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Text File | 1990-08-04 | 210KB | 5,898 lines

Interrupt List, part 2 of 4 This compilation is Copyright (c) 1989,1990 Ralf Brown --------------------------------------------- INT 20 - Minix - SEND/RECEIVE MESSAGE AX = process ID of other process BX -> message CX = 1 send 2 receive 3 send&receive Note: the message contains the system call number (numbered as in V7 Unix(tm)) and the call parameters --------------------------------------------- INT 20 - DOS - PROGRAM TERMINATION returns to DOS--identical to INT 21/AH=00h Note: IBM and Microsoft recommend using INT 21/AH=4Ch for DOS 2+ SeeAlso: INT 21/AH=00h --------------------------------------------- INT 21 - DOS - PROGRAM TERMINATION AH = 00h Return: never Note: execution continues at address pointed to by INT 22 after DOS performs whatever cleanup it needs to do SeeAlso: INT 20,INT 22 --------------------------------------------- INT 21 - DOS - KEYBOARD INPUT AH = 01h Return: AL = character read Note: ^C/^Break are checked, and INT 23h executed if read character is echoed to standard output SeeAlso: AH=06h,07h,08h,0Ah --------------------------------------------- INT 21 - DOS - DISPLAY OUTPUT AH = 02h DL = character to send to standard output Note: ^C/^Break are checked, and INT 23h executed if pressed SeeAlso: AH=06h,09h --------------------------------------------- INT 21 - DOS - AUX INPUT AH = 03h Return: AL = character read SeeAlso: AH=04h,INT 14/AH=02h --------------------------------------------- INT 21 - DOS - AUX OUTPUT AH = 04h DL = character to send SeeAlso: AH=03h,INT 14/AH=01h --------------------------------------------- INT 21 - DOS - PRINTER OUTPUT AH = 05h DL = character to print SeeAlso: INT 17/AH=00h --------------------------------------------- INT 21 - DOS - DIRECT CONSOLE I/O CHARACTER OUTPUT AH = 06h DL = character <> FFh SeeAlso: AH=02h,09h --------------------------------------------- INT 21 - DOS - DIRECT CONSOLE I/O CHARACTER INPUT AH = 06h DL = FFh Return: ZF set = no character ZF clear = character recieved AL = character Notes: character is echoed to STDOUT if received. ^C/^Break are NOT checked SeeAlso: AH=0Bh --------------------------------------------- INT 21 - DOS - DIRECT STDIN INPUT, NO ECHO AH = 07h Note: same as function 06h for input but char not echoed SeeAlso: AH=01h,06h,08h,0Ah --------------------------------------------- INT 21 - DOS - KEYBOARD INPUT, NO ECHO AH = 08h Return: AL = character Note: same as function 07h, but ^C/^Break are checked SeeAlso: AH=01h,06h,07h,0Ah,64h --------------------------------------------- INT 21 - DOS - PRINT STRING AH = 09h DS:DX -> string terminated by "$" Note: ^C/^Break checked, and INT 23h called if pressed SeeAlso: AH=02h,06h --------------------------------------------- INT 21 - DOS - BUFFERED KEYBOARD INPUT AH = 0Ah DS:DX -> buffer Note: first byte of buffer must contain maximum length on entry, second byte contains actual length of previous line which may be recalled with the DOS line-editing commands on return the second byte contains actual length, third and subsequent bytes contain the input line --------------------------------------------- INT 21 - DOS - CHECK STANDARD INPUT STATUS AH = 0Bh Return: AL = FFh if character available 00h if no character Note: ^C/^Break checked, and INT 23h called if pressed --------------------------------------------- INT 21 - DOS - CLEAR KEYBOARD BUFFER AH = 0Ch AL must be 1, 6, 7, 8, or 0Ah. Notes: flushes all typeahead input, then executes function specified by AL (effectively moving it to AH and repeating the INT 21 call). if AL contains a value not in the list above, the keyboard buffer is flushed and no other action is taken. SeeAlso: AH=01h,06h,07h,08h,0Ah --------------------------------------------- INT 21 - DOS - DISK RESET AH = 0Dh Note: flushes all disk buffers SeeAlso: INT 13/AH=00h, INT 2F/AX=1120h --------------------------------------------- INT 21 - DOS - SELECT DISK AH = 0Eh DL = new default drive number (0 = A, 1 = B, etc.) Return: AL = number of logical drives Notes: under Novell NetWare, the return value is always 32, the number of drives that NetWare supports under DOS 3+, the return value is the greatest of 5, the value of LASTDRIVE= in CONFIG.SYS, and the number of drives actually present otherwise, the return value is the highest drive actually present SeeAlso: AH=19h, AH=DBh --------------------------------------------- INT 21 - DOS - OPEN DISK FILE AH = 0Fh DS:DX -> FCB (see below) Return: AL = 00h file found FFh file not found Note: (DOS 3+) file opened in compatibility mode SeeAlso: AH=3Dh Format of File Control Block: Offset Size Description -7 BYTE extended FCB if FFh -6 5 BYTEs reserved -1 BYTE file attribute if extended FCB 00h BYTE drive number (0 = default, 1 = A, etc) 01h 8 BYTEs blank-padded file name 09h 3 BYTEs blank-padded file extension 0Ch WORD current block number 0Eh WORD logical record size 10h DWORD file size 14h WORD date of last write (see AX=5700h) 16h WORD time of last write (see AX=5700h) 18h 8 BYTEs reserved (see below) 20h BYTE record within current block 21h DWORD random access record number (if record size is > 64 bytes, high byte is omitted) Format of reserved field for DOS 1.x: Offset Size Description 18h BYTE bit 7: set if logical device bit 6: set if open??? bits 5-0: disk number or logical device ID 19h WORD absolute current cluster number 1Bh WORD starting cluster number 1Dh WORD relative current cluster number 1Fh BYTE unused??? Format of reserved field for DOS 2.x: Offset Size Description 18h BYTE bit 7: set if logical device bit 6: set if open??? bits 5-0: ??? 19h WORD starting cluster number 1Bh WORD ??? 1Dh BYTE ??? 1Eh BYTE ??? 1Fh BYTE ??? Format of reserved field for DOS 3.x: Offset Size Description 18h BYTE number of system file table entry for file 19h BYTE attributes bits 7,6: 00 = SHARE.EXE not loaded, disk file 01 = SHARE.EXE not loaded, character device 10 = SHARE.EXE loaded, remote file 11 = SHARE.EXE loaded, local file bits 5-0: low six bits of device attribute word ---SHARE.EXE loaded, local file--- 1Ah WORD starting cluster of file 1Ch WORD offset within SHARE of sharing record (see AH=52h) 1Eh BYTE file attribute 1Fh BYTE ??? ---SHARE.EXE loaded, remote file--- 1Ah WORD number of sector containing directory entry 1Ch WORD relative cluster within file of last cluster accessed 1Eh BYTE absolute cluster number of last cluster accessed 1Fh BYTE ??? ---SHARE.EXE not loaded--- 1Ah BYTE (low byte of device attribute word AND 0Ch) OR open mode 1Bh WORD starting cluster of file 1Dh WORD number of sector containing directory entry 1Fh BYTE number of directory entry within sector Note: if FCB opened on character device, DWORD at 1Ah is set to the address of the device driver header, then the BYTE at 1Ah is overwritten. --------------------------------------------- INT 21 - DOS - CLOSE DISK FILE AH = 10h DS:DX -> FCB (see AH=0Fh) Return: AL = 00h directory update successful FFh file not found in directory SeeAlso: AH=3Eh --------------------------------------------- INT 21 - DOS - SEARCH FIRST USING FCB AH = 11h DS:DX -> FCB (see AH=0Fh) Return: AL = status 00h file found [DTA] = unopened FCB for file that was found FFh file not found SeeAlso: AH=1Ah,4Eh, INT 2F/AX=111Bh --------------------------------------------- INT 21 - DOS - SEARCH NEXT USING FCB AH = 12h DS:DX -> FCB (see AH=0Fh) Return: AL = status 00h file found [DTA] = unopened FCB for file that was found FFh file not found SeeAlso: AH=1Ah,4Fh, INT 2F/AX=111Ch --------------------------------------------- INT 21 - DOS - DELETE FILE via FCB AH = 13h DS:DX -> FCB (see AH=0Fh) with filename field filled with template for deletion ('?' wildcard allowed, but not '*') Return: AL = status 00h file found FFh file not found Note: deletes everything in the current directory (including subdirectories) and sets the first byte of the name to 00h (entry never used) instead of E5h if called on an extended FCB with filename '???????????' and bits 0-4 of the attribute set (bits 1 and 2 for DOS 1). This may have originally been an optimization to minimize directory searching after a mass deletion, but can corrupt the filesystem under DOS 2+ because subdirectories are removed without deleting the files they contain. SeeAlso: AH=41h --------------------------------------------- INT 21 - DOS - SEQUENTIAL DISK FILE READ AH = 14h DS:DX -> FCB (see AH=0Fh) Return: AL = status 00h successful read 01h end of file 02h data transfer area too small 03h partial record, EOF SeeAlso: AH=3Fh, INT 2F/AX=1108h --------------------------------------------- INT 21 - DOS - SEQUENTIAL DISK RECORD WRITE AH = 15h DS:DX -> FCB (see AH=0Fh) Return: AL = status 00h successful write 01h disk full 02h data transfer area too small SeeAlso: AH=40h, INT 2F/AX=1109h --------------------------------------------- INT 21 - DOS - CREATE A DISK FILE AH = 16h DS:DX -> FCB (see AH=0Fh) Return: AL = status 00h successful creation FFh directory full Note: if file already exists, it is truncated to zero length SeeAlso: AH=3Ch --------------------------------------------- INT 21 - DOS - RENAME FILE via FCB AH = 17h DS:DX -> FCB (see AH=0Fh) FCB contains new name starting at byte 17h. Return: AL = status 00h file found FFh file not found SeeAlso: AH=56h --------------------------------------------- INT 21 - DOS internal - UNUSED AH = 18h Return: AL = 00h --------------------------------------------- INT 21 - DOS - GET DEFAULT DISK NUMBER AH = 19h Return: AL = current drive number (letter - 'A') SeeAlo: AH=0Eh --------------------------------------------- INT 21 - DOS - SET DISK TRANSFER AREA ADDRESS AH = 1Ah DS:DX -> disk transfer buffer SeeAlso: AH=2Fh --------------------------------------------- INT 21 - DOS - GET ALLOCATION TABLE INFORMATION FOR DEFAULT DRIVE AH = 1Bh Return: DS:BX -> FAT ID byte for default drive DX = number of allocation units on disk AL = number of sectors per allocation unit (cluster) CX = number of bytes per sector Note: under DOS 1.x, DS:BX points at an actual copy of the FAT SeeAlso: AH=36h --------------------------------------------- INT 21 - DOS - GET ALLOCATION TABLE INFORMATION FOR SPECIFIC DRIVE AH = 1Ch DL = drive number to check (0=default, 1=A, etc) Return: DS:BX -> FAT ID byte for specified drive DX = number of allocation units on disk AL = number of sectors per allocation unit (cluster) CX = number of bytes per sector Note: under DOS 1.x, DS:BX points at an actual copy of the FAT SeeAlso: AH=36h --------------------------------------------- INT 21 - DOS internal - UNUSED AH = 1Dh Return: AL = 00h --------------------------------------------- INT 21 - DOS internal - UNUSED AH = 1Eh Return: AL = 00h --------------------------------------------- INT 21 - DOS internal - GET DEFAULT DRIVE PARAMETER BLOCK AH = 1Fh Return: AL = 00h No Error FFh Error DS:BX -> drive parameter block (see below for DOS 1.x, AH=32h others) Note: for DOS 2+, this just invokes function 32h with DL = 00h SeeAlso: AH=32h Format of Eagle MSDOS 1.25 drive parameter block: Offset Size Description 00h BYTE entry number 01h BYTE physical drive number 02h WORD bytes per sector 04h BYTE number of sectors per cluster - 1 05h BYTE ??? 06h WORD starting sector number of first FAT 08h BYTE number of copies of FAT 09h WORD number of directory entries 0Bh WORD number of first data sector 0Dh WORD number of clusters on disk 0Fh BYTE sectors per FAT 10h WORD starting sector of directory 12h WORD address of allocation table --------------------------------------------- INT 21 - DOS internal - UNUSED AH = 20h Return: AL = 00h --------------------------------------------- INT 21 - DOS - RANDOM DISK RECORD READ AH = 21h DS:DX -> FCB (see AH=0Fh) Return: AL = status 00h successful read 01h end of file 02h data transfer area too small 03h partial record, EOF SeeAlso: AH=3Fh --------------------------------------------- INT 21 - DOS - RANDOM DISK RECORD WRITE AH = 22h DS:DX -> FCB (see AH=0Fh) Return: AL = status 00h successful write 01h disk full 02h data transfer area too small SeeAlso: AH=40h --------------------------------------------- INT 21 - DOS - GET FILE SIZE AH = 23h DS:DX -> unopened FCB (see AH=0Fh) with filename and record size fields initialized Return: AL = status 00h file found FFh file not found Note: FCB's random-record field set to number of records (rounded up) SeeAlso: AH=42h --------------------------------------------- INT 21 - DOS - SET RANDOM RECORD FIELD AH = 24h DS:DX -> open FCB (see AH=0Fh) Return: Random Record Field of FCB is set to be same as Current Block and Current Record. SeeAlso: AH=42h --------------------------------------------- INT 21 - DOS - SET INTERRUPT VECTOR AH = 25h AL = interrupt number DS:DX = new vector to be used for specified interrupt SeeAlso: AH=35h --------------------------------------------- INT 21 - Phar Lap 386/DOS-Extender - RESET 386/DOS-EXTENDER DATA STRUCTURES AX = 2501h Return: CF clear Note: Phar Lap uses INT 21/AH=25h as the entry point for all 386/DOS-Extender system calls. Only available when directly using 386/DOS-Extender, or when using a product that was created using 386-DOS/Extender --------------------------------------------- INT 21 - Phar Lap 386/DOS-Extender - GET PROTECTED-MODE INTERRUPT VECTOR AX = 2502h CL = interrupt number Return: ES:EBX -> 48-bit address of protected-mode interrupt handler CF clear --------------------------------------------- INT 21 - Phar Lap 386/DOS-Extender - GET REAL-MODE INTERRUPT VECTOR AX = 2503h CL = interrupt number Return: EBX = 32-bit address of real-mode interrupt handler CF clear SeeAlso: AX=2502h,2504h --------------------------------------------- INT 21 - Phar Lap 386/DOS-Extender - SET PROTECTED-MODE INTERRUPT VECTOR AX = 2504h CL = interrupt number DS:EDX -> 48-bit address of protected-mode interrupt handler Return: CF clear SeeAlso: AX=2502h,2505h --------------------------------------------- INT 21 - Phar Lap 386/DOS-Extender - SET REAL-MODE INTERRUPT VECTOR AX = 2505h CL = interrupt number EBX = 32-bit address of real-mode interrupt handler Return: CF clear SeeAlso: AX=2503h,2504h --------------------------------------------- INT 21 - Phar Lap 386/DOS-Extender - SET INT TO ALWAYS GAIN CONTRL IN PROT MODE AX = 2506h CL = interrupt number DS:EDX -> 48-bit address of protected-mode interrupt handler Return: CF clear Note: This function modifies both the real-mode low-memory interrupt vector table and the protected-mode Interrupt Descriptor Table (IDT) Interrupts occurring in real mode are resignaled in protected mode. --------------------------------------------- INT 21 - Phar Lap 386/DOS-Extender - SET REAL- & PROTECTED-MODE INT VECTORS AX = 2507h CL = interrupt number DS:EDX -> 48-bit address of protected-mode interrupt handler EBX = 32-bit address of real-mode interrupt handler Return: CF clear Note: interrupts are disabled until both vectors have been modified SeeAlso: AX=2504h,2505h --------------------------------------------- INT 21 - Phar Lap 386/DOS-Extender - GET SEGMENT LINEAR BASE ADDRESS AX = 2508h BX = segment selector Return: CF clear if successful ECX = linear base address of segment CF set if invalid segment selector --------------------------------------------- INT 21 - Phar Lap 386/DOS-Extender - CONVERT LINEAR TO PHYSICAL ADDRESS AX = 2509h EBX = linear address to convert Return: CF clear if successful ECX = physical address (carry flag clear) CF set if linear address not mapped in page tables --------------------------------------------- INT 21 - Phar Lap 386/DOS-Extender - MAP PHYSICAL MEMORY AT END OF SEGMENT AX = 250Ah ES = segment selector in the Local Descriptor Table (LDT) of segment to modify EBX = physical base address of memory to map (multiple of 4K) ECX = number of physical 4K pages to map Return: CF clear if successful EAX = 32-bit offset in segment of mapped memory CF set on error EAX = error code 08h insufficient memory to create page tables 09h invalid segment selector --------------------------------------------- INT 21 - Phar Lap 386/DOS-Extender - GET HARDWARE INTERRUPT VECTORS AX = 250Ch Return: CF clear AL = base interrupt vector for IRQ0-IRQ7 AH = base interrupt vector for IRQ8-IRQ15 BL = interrupt vector for BIOS print screen function --------------------------------------------- INT 21 - Phar Lap 386/DOS-Extender - GET REAL-MODE LINK INFORMATION AX = 250Dh Return: CF clear EAX = 32-bit address of real-mode 386/DOS-Extender proc that will call through from real mode to a protected-mode routine EBX = 32-bit real-mode address of intermode call data buffer ECX = size in bytes of intermode call data buffer ES:EDX -> protected-mode address of intermode call data buffer --------------------------------------------- INT 21 - Phar Lap 386/DOS-Extender - CALL REAL-MODE PROCEDURE AX = 250Eh EBX = 32-bit address of real-mode procedure to call ECX = number of two-byte words to copy from protected-mode stack to real-mode stack Return: CF clear if successful all segment registers unchanged all general registers contain values set by real-mode procedure all other flags set as they were left by real-mode procedure CF set on error EAX = error code 01h not enough real-mode stack space --------------------------------------------- INT 21 - Phar Lap 386/DOS-Extender - CONVERT PROTECTED-MODE ADDRESS TO MS-DOS AX = 250Fh ES:EBX -> 48-bit protected-mode address to convert ECX = length of data, in bytes Return: CF clear if successful ECX = 32-bit MS-DOS address CF set on error ECX destroyed SeeAlso: AX=2510h --------------------------------------------- INT 21 - Phar Lap 386/DOS-Extender - CALL REAL-MODE PROCEDURE, REGISTERS AX = 2510h EBX = 32-bit address of real-mode procedure to call ECX = number of two-byte words to copy to protected-mode stack to real-mode stack DS:EDX -> pointer to parameter block (see below) Return: CF clear if successful all segment registers unchanged, EDX unchanged