Int 2F Fn 0802  U - Driver.sys Support - Execute Device Driver Request     [D]

   AX = 0802h
   ES:BX -> device driver request header (see below)

Return: request header updated as per requested operation

Notes: supported by DR-DOS 5.0
   DOS 3.2 executes this function on any AL value from 02h through F7h;
     DOS 4+ executes this function on AL=02h and AL=04h-F7h
   the command codes and structures described below apply to all drivers
     which support the appropriate commands; this call is just one of a
     number of ways in which a device driver request may be invoked

See Also: AX=0800h,AX=0801h,AX=0803h,INT 21/AH=52h,INT 21/AH=99h,INT 21/AH=9Ah

Values for command code:
 00h   INIT
 01h   MEDIA CHECK (block devices)
 02h   BUILD BPB (block devices)
 03h   IOCTL INPUT
 04h   INPUT
 05h   NONDESTRUCTIVE INPUT, NO WAIT (character devices)
 06h   INPUT STATUS (character devices)
 07h   INPUT FLUSH (character devices)
 08h   OUTPUT
 09h   OUTPUT WITH VERIFY
 0Ah   OUTPUT STATUS (character devices)
 0Bh   OUTPUT FLUSH (character devices)
 0Ch   IOCTL OUTPUT
 0Dh   (DOS 3+) DEVICE OPEN
 0Eh   (DOS 3+) DEVICE CLOSE
 0Fh   (DOS 3+) REMOVABLE MEDIA (block devices)
 10h   (DOS 3+) OUTPUT UNTIL BUSY (character devices)
 11h   (European MS-DOS 4.0) STOP OUTPUT (console screen drivers only)
 12h   (European MS-DOS 4.0) RESTART OUTPUT (console screen drivers only)
 13h   (DOS 3.2+) GENERIC IOCTL
 14h   unused
 15h   (European MS-DOS 4.0) RESET UNCERTAIN MEDIA FLAG
 16h   unused
 17h   (DOS 3.2+) GET LOGICAL DEVICE
 18h   (DOS 3.2+) SET LOGICAL DEVICE
 19h   (DOS 5+) CHECK GENERIC IOCTL SUPPORT
 80h   (CD-ROM) READ LONG
 81h   (CD-ROM) reserved
 82h   (CD-ROM) READ LONG PREFETCH
 83h   (CD-ROM) SEEK
 84h   (CD-ROM) PLAY AUDIO
 85h   (CD-ROM) STOP AUDIO
 86h   (CD-ROM) WRITE LONG
 87h   (CD-ROM) WRITE LONG VERIFY
 88h   (CD-ROM) RESUME AUDIO

