX = error code
Note: the service routine is called by the LANtastic redirector whenever DOS
may safely be called, permitting external TSRs and drivers to hook
into LANtastic's DOS busy flag checking
SeeAlso: AX=5FE1h,INT 28,INT 2A/AH=84h
--------N-215FE1-----------------------------
INT 21 - LANtastic - SET DOS SERVICE VECTOR
AX = 5FE1h
ES:BX -> FAR routine to call when DOS services are available
Return: CF clear if successful
CF set on error
AX = error code
Note: new handler must chain to previous handler as its first action
SeeAlso: AX=5FE0h
--------N-215FE2-----------------------------
INT 21 - LANtastic - GET MESSAGE SERVICE VECTOR
AX = 5FE2h
Return: CF clear if successful
ES:BX -> current FAR message service routine
CF set on error
AX = error code
SeeAlso: AX=5FE0h,AX=5FE3h
--------N-215FE3-----------------------------
INT 21 - LANtastic - SET MESSAGE SERVICE VECTOR
AX = 5FE3h
ES:BX -> FAR routine for processing network messages
Return: CF clear if successful
CF set on error
AX = error code
Notes: handler must chain to previous handler as its first action
on invocation, ES:BX -> just-received message
SeeAlso: AX=5FE2h
--------D-2160-------------------------------
INT 21 - DOS 3.0+ - "TRUENAME" - CANONICALIZE FILENAME OR PATH
AH = 60h
DS:SI -> ASCIZ filename or path
ES:DI -> 128-byte buffer for canonicalized name
Return: CF set on error
AX = error code
02h invalid component in directory path or drive letter only
03h malformed path or invalid drive letter
ES:DI buffer unchanged
CF clear if successful
AH = 00h
AL = destroyed (00h or 5Ch or last char of current dir on drive)
buffer filled with qualified name of form D:\PATH\FILE.EXT or
\\MACHINE\PATH\FILE.EXT
Desc: determine the canonical name of the specified filename or path,
corresponding to the undocumented TRUENAME command in COMMAND.COM
Notes: the input path need not actually exist
letters are uppercased, forward slashes converted to backslashes,
asterisks converted to appropriate number of question marks, and
file and directory names are truncated to 8.3 if necessary. (DR-DOS
3.41 and 5.0 do not expand asterisks)
'.' and '..' in the path are resolved
filespecs on local drives always start with "d:", those on network
drives always start with "\\"
if path string is on a JOINed drive, the returned name is the one that
would be needed if the drive were not JOINed; similarly for a
SUBSTed, ASSIGNed, or network drive letter. Because of this, it is
possible to get a qualified name that is not legal under the current
combination of SUBSTs, ASSIGNs, JOINs, and network redirections
under DOS 3.3 through 6.00, a device name is translated differently if
the device name does not have an explicit directory or the directory
is \DEV (relative directory DEV from the root directory works
correctly). In these cases, the returned string consists of the
unchanged device name and extension appended to the string X:/
(forward slash instead of backward slash as in all other cases) where
X is the default or explicit drive letter.
functions which take pathnames require canonical paths if invoked via
INT 21/AX=5D00h
supported by OS/2 v1.1 compatibility box
NetWare 2.1x does not support characters with the high bit set; early
versions of NetWare 386 support such characters except in this call.
In addition, NetWare returns error code 3 for the path "X:\"; one
should use "X:\." instead.
for DOS 3.3-6.0, the input and output buffers may be the same, as the
canonicalized name is built in an internal buffer and copied to the
specified output buffer as the very last step
for DR DOS 6.0, this function is not automatically called when on a
network. Device drivers reportedly cannot make this call from their
INIT function. Using the same pointer for both input and output
buffers is not supported in the April 1992 and earlier versions of
DR DOS
SeeAlso: AX=5FB3h,INT 2F/AX=1123h,INT 2F/AX=1221h
--------D-2161-------------------------------
INT 21 - DOS 3+ - UNUSED
AH = 61h
Return: AL = 00h
Note: this function does nothing and returns immediately
--------O-2161--BP6467-----------------------
INT 21 U - OS/2 v1.x FAPI - OS/2 FILE SYSTEM JOIN/SUBST
AH = 61h
BP = 6467h ("dg")
AL = function
00h list
01h add
02h delete
BX = drive number
CX = size of buffer
SI = type (0002h JOIN, 0003h SUBST)
ES:DI -> buffer
Return: ???