all other general registers contain values set by real-mode proc all other flags are set as they were left by real-mode procedure real-mode register values are returned in the parameter block CF set on error EAX = error code 01h not enough real-mode stack space SeeAlso: AX=250Fh Format of parameter block: Offset Size Description 00h WORD real-mode DS value 02h WORD real-mode ES value 04h WORD real-mode FS value 06h WORD real-mode GS value 08h DWORD real-mode EAX value 0Ch DWORD real-mode EBX value 10h DWORD real-mode ECX value 14h DWORD real-mode EDX value --------------------------------------------- INT 21 - Phar Lap 386/DOS-Extender - ISSUE REAL-MODE INTERRUPT AX = 2511h DS:EDX -> pointer to parameter block (see below) Return: all segment registers unchanged EDX unchanged all other registers contain values set by the real-mode int handler the flags are set as they were left by the real-mode interrupt handler real-mode register values are returned in the parameter block SeeAlso: AX=2503h,2505h Format of parameter block: Offset Size Description 00h WORD interrupt number 02h WORD real-mode DS value 04h WORD real-mode ES value 06h WORD real-mode FS value 08h WORD real-mode GS value 0Ah DWORD real-mode EAX value 0Eh DWORD real-mode EDX value Note: all other real-mode values set from protected-mode registers --------------------------------------------- INT 21 - Phar Lap 386/DOS-Extender - LOAD PROGRAM FOR DEBUGGING AX = 2512h DS:EDX -> pointer to ASCIIZ program name ES:EBX -> pointer to parameter block (see below) ECX = size in bytes of LDT buffer Return: CF clear if successful EAX = number of segment descriptors in LDT CF set on error EAX = error code 02h file not found or path invalid 05h access denied 08h insufficient memory 0Ah environment invalid 0Bh invalid file format 80h LDT too small Format of parameter block: Offset Size Description Input: 00h DWORD 32-bit offset of environment string 04h WORD segment of environment string 06h DWORD 32-bit offset of command-tail string 0Ah WORD segment of command-tail string 0Ch DWORD 32-bit offset of LDT buffer (size in ECX) 10h WORD segment of LDT buffer Output: 12h WORD real-mode paragraph address of PSP (see also AH=26h) 14h WORD real/protected mode flag 0000h real mode 0001h protected mode 16h DWORD initial EIP value 1Ah WORD initial CS value 1Ch DWORD initial ESP value 20h WORD initial SS value 22h WORD initial DS value 24h WORD initial ES value 26h WORD initial FS value 28h WORD initial GS value --------------------------------------------- INT 21 - Phar Lap 386/DOS-Extender - ALIAS SEGMENT DESCRIPTOR AX = 2513h BX = segment selector of descriptor in GDT or LDT CL = access-rights byte for alias descriptor CH = use-type bit (USE16 or USE32) for alias descriptor Return: CF clear if successful AX = segment selector for created alias CF set on error EAX = error code 08h insufficient memory (can't grow LDT) 09h invalid segment selector in BX --------------------------------------------- INT 21 - Phar Lap 386/DOS-Extender - CHANGE SEGMENT ATTRIBUTES AX = 2514h BX = segment selector of descriptor in GDT or LDT CL = new access-rights byte CH = new use-type bit (USE16 or USE32) Return: CF clear if successful CF set on error EAX = error code 09h invalid selector in BX SeeAlso: AX=2515h --------------------------------------------- INT 21 - Phar Lap 386/DOS-Extender - GET SEGMENT ATTRIBUTES AX = 2515h BX = segment selector of descriptor in GDT or LDT Return: CF clear if successful CL = access-rights byte for segment CH = use-type bit (USE16 or USE32) ECX<16-31> destroyed CF set on error EAX = error code 09h invalid segment selector in BX SeeAlso: AX=2514h --------------------------------------------- INT 21 - Phar Lap 386/DOS-Extender - FREE ALL MEMORY OWNED BY LDT AX = 2516h ??? Return: ??? --------------------------------------------- INT 21 - Phar Lap 386/DOS-Extender - GET INFO ON DOS DATA BUFFER AX = 2517h ??? Return: ??? --------------------------------------------- INT 21 - Phar Lap 386/DOS-Extender - SPECIFY HANDLER FOR MOVED SEGMENTS AX = 2518h ??? Return: ??? --------------------------------------------- INT 21 - Phar Lap 386/DOS-Extender VMM - GET ADDITIONAL MEMORY ERROR INFO AX = 2519h Return: CF clear EAX = error code 0000h no error 0001h out of physical memory 0002h out of swap space (unable to grow swap file) 0003h out of LDT entries and unable to grow LDT 0004h unable to change extended memory allocation mark FFFFFFFFh paging disabled Note: VMM is the Virtual Memory Manager option --------------------------------------------- INT 21 - Phar Lap 386/DOS-Extender VMM - LOCK PAGES IN MEMORY AX = 251Ah EDX = number of 4k pages to lock if BL = 00h ECX = linear address of first page to lock if BL = 01h ES:ECX -> pointer to first page to lock Return: CF clear if successful CF set on error EAX = error code 08h insufficient memory 09h invalid address range SeeAlso: AX=251Bh --------------------------------------------- INT 21 - Phar Lap 386/DOS-Extender VMM - UNLOCK PAGES AX = 251Bh EDX = number of pages to unlock if BL = 00h ECX = linear address of first page to unlock if BL = 01h ES:ECX -> pointer to first page to unlock Return: CF clear if successful CF set on error EAX = error code 09h invalid address range SeeAlso: AX=251Ah --------------------------------------------- INT 21 - Phar Lap 386/DOS-Extender VMM - READ PAGE-TABLE ENTRY AX = 251Dh ??? Return: ??? --------------------------------------------- INT 21 - Phar Lap 386/DOS-Extender VMM - WRITE PAGE-TABLE ENTRY AX = 251Eh ??? Return: ??? --------------------------------------------- INT 21 - Phar Lap 386/DOS-Extender VMM - EXHANGE TWO PAGE-TABLE ENTRIES AX = 251Fh ??? Return: ??? --------------------------------------------- INT 21 - Phar Lap 386/DOS-Extender VMM - GET MEMORY STATISTICS AX = 2520h DS:EDX -> pointer to buffer at least 100 bytes in size (see below) BL = 0 (don't reset VM stats), 1 (reset VM stats) Return: carry flag clear Format of VM stats buffer: Offset Size Description 00h DWORD VM status 0001h VM subsystem is present 0000h VM not present 04h DWORD "nconvpg" number of conventional memory pages available 08h DWORD "nbimpg" number of Compaq built-in memory pages available 0Ch DWORD "nextpg" total number of extended memory pages 10h DWORD "extlim" extender memory pages limit 14h DWORD "aphyspg" number of physical memory pages allocated to appl 18h DWORD "alockpg" number of locked pages owned by application 1Ch DWORD "sysphyspg" number physical memory pages allocated to system 20h DWORD "nfreepg" number of free physical pages; approx if EMS VCPI 24h DWORD linear address of beginning of application address space 28h DWORD linear address of end of application address space 2Ch DWORD number of seconds since last time VM stats were reset 30h DWORD number of page faults since last time 34h DWORD number of pages written to swap file since last time 38h DWORD number of reclaimed pages (page faults on swapped pages) 3Ch DWORD number of virtual pages allocated to the application 40h DWORD size in pages of swap file 44h DWORD number of system pages allocated with EMS calls 48h DWORD minimum number of conventional memory pages 4Ch DWORD maximum size in bytes to which swap file can be increased 50h DWORD "vmflags" bit 0 = 1 if page fault in progress 54h 16 BYTEs reserved for future expansion (set to zero) --------------------------------------------- INT 21 - Phar Lap 386/DOS-Extender VMM - LIMIT PROGRAM'S EXTENDED MEMORY USAGE AX = 2521h EBX = max 4k pages of physical extended memory which program may use Return: CF clear if successful EBX = maximum limit in pages ECX = minimum limit in pages CF set on error EAX = error code 08h insufficient memory or -nopage switch used SeeAlso: AX=2522h --------------------------------------------- INT 21 - Phar Lap 386/DOS-Extender VMM - SPECIFY ALTERNATE PAGE-FAULT HANDLER AX = 2522h ??? Return: ??? --------------------------------------------- INT 21 - Phar Lap 386/DOS-Extender VMM - SPECIFY OUT-OF-SWAP-SPACE HANDLER AX = 2523h ??? Return: ??? --------------------------------------------- INT 21 - Phar Lap 386/DOS-Extender VMM - INSTALL PAGE-REPLACEMENT HANDLERS AX = 2524h ??? Return: ??? --------------------------------------------- INT 21 - Phar Lap 386/DOS-Extender VMM - LIMIT PROGRAM'S CONVENTIONAL MEM USAGE AX = 2525h EBX = limit in 4k pages of physical conventional memory which program may use Return: CF clear if successful EBX = maximum limit in pages ECX = minimum limit in pages CF set on error EAX = error code 08h insufficient memory or -nopage switch used SeeAlso: AX=2521h --------------------------------------------- INT 21 - Phar Lap 386/DOS-Extender - GET CONFIGURATION INFORMATION AX = 2526h ??? Return: ??? --------------------------------------------- INT 21 - Phar Lap 386/DOS-Extender - ALLOCATE MS-DOS MEMORY BLOCK AX = 25C0h BX = number of 16-byte paragraphs of MS-DOS memory requested Return: CF clear if successful AX = real-mode paragraph address of memory CF set on error AX = error code 07h MS-DOS memory control blocks destroyed 08h insufficient memory BX = size in paragraphs of largest available memory block SeeAlso: AX=25C1h,25C2h --------------------------------------------- INT 21 - Phar Lap 386/DOS-Extender - RELEASE MS-DOS MEMORY BLOCK AX = 25C1h CX = real-mode paragraph address of memory block to free Return: CF clear if successful EAX destroyed CF set on error AX = error code 07h MS-DOS memory control blocks destroyed 09h invalid memory block address in CX SeeAlso: AX=25C0h,25C2h --------------------------------------------- INT 21 - Phar Lap 386/DOS-Extender - MODIFY MS-DOS MEMORY BLOCK AX = 25C2h BX = new requested block size in paragraphs CX = real-mode paragraph address of memory block to modify Return: CF clear if successful EAX destroyed CF set on error AX = error code 07h MS-DOS memory control blocks destroyed 08h insufficient memory 09h invalid memory block address in CX BX = size in paragraphs of largest available memory block SeeAlso: AX=25C0h,25C1h --------------------------------------------- INT 21 - Phar Lap 386/DOS-Extender - EXECUTE PROGRAM AX = 25C3h ES:EBX -> pointer to parameter block (see below) DS:EDX -> pointer to ASCIIZ program filename Return: CF clear if successful all registers unchanged CF set on error EAX = error code 01h function code in AL is invalid ??? 02h file not found or path invalid 05h access denied 08h insufficient memory to load program 0Ah environment invalid 0Bh invalid file format Format of parameter block: Offset Size Description 00h DWORD 32-bit offset of environment string 04h WORD segment selector of environment string 06h DWORD 32-bit offset of command-tail string 0Ah WORD segment selector of command-tail string --------------------------------------------- INT 21 - DOS - CREATE PSP AH = 26h DX = segment number at which to set up PSP Return: current PSP is copied to specified segment Notes: new PSP is updated with memory size information; INTs 22h, 23h, 24h taken from interrupt vector table (DOS 2+) DOS assumes that the caller's CS is the segment of the PSP to copy SeeAlso: AH=50h,51h,55h,62h,67h Format of PSP: Offset Size Description 00h 2 BYTEs program exit point (INT 20h instruction) 02h WORD memory size in paragraphs 04h BYTE unused 05h 5 BYTEs CP/M entry point (FAR jump to 000C0h) BUG: (DOS 2+) PSPs created by INT 21/AH=4Bh point at 000BEh 06h WORD CP/M compatibility--size of first segment for .COM files 0Ah DWORD terminate address (old INT 22h) 0Eh DWORD break address (old INT 23h) 12h DWORD critical error handler (old INT 24h) 16h WORD parent PSP segment 18h 20 BYTEs DOS 2+ open file table, FFh = unused 2Ch WORD DOS 2+ environment segment (see below) 2Eh DWORD DOS 2+ process's SS:SP on entry to last INT 21 call 32h WORD DOS 3+ max open files 34h DWORD DOS 3+ open file table address 38h DWORD DOS 3+ pointer to previous PSP (default FFFFFFFFh in 3.x) used by SHARE in DOS 3.3 3Ch 20 BYTEs unused by DOS versions <= 4.01 50h 3 BYTEs DOS function dispatcher (FAR routine)--CDh 21h CBh 53h 9 BYTEs unused 5Ch 16 BYTEs FCB #1 (see AH=0Fh), filled in from first commandline argument (when opened, overwrites following FCB) 6Ch 20 BYTEs FCB #2 (see AH=0Fh), filled in from second commandline argument (when opened, overwrites part of command tail) 80h 128 BYTEs command tail / default DTA buffer command tail is BYTE for length of tail, N BYTEs for the tail, followed by a BYTE containing 0Dh Notes: in DOS versions 3.0 and up, the limit on simultaneously open files may be increased by allocating memory for a new open file table, filling it with FFh, copying the first 20 bytes from the default table, and adjusting the pointer and count at 34h and 32h. However, DOS versions through at least 3.30 will only copy the first 20 file handles into a child PSP (including the one created on EXEC). network redirectors based on the original MS-Net implementation use values of 80h-FEh in the open file table to indicate remote files Format of environment block: Offset Size Description 00h N BYTEs first environment variable, ASCIZ string of form "var=value" N BYTEs second environment variable, ASCIZ string ... N BYTEs last environment variable, ASCIZ string of form "var=value" BYTE 00h ---DOS 3+--- WORD number of strings following environment (normally 1) N BYTEs ASCIZ full pathname of program owning this environment other strings may follow --------------------------------------------- INT 21 - DOS - RANDOM BLOCK READ AH = 27h DS:DX -> FCB (see AH=0Fh) CX = number of records to be read Return: AL = status 00h successful read 01h end of file 02h data transfer area too small 03h partial record, EOF SeeAlso: AH=3Fh --------------------------------------------- INT 21 - DOS - RANDOM BLOCK WRITE AH = 28h DS:DX -> FCB (see AH=0Fh) CX = number of records to be written if zero, truncate file to current random file position Return: AL = status 00h successful write 01h disk full 02h data transfer area too small SeeAlso: AH=40h --------------------------------------------- INT 21 - DOS - PARSE FILENAME AH = 29h DS:SI -> string to parse ES:DI -> buffer to fill with unopened FCB (see AH=0Fh) AL = bit mask to control parsing 0 = 0: parsing stops if file separator found 1: leading separators ignored 1 = 0: drive number in FCB set to default drive if not present in string 1: drive number in FCB not changed 2 = 0: filename in FCB set to blanks if no filename in string 1: filename in FCB not changed if string does not contain a filename 3 = 0: extension in FCB set to blanks if no extension in string 1: extension left unchanged Return: AL = 00h no wildcards in name or extension 01h wildcards appeared FFh drive specifier invalid DS:SI -> first byte after parsed string ES:DI buffer filled with unopened FCB Notes: asterisks expanded to question marks in the FCB all processing stops when a filename terminator is encountered cannot be used with filespecs which include a path (DOS 2+) --------------------------------------------- INT 21 - DOS - GET CURRENT DATE AH = 2Ah Return: DL = day DH = month CX = year AL = day of the week (0=Sunday, 1=Monday, etc.) SeeAlso: AH=E7h,INT 1A/AH=04h --------------------------------------------- INT 21 - DOS - SET CURRENT DATE AH = 2Bh DL = day DH = month CX = year Return: AL = 00h if no error = FFh if bad value sent to routine Note: DOS 3.3+ also sets CMOS clock SeeAlso: INT 1A/AH=05h --------------------------------------------- INT 21 - DESQview - INSTALLATION CHECK AH = 2Bh AL = subfunction (DV v2.00+) 01h get version Return: BX = version (BH = major, BL = minor) Note: early copies of v2.00 return 0002h 02h get shadow buffer info, and start shadowing Return: BH = rows in shadow buffer BL = columns in shadow buffer DX = segment of shadow buffer 04h get shadow buffer info Return: BH = rows in shadow buffer BL = columns in shadow buffer DX = segment of shadow buffer 05h stop shadowing CX = 4445h ('DE') DX = 5351h ('SQ') Return: AL = FFh if DESQview not installed Note: in DESQview v1.x, there were no subfunctions; this call only identified whether or not DESQview was loaded SeeAlso: INT 10/AH=FEh,FFh --------------------------------------------- INT 21 - PC Tools v5.1 PC-CACHE - INSTALLATION CHECK AH = 2Bh CX = 4358h ('CX') Return: AL = FFh if PC-CACHE not installed AL = 00h if installed CX = 6378h ('cx') BX = ??? DX = ??? --------------------------------------------- INT 21 - TAME v2.10 - INSTALLATION CHECK AX = 2B01h CX = 5441h ('TA') DX = 4D45h ('ME') Return: AL = 02h if installed ES:DX -> data area in TAME-RES (see below) Note: TAME is a shareware program by David G. Thomas which gives up CPU time to other partitions under a multitasker when the current partition's program incessantly polls the keyboard or system time Format of TAME 2.10-2.20 data area: Offset Size Description 00h BYTE data structure minor version number (01h in TAME 2.20) 01h BYTE data structure major version number (07h in TAME 2.20) 02h DWORD number of task switches 06h DWORD number of keyboard polls 0Ah DWORD number of time polls 0Eh DWORD number of times DESQview told program runs only in foreground 12h DWORD original INT 10h 16h DWORD original INT 14h 1Ah DWORD original INT 15h 1Eh DWORD original INT 16h 22h DWORD original INT 17h 26h DWORD original INT 21h 2Ah DWORD original INT 28h 2Eh WORD offset of TAME INT 10h handler 30h WORD offset of TAME INT 14h handler 32h WORD offset of TAME INT 15h handler 34h WORD offset of TAME INT 16h handler 36h WORD offset of TAME INT 17h handler 38h WORD offset of TAME INT 21h handler 3Ah WORD offset of TAME INT 28h handler 3Ch WORD X in /max:X,Y or /freq:X,Y 3Eh WORD Y in /max:X,Y or /freq:X,Y 40h WORD number of polls remaining before next task switch 42h WORD /KEYIDLE value 44h BYTE flags for interrupts already grabbed by TAME bit 0: INT 10h 1: INT 14h 2: INT 15h 3: INT 16h 4: INT 17h 5: INT 21h 6: INT 28h 45h BYTE flags for interrupts which may be acted on (same bits as above) 46h BYTE TAME enabled (01h) or disabled (00h) 47h BYTE /TIMEPOLL (01h) or /NOTIMEPOLL (00h) 48h BYTE /NOTIMER (01h) or /TIMER (00h) 49h BYTE window or task number for this task 4Ah BYTE multitasker type ??? 