Device Requests
DOS
Cmd Name Ver. Usage Flags
▀▀▀ ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ ▀▀▀▀ ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀
00H Initialize device ◄Chr►◄Blk►
01H Media Check ◄Blk►
02H Build BPB ◄Blk►
03H IOCTL Input ◄Chr►◄Blk►◄IRW►
04H Input (read from device) ◄Chr►◄Blk►
05H Non-destructive Input ◄Chr►
06H Input status ◄Chr►
07H Input Flush ◄Chr►
08H Output (write to device) ◄Chr►◄Blk►
09H Output with verify ◄Chr►◄Blk►
0aH Output Status ◄Chr►
0bH Output Flush ◄Chr►
0cH IOCTL Output ◄Chr►◄Blk►◄IRW►
0dH Device Open 3.0+ ◄Chr►◄Blk► ◄OCR►
0eH Device Close 3.0+ ◄Chr►◄Blk► ◄OCR►
0fH Removable Media 3.0+ ◄Blk► ◄OCR►
10H Output until busy 3.0+ ◄Chr► ◄OTB►
13H Generic IOCTL Request 3.2 ◄Chr►◄Blk► ◄Gen►
17H Get Logical Device 3.2 ◄Blk► ◄Gen►
18H Set Logical Device 3.2 ◄Blk► ◄Gen►
19H IOCTL Support Query 5.0 ◄Chr►◄Blk► ◄Gen► ◄Qry►
▀▀▀ ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ ▀▀▀▀ ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀
On entry to the Strategy routine (see Device Driver Basics), DOS passes
the address of a request structure in ES:BX (see DevRequestHdrRec). The
bCmd field of that structure (at offset 2) will contain one of the above
command codes.
The variable-length data that follows the DevRequestHdrRec varies from
command to command. Some commands share identical request structures.
Others have a unique structure and some use only the request header to
communicate with DOS.
See Also: IOCTL Functions
Device Attribute
Device Status Word
Installable Device Drivers
-♦-