Notes: used by JOIN and SUBST to communicate with the OS/2 file system
also supported by OS/2 v2.0+ Virtual DOS Machines
--------D-2162-------------------------------
INT 21 - DOS 3+ - GET CURRENT PSP ADDRESS
AH = 62h
Return: BX = segment of PSP for current process
Notes: under DOS 3+, this function does not use any of the DOS-internal stacks
and may thus be called at any time, even during another INT 21h call
the current PSP is not necessarily the caller's PSP
identical to the undocumented AH=51h
SeeAlso: AH=50h,AH=51h
--------D-216300-----------------------------
INT 21 - DOS 2.25 only - GET LEAD BYTE TABLE ADDRESS
AX = 6300h
Return: CF clear if successful
DS:SI -> lead byte table (see below)
CF set on error
AX = error code (01h) (see AH=59h)
Notes: does not preserve any registers other than SS:SP
the US version of MS-DOS 3.30 treats this as an unused function,
setting AL=00h and returning immediately
SeeAlso: AX=6301h,AH=07h,AH=08h,AH=0Bh
Format of lead byte table entry:
Offset Size Description
00h 2 BYTEs low/high ends of a range of leading byte of double-byte chars
02h 2 BYTEs low/high ends of a range of leading byte of double-byte chars
...
N 2 BYTEs 00h,00h end flag
--------D-216300-----------------------------
INT 21 - Far East DOS 3.2+ - GET DOUBLE BYTE CHARACTER SET LEAD-BYTE TABLE
AX = 6300h
Return: AL = error code
00h successful
DS:SI -> DBCS table (see below)
all other registers except CS:IP and SS:SP destroyed
FFh not supported
Notes: probably identical to AH=63h/AL=00h for DOS 2.25
the US version of MS-DOS 3.30 treats this as an unused function,
setting AL=00h and returning immediately
the US version of DOS 4.0+ accepts this function, but returns an empty
list
SeeAlso: AX=6300h"DOS 2.25"
Format of DBCS table:
Offset Size Description
00h 2 BYTEs low/high ends of a range of leading byte of double-byte chars
02h 2 BYTEs low/high ends of a range of leading byte of double-byte chars
...
N 2 BYTEs 00h,00h end flag
--------D-216301-----------------------------
INT 21 - DOS 2.25, Far East DOS 3.2+ - SET KOREAN (HANGEUL) INPUT MODE
AX = 6301h
DL = new mode
00h return only full characters on DOS keyboard input functions
01h return partially-formed (interim) characters also
Return: AL = status
00h successful
FFh invalid mode
SeeAlso: AH=07h,AH=08h,AH=0Bh,AH=63h,AX=6302h
--------D-216302-----------------------------
INT 21 - DOS 2.25, Far East DOS 3.2+ - GET KOREAN (HANGEUL) INPUT MODE
AX = 6302h
Return: AL = status
00h successful
DL = current input mode
00h return only full characters (clears interim flag)
01h return partial characters (sets interim flag)
FFh not supported
SeeAlso: AH=07h,AH=08h,AH=0Bh,AH=63h,AX=6301h
--------D-2164-------------------------------
INT 21 - DOS 3.2+ internal - SET DEVICE DRIVER LOOKAHEAD FLAG
AH = 64h
AL = flag
00h (default) call device driver function 5 (non-dest read)
before INT 21/AH=01h,08h,0Ah
nonzero don't call driver function 5
Return: nothing (MS-DOS)
CF set, AX=error code??? (DR-DOS 5.0, which does not support this call)
Notes: this function is called by the DOS 3.3+ PRINT.COM
under MS-DOS, this function does not use any of the DOS-internal stacks
and may thus be called at any time, even during another DOS call
SeeAlso: AH=01h,AH=08h,AH=0Ah,AX=5D06h
--------O-2164--DX0000-----------------------
INT 21 U - OS/2 v2.0+ Virtual DOS Machine - ENABLE AUTOMATIC TITLE SWITCH
AH = 64h
DX = 0000h (function number)
CX = 636Ch (magic value, "cl")
BX = 0000h (indicates special request)
Note: if CX is not 636Ch on entry, INT 21/AH=6Ch is invoked, because a bug
in OS/2 1.x FAPI erroneously called AH=64h instead of AH=6Ch
SeeAlso: AH=64h/BX=0001h,INT 21/AH=4Bh
--------O-2164--DX0001-----------------------
INT 21 U - OS/2 v2.0+ Virtual DOS Machine - SET SESSION TITLE