01h DESQview 02h DoubleDOS 03h TopView ??? 4Bh BYTE type of task switching selected bit 0: DESQview??? 1: DoubleDOS??? 2: TopView??? 3: KeySwitch 4: HLT instruction 4Ch BYTE ??? 4Dh BYTE flags bit 1: /FREQ instead of /MAX 4Eh BYTE /FG: value 4Fh BYTE task switches left until next FGONLY DESQview API call 50h BYTE ??? Format of TAME 2.30 data area: Offset Size Description 00h BYTE data structure minor version number (02h in TAME 2.30) 01h BYTE data structure major version number (0Ah in TAME 2.30) 02h DWORD number of task switches 06h DWORD number of keyboard polls 0Ah DWORD number of time polls 0Eh DWORD number of times DESQview told program runs only in foreground 12h DWORD time of last /CLEAR or TAME-RES load 16h DWORD time yielded 1Ah DWORD time spent polling 1Eh DWORD time spent waiting on key input with INT 16/AH=01h,11h 22h DWORD original INT 10h 26h DWORD original INT 14h 2Ah DWORD original INT 15h 2Eh DWORD original INT 16h 32h DWORD original INT 17h 36h DWORD original INT 21h 3Ah DWORD original INT 28h 3Eh WORD offset of TAME INT 10h handler 40h WORD offset of TAME INT 14h handler 42h WORD offset of TAME INT 15h handler 44h WORD offset of TAME INT 16h handler 46h WORD offset of TAME INT 17h handler 48h WORD offset of TAME INT 21h handler 4Ah WORD offset of TAME INT 28h handler 4Ch WORD X in /max:X,Y or /freq:X,Y 4Eh WORD Y in /max:X,Y or /freq:X,Y 50h WORD number of polls remaining before next task switch 52h WORD /KEYIDLE value 54h WORD /FG: value 56h WORD task switches left until next FGONLY DESQview API call 58h WORD multitasker version 5Ah WORD virtual screen segment 5Ch BYTE flags for interrupts already grabbed by TAME bit 0: INT 10h 1: INT 14h 2: INT 15h 3: INT 16h 4: INT 17h 5: INT 21h 6: INT 28h 5Dh BYTE flags for interrupts which may be acted on (same bits as above) 5Eh BYTE window or task number for this task 5Fh BYTE multitasker type 01h DESQview 02h DoubleDOS 03h TopView 04h OmniView 05h VM/386 60h BYTE type of task switching selected (bit flags) bit 0: DESQview 1: DoubleDOS 2: TopView 3: OmniView 4: KeySwitch 5: HLT instruction 61h BYTE watch_DOS 62h BYTE bit flags bit 0: TAME enabled 1: /FREQ instead of /MAX (counts in 3Ch and 3Eh per tick) 2: /TIMEPOLL 3: /KEYPOLL 4: inhibit timer 5: enable status monitoring 63h BYTE old status 64h WORD signature DA34h --------------------------------------------- INT 21 - DOS - GET CURRENT TIME AH = 2Ch Return: CH = hours CL = minutes DH = seconds DL = hundredths of seconds Note: time is updated approximately every 5/100 second SeeAlso: AH=E7h,INT 1A/AH=00h,02h,FEh --------------------------------------------- INT 21 - DOS - SET CURRENT TIME AH = 2Dh CH = hours CL = minutes DH = seconds DL = hundredths of seconds Return: AL = 00h if no error = FFh if bad value sent to routine Note: DOS 3.3+ also sets CMOS clock SeeAlso: INT 1A/AH=01h,03h,FFh --------------------------------------------- INT 21 - DOS - SET VERIFY FLAG AH = 2Eh DL = 00h AL = 01h VERIFY on 00h VERIFY off Note: when ON, all disk writes are verified SeeAlso: AH=54h --------------------------------------------- INT 21 - DOS 2+ - GET DISK TRANSFER AREA ADDRESS AH = 2Fh Return: ES:BX -> DTA SeeAlso: AH=1Ah --------------------------------------------- INT 21 - DOS 2+ - GET DOS VERSION AH = 30h Return: AL = major version number (00h for DOS 1.x) AH = minor version number BH = OEM number 00h IBM 16h DEC FFh Phoenix BL:CX = 24-bit user number Notes: the OS/2 Compatibility Box returns 0Ah for the major version DOS 4.01 identifies itself as version 4.00 --------------------------------------------- INT 21 - Phar Lap 386/DOS-Extender - GET VERSION AH = 30h EBX = 50484152h ("PHAR") Return: ??? --------------------------------------------- INT 21 - CTask 2.0 - INSTALLATION CHECK AX = 3000h BX = 1234h DS:DX -> version string??? (8 bytes) Return: AL = DOS major version AH = DOS minor version CX:BX -> ??? Notes: if first eight bytes of returned data block equal eight bytes passed in, CTask is resident CTask is a multitasking kernel for C written by Thomas Wagner --------------------------------------------- INT 21 - DOS 2+ - TERMINATE BUT STAY RESIDENT AH = 31h AL = exit code DX = program size, in paragraphs Note: most TSRs can save some memory by releasing their environment block before terminating (see AH=26h) SeeAlso: INT 22, INT 27 --------------------------------------------- INT 21 - DOS 2+ internal - GET DRIVE PARAMETER BLOCK AH = 32h DL = drive number 0 = default, 1 = A, etc. Return: AL = FFh if invalid drive number, else DS:BX -> drive parameter block (see below) Note: the OS/2 compatibility box supports the DOS 3.3 version of this call except for the DWORD at offset 12h SeeAlso: AH=1Fh Format of DOS Drive Parameter Block: Offset Size Description 00h BYTE drive number (0 = A, etc.) 01h BYTE unit number within device driver 02h WORD number of bytes per sector 04h BYTE largest sector number in cluster (one less than sect/clust) 05h BYTE log base two of the cluster size 06h WORD number of reserved (boot) sectors 08h BYTE number of copies of the FAT 09h WORD number of root directory entries 0Bh WORD first data sector on medium 0Dh WORD largest possible cluster number (one more than # data clust) ---DOS 2.x--- 0Fh BYTE number of sectors in one FAT copy 10h WORD first sector of root directory 12h DWORD address of device driver for this drive 16h BYTE media descriptor byte for medium 17h BYTE FFh indicates block must be rebuilt 18h DWORD address of next device block, offset = FFFFh indicates last 1Ch WORD starting cluster of current directory (0 = root directory) 1Eh 64 BYTEs ASCIZ current directory path string ---DOS 3.x--- 0Fh BYTE number of sectors in one FAT copy 10h WORD first sector of root directory 12h DWORD address of device driver for this drive 16h BYTE media descriptor byte for medium 17h BYTE FFh = block must be rebuilt, 00h indicates block accessed 18h DWORD address of next device block, offset = FFFFh indicates last 1Ch WORD cluster at which to start search for free space when writing 1Eh WORD number of free clusters on drive, FFFFh = unknown ---DOS 4.0--- 0Fh WORD number of sectors in one FAT copy 11h WORD first sector of root directory 13h DWORD address of device driver for this drive 17h BYTE media descriptor byte for medium 18h BYTE FFh = block must be rebuilt, 00h indicates block accessed 19h DWORD address of next device block, offset = FFFFh indicates last 1Dh WORD cluster at which to start search for free space when writing 1Fh WORD number of free clusters on drive, FFFFh = unknown --------------------------------------------- INT 21 - DOS 2+ - EXTENDED CONTROL-BREAK CHECKING AH = 33h AL = subfunction 00h get state Return: DL = current BREAK setting 00h BREAK=OFF 01h BREAK=ON 01h set state DL = 00h for OFF or 01h for ON Return: AL = FFh if error Note: under DOS 3+, this function does not use any of the DOS-internal stacks and is thus fully reentrant --------------------------------------------- INT 21 - DOS 3.x internal - GET AND SET EXTENDED CONTROL-BREAK CHECKING STATE AX = 3302h DL = new state 00h for OFF or 01h for ON Return: DL = old state of extended BREAK checking Note: this function does not use any of the DOS-internal stacks and is thus fully reentrant --------------------------------------------- INT 21 - DOS 4.0 - GET BOOT DRIVE AX = 3305h Return: DL = boot drive (1=A:,...) --------------------------------------------- INT 21 - DOS 2+ internal - RETURN CritSectFlag (InDOS) POINTER AH = 34h Return: ES:BX -> 1-byte DOS "Critical Section Flag", also known as InDOS flag Notes: when the critical section flag is nonzero, code within DOS is being executed. It is safe to enter DOS when both the critical section flag and the critical error flag are zero. The critical error flag is the byte after the critical section flag in DOS 2.x, and the byte BEFORE the critical section flag in DOS 3.x (except COMPAQ DOS 3.0, where the critical error flag is located 1AAh bytes BEFORE the critical section flag) For DOS 3.1+, an undocumented call exists to get the address of the critical error flag (see AX=5D06h) --------------------------------------------- INT 21 - DOS 2+ - GET INTERRUPT VECTOR AH = 35h AL = interrupt number Return: ES:BX = value of interrupt vector SeeAlso: AH=25h --------------------------------------------- INT 21 - DOS 2+ - GET DISK SPACE AH = 36h DL = drive code (0 = default, 1 = A, 2 = B, etc.) Return: AX = number of sectors per cluster or 0FFFFh if invalid drive BX = number of available clusters CX = bytes per sector DX = total clusters Notes: multiply AX * CX * BX for free space on disk multiply AX * CX * DX for total disk space according to Dave Williams' MSDOS reference, the value in DX is incorrect for non-default drives after ASSIGN is run SeeAlso: AH=1Ch --------------------------------------------- INT 21 - DOS 2+ internal - GET SWITCHAR AX = 3700h Return: AL = FFh unsupported subfunction DL = current switch character Notes: documented in some OEM versions of some releases of DOS supported by OS/2 compatibility box SeeAlso: AX=3701h --------------------------------------------- INT 21 - DOS 2+ internal - SET SWITCHAR AX = 3701h DL = new switch character Return: AL = FFh unsupported subfunction Notes: documented in some OEM versions of some releases of DOS supported by OS/2 compatibility box SeeAlso: AX=3700h --------------------------------------------- INT 21 - DOS 2.x and 4.0 only internal - AVAILDEV AH = 37h AL = subfunction 02h read device availability (as set by AL=03h) Return: DL = device availability (always FFh under DOS 4.0) 03h set device availability, where: DL = 00h means \DEV\ must preceed device names DL <> 00h means \DEV\ need not preceed device names Return: AL = FFh if invalid subfunction Notes: all versions of DOS from 2.00 allow \DEV\ to be prepended to device names without generating an error even if the directory \DEV does not actually exist (other paths generate an error if they do not exist). although DOS 4.0 accepts these calls, they have no effect --------------------------------------------- INT 21 - DOS 2+ - GET COUNTRY-DEPENDENT INFORMATION AH = 38h --DOS 2.x-- AL = 00h get current-country info DS:DX -> buffer for returned info (see below) Return: AX = country code (MSDOS 2.11 only) buffer at DS:DX filled --DOS 3+-- AL = 00h for current country AL = 01h thru 0FEh for specific country with code <255 AL = 0FFh for specific country with code >= 255 BX = 16-bit country code DS:DX -> buffer for returned info (see below) Return: CF set on error AX = error code (02h) CF clear if successful BX = country code DS:DX buffer filled SeeAlso: AH=65h, INT 2F/AX=110Ch,1404h Format of PCDOS 2.x country info: Offset Size Description 00h WORD date format 0 = USA mm dd yy 1 = Europe dd mm yy 2 = Japan yy mm dd 02h BYTE currency symbol 03h BYTE 00h 04h BYTE thousands separator char 05h BYTE 00h 06h BYTE decimal separator char 07h BYTE 00h 08h 24 BYTEs reserved Format of MSDOS 2.x, DOS 3+ country info: Offset Size Description 00h WORD date format (see above) 02h 5 BYTEs ASCIZ currency symbol string 07h BYTE thousands separator char 08h BYTE 00h 09h BYTE decimal separator char 0Ah BYTE 00h 0Bh BYTE date separator char 0Ch BYTE 00h 0Dh BYTE time separator char 0Eh BYTE 00h 0Fh BYTE currency format bit 2 = set if currency symbol replaces decimal point bit 1 = number of spaces between value and currency symbol bit 0 = 0 if currency symbol precedes value 1 if currency symbol follows value 10h BYTE number of digits after decimal in currency 11h BYTE time format bit 0 = 0 if 12-hour clock 1 if 24-hour clock 12h DWORD address of case map routine (FAR CALL, AL = char to map to upper case [>= 80h]) 16h BYTE data-list separator char 17h BYTE 00h 18h 10 BYTEs reserved --------------------------------------------- INT 21 - DOS 3+ - SET COUNTRY CODE AH = 38h AL = 01h thru 0FEh for specific country with code <255 AL = FFh for specific country with code >= 255 BX = 16-bit country code DX = FFFFh Return: CF set on error AX = error code (see AH=59h) CF clear if successful SeeAlso: INT 2F/AX=1403h --------------------------------------------- INT 21 - DOS 2+ - CREATE A SUBDIRECTORY (MKDIR) AH = 39h DS:DX -> ASCIZ pathname (may include drive) Return: CF set on error AX = error code (03h,05h) (see AH=59h) CF clear if successful Note: all directories in the given path except the last must exist SeeAlso: AH=3Ah,3Bh, INT 2F/AX=1103h --------------------------------------------- INT 21 - DOS 2+ - REMOVE A DIRECTORY ENTRY (RMDIR) AH = 3Ah DS:DX -> ASCIZ pathname (may include drive) Return: CF set on error AX = error code (03h,05h,06h,10h) (see AH=59h) CF clear if successful SeeAlso: AH=39h,3Bh, INT 2F/AX=1101h --------------------------------------------- INT 21 - DOS 2+ - CHANGE THE CURRENT DIRECTORY (CHDIR) AH = 3Bh DS:DX -> ASCIZ directory name (may include drive) Return: CF set on error AX = error code (03h) (see AH=59h) CF clear if successful Note: if new directory name includes a drive letter, the default drive is not changed, only the current directory on that drive SeeAlso: AH=47h, INT 2F/AX=1105h --------------------------------------------- INT 21 - DOS 2+ - CREATE A FILE WITH HANDLE (CREAT) AH = 3Ch CX = attributes for file bit 0: read-only 1: hidden 2: system 3: volume label (ignored) 4: reserved, must be zero (directory) 5: archive bit 7: if set, file is shareable under Novell NetWare DS:DX -> ASCIZ filename (may include drive and path) Return: CF set on error AX = error code (03h,04h,05h) (see AH=59h) CF clear if successful AX = file handle Note: if a file with the given name exists, it is truncated to zero length SeeAlso: AH=3Dh --------------------------------------------- INT 21 - DOS 2+ - OPEN DISK FILE WITH HANDLE AH = 3Dh AL = access mode 00h read only 01h write only 02h read/write AL bits 7-3 = file-sharing modes (DOS 3+) bit 7 = inheritance flag, set for no inheritance bits 4-6 = sharing mode 000 compatibility mode 001 exclusive (deny all) 010 write access denied (deny write) 011 read access denied (deny read) 100 full access permitted (deny none) 111 used internally by SHARE bit 3 = reserved, should be zero DS:DX -> ASCIZ filename Return: CF set on error AX = error code (01h,02h,03h,04h,05h,0Ch) (see AH=59h) CF clear if successful AX = file handle Notes: file pointer is set to start of file file handles which are inherited from a parent also inherit sharing and access restrictions SeeAlso: AH=0Fh,3Ch, INT 2F/AX=1226h File sharing behavior: | Second and subsequent Opens First |Compat Deny Deny Deny Deny Open | All Write Read None |R W RW R W RW R W RW R W RW R W RW - - - - -| - - - - - - - - - - - - - - - - - Compat R |Y Y Y N N N 1 N N N N N 1 N N W |Y Y Y N N N N N N N N N N N N RW|Y Y Y N N N N N N N N N N N N - - - - -| Deny R |C C C N N N N N N N N N N N N All W |C C C N N N N N N N N N N N N RW|C C C N N N N N N N N N N N N - - - - -| Deny R |2 C C N N N Y N N N N N Y N N Write W |C C C N N N N N N N N N N N N RW|C C C N N N N N N N N N N N N - - - - -| Deny R |C C C N N N N Y N N N N N Y N Read W |C C C N N N N N N N N N N Y N RW|C C C N N N N N N N N N N Y N - - - - -| Deny R |2 C C N N N Y Y Y N N N Y Y Y None W |C C C N N N N N N Y Y Y Y Y Y RW|C C C N N N N N N N N N Y Y Y Legend: Y = open succeeds, N = open fails with error code 05h C = open fails, INT 24 generated 1 = open succeeds if file read-only, else fails with error code 2 = open succeeds if file read-only, else fails with INT 24 --------------------------------------------- INT 21 - DOS 2+ - CLOSE A FILE WITH HANDLE AH = 3Eh BX = file handle Return: CF set on error AX = error code (06h) (see AH=59h) CF clear if successful Note: if the file was written to, the time and date stamps are set to the current time SeeAlso: AH=10h,3Ch,3Dh, INT 2F/AX=1106h,1227h --------------------------------------------- INT 21 - DOS 2+ - READ FROM FILE WITH HANDLE AH = 3Fh BX = file handle CX = number of bytes to read DS:DX -> buffer Return: CF set on error AX = error code (05h,06h) (see AH=59h) CF clear if successful AX = number of bytes read (0 if at EOF before call) Notes: the returned AX may be smaller than the request in CX if a partial read occurred if reading from CON, read stops at first CR SeeAlso: AH=27h,40h, INT 2F/AX=1108h,1229h --------------------------------------------- INT 21 - DOS 2+ - WRITE TO FILE WITH HANDLE AH = 40h BX = file handle CX = number of bytes to write DS:DX -> buffer Return: CF set on error AX = error code (05h,06h) (see AH=59h) CF clear if successful AX = number of bytes actually written Notes: if CX is zero, no data is written, and the file is truncated or extended to the current position the usual cause for AX < CX on return is a full disk SeeAlso: AH=28h,3Fh, INT 2F/AX=1109h --------------------------------------------- INT 21 - DOS 2+ - DELETE A FILE (UNLINK) AH = 41h DS:DX -> ASCIZ pathname of file to delete (no wildcards allowed) Return: CF set on error AX = error code (02h,05h) (see AH=59h) CF clear if successful Note: (DOS 3.1+) wildcards are allowed if invoked via AX=5D00h, in which case the filespec must be canonical (as returned by AH=60h) SeeAlso: AH=13h,AX=5D00h,AH=60h, INT 2F/AX=1113h --------------------------------------------- INT 21 - DOS 2+ - MOVE FILE READ/WRITE POINTER (LSEEK) AH = 42h AL = method 00h offset from beginning of file 01h offset from present location 02h offset from end of file BX = file handle CX:DX = offset in bytes Return: CF set on error AX = error code (01h,06h) (see AH=59h) CF clear if successful DX:AX = new absolute offset from beginning of file SeeAlso: AH=24h, INT 2F/AX=1228h --------------------------------------------- INT 21 - DOS 2+ - GET FILE ATTRIBUTES AX = 4300h DS:DX -> ASCIZ file name or directory name without trailing