Format of device driver request header:
Offset Size    Description
 00h   BYTE    length of request header
 01h   BYTE    subunit within device driver
 02h   BYTE    command code (see above)
 03h   WORD    status (filled in by device driver)
       bit 15: error
       bits 14-11: reserved
       bit 10: ??? set by DOS kernel on entry to some driver calls
       bit 9: busy
       bit 8: done (may be clear on return under European MS-DOS 4.0)
       bits 7-0: error code if bit 15 set (see below)
---DOS---
 05h  4 BYTEs  reserved (unused in DOS 2.x and 3.x)
 09h   DWORD   (European MS-DOS 4.0 only) pointer to next request header in
           device's request queue
       (other versions) reserved (unused in DOS 2.x and 3.x)
---STARLITE architecture---
 05h   DWORD   pointer to next request header
 09h  4 BYTEs  reserved
---command code 00h---
 0Dh   BYTE    (return) number of units
 0Eh   DWORD   (call) pointer to DOS device helper function (see below)
           (European MS-DOS 4.0 only)
       (call) pointer past end of memory available to driver (DOS 5+)
       (return) address of first free byte following driver
 12h   DWORD   (call) pointer to commandline arguments
       (return) pointer to BPB array (block drivers) or
               0000h:0000h (character drivers)
 16h   BYTE    (DOS 3+) drive number for first unit of block driver (0=A)
   ---European MS-DOS 4.0---
 17h   DWORD   pointer to function to save registers on stack
   ---DOS 5+ ---
 17h   WORD    (return) error-message flag
           0001h MS-DOS should display error msg on init failure
---command code 01h---
 0Dh   BYTE    media descriptor
 0Eh   BYTE    returned status
       00h don't know
       01h media has not changed
       FFh media has been changed
 0Fh   DWORD   (return, DOS 3+) pointer to previous volume ID if OPEN/CLOSE/RM
         bit in device header is set and disk changed
---command code 02h---
 0Dh   BYTE    media descriptor
 0Eh   DWORD   transfer address
       -> scratch sector if NON-IBM FORMAT bit in device header set
       -> first FAT sector otherwise
 12h   DWORD   pointer to BPB (set by driver) (see INT 21/AH=53h)
---command codes 03h,0Ch--- (see also INT 21/AX=4402h,INT 21/AX=4403h)
 0Dh   BYTE    media descriptor (block devices only)
 0Eh   DWORD   transfer address
 12h   WORD    (call) number of bytes to read/write
       (return) actual number of bytes read or written
---command codes 04h,08h,09h---
 0Dh   BYTE    media descriptor (block devices only)
 0Eh   DWORD   transfer address
 12h   WORD    byte count (character devices) or sector count (block devices)
 14h   WORD    starting sector number (block devices only)
 16h   DWORD   (DOS 3+) pointer to volume ID if error 0Fh returned
 1Ah   DWORD   (DOS 4+) 32-bit starting sector number (block devices with
       device attribute word bit 1 set only) if starting sector number
       above is FFFFh (see INT 21/AH=52h)
---command code 05h---
 0Dh   BYTE    byte read from device if BUSY bit clear on return
---command codes 06h,07h,0Ah,0Bh,0Dh,0Eh,0Fh---
 no further fields
---command code 10h---
 0Dh   BYTE    unused
 0Eh   DWORD   transfer address
 12h   WORD    (call) number of bytes to write
       (return) actual number of bytes written
---command codes 11h,12h---
 0Dh   BYTE    reserved
---command code 15h---
 no further fields
---command codes 13h,19h---
 0Dh   BYTE    category code
       00h unknown
       01h COMn:
       03h CON
       05h LPTn:
       07h mouse (European MS-DOS 4.0)
       08h disk
       9Eh (STARLITE) Media Access Control driver
 0Eh   BYTE    function code
       00h (STARLITE) MAC Bind request
 0Fh   WORD    copy of DS at time of IOCTL call (apparently unused in DOS 3.3)
       SI contents (European MS-DOS 4.0)
 11h   WORD    offset of device driver header
       DI contents (European MS-DOS 4.0)
 13h   DWORD   pointer to parameter block from INT 21/AX=440Ch or AX=440Dh
---command codes 80h,82h---
 0Dh   BYTE    addressing mode
       00h HSG (default)
       01h Phillips/Sony Red Book
 0Eh   DWORD   transfer address (ignored for command 82h)
 12h   WORD    number of sectors to read
       (if 0 for command 82h, request is an advisory seek)
 14h   DWORD   starting sector number
       logical sector number in HSG mode
       frame/second/minute/unused in Red Book mode
       (HSG sector = minute * 4500 + second * 75 + frame - 150)
 18h   BYTE    data read mode
       00h cooked (2048 bytes per frame)
       01h raw (2352 bytes per frame, including EDC/ECC)
 19h   BYTE    interleave size (number of sectors stored consecutively)
 1Ah   BYTE    interleave skip factor (# sectors between consec portions)
---command code 83h---
 0Dh   BYTE    addressing mode (see above)
 0Eh   DWORD   transfer address (ignored)
 12h   WORD    number of sectors to read (ignored)
 14h   DWORD   starting sector number (see also above)
---command code 84h---
 0Dh   BYTE    addressing mode (see above)
 0Eh   DWORD   starting sector number (see also above)
 12h   DWORD   number of sectors to play
---command codes 85h,88h---
 no further fields
---command codes 86h,87h---
 0Dh   BYTE    addressing mode (see above)
 0Eh   DWORD   transfer address (ignored in write mode 0)
 12h   WORD    number of sectors to write
 14h   DWORD   starting sector number (see also above)
 18h   BYTE    write mode
       00h mode 0 (write all zeros)
       01h mode 1 (default) (2048 bytes per sector)
       02h mode 2 form 1 (2048 bytes per sector)
       03h mode 2 form 2 (2336 bytes per sector)
 19h   BYTE    interleave size (number of sectors stored consecutively)
 1Ah   BYTE    interleave skip factor (# sectors between consec portions)