AH = 64h
DX = 0001h (function number)
CX = 636Ch (magic value, "cl")
BX = 0000h (indicates special request)
ES:DI -> new ASCIZ title (max 12 char) or "" to restore default title
Note: if CX is not 636Ch on entry, INT 21/AH=6Ch is invoked, because a bug
in OS/2 1.x FAPI erroneously called AH=64h instead of AH=6Ch
SeeAlso: AH=64h/BX=0000h,AH=64h/BX=0002h,INT 15/AH=12h/BH=05h
--------O-2164--DX0002-----------------------
INT 21 U - OS/2 v2.0+ Virtual DOS Machine - GET SESSION TITLE
AH = 64h
DX = 0002h (function number)
CX = 636Ch (magic value, "cl")
BX = 0000h (indicates special request)
ES:DI -> 13-byte buffer for current title
Return: buffer filled (single 00h if title never changed)
Note: if CX is not 636Ch on entry, INT 21/AH=6Ch is invoked, because a bug
in OS/2 1.x FAPI erroneously called AH=64h instead of AH=6Ch
SeeAlso: AH=64h/BX=0000h,AH=64h/BX=0001h,INT 15/AH=12h/BH=05h
--------O-2164--DX0003-----------------------
INT 21 U - OS/2 v2.1+ Virtual DOS Machine - GET LASTDRIVE
AH = 64h
DX = 0003h (function number)
CX = 636Ch (magic value, "cl")
BX = 0000h (indicates special request)
Return: AL = highest drive supported
Notes: if CX is not 636Ch on entry, INT 21/AH=6Ch is invoked, because a bug
in OS/2 1.x FAPI erroneously called AH=64h instead of AH=6Ch
used by WinOS2
--------O-2164--DX0004-----------------------
INT 21 U - OS/2 v2.1+ Virtual DOS Machine - GET SIZE OF PTDA JFT
AH = 64h
DX = 0004h (function number)
CX = 636Ch (magic value, "cl")
BX = 0000h (indicates special request)
Return: AX = number of entries in OS/2 JFT for VDM
Notes: if CX is not 636Ch on entry, INT 21/AH=6Ch is invoked, because a bug
in OS/2 1.x FAPI erroneously called AH=64h instead of AH=6Ch
in an OS/2 VDM, the DOS Job File Table in the PSP contains an index
into the OS/2 JFT in the Per-Task Data Area rather than an SFT index
because the OS/2 SFT can contain more than 255 entries
--------O-2164--DX0005-----------------------
INT 21 U - OS/2 v2.1+ Virtual DOS Machine - GET SECOND SFT FLAGS WORD
AH = 64h
DX = 0005h (function number)
CX = 636Ch (magic value, "cl")
BX = 0000h (indicates special request)
DI = DOS file handle
Return: AX = value of second flags word from OS/2 SFT entry for file
Notes: if CX is not 636Ch on entry, INT 21/AH=6Ch is invoked, because a bug
in OS/2 1.x FAPI erroneously called AH=64h instead of AH=6Ch
the OS/2 SFT has two flags words rather than DOS's one word, and this
function provides access to the word which is not present in DOS
--------O-2164--DX0006-----------------------
INT 21 U - OS/2 v2.1+ Virtual DOS Machine - UNLOAD DOSKRNL SYMBOLS & LOAD PROGR
AH = 64h
DX = 0006h (function number)
CX = 636Ch (magic value, "cl")
BX = 0000h (indicates special request)
ES:DI -> ASCIZ filespec
DS = base address for loading
Notes: if CX is not 636Ch on entry, INT 21/AH=6Ch is invoked, because a bug
in OS/2 1.x FAPI erroneously called AH=64h instead of AH=6Ch
this function is only supported by the kernel debugging version of
OS2KRNL
--------O-2164--DX0007-----------------------
INT 21 U - OS/2 v2.1+ Virtual DOS Machine - GET WinOS2 CALL GATE ADDRESS
AH = 64h
DX = 0007h (function number)
CX = 636Ch (magic value, "cl")
BX = 0000h (indicates special request)
Return: AX = call gate address
Notes: if CX is not 636Ch on entry, INT 21/AH=6Ch is invoked, because a bug
in OS/2 1.x FAPI erroneously called AH=64h instead of AH=6Ch
used by WinOS2 to make direct calls to OS2KRNL, bypassing the overhead
of DOSKRNL
--------O-2164--DX0008-----------------------
INT 21 U - OS/2 v2.1+ Virtual DOS Machine - GET LOADING MESSAGE
AH = 64h
DX = 0008h (function number)
CX = 636Ch (magic value, "cl")
BX = 0000h (indicates special request)
Return: DS:DX -> '$'-terminated message "Loading. Please wait."