slash Return: CF set on error AX = error code (01h,02h,03h,05h) (see AH=59h) CF clear if successful CX = file attributes (see AX=4301h) SeeAlso: AX=4301h, INT 2F/AX=110Fh --------------------------------------------- INT 21 - DOS 2+ - PUT FILE ATTRIBUTES (CHMOD) AX = 4301h CX = file attribute bits bit 0 = read only 1 = hidden file 2 = system file 3 = volume label 4 = subdirectory 5 = written since backup ("archive" bit) 8 = shareable (Novell NetWare) DS:DX -> ASCIZ file name Return: CF set on error AX = error code (01h,02h,03h,05h) (see AH=59h) CF clear if successful Note: will not change volume label or directory attributes SeeAlso: AX=4300h, INT 2F/AX=110Eh --------------------------------------------- INT 21 - DOS 2+ - IOCTL - GET DEVICE INFORMATION AX = 4400h BX = file or device handle Return: CF set on error AX = error code (see AH=59h) CF clear if successful DX = device info If bit 7 set: (character device) bit 0: console input device 1: console output device 2: NUL device 3: CLOCK$ device 4: device is special (uses INT 29) 5: binary (raw) mode 6: Not EOF 12: network device (DOS 3+) 14: can process IOCTL control strings (see AL = 02h-05h) If bit 7 clear: (file) bits 0-5 are block device number 6: file has not been written 12: network device (DOS 3+) 14: can process IOCTL control strings (DOS 3+) 15: file is remote (DOS 3+) SeeAlso: AX=4401h, INT 2F/AX=122Bh --------------------------------------------- INT 21 - DOS 2+ - IOCTL - SET DEVICE INFORMATION AX = 4401h BX = device handle DH = 0 DL = device information to set (bits 0-7 from function 0) Return: CF set on error AX = error code (see AH=59h) CF clear if successful SeeAlso: AX=4400h, INT 2F/AX=122Bh --------------------------------------------- INT 21 - DOS 2+ - IOCTL - READ CHARACTER DEVICE CONTROL STRING AX = 4402h BX = device handle CX = number of bytes to read DS:DX -> buffer Return: CF set on error AX = error code (see AH=59h) CF clear if successful AX = number of bytes read SeeAlso: AX=4403h,4404h, INT 2F/AX=122Bh --------------------------------------------- INT 21 - Network Driver Interface Spec 2.0.1 - PROTOCOL MANAGER AX = 4402h BX = file handle for device "PROTMAN$" DS:DX -> request block (see below) CX = 000Eh (size of request block) 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 Values of 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 01h Media Access Control 02h Data link 03h network 04h transport 05h session FFh not specified 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 00h physical 01h Media Access Control 02h Data link 03h network 04h transport 05h session FFh not specified 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 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 DWORD reserved, must be 0 3Ch DWORD reserved, must be 0 Note: for compatibility with NDIS 1.x.x, a major version of 00h is interpreted as 01h 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 bit 0: supports broadcast 1: supports multicast 2: supports functional/group addressing 3: supports promiscuous mode 4: station address software settable 5: statistics always current 6: supports InitiateDiagnostics 7: supports loopback 8: MAC does primarily ReceiveChain indications instead of ReceiveLookahead indications 9: supports IBM source routing 10: supports MAC reset 11: supports Open/Close adapter 12: supports interrupt request 13: supports source routing bridge 14: supports GDT virtual addresses (OS/2 version) 15: multiple TransferDatas allowed durign a single indication 16: MAC normally sets FrameSize = 0 in ReceiveLookahead 17-31: reserved, must be 0 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 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 bits 0-2: 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 4: MAC open 5: diagnostics in progress 6-31: reserved 0Ah WORD current packet filter flags bit 0: directed/multicast or group/functional 1: broadcast 2: promiscuous 3: all source routing 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 --------------------------------------------- INT 21 - DOS 2+ - IOCTL - WRITE CHARACTER DEVICE CONTROL STRING AX = 4403h BX = device handle CX = number of bytes to write DS:DX -> buffer Return: CF set on error AX = error code (see AH=59h) CF clear if successful AX = number of bytes written SeeAlso: AX=4402h,4405h, INT 2F/AX=122Bh --------------------------------------------- INT 21 - DOS 2+ - IOCTL - READ BLOCK DEVICE CONTROL STRING AX = 4404h BL = drive number (0=default) CX = number of bytes to read DS:DX -> buffer Return: CF set on error AX = error code (see AH=59h) CF clear if successful AX = number of bytes read SeeAlso: AX=4402h,4405h, INT 2F/AX=122Bh --------------------------------------------- INT 21 - DOS 2+ - IOCTL - WRITE BLOCK DEVICE CONTROL STRING AX = 4405h BL = drive number (0=default) CX = number of bytes to write DS:DX -> buffer Return: CF set on error AX = error code (see AH=59h) CF clear if successful AX = number of bytes written SeeAlso: AX=4403h,4404h, INT 2F/AX=122Bh --------------------------------------------- INT 21 - DOS 2+ - IOCTL - GET INPUT STATUS AX = 4406h BX = file or device handle Return: AL = FFh device ready 00h device not ready (or file at EOF) SeeAlso: AX=4407h, INT 2F/AX=122Bh --------------------------------------------- INT 21 - DOS 2+ - IOCTL - GET OUTPUT STATUS AX = 4407h BX = file or device handle Return: AL = FFh device ready 00h device not ready Note: for DOS 2.x, files are always ready for output SeeAlso: AX=4406h, INT 2F/AX=122Bh --------------------------------------------- INT 21 - DOS 3+ - IOCTL - BLOCK DEVICE CHANGEABLE AX = 4408h BL = drive number (0=default) Return: CF set on error AX = error code (0Fh invalid drive) (see AH=59h) CF clear if successful AX = 00h removable 01h fixed SeeAlso: AX=4400h,4409h, INT 2F/AX=122Bh --------------------------------------------- INT 21 - DOS 3+ - IOCTL - BLOCK DEVICE LOCAL AX = 4409h BL = drive number (0=default) Return: DX = attribute word, bit 12 set if device is remote SeeAlso: AX=4400h,4408h,440Ah, INT 2F/AX=122Bh --------------------------------------------- INT 21 - DOS 3+ - IOCTL - HANDLE LOCAL AX = 440Ah BX = file handle Return: DX = attribute word, bit 15 set if file is remote Note: if file is remote, Novell Advanced NetWare 2.0 returns the number of the file server on which the handle is located in CX SeeAlso: AX=4400h,4409h, INT 2F/AX=122Bh --------------------------------------------- INT 21 - DOS 3+ - IOCTL - SET SHARING RETRY COUNT AX = 440Bh CX = delay (default 1) DX = retry count (default 3) Return: CF set on error AX = error code (see AH=59h) CF clear if successful Note: delay is dependent on processor speed (value in CX specifies number of 64K-iteration empty loops to execute) SeeAlso: AH=52h, INT 2F/AX=1224h,122Bh --------------------------------------------- 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: CL = function 45h set iteration count 4Ah select code page 4Ch start code-page preparation 4Dh end code-page preparation 5Fh set display information (DOS 4.0) 65h get iteration count 6Ah query selected code page 6Bh query prepare list 7Fh get display information (DOS 4.0) 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 (see AH=59h) DS:DX -> (OS/2 comp box) data block SeeAlso: AX=440Dh, INT 2F/AX=122Bh,1A01h 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 4Dh: Offset Size Description 00h WORD length of data 02h WORD code page ID 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 functions 5Fh and 7Fh: Offset Size Description 00h BYTE level (0 for DOS 4.0) 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 --------------------------------------------- INT 21 - DOS 3.2+ - IOCTL - GENERIC BLOCK DEVICE REQUEST AX = 440Dh BL = drive number (0=default) CH = category code 08h disk drive CL = function 40h set device parameters 41h write logical device track 42h format and verify logical device track 46h (DOS 4.0) set ??? 47h (DOS 4.0) set access flag 60h get device parameters 61h read logical device track 62h verify logical device track 67h (DOS 4.0) get access flag 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 (see AH=59h) DS:DX -> (OS/2 comp box) data block Note: DOS 4.01 seems to ignore the high byte of the number of directory entries in the BPB for diskettes. SeeAlso: AX=440Ch, INT 2F/AX=122Bh 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 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 1.44M disk 08h other type of block device 02h WORD device attributes bit 0 set if nonremovable medium bit 1 set if door lock supported bits 2-15 reserved 04h WORD number of cylinders 06h BYTE media type 00h 1.2M disk (default) 01h 320K/360K disk 07h 31 BYTEs device BPB (see AH=53h) 26h WORD number of sectors per track (start of track layout field) 28h N word pairs: number,size of each sector in track Format of parameter block for functions 41h, 61h: Offset Size Description 00h BYTE 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 functions 42h, 62h: 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+) bits 1-7 reserved, must be zero on return (DOS 4.0): bit 0: set if specified tracks, sectors/track supported bit 1: set if function not supported by BIOS bit 2: set if specified tracks, sectors/track not supported bit 3: set if no disk in drive 01h WORD number of disk head 03h WORD number of disk cylinder 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 --------------------------------------------- INT 21 - DOS 3.2+ - IOCTL - GET LOGICAL DRIVE MAP AX = 440Eh BL = drive number (0=default) Return: CF set on error AX = error code (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) SeeAlso: AX=440Fh, INT 2F/AX=122Bh --------------------------------------------- INT 21 - DOS 3.2+ - IOCTL - SET LOGICAL DRIVE MAP AX = 440Fh BL = physical drive number (0=default) Return: CF set on error AX = error code (see AH=59h) CF clear if successful Note: maps logical drives to physical drives, similar to DOS's treatment of a single physical floppy drive as both A: and B: SeeAlso: AX=440Eh, INT 2F/AX=122Bh --------------------------------------------- INT 21 - DOS 2+ - CREATE DUPLICATE HANDLE (DUP) AH = 45h BX = file handle to duplicate Return: CF set on error AX = error code (04h,06h) (see AH=59h) CF clear if successful AX = new file handle Note: moving file pointer for either handle will also move it for the other SeeAlso: AH=46h --------------------------------------------- INT 21 - DOS 2+ - FORCE DUPLICATE HANDLE (FORCDUP,DUP2) AH = 46h BX = existing file handle CX = new file handle Return: CF set on error AX = error code (04h,06h) (see AH=59h) CF clear if successful Notes: closes file with handle BX if it is still open moving file pointer for either handle will also move it for the other SeeAlso: AH=45h --------------------------------------------- INT 21 - DOS 2+ - GET CURRENT DIRECTORY AH = 47h DL = drive (0=default, 1=A, etc.) DS:SI points to 64-byte buffer area Return: CF set on error AX = error code (0Fh) (see AH=59h) CF clear if successful Note: the returned path does not include a drive or the initial backslash SeeAlso: AH=3Bh --------------------------------------------- INT 21 - DOS 2+ - ALLOCATE MEMORY AH = 48h BX = number of 16-byte paragraphs desired Return: CF set on error AX = error code (07h,08h) (see AH=59h) BX = size of largest available block CF clear if successful AX = segment of allocated memory block SeeAlso: AH=49h,4Ah,58h --------------------------------------------- INT 21 - DOS 2+ - FREE MEMORY AH = 49h ES = segment address of area to be freed Return: CF set on error AX = error code (07h,09h) (see AH=59h) CF clear if successful SeeAlso: AH=48h,4Ah --------------------------------------------- INT 21 - DOS 2+ - ADJUST MEMORY BLOCK SIZE (SETBLOCK) AH = 4Ah ES = segment address of block to change BX = new size in paragraphs Return: CF set on error AX = error code (07h,08h,09h) (see AH=59h) BX = maximum size possible for the block (if AX=08h) CF clear if successful Notes: under PCDOS 2.1 and 3.1 and MSDOS 3.2 and 3.3, if there is insufficient memory to expand the block as much as requested, the block will be made as large as possible SeeAlso: AH=48h,49h --------------------------------------------- INT 21 - DOS 2+ - LOAD OR EXECUTE (EXEC) AH = 4Bh AL = subfunction 00h load and execute program 01h load but do not execute (internal) 03h load overlay; do not create PSP 04h called by MSC spawn(P_NOWAIT,...) when running DOS 4.x. returns unsuccessfully under DOS 4.0 (but may be successful in the original European OEM MSDOS 4.0, which has limited multitasking built in) DS:DX -> ASCIZ filename ES:BX -> parameter block (see below) Return: CF set on error AX = error code (01h,02h,05h,08h,0Ah,0Bh) (see AH=59h) CF clear if successful if subfunction 01h, process ID set to new program's PSP; get with INT 21/AH=62h Notes: DOS 2.x destroys all registers, including SS:SP 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 SeeAlso: AH=4Ch,4Dh,INT 2E Format of EXEC parameter block for AL=00h,01h: Offset Size Description 00h WORD segment of environment (0 = use current) (see AH=26h) 02h DWORD pointer to command line 06h DWORD pointer to first FCB (see AH=0Fh) 0Ah DWORD pointer to second FCB (see AH=0Fh) 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 load address 02h WORD segment relocation factor Format of .EXE file header: Offset Size Description 00h WORD 4Dh, 5Ah signature (sometimes 5Ah, 4Dh) 02h WORD image size remainder (program size mod 512, not including header) 04h WORD number of 512-byte pages needed to hold .EXE file (incl header) 06h WORD number of relocation items 08h WORD header size in paragraphs 0Ah WORD minimum extra paragraphs needed 0Ch WORD maximum extra paragraphs needed 0Eh WORD stack segment 10h WORD stack offset 12h WORD word checksum of entire file 14h DWORD initial CS:IP 18h WORD offset of relocation table 1Ah WORD overlay number Note: 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 --------------------------------------------- INT 21 - DOS 2+ - QUIT WITH EXIT CODE (EXIT) AH = 4Ch AL = exit code Return: never returns Note: unless the process is its own parent (see AH=26h, offset 16h in PSP), all open files are closed SeeAlso: AH=26h,4Bh,4Dh, INT 22 --------------------------------------------- INT 21 - DOS 2+ - GET EXIT CODE OF SUBPROGRAM (WAIT) AH = 4Dh Return: AL = exit code of subprogram (from AH=31h or AH=4Ch) AH = circumstance which caused termination 00h Terminate/abort 01h Control-C/Control-Break 02h Hard error 03h Terminate and stay resident SeeAlso: AH=4Bh,4Ch --------------------------------------------- INT 21 - WILDUNIX.COM internal - INSTALLATION CHECK AH = 4Eh DS:DX = 0000h:0000h Return: AH = 99h if installed Note: WILDUNIX.COM is a resident Unix-style wildcard expander by Steve Hosgood and Terry Barnaby --------------------------------------------- INT 21 - DOS 2+ - FIND FIRST ASCIZ (FINDFIRST) AH = 4Eh CX = search attributes (see AX=4301h) DS:DX -> ASCIZ filespec (drive, path, and wildcards allowed) Return: CF set on error AX = error code (02h,12h) (see AH=59h) CF clear if successful [DTA] = data block (see below) Notes: for search attributes other than 08h, all files with at MOST the specified attribute bits, the archive (20h) bit, and the read-only (01h) bits set 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. BUG: 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) SeeAlso: AH=11h, AH=4Fh, AX=4301h, INT 2F/AX=111Bh Format of FindFirst data block: Offset Size Description ---PCDOS 3.10, PCDOS 4.01, MSDOS 3.2/3.3--- 00h BYTE drive letter 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 ---PCDOS 4.01, MSDOS 3.2/3.3--- 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 --------------------------------------------- INT 21 - DOS 2+ - FIND NEXT ASCIZ (FINDNEXT) AH = 4Fh [DTA] = data block from last AH = 4Eh/4Fh call Return: CF set on error AX = error code (12h) (see AH=59h) CF clear if successful [DTA] = data block (see AH=4Eh) SeeAlso: AH=12h, AH=4Eh --------------------------------------------- INT 21 - DOS 2+ internal - SET PSP SEGMENT AH = 50h BX = segment address of new PSP (see AH=26h for format) Notes: 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 is thus fully reentrant supported by OS/2 compatibility box SeeAlso: AH=26h,51h,62h --------------------------------------------- INT 21 - DOS 2+ internal - GET PSP SEGMENT AH = 51h Return: BX = current PSP segment (see AH=26h for format) Notes: 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 is thus fully reentrant supported by OS/2 compability box identical to the documented AH=62h SeeAlso: AH=26h,50h,62h --------------------------------------------- INT 21 - DOS 2+ internal - GET LIST OF LISTS AH = 52h Return: ES:BX -> DOS list of lists Note: 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). Format of List of Lists: Offset Size Description -12 WORD (DOS 3.1-3.3) sharing retry count (see AX=440Bh) -10 WORD (DOS 3.1-3.3) sharing retry delay (see AX=440Bh) -8 DWORD (DOS 3.x) pointer to current disk buffer -4 WORD (DOS 3.x) pointer in DOS code 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 DOS Drive Parameter Block (see AH=32h) 04h DWORD pointer to list of DOS file tables (see below) 08h DWORD pointer to CLOCK$ device driver, resident or installable 0Ch DWORD pointer to actual CON device driver, resident or installable ---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!) This is the first device on DOS's linked list of device drivers. (see below for format) ---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!) This is the first device on DOS's linked list of device drivers. (see below for format) ---DOS 3.1-3.3--- 10h WORD maximum bytes/block of any block device 12h DWORD pointer to first disk buffer (see below) 16h DWORD pointer to array of current directory structures (see below) 1Ah DWORD pointer to FCB table (if CONFIG.SYS contains FCBS=) 1Eh WORD number of protected FCBs (the y in FCBS=x,y) 20h BYTE number of block devices 21h BYTE value of LASTDRIVE command in CONFIG.SYS (default 5) 22h 18 BYTEs actual NUL device driver header (not a pointer!) This is the first device on DOS's linked list of device drivers. (see below for format) (see also INT 2F/AX=122Ch) 34h BYTE number of JOIN'ed drives ---DOS 4.x--- 10h WORD maximum bytes/block of any block device 12h DWORD pointer to disk buffer info (see below) 16h DWORD pointer to array of current directory structures (see below) 1Ah DWORD pointer to FCB table (if CONFIG.SYS contains FCBS=) 1Eh WORD number of protected FCBs (the y in FCBS=x,y) 20h BYTE number of block devices 21h BYTE value of LASTDRIVE command in CONFIG.SYS (default 5) 22h 18 BYTEs actual NUL device driver header (not a pointer!) This is the first device on DOS's linked list of device drivers. (see below for format) (see also INT 2F/AX=122Ch) 34h BYTE number of JOIN'ed drives??? 