Values for error code:
 00h   write-protect violation
 01h   unknown unit
 02h   drive not ready
 03h   unknown command
 04h   CRC error
 05h   bad drive request structure length
 06h   seek error
 07h   unknown media
 08h   sector not found
 09h   printer out of paper
 0Ah   write fault
 0Bh   read fault
 0Ch   general failure
 0Dh   reserved
 0Eh   (CD-ROM) media unavailable
 0Fh   invalid disk change

Call European MS-DOS 4.0 device helper function with:
   DL = function
       00h "SchedClock" called on each timer tick
       AL = tick interval in milliseconds
       01h "DevDone" device I/O complete
       ES:BX -> request header

       Note:   must update status word first; may be called from
             an interrupt handler
       02h "PullRequest" pull next request from queue
       DS:SI -> DWORD pointer to start of device's request queue

       Return: ZF clear if pending request
               ES:BX -> request header
           ZF set if no more requests
       03h "PullParticular" remove specific request from queue
       DS:SI -> DWORD pointer to start of device's request queue
       ES:BX -> request header

       Return: ZF set if request header not found
       04h "PushRequest" push the request onto the queue
       DS:SI -> DWORD pointer to start of device's request queue
       ES:BX -> request header
       interrupts disabled
       05h "ConsInputFilter" keyboard input check
       AX = character (high byte 00h if PC ASCII character)

       Return: ZF set if character should be discarded
           ZF clear if character should be handled normally

       Note:   called by keyboard interrupt handler so DOS can scan
             for special input characters
       06h "SortRequest" push request in sorted order by starting sector
       DS:SI -> DWORD pointer to start of device's request queue
       ES:BX -> request header
       interrupts disabled
       07h "SigEvent" send signal on keyboard event
       AH = event identifier

       Return: AL,FLAGS destroyed
       09h "ProcBlock" block on event
       AX:BX = event identifier (typically a pointer)
       CX = timeout in ms or 0000h for never
       DH = interruptable flag (nonzero if pause may be interrupted)
       interrupts disabled

       Return: after corresponding ProcRun call
           CF clear if event wakeup, set if unusual wakeup
           ZF set if timeout wakeup, clear if interrupted
           AL = wakeup code, nonzero if unusual wakeup
           interrupts enabled
           BX,CX,DX destroyed

       Note:   block process and schedules another to run
       0Ah "ProcRun" unblock process
       AX:BX = event identifier (typically a pointer)

       Return: AX = number of processes awakened
           ZF set if no processes awakened
           BX,CX,DX destroyed
       0Bh "QueueInit" initialize/clear character queue
       DS:BX -> character queue structure (see below)

       Note:   the queue size field must be set before calling
       0Dh "QueueWrite" put a character in the queue
       DS:BX -> character queue (see below)
       AL = character to append to end of queue

       Return: ZF set if queue is full
           ZF clear if character stored
       0Eh "QueueRead" get a character from the queue
       DS:BX -> character queue (see below)

       Return: ZF set if queue is empty
           ZF clear if characters in queue
               AL = first character in queue
       10h "GetDOSVar" return pointer to DOS variable
       AL = index of variable
           03h current process ID
       BX = index into variable if AL specifies an array
       CX = expected length of variable

       Return: CF clear if successful
               DX:AX -> variable
           CF set on error
               AX,DX destroyed
           BX,CX destroyed

       Note:   the variables may not be modified
       14h "Yield" yield CPU if higher-priority task ready to run

       Return: FLAGS destroyed
       1Bh "CritEnter" begin system critical section
       DS:BX -> semaphore (6 BYTEs, initialized to zero)

       Return: AX,BX,CX,DX destroyed
       1Ch "CritLeave" end system critical section
       DS:BX -> semaphore (6 BYTEs, initialized to zero)

       Return: AX,BX,CX,DX destroyed


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