Notes: if CX is not 636Ch on entry, INT 21/AH=6Ch is invoked, because a bug
in OS/2 1.x FAPI erroneously called AH=64h instead of AH=6Ch
this function permits National Language Support for the initial message
displayed while WinOS2 starts a full-screen session
--------O-2164--CX636C-----------------------
INT 21 U - OS/2 v2.1+ Virtual DOS Machine - OS/2 API support
AH = 64h
CX = 636Ch ("cl")
BX = API ordinal (see below)
other registers as appropriate for API call
if ordinal 0025h:
DS:SI -> STARTDATA structure (see below)
Return: as appropriate for API call
if ordinal 0025h:
AX = return code
Values for API ordinal:
0025h DOS32StartSession
0082h DosGetCP
00A7h DosQFSAttach
00BFh DosEditName
00CBh DosForceDelete
0144h Dos32CreateEventSem
0145h Dos32OpenEvenSem
0146h Dos32CloseEventSem
0147h Dos32ResetEventSem
0148h Dos32PostEventSem
0149h Dos32WaitEventSem
014Ah Dos32QueryEventSem
014Bh Dos32CreateMutexSem
014Ch Dos32OpenMutexSem
014Dh Dos32CloseMutexSem
014Eh Dos32RequestMutexSem
014Fh Dos32ReleaseMutexSem
0150h Dos32QueryMutexSem
0151h Dos32CreateMuxWaitSem
0152h Dos32OpenMuxWaitSem
0153h Dos32CloseMuxWaitSem
0154h Dos32WaitMuxWaitSem
0155h Dos32AddMuxWaitSem
0156h Dos32DeleteMuxWaitSem
0157h Dos32QueryMuxWaitSem
Format of STARTDATA structure:
Offset Size Description
00h WORD length of structure (must be 0018h,001Eh,0020h,0032h,or 003Ch)
02h WORD relation of new process to caller (00h independent, 01h child)
04h WORD fore/background (00h foreground, 01h background)
06h WORD trace options (00h-02h, 00h = no trace)
08h DWORD pointer to ASCIZ program title (max 62 chars) or 0000h:0000h
0Ch DWORD pointer to ASCIZ program name (max 128 chars) or 0000h:0000h
10h DWORD pointer to ASCIZ program args (max 144 chars) or 0000h:0000h
14h DWORD "TermQ" (currently reserved, must be 00000000h)
18h DWORD pointer to environment (max 486 bytes) or 0000h:0000h
1Ch WORD inheritance (00h or 01h)
1Eh WORD session type
00h OS/2 session manager determines type (default)
01h OS/2 full-screen
02h OS/2 window
03h PM
04h VDM full-screen
07h VDM window
20h DWORD pointer to ASCIZ icon filename (max 128 chars) or 0000h:0000h
24h DWORD "PgmHandle" (currently reserved, must be 00000000h)
28h WORD "PgmControl"
2Ah WORD initial column
2Ch WORD initial row
2Eh WORD initial width
30h WORD initial height
32h WORD reserved (0)
34h DWORD "ObjectBuffer" (currently reserved, must be 00000000h)
38h DWORD "ObjectBufferLen" (currently reserved, must be 00000000h)
--------D-2165-------------------------------
INT 21 - DOS 3.3+ - GET EXTENDED COUNTRY INFORMATION
AH = 65h
AL = info ID
01h get general internationalization info
02h get pointer to uppercase table
04h get pointer to filename uppercase table
05h get pointer to filename terminator table
06h get pointer to collating sequence table
07h (DOS 4+) get pointer to Double-Byte Character Set table
BX = code page (FFFFh=global code page)
DX = country ID (FFFFh=current country)
ES:DI -> country information buffer (see below)
CX = size of buffer (>= 5)
Return: CF set on error
AX = error code (see AH=59h)
CF clear if successful
CX = size of country information returned
ES:DI -> country information
Notes: AL=05h appears to return same info for all countries and codepages; it
has been documented for DOS 5+, but was undocumented in ealier
versions
NLSFUNC must be installed to get info for countries other than the
default
subfunctions 02h and 04h are identical under OS/2
SeeAlso: AH=38h,INT 2F/AX=1401h,INT 2F/AX=1402h,INT 2F/AX=14FEh
Format of country information:
Offset Size Description
00h BYTE info ID
---if info ID = 01h---
01h WORD size
03h WORD country ID
05h WORD code page
07h 34 BYTEs country-dependent info (see AH=38h)
---if info ID = 02h---
01h DWORD pointer to uppercase table (see below)
---if info ID = 04h---
01h DWORD pointer to filename uppercase table (see below)
---if info ID = 05h---
01h DWORD pointer to filename character table (see below)
---if info ID = 06h---
01h DWORD pointer to collating table (see below)
---if info ID = 07h (DOS 4+)---
01h DWORD pointer to DBCS lead byte table (see below)
Format of uppercase table:
Offset Size Description
00h WORD table size