35h WORD pointer within IBMDOS code segment to list of special program names (see below) 37h DWORD pointer to FAR routine for utility functions (see below) 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 the y in BUFFERS x,y 43h BYTE boot drive (1=A:) 44h BYTE ??? 45h WORD extended memory size in K Call utility functions at [LoL+37h] 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 = 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 Format of 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 3 BYTEs unused ---DOS 2.x,3.x--- 08h 8 BYTEs unused ---DOS 4.x--- 08h 8 BYTEs ASCII program name if PSP memory block, else garbage null-terminated if less than 8 characters Notes: under DOS 3.1+, the first memory block is the DOS data segment, containing installable drivers, buffers, etc. under DOS 4.x it is divided into subsegments, each with its own memory control block (see below), the first of which is at offset 0000h Format of DOS 4.x 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) 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 ptr 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.x: Identified by sub-segment control block type "S" within the DOS data segment. 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 3.1-4.01): (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 MSDOS 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 assumes DS=SS=DOS CS, direct-accesses DOS internals to get name of file just opened -34h DWORD pointer to FAR routine called on closing file ES:DI -> system file table Note: SHARE assumes SS=DOS CS, directly accesses DOS internals does something to every lock record for file -30h DWORD pointer to FAR routine to close all files for given computer (called by AX=5D03h) Note: SHARE assumes SS=DOS CS, directly accesses DOS internals -2Ch DWORD pointer to FAR routine to close all files for given process (called by AX=5D04h) Note: SHARE assumes SS=DOS CS, directly accesses DOS internals -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) Note: SHARE assumes SS=DOS CS, directly accesses DOS internals -24h DWORD pointer to FAR routine to lock region of file call with BX = file handle CX:DX = starting offset SI:AX = size Return: CF set on error AL = DOS error code (21h) (see AH=59h) Note: only called if file is marked as remote Note: SHARE assumes SS=DOS CS, directly accesses DOS internals -20h DWORD pointer to FAR routine to unlock region of file call with BX = file handle CX:DX = starting offset SI:AX = size Return: CF set on error AL = DOS error code (21h) (see AH=59h) Note: only called if file is marked as remote Note: SHARE assumes SS=DOS CS, directly accesses DOS internals -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 Note: SHARE assumes SS=DOS CS, directly accesses DOS internals -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 Note: SHARE assumes SS=DOS CS, directly accesses DOS internals -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: SHARE assumes SS=DOS CS, directly accesses DOS internals 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 ??? Note: SHARE assumes SS=DS=DOS CS, direct-accesses DOS internals 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 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 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 Format of SHARE.EXE lock record: Offset Size Description 00h WORD offset in SHARE's DS of next lock table in list 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 Format of DOS 2.x system file tables: Offset Size Description 00h DWORD pointer to next file table 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.x system file tables and FCB tables: Offset Size Description 00h DWORD pointer to next file table 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 05h WORD device info word (see AX=4400h) 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) 0Fh WORD file date in packed format (see AX=5700h) 11h DWORD file size 15h DWORD current offset in file 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 31h WORD PSP segment of file's owner (see AH=26h) 33h WORD offset within SHARE.EXE code segment of sharing record (see below) 0000h = none Format of DOS 4+ system file tables and FCB tables: Offset Size Description 00h DWORD pointer to next file table 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 02h WORD file open mode (see AH=3Dh) bit 15 set if this file opened via FCB 04h BYTE file attribute 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 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 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 ---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 31h WORD PSP segment of file's owner (see AH=26h) 33h WORD offset within SHARE.EXE code segment of sharing record (see below) 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 Format of current directory structure (array, 51h bytes [58h for DOS 4.x] per drive): Offset Size Description 00h 67 BYTEs current path as ASCIZ, starting with 'x:\' 43h WORD bit flags bit 15: network drive \ installable file system if both set bit 14: physical drive / invalid drive if neither bit set bit 13: JOIN'ed, current path is actual path without JOIN drive letter in path may differ from logical drive name bit 12: SUBST'ed, current path is actual path without SUBST drive letter in path may differ from logical drive name 45h DWORD pointer to DOS Disk Block for this drive ---local drives--- 49h WORD starting cluster of current directory 0000h = root, FFFFh never accessed 4Bh WORD ??? seems always to be FFFFh 4Dh WORD ??? seems always to be FFFFh ---network drives--- 49h DWORD pointer to a redirector/REDIRIFS record, else FFFFFFFFh 4Dh WORD stored parameter from INT 21/AX=5F03h??? ------ 4Fh WORD Offset of '\' in current path field representing root directory of logical drive (2 if not SUBST'ed or JOIN'ed, otherwise number of bytes in SUBST/JOIN path) ---DOS 4.x--- 51h BYTE ??? used by network 52h DWORD pointer to IFS driver for this drive, 00000000h if native DOS 56h WORD ??? 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 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 10-7 reserved bit 6 (DOS 3.2+) Generic IOCTL call supported (command 13h) (see AX=440Ch,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 bit 14 IOCTL supported bit 13 non-IBM format bit 12 reserved bit 11 (DOS 3+) OPEN/CLOSE/RemMedia calls supported bit 10 reserved bit 9 ??? set by DOS 3.3 DRIVER.SYS for "new" drives bit 8 ??? set by DOS 3.3 DRIVER.SYS for "new" drives bit 7 reserved bit 6 (DOS 3.2+) Generic IOCTL call supported (command 13h) implies support for commands 17h and 18h (see AX=440Ch,440Dh,440Eh,440Fh) bits 5-2 reserved bit 1 driver supports 32-bit sector addressing bit 0 reserved 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 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 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 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 ??? 0Dh WORD EMS handle for buffers, zero if not in EMS 0Fh WORD EMS physical page number used for buffers (usually 255) 11h WORD ??? 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 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 8 BYTEs ??? 14h DWORD pointer to workspace buffer, purpose ???, allocated in main memory if BUFFERS/XS or /XD options in effect 18h WORD EMS handle for buffers, zero if not in EMS 1Ah WORD EMS physical page number used for buffers (usually 255) 1Ch WORD ??? 1Eh WORD segment of EMS physical page frame 20h WORD ??? 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.x 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), FFh if not in use 05h BYTE flags bit 7: remote buffer bit 6: buffer dirty bit 5: buffer has been referenced 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 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 buffer use count if remote buffer (see flags above) 13h BYTE reserved 14h buffered data Note: 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 NDBCH) are on the same doubly-linked circular chain the links consist of offset addresses only, the segment being the same for all buffers in the chain. Format of IFS driver list: Offset Size Description 00h DWORD pointer to next driver header 04h 12 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 = 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 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 3 BYTEs ??? --------------------------------------------- INT 21 - DOS 2+ internal - TRANSLATE BIOS PARAMETER BLOCK AH = 53h DS:SI -> BPB (BIOS Parameter Block) ES:BP -> buffer for DOS Drive Parameter Block (see below) Note: translates BPB into a DOS Drive Parameter Block (see AH=32h) Format of BIOS Parameter Block: Offset Size Description 00h WORD bytes/sector 02h BYTE sectors/cluster. Get from (DPB byte 4) + 1 03h WORD number of reserved sectors 05h BYTE number of FATs 06h WORD number of root directory entries 08h WORD total number of sectors. Get from: ((DPB bytes 0Dh-0Eh) - 1) * (sectors/cluster (BPB byte 2)) + (DPB Bytes 0Bh-0Ch) for DOS 4.0, set to zero if partition >32M, then set DWORD at 15h to actual number of sectors 0Ah BYTE media descriptor 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 4.0--- 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) --------------------------------------------- INT 21 - DOS 2+ - GET VERIFY FLAG AH = 54h Return: AL = 00h if flag OFF AL = 01h if flag ON SeeAlso: AH=2Eh --------------------------------------------- INT 21 - DOS 2+ internal - CREATE PSP AH = 55h DX = segment number at which to set up PSP (see AH=26h) SI = (DOS 3+) value to place in memory size field at DX:[0002h] Notes: like AH=26h but creates "child" PSP rather than copying existing one, incrementing the reference count for each inherited file (DOS 2+) sets current PSP to DX (DOS 3+) marks "no inherit" file handles as closed in child PSP SeeAlso: AH=26h, AH=50h --------------------------------------------- INT 21 - DOS 2+ - RENAME A FILE AH = 56h DS:DX -> ASCIZ old name (drive and path allowed, no wildcards) ES:DI -> ASCIZ new name Return: CF set on error AX = error code (02h,03h,05h,11h) (see AH=59h) CF clear if successful Notes: allows move between directories on same logical volume (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. SeeAlso: AH=17h,60h, AX=5D00h --------------------------------------------- INT 21 - DOS 2+ - GET FILE'S DATE/TIME AX = 5700h BX = file handle Return: CF set on error AX = error code (01h,06h) (see AH=59h) CF clear if successful CX = time of last write bits 11-15: hour 5-10: minute 0-4: seconds/2 DX = date of last write bits 9-15: year-1980 (max 119 = 2099) 5-8: month 0-4: day SeeAlso: AX=5701h --------------------------------------------- INT 21 - DOS 2+ - SET FILE'S DATE/TIME AX = 5701h BX = file handle CX = time to be set (see AX=5700h) DX = date to be set (see AX=5700h) Return: CF set on error AX = error code (01h,06h) (see AH=59h) CF clear if successful SeeAlso: AX=5700h --------------------------------------------- INT 21 - DOS 4.0 - GET ??? AX = 5702h BX = ??? (0000h through 0004h) DS:SI -> ??? ES:DI -> result buffer CX = size of result buffer Return: CX = size of returned data --------------------------------------------- INT 21 - DOS 4.0 - GET ??? AX = 5703h BX = ??? (0000h through 0004h) DS:SI -> ??? ES:DI -> result buffer CX = size of result buffer Return: CX = size of returned data --------------------------------------------- INT 21 - DOS 4.0 - ??? AX = 5704h BX = ??? (0000h through 0004h) DS:SI -> ??? ES:DI -> result buffer CX = size of result buffer Return: nothing??? --------------------------------------------- INT 21 - DOS 3+ - GET/SET MEMORY ALLOCATION STRATEGY AH = 58h AL = function code 00h get allocation strategy 01h set allocation strategy BL = strategy code 00h first fit (use first memory block large enough) 01h best fit (use smallest memory block large enough) 02h last fit (use high part of last usable memory block) Return: CF set on error AX = error code (01h) (see AH=59h) CF clear if successful AX = strategy code Note: the Set subfunction accepts any value in BL; 2 or greater means last fit. the Get subfunction returns the last value set, so programs should check whether the value is >= 2, not just equal to 2. SeeAlso: AH=48h,49h,4Ah --------------------------------------------- INT 21 - DOS 3+ - GET EXTENDED ERROR CODE AH = 59h BX = version code (0000h for DOS 3.x) Return: AX = extended error code (see below) BH = class of error (see below) BL = suggested action (see below) CH = locus (where error occurred) (see below) CL, DX, SI, DI, BP, DS, and ES 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 SeeAlso: AX=5D0Ah,INT 2F/AX=122Dh Values for extended error code: 01h function number invalid 02h file not found 03h path not found 04h too many open files (no handles available) 05h access denied 06h invalid handle 07h memory control block destroyed 08h insufficient memory 09h memory block address invalid 0Ah environment invalid (usually >32K in length) 0Bh format invalid 0Ch access code invalid 0Dh data invalid 0Fh invalid drive 10h attempted to remove current directory 11h not same device 12h no more files 13h disk write-protected 14h unknown unit 15h drive not ready 16h unknown command 17h data error (CRC) 18h bad request structure length 19h seek error 1Ah unknwon media type (non-DOS disk) 1Bh sector not found 1Ch printer out of paper 1Dh write fault 1Eh read fault 1Fh general failure 20h sharing violation 21h lock violation 22h disk change invalid ES:DI -> ASCIZ volume label of required disk 23h FCB unavailable 24h sharing buffer overflow 25h reserved 26h (LANtastic) cannot complete file operation 27h-31h reserved 32h Network request not supported (DOS 3.1 + MS Networks) 33h Remote computer not listening 34h Duplicate name on network 35h Network name not found 36h Network busy 37h Network device no longer exists 38h Network BIOS command limit exceeded 39h Network adapter hardware error 3Ah Incorrect response from network 3Bh Unexpected network error 3Ch Incompatible remote adapter 3Dh Print queue full 3Eh Queue not full 3Fh Not enough space to print file 40h Network name was deleted 41h Network: Access denied 42h Network device type incorrect 43h Network name not found 44h Network name limit exceeded 45h Network BIOS session limit exceeded 46h Temporarily paused 47h Network request not accepted 48h (DOS 3.1 + MS Networks) Print/disk redirection paused 49h (LANtastic) invalid network version 4Ah (LANtastic) account expired 4Bh (LANtastic) password expired 4Ch (LANtastic) login attempt invalid at this time 4Dh-4Fh reserved 50h file exists 51h reserved 52h cannot make directory 53h fail on INT 24h 54h (DOS 3.3+) too many redirections 55h (DOS 3.3+) duplicate redirection 56h (DOS 3.3+) invalid password 57h (DOS 3.3+) invalid parameter 58h (DOS 3.3+) network write fault 59h (LANtastic) function not supported on network 5Ah (LANtastic) required system component not installed 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 --------------------------------------------- INT 21 - DOS 3+ - CREATE UNIQUE FILE AH = 5Ah DS:DX -> ASCIZ directory path name ending with a '\' + 13 bytes to receive generated filename CX = file attributes (only bits 0,1,2,5 may be set) Return: CF set on error AX = error code (03h,05h) (see AH=59h) CF clear if successful AX = file handle DS:DX -> path name Note: The file created is not truly temporary. It MUST be removed by the user. SeeAlso: AH=3Ch,5Bh --------------------------------------------- INT 21 - DOS 3+ - CREATE NEW FILE AH = 5Bh DS:DX -> ASCIZ directory path name CX = file attribute (see AX=4301h) Return: CF set on error AX = error code (03h,04h,05h,50h) (see AH=59h) CF clear if successful AX = file handle Note: unlike function 3Ch, function 5Bh will fail if the file already exists SeeAlso: AH=3Ch,5Ah --------------------------------------------- INT 21 - DOS 3+ - LOCK/UNLOCK FILE ACCESS AH = 5Ch AL = 00h lock 01h unlock BX = file handle CX:DX = starting offset of region to lock SI:DI = size of region to lock Return: CF set on error AX = error code (01h,06h,21h) (see AH=59h) CF clear if successful Note: error returned unless SHARE or network installed SeeAlso: AX=440Bh, INT 2F/AX=110Ah,110Bh --------------------------------------------- INT 21 - 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 functions which take filenames require canonical names (as returned by AH=60h); this is apparently to prevent multi-hop file forwarding SeeAlso: 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) --------------------------------------------- INT 21 - 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 SeeAlso: AH=68h, INT 2F/AX=1107h --------------------------------------------- INT 21 - 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 SeeAlso: AX=5D03h,5D04h,AH=3Eh,60h --------------------------------------------- INT 21 - 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 Note: error unless SHARE is loaded (calls [SysFileTable-30h]) (see AH=52h) SeeAlso: AX=5D02h,5D04h --------------------------------------------- INT 21 - 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 Note: error unless SHARE is loaded (calls [SysFileTable-2Ch]) (see AH=52h) SeeAlso: AX=5D02h,5D03h --------------------------------------------- INT 21 - 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 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 SeeAlso: AH=5Ch,60h --------------------------------------------- INT 21 - 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 SeeAlso: AX=5D0Bh, INT 2A/AH=80h,81h,82h Format of DOS 3.10-3.30 Swappable Data Area: Offset Size Description 00h BYTE critical error flag 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 ---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 2 BYTEs ??? (don't seem to be referenced) 26h WORD ??? 