02h 128 BYTEs uppercase equivalents (if any) of chars 80h to FFh
Format of collating table:
Offset Size Description
00h WORD table size
02h 256 BYTEs values used to sort characters 00h to FFh
Format of filename terminator table:
Offset Size Description
00h WORD table size (not counting this word)
02h BYTE ??? (01h for MS-DOS 3.30-6.00)
03h BYTE lowest permissible character value for filename
04h BYTE highest permissible character value for filename
05h BYTE ??? (00h for MS-DOS 3.30-6.00)
06h BYTE first excluded character in range \ all characters in this
07h BYTE last excluded character in range / range are illegal
08h BYTE ??? (02h for MS-DOS 3.30-6.00)
09h BYTE number of illegal (terminator) characters
0Ah N BYTEs characters which terminate a filename: ."/\[]:|<>+=;,
Note: partially documented for DOS 5+, but undocumented for earlier versions
Format of filename uppercase table:
Offset Size Description
00h WORD table size
02h 128 BYTEs uppercase equivalents (if any) of chars 80h to FFh
Format of DBCS lead byte table:
Offset Size Description
00h WORD length
02h 2N BYTEs start/end for N lead byte ranges
WORD 0000h (end of table)
--------D-2165-------------------------------
INT 21 - DOS 4+ - COUNTRY-DEPENDENT CHARACTER CAPITALIZATION
AH = 65h
AL = function
20h capitalize character
DL = character to capitalize
Return: DL = capitalized character
21h capitalize string
DS:DX -> string to capitalize
CX = length of string
22h capitalize ASCIZ string
DS:DX -> ASCIZ string to capitalize
Return: CF set on error
AX = error code (see AH=59h)
CF clear if successful
Note: these calls have been documented for DOS 5+, but were undocumented in
DOS 4.x.
--------D-216523-----------------------------
INT 21 U - DOS 4+ internal - DETERMINE IF CHARACTER REPRESENTS YES/NO RESPONSE
AX = 6523h
DL = character
DH = second character of double-byte character (if applicable)
Return: CF set on error
CF clear if successful
AX = type
00h no
01h yes
02h neither yes nor no
--------D-2165-------------------------------
INT 21 U - DOS 4+ internal - COUNTRY-DEPENDENT FILENAME CAPITALIZATION
AH = 65h
AL = function
A0h capitalize filename character
DL = character to capitalize
Return: DL = capitalized character
A1h capitalize counted filename string
DS:DX -> filename string to capitalize
CX = length of string
A2h capitalize ASCIZ filename
DS:DX -> ASCIZ filename to capitalize
Return: CF set on error
AX = error code (see AH=59h)
CF clear if successful
Note: nonfunctional in DOS 4.00 through 6.00 due to a bug (the code sets a
pointer depending on the high bit of AL, but doesn't clear the
bit before branching by function number).
--------D-216601-----------------------------
INT 21 - DOS 3.3+ - GET GLOBAL CODE PAGE TABLE
AX = 6601h
Return: CF set on error
AX = error code (see AH=59h)
CF clear if successful
BX = active code page (see AX=6602h)
DX = system code page
SeeAlso: AX=6602h
--------D-216602-----------------------------
INT 21 - DOS 3.3+ - SET GLOBAL CODE PAGE TABLE
AX = 6602h
BX = active code page (see below)
DX = system code page (active page at boot time)
Return: CF set on error
AX = error code (see AH=59h)
CF clear if successful
SeeAlso: AX=6601h,INT 2F/AX=14FFh
Values for code page:
437 US
850 Multilingual
852 Slavic/Latin II (DOS 5+)
857 Turkish
860 Portugal
861 Iceland
863 Canada (French)
865 Norway/Denmark
--------D-2167-------------------------------
INT 21 - DOS 3.3+ - SET HANDLE COUNT
AH = 67h
BX = size of new file handle table for process
Return: CF clear if successful
CF set on error
AX = error code (see AH=59h)
Desc: adjust the size of the per-process open file table, thus raising or
lowering the limit on the number of files the caller can open
simultaneously
Notes: if BX <= 20, no action is taken if the handle limit has not yet been
increased, and the table is copied back into the PSP if the limit
is currently > 20 handles
for file handle tables of > 20 handles, DOS 3.30 never reuses the
same memory block, even if the limit is being reduced; this can lead
to memory fragmentation as a new block is allocated and the existing
one freed
only the first 20 handles are copied to child processes in DOS 3.3-6.0
increasing the file handles here will not, in general, increase the