28h BYTE ??? 29h BYTE ??? 2Ah BYTE ??? 2Bh BYTE ??? flag of some kind 2Ch BYTE ??? flag of some kind 2Dh BYTE ??? (doesn't seem to be referenced) 2Eh BYTE day of month 2Fh BYTE month 30h WORD year - 1980 32h WORD number of days since 1-1-1980 32h BYTE day of week (0 = Sunday) 35h BYTE ??? 36h BYTE ??? flag 37h BYTE ??? flag 38h 26 BYTEs device driver request header 52h DWORD pointer to device driver entry point (used in calling driver) 56h 22 BYTEs device driver request header 6Ch 22 BYTEs device driver request header 82h BYTE type of PSP copy (00h=simple for INT 21/AH=26h, FFh=make child) 83h BYTE ??? apparently not reference by kernel 84h WORD ??? 86h WORD ??? 88h 2 BYTEs ??? 8Ah 6 BYTEs CLOCK$ transfer record (see AH=52h) 90h 2 BYTEs ??? 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 1C7h 81 BYTEs copy of current directory structure for drive being accessed 218h 11 BYTEs ??? FCB-format filename 223h BYTE ??? 224h 11 BYTEs wildcard destination specification for rename (FCB format) 22Fh 2 BYTEs ??? 231h WORD ??? 233h 5 BYTEs ??? 238h BYTE directory search attributes 239h BYTE type of FCB (00h regular, FFh extended) 23Ah BYTE extended FCB file attribute 23Bh BYTE file open mode??? 23Ch BYTE ??? flag bits 23Dh BYTE ??? flag or counter 23Eh BYTE ??? flag 23Fh BYTE flag indicating how DOS function was invoked (00h = direct INT 20/INT 21, FFh = server call AX=5D00h) 240h WORD ??? 242h BYTE ??? 243h BYTE ??? 244h BYTE ??? 245h BYTE ??? flag or counter 246h BYTE ??? flag 247h BYTE ??? flag 248h BYTE ??? flag 249h BYTE type of process termination (00h-03h) 24Ah BYTE ??? flag 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 250h DWORD pointer to stack frame containing user registers on INT 21 254h WORD stores SP??? 256h DWORD pointer to DOS Drive Parameter Block for ??? 25Ah WORD ??? 25Ch WORD ??? 25Eh WORD ??? flag 260h WORD ??? 262h BYTE Media ID byte returned by AH=1Bh,1Ch 263h BYTE ??? (doesn't seem to be referenced) 264h DWORD pointer to ??? 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 ??? 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 CS of first filename argument 27Eh WORD offset in DOS CS of second filename argument 280h WORD ??? 282h WORD ??? 284h WORD ??? 286h WORD ??? 288h WORD ??? 28Ah WORD ??? 28Ch WORD ??? 28Eh 2 BYTEs ??? 290h WORD ??? 292h DWORD current offset in file 296h WORD ??? 298h WORD ??? 29Ah WORD ??? 29Ch WORD ??? 29Eh WORD ??? 2A0h WORD ??? 2A2h DWORD number of bytes appended to file 2A6h DWORD pointer to ??? disk buffer 2AAh DWORD pointer to ??? 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 2EDh 331 BYTEs critical error stack 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 3.3 only--- 738h BYTE flag affecting AH=08h (see AH=64h) 739h BYTE ??? looks like a drive number 73Ah BYTE ??? flag of some kind 73Ah BYTE ??? --------------------------------------------- INT 21 - 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,5D09h, INT 2F/AX=1125h --------------------------------------------- INT 21 - 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,5D09h, INT 2F/AX=1125h --------------------------------------------- INT 21 - DOS 3.1+ network - FLUSH REDIRECTED PRINTER OUTPUT AH = 5D09h Note: forces redirected printer output to be printed, and starts a new print job SeeAlso: AX=5D07h,5D08h, INT 2F/AX=1125h --------------------------------------------- INT 21 - DOS 3.1+ internal - 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 SeeAlso: AH=59h --------------------------------------------- INT 21 - DOS 4.x 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) Note: 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 SeeAlso: AX=5D06h, INT 2A/AH=80h,81h,82h Format of 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 PCDOS 4.01 swappable data area: Offset Size Description 00h BYTE critical error flag 01h BYTE InDOS flag (count of active INT 21 calls) 02h BYTE ??? drive number 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 2 BYTEs ??? ---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 2 BYTEs ??? (don't seem to be referenced) 28h WORD ??? 2Ah BYTE ??? 2Bh BYTE ??? 2Ch BYTE ??? 2Dh BYTE ??? 2Eh BYTE ??? 2Fh BYTE ??? (doesn't seem to be referenced) 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 ??? 38h BYTE ??? 39h BYTE ??? 38h 30 BYTEs device driver request header 58h DWORD pointer to device driver entry point (used in calling driver) 5Ch 22 BYTEs device driver request header 72h 30 BYTEs device driver request header 90h 6 BYTEs ??? 96h 6 BYTEs CLOCK$ transfer record (see AH=52h) 9Ch 2 BYTEs ??? 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 1D3h 88 BYTEs copy of current directory structure for drive being accessed 22Bh 11 BYTEs ??? FCB-format filename 236h BYTE ??? 237h 11 BYTEs wildcard destination specification for rename (FCB format) 242h 2 BYTEs ??? 244h WORD ??? 246h 5 BYTEs ??? 24Bh BYTE ??? 24Ch BYTE ??? 24Dh BYTE attribute mask for directory search??? 24Eh BYTE ??? 24Fh BYTE ??? flag bits 250h BYTE ??? 251h BYTE ??? 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 ??? 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 ??? 28Ch WORD ??? 28Eh DWORD pointer to a JFT entry in process handle table (see AH=26h) 292h WORD offset in DOS CS of first filename argument 294h WORD offset in DOS CS 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 ??? 2D6h BYTE ??? 2D7h WORD ??? 2D9h DWORD pointer to ??? 2DDh WORD ??? 2DFh WORD ??? 2E1h WORD ??? 2E3h DWORD ??? 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 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 flag affecting AH=08h (see AH=64h) 781h BYTE ??? looks like a drive number 782h BYTE ??? flag of some kind 783h BYTE ??? 784h WORD ??? 786h WORD ??? 788h WORD ??? 78Ah WORD ??? --------------------------------------------- INT 21 - DOS 3.1 + Microsoft Networks - GET MACHINE NAME AX = 5E00h DS:DX -> buffer for blank-padded ASCIZ name (16 bytes) Return: CF set on error AX = error code (01h) (see AH=59h) CH = 00h if name not defined <> 00h defined CL = NETBIOS name number DS:DX buffer filled with ASCIZ machine name SeeAlso: AX=5E01h --------------------------------------------- INT 21 - DOS 3.1 + Microsoft Networks - SET MACHINE NAME AX = 5E01h CH = 00h undefine name <> 0 define name CL = name number DS:DX -> 15-character blank-padded ASCIZ name SeeAlso: AX=5E00h --------------------------------------------- INT 21 - DOS 3.1 + Microsoft Networks - SET PRINTER SETUP AX = 5E02h BX = redirection list index CX = length of setup string (<= 64) DS:SI -> string buffer Return: CF set on error AX = error code (01h) (see AH=59h) CF clear if successful SeeAlso: AX=5E03h, INT 2F/AX=111Fh --------------------------------------------- INT 21 - DOS 3.1 + Microsoft Networks - GET PRINTER SETUP AX = 5E03h BX = redirection list index ES:DI -> string buffer Return: CF set on error AX = error code (01h) (see AH=59h) CX = length of setup string (<= 64) SeeAlso: AX=5E02h, INT 2F/AX=111Fh --------------------------------------------- INT 21 - DOS 3.1 + Microsoft Networks - SET PRINTER MODE AX = 5E04h BX = redirection list index 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, INT 2F/AX=111Fh --------------------------------------------- INT 21 - DOS 3.1 + Microsoft Networks - GET PRINTER MODE AX = 5E05h BX = redirection list index 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, INT 2F/AX=111Fh --------------------------------------------- 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 SeeAlso: AX=5F01h --------------------------------------------- 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 Note: when redirection is off, the local device (if any) rather than the remote device is used SeeAlso: AX=5F00h, INT 2F/AX=111Eh --------------------------------------------- INT 21 - DOS 3.1 + Microsoft Networks, VINES - GET REDIRECTION LIST ENTRY AX = 5F02h BX = redirection list index DS:SI -> 16 char local device name buffer ES:DI -> 128 char network name buffer Return: CF set on error AX = error code (01h,12h) (see AH=59h) CF clear if successful BH = device status flag (bit 0 = 0 if valid) BL = device type (03h if printer, 04h if drive) CX = stored parameter value (user data) DS:SI and ES:DI buffers filled Notes: DX and BP are destroyed by this call! error code 12h is returned if BX is greater than the size of the list SeeAlso: AX=5F03h, INT 2F/AX=111Eh --------------------------------------------- INT 21 - DOS 3.1 + Microsoft Networks, Banyan VINES - REDIRECT DEVICE AX = 5F03h BL = device type 03h = printer device 04h = file device CX = stored parameter value DS:SI -> ASCIZ source device name ES:DI -> destination ASCIZ network path + ASCIZ password Return: CF set on error AX = error code (01h,03h,05h,08h,54h,55h,57h) (see AH=59h) CF clear if successful SeeAlso: AX=5F02h,5F04h, INT 2F/AX=111Eh --------------------------------------------- INT 21 - DOS 3.1 + Microsoft Networks, Banyan VINES - CANCEL REDIRECTION AX = 5F04h DS:SI -> ASCIZ device name or network path Return: CF set on error AX = error code (01h,0Fh,57h) (see AH=59h) CF clear if successful SeeAlso: AX=5F03h, INT 2F/AX=111Eh --------------------------------------------- INT 21 - DOS 4.x + Microsoft Networks - GET REDIRECTION LIST EXTENDED 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 BH = device status flag (bit 0 clear if valid) BL = device type (03h if printer, 04h if drive) CX = stored parameter value (user data) 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 SeeAlso: INT 2F/AX=111Eh --------------------------------------------- INT 21 - Network - GET REDIRECTION LIST??? AX = 5F06h ??? Return: ??? Note: appears to be similar to AX=5F02h and AX=5F05h SeeAlso: AX=5F05h, INT 2F/AX=111Eh --------------------------------------------- INT 21 - LANtastic - GET LOGIN ENTRY AX = 5F80h BX = login entry index ES:DI -> 16-byte buffer for machine name Return: CF clear if successful buffer filled with machine name ("\\" prefix removed) CF set on error AX = error code --------------------------------------------- INT 21 - LANtastic - LOGIN TO SERVER AX = 5F81h ES:DI -> ASCIZ login path followed immediately by ASCIZ password BL = adapater number FFh try all valid adapters 00h-03h try only specified adapter Return: CF clear if successful CF set on error AX = error code Note: login path is of form "\\machine\username" SeeAlso: AX=5F82h --------------------------------------------- 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 --------------------------------------------- INT 21 - LANtastic - GET USERNAME ENTRY AX = 5F83h BX = login entry index ES:DI -> 16-byte buffer for username currently logged into Return: CF clear if successful CF set on error AX = error code --------------------------------------------- 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 --------------------------------------------- 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 Note: must be logged into the named machine --------------------------------------------- INT 21 - LANtastic - DISABLE ACCOUNT AX = 5F86h ES:DI -> ASCIZ machine name in form "\\machine" 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. --------------------------------------------- INT 21 - LANtastic - COPY FILE AX = 5F97h CX:DX = number of bytes to copy SI = source file handle DI = destination file handle Return: CF clear if successful AX:DX = number of bytes copied CF set on error AX = error code --------------------------------------------- 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 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 --------------------------------------------- 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 --------------------------------------------- INT 21 - LANtastic - GET MESSAGE PROCESSING FLAG AX = 5F9Ah Return: CF clear if successful DL = bits describing processing for received unsolicited messages bit 0: beep before message is delivered 1: deliver message to message service CF set on error AX = error code SeeAlso: AX=5F9Bh --------------------------------------------- INT 21 - LANtastic - SET MESSAGE PROCESSING FLAG 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 --------------------------------------------- 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 SeeAlso: AX=5FA1h,5FA2h Format of queue entry: Offset Size Description 00h BYTE 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 01h DWORD size of spooled file 05h BYTE type of entry 00h printer queue file 01h message 02h local file 03h remote file 04h to remote modem 05h batch processor file 06h BYTE control of despooled file bit 6: don't delete (for 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 --------------------------------------------- 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 SeeAlso: AX=5FA0h,5FA2h --------------------------------------------- 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 ES:DI -> ASCIZ computer name Return: CF clear if successful CF set on error AX = error code --------------------------------------------- INT 21 - LANtastic - CREATE USER AUDIT ENTRY AX = 5FA7h DS:DX -> ASCIZ reason code (max 8 bytes) DS:SI -> ASCIZ variable reason code (max 128 bytes) ES:DI -> ASCIZ machine name in form "\\machine" Return: CF clear if successful CF set on error AX = error code --------------------------------------------- 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 Format of active user entry: Offset Size Description 00h WORD virtual circuit number 02h BYTE login state bit 0: fully logged in 1: remote program load login 3: user can create audit entries 4: bypass mail protection 5: treat as local process 6: bypass queue protection 7: bypass access control lists 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 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 --------------------------------------------- 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 privilege bits for requesting user bit 5: allow attribute changing 6: allow physical access to device 7: allow program execution 8: allow file renaming 9: allow directory deletion 10: allow file deletion 11: allow file/directory lookups 12: allow directory creation 13: allow file creation 14: allow open for write and writing 15: allow open for read and reading CF set on error AX = error code --------------------------------------------- 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 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 --------------------------------------------- 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 --------------------------------------------- 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 --------------------------------------------- INT 21 - 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 SeeAlso: AX=5FE1h --------------------------------------------- INT 21 - LANtastic - SET DOS SERVICE VECTOR AX = 5FE1h ES:BX -> FAR routine to call for DOS service 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 --------------------------------------------- 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=5FE3h --------------------------------------------- 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 -> Network Control Block SeeAlso: AX=5FE2h --------------------------------------------- INT 21 - DOS 3+ internal - RESOLVE PATH STRING TO CANONICAL PATH STRING AH = 60h DS:SI -> ASCIZ relative path string or directory name ES:DI -> 128-byte buffer for ASCIZ canonical fully qualified name Return: CF set on error AX = error code 02h invalid source name 03h invalid drive or malformed path others??? 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 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. '.' 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 functions which take pathnames require canonical paths if invoked via INT 21/AX=5D00h supported by OS/2 v1.1 compatibility box SeeAlso: INT 2F/AX=1123h,1221h --------------------------------------------- INT 21 - DOS 3+ internal - UNUSED AH = 61h Return: AL = 00h --------------------------------------------- INT 21 - DOS 3+ - GET PSP ADDRESS AH = 62h Return: BX = current PSP segment address (see AH=26h for format) Notes: under DOS 3+, this function does not use any of the DOS-internal stacks and is thus fully reentrant identical to the undocumented AH=51h SeeAlso: AH=50h, AH=51h --------------------------------------------- INT 21 - DOS 2.25 only - GET LEAD BYTE TABLE (2-BYTE CHARACTER SUPPORT) AH = 63h AL = subfunction 00h get system lead byte table Return: DS:SI -> lead byte table 01h set/clear interim console flag (determine whether interim bytes are returned on some console functions) DL = 01h/00h to set/clear interim console flag 02h get interim console flag Return: DL = interim console flag Return: CF set on error AX = error code (01h) (see AH=59h) CF clear if successful Note: does not preserve any registers other than SS:SP --------------------------------------------- INT 21 - Asian DOS 3.2+ only - GET DOUBLE BYTE CHARACTER SET LEAD TABLE AX = 6300h Return: AL = error code 00h successful DS:SI -> DBCS table (see below) BX, CX, DX, BP, DI, and ES destroyed FFh not supported Notes: probably identical to AX=6300h for DOS 2.25 The US version of DOS 4.0 accepts this function, but returns an empty list 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 --------------------------------------------- INT 21 - Asian DOS 3.2+ only - SET KOREAN (HONGEUL) INPUT MODE AX = 6301h DL = new mode 00h return only full characters on DOS keyboard input functions 01h return partially-formed characters also Return: AL = status 00h successful FFh invalid mode SeeAlso: AX=6302h --------------------------------------------- INT 21 - Asian DOS 3.2+ only - GET KOREAN (HONGEUL) INPUT MODE AX = 6302h Return: AL = status 00h successful DL = current input mode 00h return only full characters 01h return partial characters FFh not supported SeeAlso: AX=6301h --------------------------------------------- INT 21 - DOS 3.2 internal - GET/SET ??? AH = 64h AL = subfunction 00h get ??? Return: DL = ??? 