number of files that can be opened using the runtime library of a
high-level language such as C
BUGS: the original release of DOS 3.30 allocates a full 64K for the handle
table on requests for an even number of handles
DR-DOS 3.41 and 5.0 will lose track of any open file handles beyond
the portion of the JFT retained after the call; MS-DOS will indicate
error 04h if any of the JFT entries to be removed are open
SeeAlso: AH=26h,AH=86h
--------D-2168-------------------------------
INT 21 - DOS 3.3+ - "FFLUSH" - COMMIT FILE
AH = 68h
BX = file handle
Return: CF clear if successful
all data still in DOS disk buffers is written to disk immediately,
and the file's directory entry is updated
CF set on error
AX = error code (see AH=59h)
SeeAlso: AX=5D01h,AH=6Ah,INT 2F/AX=1107h
--------D-2169-------------------------------
INT 21 U - DOS 4+ internal - GET/SET DISK SERIAL NUMBER
AH = 69h
AL = subfunction
00h get serial number
01h set serial number
BL = drive (0=default, 1=A, 2=B, etc)
DS:DX -> disk info (see below)
Return: CF set on error
AX = error code (see AH=59h)
CF clear if successful
AX destroyed
(AL = 00h) buffer filled with appropriate values from extended BPB
(AL = 01h) extended BPB on disk set to values from buffer
Notes: does not generate a critical error; all errors are returned in AX
error 0005h given if no extended BPB on disk
does not work on network drives (error 0001h)
buffer after first two bytes is exact copy of bytes 27h thru 3Dh of
extended BPB on disk
this function is supported under Novell NetWare versions 2.0A through
3.11; the returned serial number is the one a DIR would display,
the volume label is the NetWare volume label, and the file system
is set to "FAT16".
the serial number is computed from the current date and time when the
disk is created; the first part is the sum of the seconds/hundredths
and month/day, the second part is the sum of the hours/minutes and
year
the volume label which is read or set is the one stored in the extended
BPB on disks formatted with DOS 4.0+, rather than the special root
directory entry used by the DIR command in COMMAND.COM (use AH=11h
to find that volume label)
SeeAlso: AX=440Dh
Format of disk info:
Offset Size Description
00h WORD info level (zero)
02h DWORD disk serial number (binary)
06h 11 BYTEs volume label or "NO NAME " if none present
11h 8 BYTEs (AL=00h only) filesystem type--string "FAT12 " or "FAT16 "
--------O-2169-------------------------------
INT 21 - DR-DOS 5.0 - NULL FUNCTION
AH = 69h
Return: AL = 00h
SeeAlso: AH=18h
--------v-216969-----------------------------
INT 21 - VIRUS - "Rape-747" - INSTALLATION CHECK
AX = 6969h
Return: AX = 0666h if resident
SeeAlso: AX=58CCh,AH=76h"VIRUS"
--------d-2169FFDX0000-----------------------
INT 21 U - CUBIT v4.00 - GET CUBIT INT 21 HANDLER
AX = 69FFh
DX = 0000h
BX = CB00h (magic value)
Return: ES:BX -> CUBITR.EXE handler for INT 21
Note: the installation check consists of testing that the first eight bytes
at the returned interrupt handler are EBh 07h "CUBITR" (a short
jump around the signature followed by the signature); the byte
following the signature (i.e. ES:[BX+8]) indicates whether CUBITR
is active (01h) or disabled (00h)
SeeAlso: AX=69FFh/DX=CFBFh
Index: installation check;CUBIT
--------d-2169FFDXCFBF-----------------------
INT 21 U - CUBIT v4.00 - UNINSTALL
AX = 69FFh
DX = CFBFh
CX = EFCFh
BX = CB00h (magic value)
Return: ES:BX -> CUBITR.EXE handler for INT 21
CX = status
2020h successful
2222h failed
Note: if DX is neither 0000h nor CFBFh on entry, some other code is executed
SeeAlso: AX=69FFh/DX=0000h
--------D-216A-------------------------------
INT 21 U - DOS 4+ - COMMIT FILE
AH = 6Ah
BX = file handle
Return: CF clear if successful
AH = 68h
CF set on error
AX = error code (06h) (see AH=59h)
Note: identical to AH=68h in DOS 5.0-6.0; not known whether this is the case
in DOS 4.x
SeeAlso: AH=68h
--------D-216B-------------------------------
INT 21 U - DOS 4.0 internal - IFS IOCTL
AH = 6Bh
AL = subfunction
00h ???
DS:SI -> Current Directory Structure???
CL = drive (1=A:)
01h ???
DS:SI -> ???
CL = file handle???
02h ???
DS:SI -> Current Directory Structure???
DI = ???