01h set ??? DL = ??? 02h get and set ??? DL = new ??? Return: DL = old ??? --------------------------------------------- INT 21 - DOS 3.3+ internal - SET ??? AH = 64h AL = flag 00h ??? nonzero ??? Return: nothing Notes: affects operation of AH=08h called by DOS 3.3+ PRINT.COM --------------------------------------------- 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 (DOS 3.3+ internal) get pointer to filename terminator table 06h get pointer to collating sequence table 07h (DOS 4.x) get pointer to Double-Byte Character Set table BX = code page (-1=global code page) DX = country ID (-1=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 succesful CX = size of country information returned ES:DI -> country information Notes: AL=05h appears to return same info for all countries and codepages NLSFUNC must be installed to get info for countries other than the default SeeAlso: AH=38h,INT 2F/AX=1401h,1402h 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 collating table (see below) ---if info ID = 05h--- 01h DWORD pointer to filename character table (see below) ---if info ID = 06h--- 01h DWORD pointer to filename uppercase table (see below) ---if info ID = 07h (DOS 4.x)--- 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 02h 7 BYTEs ??? (01h 00h FFh 00h 00h 20h 02h in MSDOS 3.30) 09h BYTE length of following data 0Ah N BYTES characters which terminate a filename: ."/\[]:|<>+=;, 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) --------------------------------------------- INT 21 - DOS 4.x internal - 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 --------------------------------------------- INT 21 - DOS 4.x 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 --------------------------------------------- INT 21 - DOS 4.x 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 and 4.01 due to a bug --------------------------------------------- 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 DX = system code page SeeAlso: AX=6602h --------------------------------------------- INT 21 - DOS 3.3+ - SET GLOBAL CODE PAGE TABLE AX = 6602h BX = active code page 437 US 850 Multilingual 860 Portugal 863 Canada (French) 865 Norway/Denmark 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 21 - DOS 3.3+ - SET HANDLE COUNT AH = 67h BX = desired number of handles (max 255) Return: CF set if error (and error code in AX) Notes: if BX <= 20, no action is taken only the first 20 handles are copied to child processes in DOS 3.3 a bug in DOS 3.30 results in requests for an even number of handles allocating a full 64K for the handle table SeeAlso: AH=26h --------------------------------------------- INT 21 - DOS 3.3+ - COMMIT FILE, WRITE ALL BUFFERED DATA TO DISK AH = 68h BX = file handle Return: CF set on error AX = error code (see AH=59h) CF clear if successful SeeAlso: AX=5D01h, INT 2F/AX=1107h --------------------------------------------- INT 21 - DOS 4.0 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 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 " --------------------------------------------- INT 21 - DOS 4.0 internal - ??? AH = 6Ah ??? Return: ??? --------------------------------------------- INT 21 - DOS 4.0 internal - ??? 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 Return: ??? Note: passed through to INT 2F/AX=112Fh with AX on top of stack SeeAlso: INT 2F/AX=112Fh --------------------------------------------- INT 21 - DOS 4.0 - EXTENDED OPEN/CREATE AX = 6C00h BL = open mode as in AL for normal open (INT 21h/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 write 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 exists 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 = 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,3Dh --------------------------------------------- INT 21 - ??? AH = 89h ??? Note: reportedly called by Microsoft C 4.0 startup code --------------------------------------------- INT 21 - Novell NetWare SFT Level II - EXTENDED FILE ATTRIBUTES AH = B6h AL = subfunction 00h get extended file attributes 01h set extended file attributes CL = attributes bit 4: transaction tracking file 5: indexing file (to be implemented) 6: read audit (to be implemented) 7: write audit (to be implemented) DS:DX -> ASCIZ pathname Return: CF set on error AL = error code FFh file not found 8Ch caller lacks privileges CL = current extended file attributes SeeAlso: AX=4300h --------------------------------------------- INT 21 - Novell Advanced NetWare 2.0+ - PRINT JOBS AH = B8h AL = subfunction 00h get default print job flags 01h set default capture flags 02h get specific capture flags 03h set specific print job flags 04h get default local printer 05h set default local printer 06h set capture print queue 07h set capture print job 08h get banner user name 09h set banner user name CX = buffer size ES:BX -> buffer Return: none --------------------------------------------- INT 21 - Novell NetWare 4.0 - SET END OF JOB STATUS AH = BBh AL = new EOJ flag 00h disable EOJs otherwise enable EOJs Return: AL = old EOJ flag SeeAlso: AH=D6h --------------------------------------------- INT 21 - Novell NetWare 4.6 - LOG/LOCK PHYSICAL RECORD AH = BCh AL = flags bit 0: lock as well as log record 1: non-exclusive lock BX = file handle CX:DX = offset BP = timeout in timer ticks (1/18 sec) SI:DI = length Return: AL = error code SeeAlso: AH=BFh --------------------------------------------- INT 21 - Novell NetWare 4.6 - RELEASE PHYSICAL RECORD AH = BDh BX = file handle CX:DX = offset Return: AL = error code SeeAlso: AH=C0h --------------------------------------------- INT 21 - Novell NetWare 4.6 - CLEAR PHYSICAL RECORD AH = BEh BX = file handle CX:DX = offset Return: AL = error code SeeAlso: AH=C1h --------------------------------------------- INT 21 - Novell NetWare 4.6 - LOG/LOCK RECORD (FCB) AH = BFh AL = flags bit 0: lock as well as log record 1: non-exclusive lock DS:DX -> FCB BX:CX = offset BP = timeout in timer ticks (1/18 sec) SI:DI = length Return: AL = error code SeeAlso: AH=BCh,C2h --------------------------------------------- INT 21 - Novell NetWare 4.6 - RELEASE RECORD (FCB) AH = C0h DS:DX -> FCB BX:CX = offset Return: AL = error code SeeAlso: AH=BDh,C3h --------------------------------------------- INT 21 - Novell NetWare 4.6 - CLEAR RECORD (FCB) AH = C1h DS:DX -> FCB BX:CX = offset Return: AL = error code SeeAlso: AH=BEh,C4h --------------------------------------------- INT 21 - Novell NetWare 4.6 - LOCK PHYSICAL RECORD SET AH = C2h AL = flags bit 1: non-exclusive lock BP = timeout in timer ticks (1/18 sec) Return: AL = error code SeeAlso: AH=BFh --------------------------------------------- INT 21 - Novell NetWare 4.6 - RELEASE PHYSICAL RECORD SET AH = C3h Return: AL = error code SeeAlso: AH=C0h --------------------------------------------- INT 21 - Novell NetWare 4.6 - CLEAR PHYSICAL RECORD SET AH = C4h Return: AL = error code SeeAlso: AH=C1h --------------------------------------------- INT 21 - Novell NetWare 4.6 - SEMAPHORES AH = C5h AL = subfunction 00h open semaphore DS:DX -> semaphore name CL = initial value 01h examine semaphore Return: CX = semaphore value (sign extended) DL = open count 02h wait on semaphore BP = timeout in timer ticks (1/18 sec) 03h signal semaphore 04h close semaphore CX:DX = semaphore handle (except function 00h) Return: AL = error code if function 00h CX:DX = semaphore handle BL = open count --------------------------------------------- INT 21 - Novell NetWare 4.6 - GET OR SET LOCK MODE AH = C6h AL = subfunction 00h set old "compatibility" mode 01h set new extended locks mode 02h get lock mode Return: AL = current lock mode --------------------------------------------- INT 21 - Novell NetWare 4.0 - TTS AH = C7h AL = subfunction 00h begin transaction (NetWare SFT level II) Return: AL = error code 01h end transaction (NetWare SFT level II) Return: AL = error code CX:DX = transaction reference number 02h TTS available (NetWare SFT level II) Return: AL = completion code 00h TTS not available 01h TTS available FDh TTS available but disabled 03h abort transaction (NetWare SFT level II) Return: AL = error code 04h transaction status 05h get application thresholds 06h set application thresholds 07h get workstation thresholds 08h set workstation thresholds Return: ??? --------------------------------------------- INT 21 - Novell NetWare 4.0 - BEGIN LOGICAL FILE LOCKING AH = C8h if function C6h lock mode 00h: DL = mode 00h no wait 01h wait if function C6h lock mode 01h: BP = timeout in timer ticks (1/18 sec) Return: AL = error code SeeAlso: AH=C9h --------------------------------------------- INT 21 - Novell NetWare 4.0 - END LOGICAL FILE LOCKING AH = C9h Return: AL = error code SeeAlso: AH=C8h --------------------------------------------- INT 21 - Novell NetWare 4.0 - LOG/LOCK PERSONAL FILE (FCB) AH = CAh DS:DX -> FCB if function C6h lock mode 01h: AL = log and lock flag 00h log file only 01h lock as well as log file BP = timeout in timer ticks (1/18 sec) Return: AL = error code SeeAlso: AH=CBh --------------------------------------------- INT 21 - Novell NetWare 4.0 - LOCK FILE SET AH = CBh if function C6h lock mode 00h: DL = mode 00h no wait 01h wait if function C6h lock mode 01h: BP = timeout in timer ticks (1/18 sec) Return: AL = error code SeeAlso: AH=CAh --------------------------------------------- INT 21 - Novell NetWare 4.0 - RELEASE FILE (FCB) AH = CCh DS:DX -> FCB Return: none SeeAlso: AH=CDh --------------------------------------------- INT 21 - Novell NetWare 4.0 - RELEASE FILE SET AH = CDh Return: none SeeAlso: AH=CCh --------------------------------------------- INT 21 - Novell NetWare 4.0 - CLEAR FILE (FCB) AH = CEh DS:DX -> FCB Return: AL = error code SeeAlso: AH=CFh --------------------------------------------- INT 21 - Novell NetWare 4.0 - CLEAR FILE SET AH = CFh Return: AL = 00h SeeAlso: AH=CEh --------------------------------------------- INT 21 - Novell NetWare 4.6, Banyan VINES - LOCK LOGICAL RECORD AH = D0h DS:DX -> record string if function C6h lock mode 01h: (Novell only) AL = flags bit 0: lock as well as log the record bit 1: non-exclusive lock BP = timeout in timer ticks (1/18 sec) Return: AL = error code 00h successful FFh unsuccessful SeeAlso: AH=D1h,D2h --------------------------------------------- INT 21 - Novell NetWare 4.6, Banyan VINES - LOCK LOGICAL RECORD SET AH = D1h if function C6h lock mode 00h: DL = mode 00h no wait 01h wait if function C6h lock mode 01h: (Novell only) BP = timeout in timer ticks (1/18 sec) Return: AL = error code (see AH=D0h) SeeAlso: AH=D0h,D3h --------------------------------------------- INT 21 - Novell NetWare 4.0, Banyan VINES - UNLOCK LOGICAL RECORD AH = D2h DS:DX -> semaphore identifier (counted string up to 100 chars long) Return: AL = error code (see AH=D0h) SeeAlso: AH=D0h,D3h --------------------------------------------- INT 21 - Novell NetWare 4.0, Banyan VINES - UNLOCK LOGICAL RECORD SET AH = D3h Return: AL = error code (see AH=D0h) Note: unlocks all semaphores logged in the semaphore set of the requesting PC SeeAlso: AH=D1h,D2h --------------------------------------------- INT 21 - Novell NetWare 4.0, Banyan VINES - CLEAR LOGICAL RECORD AH = D4h DS:DX -> semaphore identifier (counted string up to 100 chars long) Return: AL = error code 00h successful FFh not successful SeeAlso: AH=D5h --------------------------------------------- INT 21 - Novell NetWare 4.0, Banyan VINES - CLEAR LOGICAL RECORD SET AH = D5h Return: AL = error code (see AH=D4h) Note: unlocks and clears all semaphores associated with the semaphore set of the requesting PC SeeAlso: AH=D4h --------------------------------------------- INT 21 - Novell NetWare 4.0 - END OF JOB AH = D6h Return: AL = error code SeeAlso: AH=BBh --------------------------------------------- INT 21 - Novell NetWare 4.0 - SYSTEM LOGOUT AH = D7h Return: AL = error code --------------------------------------------- INT 21 - Novell NetWare, Banyan VINES - ALLOCATE RESOURCE AH = D8h DL = resource number Return: AL = status 00h successful FFh unsucessful SeeAlso: AH=D9h --------------------------------------------- INT 21 - Novell NetWare, Banyan VINES - DEALLOCATE RESOURCE AH = D9h DL = resource number Return: AL = status (see AH=D8h) SeeAlso: AH=D8h --------------------------------------------- INT 21 - Novell NetWare 4.0 - GET VOLUME STATISTICS AH = DAh DL = volume number ES:DI -> reply buffer (see below) Return: AL = 00h SeeAlso: AH=36h Format of reply buffer: Offset Size Description 00h WORD sectors/block 02h WORD total blocks 04h WORD unused blocks 06h WORD total directory entries 08h WORD unused directory entries 0Ah 16 BYTEs volume name, null padded 1Ah WORD removable flag, 0000h = not removable --------------------------------------------- INT 21 - Novell NetWare 4.0 - GET NUMBER OF LOCAL DRIVES AH = DBh Return: AL = number of local disks SeeAlso: AH=0Eh --------------------------------------------- INT 21 - Novell NetWare 4.0, Banyan VINES - GET STATION NUMBER AH = DCh Return: AL = station number 00h if NetWare not loaded or this machine is a non-dedicated server CX = station number in ASCII Note: station number only unique for those PCs connected to same semaphore service --------------------------------------------- INT 21 - PCMag PCMANAGE/DCOMPRES - TURN ON/OFF AH = DCh DX = state 0000h turn on 0001h turn off SeeAlso: AX=FEDCh --------------------------------------------- INT 21 - Novell NetWare 4.0 - SET ERROR MODE AH = DDh DL = error mode 00h display critical I/O errors 01h extended errors for all I/O in AL 02h extended errors for critical I/O in AL Return: AL = previous error mode --------------------------------------------- INT 21 - Novell NetWare 4.0 - SET BROADCAST MODE AH = DEh AL = broadcast mode 00h receive console and workstation broadcasts 01h receive console broadcasts only 02h receive no broadcasts 03h store all broadcasts for retrieval 04h get broadcast mode 05h disable shell timer interrupt checks 06h enable shell timer interrupt checks Return: AL = old broadcast mode --------------------------------------------- INT 21 - Novell NetWare 4.0 - CAPTURE AH = DFh AL = subfunction 00h start LPT capture 01h end LPT capture 02h cancel LPT capture 03h flush LPT capture 04h start specific capture 05h end specific capture 06h cancel specific capture 07h flush specific capture Return: AL = error code --------------------------------------------- INT 21 - Novell NetWare 4.0 - PRINT SPOOLING AH = E0h DS:SI -> request buffer ES:DI -> reply buffer subfunction in third byte of request buffer 00h spool data to a capture file 01h close and queue capture file 02h set spool flags 03h spool existing file 04h get spool queue entry 05h remove entry from spool queue 06h get printer status 09h create a disk capture file Return: AL = error code --------------------------------------------- INT 21 - OS/286, OS/386 - INITIALIZE REAL PROCEDURE AH = E0h ??? Return: ??? --------------------------------------------- INT 21 - Novell NetWare 4.0 - BROADCAST MESSAGES AH = E1h DS:SI -> request buffer ES:DI -> reply buffer subfunction in third byte of request buffer 00h send broadcast message 01h get broadcase message 02h disable station broadcasts 03h enable station broadcasts 04h send personal message 05h get personal message 06h open message pipe 07h close message pipe 08h check pipe status 09h broadcast to console Return: AL = error code --------------------------------------------- INT 21 - OS/286, OS/386 - ISSUE REAL PROCEDURE CALL AH = E1h ??? Return: ??? Note: protected mode only??? --------------------------------------------- INT 21 - Novell NetWare 4.0 - DIRECTORY FUNCTIONS AH = E2h DS:SI -> request buffer ES:DI -> reply buffer subfunction in third byte of request buffer 00h set directory handle 01h get directory path 02h scan directory information 03h get effective directory rights 04h modify maximum rights mask 05h get volume number 06h get volume name 0Ah create directory 0Bh delete directory 0Ch scan directory for trustees 0Dh add trustee to directory 0Eh delete trustee from directory 0Fh rename directory 10h purge erased files 11h restore erased file 12h allocate permanent directory handle 13h allocate temporary directory handle 14h deallocate directory handle 15h get volume info with handle 16h allocate special temporary directory handle 17h retrieve a short base handle (Advanced NetWare 2.0) 18h restore a short base handle (Advanced NetWare 2.0) 19h set directory information Return: AL = error code --------------------------------------------- INT 21 - OS/286, OS/386 - SET REAL PROCEDURE SIGNAL HANDLER AH = E2h ??? Return: ??? --------------------------------------------- INT 21 - Novell NetWare 4.0 - CONNECTION CONTROL AH = E3h DS:SI -> requst buffer ES:DI -> reply buffer subfunction in third byte of request buffer 00h login 01h change password 02h map user to station set 03h map object to number 04h map number to object 05h get station's logged information 06h get station's root mask (obsolete) 07h map group name to number 08h map number to group name 09h get memberset M of group G 0Ah enter login area 0Bh ??? 0Ch ??? 0Dh log network message 0Eh get disk utilization (Advanced NetWare 1.0) 0Fh scan file information (Advanced NetWare 1.0) 10h set file information (Advanced NetWare 1.0) 11h get file server information (Advanced NetWare 1.0) 12h ??? 13h get internet address (Advanced NetWare 1.02) 14h login to file server (Advanced NetWare 2.0) 15h get object connection numbers (Advanced NetWare 2.0) 16h get connection information (Advanced NetWare 1.0) 32h create object (Advanced NetWare 1.0) 33h delete object (Advanced NetWare 1.0) 34h rename object (Advanced NetWare 1.0) 35h get object ID (Advanced NetWare 1.0) 36h get object name (Advanced NetWare 1.0) 37h scan object (Advanced NetWare 1.0) 38h change object security (Advanced NetWare 1.0) 39h create propery (Advanced NetWare 1.0) 3Ah delete property (Advanced NetWare 1.0) 3Bh change property security (Advanced NetWare 1.0) 3Ch scan property (Advanced NetWare 1.0) 3Dh read property value (Advanced NetWare 1.0) 3Eh write property value (Advanced NetWare 1.0) 3Fh verify object password (Advanced NetWare 1.0) 40h change object password (Advanced NetWare 1.0) 41h add object to set (Advanced NetWare 1.0) 42h delete object from set (Advanced NetWare 1.0) 43h is object in set? (Advanced NetWare 1.0) 44h close bindery (Advanced NetWare 1.0) 45h open bindery (Advanced NetWare 1.0) 46h get bindery access level (Advanced NetWare 1.0) 47h scan object trustee paths (Advanced NetWare 1.0) C8h check console priviledges C9h get file server description strings CAh set file server date and time CBh disable file server login CCh enable file server login CDh get file server login status CEh purge all erased files CFh disable transaction tracking D0h enable transaction tracking D1h send console broadcast D2h clear connection number D3h down file server D4h get file system statistics D5h get transaction tracking statistics D6h read disk cache statistics D7h get drive mapping table D8h read physical disk statistics D9h get disk channel statistics DAh get connection's task information DBh get list of connection's open files DCh get list of connections using a file DDh get physical record locks by connection and file DEh get physical record locks by file DFh get logical records by connection E0h get logical record information E1h get connection's semaphores E2h get semaphore information E3h get LAN driver's configuration information E5h get connection's usage statistics E6h get object's remaining disk space E7h get server LAN I/O statistics E8h get server miscellaneous information E9h get volume information Return: AL = error code --------------------------------------------- INT 21 - OS/286, OS/386 - ISSUE REAL INTERRUPT AH = E3h ??? Return: ??? Note: protected mode only??? --------------------------------------------- INT 21 - Novell NetWare 4.0 - SET FILE ATTRIBUTES (FCB) AH = E4h CL = file attributes bit 0: read only 1: hidden 2: system 7: shareable DX:DX -> FCB Return: AL = error code SeeAlso: AX=4301h --------------------------------------------- INT 21 - DoubleDos - INSTALLATION CHECK AX = E400h Return: AL <> 00h if DoubleDos is active AL = 02h if caller is running in the invisible partition --------------------------------------------- INT 21 - OS/286, OS/386 - CHAIN TO REAL-MODE HANDLER AX = E400h ??? Return: ??? Note: protected mode only??? --------------------------------------------- INT 21 - OS/286, OS/386 - SET PROTECTED-MODE TASK GATE AX = E402h ??? Return: ??? Note: protected mode only??? --------------------------------------------- INT 21 - OS/286, OS/386 - REMOVE PROTECTED-MODE TASK GATE AX = E403h ??? Return: ??? Note: protected mode only??? --------------------------------------------- INT 21 - Novell NetWare 4.0 - UPDATE FILE SIZE (FCB) AH = E5h DS:DX -> FCB Return: AL = error code --------------------------------------------- INT 21 - OS/286, OS/386 - HEAP MANAGEMENT STRATEGY AX = E500h ??? Return: ??? --------------------------------------------- INT 21 - OS/286, OS/386 - FORCE HEAP COMPACTION AX = E501h ??? Return: ??? --------------------------------------------- INT 21 - Novell NetWare 4.0 - COPY FILE TO FILE (FCB) AH = E6h CX:DX = number of bytes to copy DS:SI -> source FCB ES:DI -> destination FCB Return: AL = error code --------------------------------------------- INT 21 - OS/286, OS/386 - ISSUE REAL PROCEDURE SIGNAL FROM PROTECTED MODE AH = E6h ??? Return: ??? Note: protected mode only??? --------------------------------------------- INT 21 - Novell NetWare 4.0, Banyan VINES - GET FILE SERVER DATE AND TIME AH = E7h DS:DX -> reply buffer BYTE year - 1900 BYTE month BYTE day BYTE hours BYTE minutes BYTE seconds BYTE day of week (0 = Sunday) (Novell only) Return: AL = error code 00h successful FFh unsuccessful SeeAlso: AH=2Ah,2Ch --------------------------------------------- INT 21 - OS/286, OS/386 - CREATE CODE SEGMENT AH = E7h ??? Return: ??? --------------------------------------------- INT 21 - Novell NetWare 4.6 - SET FCB RE-OPEN MODE AH = E8h DL = mode 00h no automatic re-open 01h auto re-open Return: AL = error code --------------------------------------------- INT 21 - OS/286, OS/386 - SEGMENT CREATION AH = E8h AL = type 00h data segment 01h data window/alias 02h real segment 03h real window/alias 06h shareable segment ??? Return: ??? --------------------------------------------- INT 21 - Novell NetWare 4.6 - SHELL'S "GET BASE STATUS" AH = E9h AL = subfunction 00h get directory handle DX = drive number to check (0 = A:) Return: AL = network pathbase AH = base flags 00h drive not currently mapped to a base 01h drive is mapped to a permanent base 02h drive is mapped to a temporary base 03h drive exists locally --------------------------------------------- INT 21 - OS/286, OS/386 - CHANGE SEGMENTS AH = E9h AL = function 01h change code segment parameters 02h change data segment parameters 05h adjust segment limit 06h change segment base address ??? Return: ??? Note: protected mode only??? --------------------------------------------- INT 21 - Novell NetWare 4.6 - RETURN SHELL VERSION AH = EAh AL = subfunction 00h return code in AL Return: AL = hardware type 00h IBM PC 01h Victor 9000 01h get workstation environment string ES:DI -> 40-byte buffer Return: buffer filled with three null-terminated entries: major operating system version hardware type Return: AH = 00h if DOS --------------------------------------------- INT 21 - DoubleDOS - TURN OFF TASK SWITCHING AH = EAh Return: task switching turned off SeeAlso: AH=EBh"DoubleDOS" --------------------------------------------- INT 21 - OS/286, OS/386 - ALLOCATE HUGE SEGMENT AH = EAh ??? Return: ??? Note: protected mode only??? --------------------------------------------- INT 21 - Novell NetWare 4.6 - LOG FILE AH = EBh DS:DX -> ASCIZ filename if function C6h lock mode 01h: AL = flags 00h log file only 01h lock as well as log file BP = timeout in timer ticks (1/18 second) Return: AL = error code --------------------------------------------- INT 21 - DoubleDOS - TURN ON TASK SWITCHING AH = EBh Return: task switching turned on SeeAlso: AH=EAh"DoubleDOS" --------------------------------------------- INT 21 - OS/386 VMM - GET A PAGE TABLE ENTRY BY LINEAR ADDRESS AX = EB00h ??? Return: ??? Note: protected mode only??? --------------------------------------------- INT 21 - OS/386 VMM - GET A PAGE TABLE ENTRY BY 16-BIT SEGMENT:OFFSET AX = EB02h ??? Return: ??? Note: protected mode only??? --------------------------------------------- INT 21 - OS/386 VMM - FREE MAPPED PAGES AX = EB03h ??? Return: ??? Note: protected mode only??? --------------------------------------------- INT 21 - OS/386 VMM - GET A PAGE TABLE ENTRY BY 32-BIT SEGMENT:OFFSET AX = EB04h ??? Return: ??? Note: protected mode only??? --------------------------------------------- INT 21 - OS/386 VMM - MAP PAGES AX = EB05h ??? Return: ??? Note: protected mode only??? --------------------------------------------- INT 21 - OS/386 VMM - LOCK PAGES IN MEMORY AX = EB06h ??? Return: ??? Note: protected mode only??? --------------------------------------------- INT 21 - OS/386 VMM - UNLOCK MEMORY PAGES AX = EB07h ??? Return: ??? Note: protected mode only??? --------------------------------------------- INT 21 - Novell NetWare 4.6 - RELEASE FILE AH = ECh DS:DX -> ASCIZ filename Return: none --------------------------------------------- INT 21 - DoubleDOS - GET VIRTUAL SCREEN ADDRESS AH = ECh Return: ES = segment of virtual screen Note: screen address can change if task-switching is on!! --------------------------------------------- INT 21 - OS/286, OS/386 - BLOCK TRANSFER AH = ECh ??? Return: ??? --------------------------------------------- INT 21 - Novell NetWare - CLEAR FILE AH = EDh DS:DX -> ASCIZ filename Return: AL = error code --------------------------------------------- INT 21 - OS/286, OS/386 - GET SEGMENT OR WINDOW DESCRIPTOR AH = EDh ??? Return: ??? Note: protected mode only??? --------------------------------------------- INT 21 - Novell NetWare 4.6 - GET PHYSICAL STATION NUMBER AH = EEh Return: CX:BX:AX = six-byte address --------------------------------------------- INT 21 - DoubleDOS - GIVE AWAY TIME TO OTHER TASKS AH = EEh AL = number of 55ms time slices to give away Return: returns after giving away time slices --------------------------------------------- INT 21 - Novell Advanced NetWare 1.0+ - GET DRIVE INFO AH = EFh AL = subfunction 00h get drive handle table 01h get drive flag table 02h get drive connection ID table 03h get connection ID table 04h get file server name table Return: ES:DI -> shell status table --------------------------------------------- INT 21 - Novell Advanced NetWare 1.0+ - CONNECTION ID AH = F0h AL = subfunction 00h set preferred connection ID 01h get preferred connection ID 02h get default connection ID 03h LPT capture active 04h set primary connection ID 05h get primary connection ID DL = preferred file server Return: AL = selected file server --------------------------------------------- INT 21 - Novell Advanced NetWare 1.0+ - FILE SERVER CONNECTION AH = F1h AL = subfunction 00h attach to file server DL = preferred file server 01h detach from file server 02h logout from file server Return: AL = completion code --------------------------------------------- INT 21 - Novell NetWare - ??? AH = F2h ??? Return: ??? --------------------------------------------- INT 21 - Novell Advanced NetWare 2.0+ - FILE SERVER FILE COPY AH = F3h ES:DI -> request string (see below) Return: AL = status/error code CX:DX = number of bytes copied Format of request string: Offset Size Description 00h WORD source file handle 02h WORD destination file handle 04h DWORD starting offset in source 08h DWORD starting offset in destination 0Ch DWORD number of bytes to copy --------------------------------------------- INT 21 - DOS v??? - SET OEM INT 21 HANDLER AH = F8h DS:DX -> OEM INT 21 handler for functions F9h to FFh FFFFh:FFFFh resets to original handlers Notes: calls to AH=F9h through AH=FFH will return CF set and AX=1 (invalid function) if no handler set handler is called with all registers exactly as set by caller, and should exit with IRET --------------------------------------------- INT 21 - DOS v??? - OEM FUNCTION AH = F9h --------------------------------------------- INT 21 - DOS v??? - OEM FUNCTION AH = FAh --------------------------------------------- INT 21 - DOS v??? - OEM FUNCTION AH = FBh --------------------------------------------- INT 21 - DOS v??? - OEM FUNCTION AH = FCh --------------------------------------------- INT 21 - DOS v??? - OEM FUNCTION AH = FDh --------------------------------------------- INT 21 - DOS v??? - OEM FUNCTION AH = FEh --------------------------------------------- INT 21 - PCMag PCMANAGE/DCOMPRES - INSTALLATION CHECK AX = FEDCh Return: AX = CDEFh if installed SeeAlso: AH=DCh --------------------------------------------- INT 21 - DOS v??? - OEM FUNCTION AH = FFh --------------------------------------------- INT 21 - CED - INSTALLABLE COMMANDS AH = FFh AL = 00h add installable command BL = mode - bit 0 = 1 callable from DOS prompt bit 1 = 1 callable from application DS:SI -> CR-terminated command name ES:DI -> FAR routine entry point AL = 01h remove installable command DS:SI -> CR-terminated command name AL = 02h reserved, may be used to test for CED installation Return: CF set on error AX = 01h invalid function 02h command not found (subfunction 01h only) 08h insufficient memory (subfunction 00h only) 0Eh bad data (subfunction 00h only) AH = 0FFh if CED not installed --------------------------------------------- INT 22 - DOS - TERMINATE ADDRESS FAR (DWORD) address to jump to when program "returns to DOS". Normally points at the instruction immediately following INT 21/AH=4Bh call which loaded the current program. Should NEVER be called directly. SeeAlso: INT 20, INT 21/AH=00h,31h,4Ch --------------------------------------------- INT 23 - DOS - CONTROL "C" EXIT ADDRESS Automatically called by DOS when CTRL-C or CTRL-BREAK is detected. Normally aborts program and returns to DOS, but may be changed. SeeAlso: INT 1B --------------------------------------------- INT 24 - DOS - FATAL ERROR HANDLER ADDRESS Automatically called upon detection of unrecoverable I/O error. Normally points to routine in resident part of COMMAND.COM that prints "Abort, Retry, Ignore?" message and takes the reply, but may be overridden if desired. Provides the following values in registers on entry to interrupt handler: AH: bit 7 = 0 disk I/O error = 1 other error -- if block device, bad FAT -- if char device, code in DI bit 6 unused bit 5 = 1 if Ignore allowed, 0 if not (DOS 3+) bit 4 = 1 if Retry allowed, 0 if not (DOS 3+) bit 3 = 1 if Fail allowed, 0 if not (DOS 3+) bit 2 \ disk area of error 00 = DOS area 01 = FAT bit 1 / 10 = root dir 11 = data area bit 0 = 1 if write, 0 if read AL = drive number if AH bit 7 = 1, otherwise undefined BP:SI -> header of device driver for which error occurred block device if high bit of BP:[SI+4] set low byte of DI: 00h write-protect error 01h unknown unit 02h drive not ready 03h unknown command 04h data error (bad CRC) 05h bad request structure length 06h seek error 07h unknown media type 08h sector not found 09h printer out of paper 0Ah write fault 0Bh read fault 0Ch general failure 0Dh (DOS 3+) sharing violation 0Eh (DOS 3+) lock violation 0Fh (DOS 3+) invalid disk change 10h (DOS 3+) FCB unavailable 11h (DOS 3+) sharing buffer overflow Handler must return AL = 00h ignore error = 01h retry operation = 02h terminate program through INT 22h = 03h fail system call in progress (DOS 3+) Notes: for DOS 3.1+, IGNORE (AL=00h) is turned into FAIL (AL=03h) on network critical errors if IGNORE specified but not allowed, it is turned into FAIL if RETRY specified but not allowed, it is turned into FAIL if FAIL specified but not allowed, it is turned into ABORT --------------------------------------------- INT 25 - DOS - ABSOLUTE DISK READ (except DOS 4.0/COMPAQ DOS 3.31 >32M partitn) AL = drive number (0=A, 1=B, etc) DS:BX = Disk Transfer Address (buffer) CX = number of sectors to read DX = first relative sector to read Return: CF set on error AL = error code issued to INT 24h in low half of DI AH = 80h if attachment failed to respond 40h if seek operation failed 20h if controller failed 10h if data error (bad CRC) 08h if DMA failure 04h if requested sector not found 03h if write-protected disk (INT 26 only) 02h if bad address mark 01h if bad command CF clear if successful AL = 00h Notes: ORIGINAL FLAGS ON STACK! Must be popped or discarded by adjusting SP May destroy all registers except segment regs BUG: DOS 3.1 through 3.3 set the word at ES:[BP+1Eh] to FFFFh if AL is an invalid drive number SeeAlso: INT 26, INT 13/AH=02h --------------------------------------------- INT 25 - DOS 4.0/COMPAQ DOS 3.31 - ABSOLUTE DISK READ (>32M hard-disk partitn) AL = drive number (0=A, 1=B, etc) CX = FFFFh DS:BX -> disk read packet (see below) Return: same as above Notes: partition is potentially >32M (and requires this form of the call) if bit 1 of device attribute word in device driver is set ORIGINAL FLAGS LEFT ON STACK! Must be popped or discarded by adj SP SeeAlso: INT 26, INT 13/AH=02h Format of disk read packet: Offset Size Description 00h DWORD sector number 04h WORD number of sectors to read 06h DWORD transfer address --------------------------------------------- INT 26 - DOS - ABSOLUTE DISK WRITE (except DOS 4.0/COMPAQ DOS 3.31 >32M partn) AL = drive number (0=A, 1=B, etc) DS:BX = Disk Transfer Address (buffer) CX = number of sectors to write DX = first relative sector to write Return: CF set on error AL = error code issued to INT 24h in low half of DI AH = same error codes as for INT 25h CF clear if successful AL = 00h Note: ORIGINAL FLAGS ON STACK! Must be popped or discarded by adjusting SP BUG: DOS 3.1 through 3.3 set the word at ES:[BP+1Eh] to FFFFh if AL is an invalid drive number SeeAlso: INT 25, INT 13/AH=03h --------------------------------------------- INT 26 - DOS 4.0/COMPAQ DOS 3.31 - ABSOLUTE DISK WRITE (>32M hard-disk partitn) AL = drive number (0=A, 1=B, etc) CX = FFFFh DS:BX -> disk write packet (see below) Return: same as above Notes: partition is potentially >32M (and requires this form of the call) if bit 1 of device attribute word in device driver is set ORIGINAL FLAGS LEFT ON STACK! Must be popped or discarded by adj SP SeeAlso: INT 25, INT 13/AH=03h Format of disk write packet: Offset Size Description 00h DWORD sector number 04h WORD number of sectors to read 06h DWORD transfer address --------------------------------------------- INT 27 - DOS - TERMINATE BUT STAY RESIDENT CS = current program segment DX = last program byte + 1 Return: never Note: this is an obsolete call SeeAlso: INT 21/AH=31h ---------------------------------------------