CX = drive (1=A:)
Return: CF set on error
AX = error code (see INT 21/AH=59h)
CF clear if successful
Note: passed through to INT 2F/AX=112Fh with AX on top of stack
SeeAlso: AH=6Bh"DOS 5",INT 2F/AX=112Fh
--------D-216B-------------------------------
INT 21 U - DOS 5+ - NULL FUNCTION
AH = 6Bh
Return: AL = 00h
Note: this function does nothing and returns immediately
SeeAlso: AH=6Bh"DOS 4"
--------D-216C00-----------------------------
INT 21 - DOS 4+ - EXTENDED OPEN/CREATE
AX = 6C00h
BL = open mode as in AL for normal open (see INT 21/AH=3Dh)
bit 7: inheritance
bits 4-6: sharing mode
bit 3 reserved
bits 0-2: access mode
BH = flags
bit 6 = auto commit on every write (see also AH=68h)
bit 5 = return error rather than doing INT 24h
CX = create attribute
bits 6-15 reserved
bit 5: archive
bit 4: reserved
bit 3: volume label
bit 2: system
bit 1: hidden
bit 0: readonly
DL = action if file exists/does not exist
bits 7-4 action if file does not exist
0000 fail
0001 create
bits 3-0 action if file exists
0000 fail
0001 open
0010 replace/open
DH = 00h (reserved)
DS:SI -> ASCIZ file name
Return: CF set on error
AX = error code (see AH=59h)
CF clear if successful
AX = file handle
CX = status
1 file opened
2 file created
3 file replaced
Note: the PC LAN Program only supports DL=01h, DL=10h/sharing=compatibility,
and DL=12h
SeeAlso: AH=3Ch,AH=3Dh,AX=6C01h,AH=71h
--------O-216C01-----------------------------
INT 21 U - OS/2 v2.0 - "DosOpen2"
AX = 6C01h
???
Return: ???
Note: this function is similar to AX=6C00h, but supports OS/2's extended
attributes
SeeAlso: AX=5704h,AX=6C00h,AH=6Fh"OS/2"
--------D-216D-------------------------------
INT 21 U - DOS 5+ ROM - FIND FIRST ROM PROGRAM
AH = 6Dh
DS:DX -> ASCIZ program name
Return: CF clear if found
[DTA] = ASCIZ name found
CF set if not found
SeeAlso: AH=6Eh,AH=6Fh
--------O-216D-------------------------------
INT 21 U - OS/2 v1.x FAPI - "DosMkDir2"
AH = 6Dh
???
Return: ???
Note: also supported by OS/2 v2.0+ Virtual DOS Machines
SeeAlso: AH=39h
--------D-216E-------------------------------
INT 21 U - DOS 5+ ROM - FIND NEXT ROM PROGRAM
AH = 6Eh
[DTA] = result of previous FindFirst ROM
Return: CF clear if found
[DTA] = ASCIZ name found
CF set if not found
SeeAlso: AH=6Dh
--------O-216E-------------------------------
INT 21 U - OS/2 v1.x FAPI - "DosENumAttrib"
AH = 6Eh
???
Return: ???
Note: also supported by OS/2 v2.0+ Virtual DOS Machines
SeeAlso: AX=5703h,AH=6Fh"OS/2",INT 2F/AX=112Dh
--------O-216F-------------------------------
INT 21 U - OS/2 v1.x FAPI - "DosQMaxEASize" - GET MAXIMUM SIZE OF EXTENDED ATTR
AH = 6Fh
???
Return: ???
Note: also supported by OS/2 v2.0+ Virtual DOS Machines
SeeAlso: AX=5703h,AX=6C01h,AH=6Eh"OS/2"
--------D-216F00-----------------------------
INT 21 U - DOS 5+ ROM - GET ROM SCAN START ADDRESS
AX = 6F00h
Return: BX = current ROM scan starting segment
SeeAlso: AH=6Dh,AX=6F01h,AX=6F02h
--------D-216F01-----------------------------
INT 21 U - DOS 5+ ROM - SET ROM SCAN START ADDRESS
AX = 6F01h
BX = new ROM scan starting address
SeeAlso: AX=6F00h,AX=6F03h
--------D-216F02-----------------------------
INT 21 U - DOS 5+ ROM - GET EXCLUSION REGION LIST
AX = 6F02h
ES:BX -> buffer for exclusion region list (see below)
Return: ES:BX = 0000h:0000h on error, unchanged if buffer filled
SeeAlso: AX=6F00h,AX=6F03h
Format of exclusion region list:
Offset Size Description
00h WORD number of entries
02h 2N WORDs start/end segments of N excluded regions
--------D-216F03-----------------------------
INT 21 U - DOS 5+ ROM - SET EXCLUSION REGION LIST
AX = 6F03h
DS:DX -> new exclusion region list (see AX=6F02h)
Note: DOS saves only the pointer and assumes that the contents of the list
are never changed, and that regions do not overlap
SeeAlso: AX=6F01h,AX=6F02h
----------217070BX6060-----------------------
INT 21 - PCW Weather Card interface - GET DATA SEGMENT
AX = 7070h
BX = 6060h
CX = 7070h
DX = 7070h
SI = 7070h
DI = 7070h
Return: AX = segment of data structure
Notes: the data structure is at offset 516 from this segment.
the update byte is at offset 514 from this segment. Updates are
once per second while this byte is nonzero and it is decremented
once per second. While this byte is 0 updates are once per minute.
SeeAlso: AX=7070h/BX=7070h
Format of data structure:
Offset Type Description
00h WORD hour
02h WORD minute
04h WORD second
06h WORD day
08h WORD month
0Ah WORD year
0Ch WORD ???
0Eh WORD relative barometric pressure (in 1/100 inches)
10h WORD ???
12h WORD ???
14h WORD temperature 1 (in 1/10 degrees F)
16h WORD temperature 1 lowest (in 1/10 degrees F)
18h WORD temperature 1 highest (in 1/10 degrees F)
1Ah WORD temperature 2 (in 1/10 degrees F)
1Ch WORD temperature 2 lowest (in 1/10 degrees F)
1Eh WORD temperature 2 highest (in 1/10 degrees F)
20h WORD wind speed (in MPH)
22h WORD average of 60 wind speed samples (in MPH)
24h WORD highest wind speed (in MPH)
26h WORD wind chill factor (in 1/10 degrees F)
28h WORD lowest wind chill factor (in 1/10 degrees F)
2Ah WORD ???
2Ch WORD wind direction (in degrees)
2Eh WORD accumulated daily rainfall (in 1/10 inches)
30h WORD accumulated annual rainfall (in 1/10 inches)
----------217070BX7070-----------------------
INT 21 - PCW Weather Card interface - INSTALLATION CHECK
AX = 7070h
BX = 7070h
CX = 7070h
DX = 7070h
SI = 7070h
DI = 7070h
Return: AX = 0070h
BX = 0070h
CX = 0070h
DX = 0070h
SI = 0070h
DI = 0070h
SeeAlso: AX=7070h/BX=6060h,AX=8080h
--------D-2171-------------------------------
INT 21 - DOS 7 (Chicago) - LONG FILENAME FUNCTIONS
AH = 71h
AL = function
39h create directory
3Ah remove directory
3Bh set current directory
41h delete file
43h get file attributes (BL=00h), set file attributes (BL=01h)
47h get current directory
4Eh find first file
4Fh find next file
56h move (rename) file
6Ch create/open file
Return: CF set on error
AX = error code
7100h if function not supported
CF clear if successful
other registers as for corresponding "old" DOS function
Notes: if error 7100h is returned, the old-style function should be called
AX=714Eh returns a "search handle" which must be passed to AX=714Fh;
when the search is complete, AH=72h must be called to terminate
the search
SeeAlso: AH=39h,AH=3Ah,AH=3Bh,AH=41h,AH=43h,AH=47h,AH=4Eh,AH=4Fh,AH=56h,AH=6Ch
SeeAlso: AH=72h
--------D-2172-------------------------------
INT 21 - DOS 7 (Chicago) - "FindClose" - TERMINATE DIRECTORY SEARCH
AH = 72h
details not yet available
Note: this function must be called after starting a search with AX=714Eh,
to indicate that the search handle returned by that function will
no longer be used
SeeAlso: AH=4Eh,AH=71h
--------v-2176-------------------------------
INT 21 - VIRUS - "Klaeren"/"Hate" - INSTALLATION CHECK
AH = 76h
Return: AL = 48h if resident
SeeAlso: AX=6969h,AX=7700h"VIRUS"
--------v-217700-----------------------------
INT 21 - VIRUS - "Growing Block" - INSTALLATION CHECK
AX = 7700h
Return: AX = 0920h if resident
SeeAlso: AH=76h,AH=7Fh
--------V-217734-----------------------------
INT 21 U - SCROLLit v1.7 - INSTALLATION CHECK
AX = 7734h
Return: DX = 3477h if installed
AX = segment of resident code
Program: ScrollIt is a shareware backscroll utility by Bromfield Software
Products
--------U-217761-----------------------------
INT 21 - WATCH.COM v3.2+ - INSTALLATION CHECK
AX = 7761h ('wa')
Return: AX = 6177h
Note: WATCH.COM is part of the "TSR" package by TurboPower Software
SeeAlso: INT 16/AX=7761h
--------v-217F-------------------------------
INT 21 - VIRUS - "Squeaker" - INSTALLATION CHECK
AH = 7Fh
Return: AH = 80h if resident
SeeAlso: AX=7700h,AH=83h"VIRUS"
--------!------------------------------------