Int 2F/AX=1607h/BX=0015h

MS Windows - DOSMGR VIRTUAL DEVICE API

AX = 1607h
BX = 0015h (VxD identifier of "DOSMGR")
CX = function
0000h query instance processing
DX = 0000h
Return:
CX = state
0000h not instanced
other instanced (DOS 5+ kernel returns 0001h)
DX = segment of DOS drivers or 0000h for
default of 0070h
ES:BX -> patch table (see #02637)
0001h set patches in DOS
DX = bit mask of patch requests (see #02636)
Return:
AX = B97Ch
BX = bit mask of patches applied (see #02636)
DX = A2ABh
0002h remove patches in DOS (ignored by DOS 5.0 kernel)
DX = bit mask of patch requests (see #02636)
Return:
CX = 0000h (DOS 5-6)

Note: Return values are ignored by DOSMGR in Windows 3.1 0003h get size of DOS data structures DX = bit mask of request (only one bit can be set)

bit 0:
Current Directory Structure size

Return:
If supported request: AX = B97Ch CX = size in bytes of requested structure DX = A2ABh else: CX = 0000h all other registers preserved 0004h determine instanced data structures

Return:
AX = B97Ch if supported DX = A2ABh if supported (DOS 5+ kernel returns 0000h) BX = bit mask of instanced items

bit 0:
CDS

bit 1:
SFT

bit 2:
Device list

bit 3:
DOS swappable data area 0005h get device driver size ES = segment of device driver

Return:
DX:AX = 0000h:0000h on error (not dev. driver segment) DX:AX = A2ABh:B97Ch if successful BX:CX = size of device driver in bytes

Notes: DOSMGR (DOS Manager) will check whether the OEM DOS/BIOS data has been instanced via this API and will not perform its own default instancing of the normal DOS/BIOS data if so; if this API is not supported, DOSMGR will also try to access instancing data through INT 2F/AX=1603h. These functions are supported by the DOS 5+ kernel; DOSMGR contains tables of instancing information for earlier versions of DOS. See Geoff Chappell's book _DOS_Internals_ for additional discussions of DOSMGR's behavior and instancing in general

See Also: AX=1603h - AX=1605h - AX=1607h/BX=000Ch - AX=16

See Also: AX=1684h"DEVICE API"

Bitfields for DOSMGR patch requests: Bit(s) Description (Table 02636) 0 enable critical sections 1 NOP setting/checking user ID 2 turn INT 21/AH=3Fh on STDIN into polling loop 3 trap stack fault in "SYSINIT" to WIN386 4 BIOS patch to trap "Insert disk X:" to WIN386

Format of DOSMGR patch table: Offset Size Description (Table 02637) 00h 2 BYTEs DOS version (major, minor) 02h WORD offset in DOS data segment of "SAVEDS" 04h WORD offset in DOS data segment of "SAVEBX" 06h WORD offset in DOS data segment of InDOS flag 08h WORD offset in DOS data segment of User ID word 0Ah WORD offset in DOS data segment of "CritPatch" table to enable critical section calls (see INT 2A/AH=80h) 0Ch WORD (DOS 5+ only) offset in DOS data segment of "UMB_HEAD", containing segment of last MCB in conventional memory

Category: DOS Kernel - Int 2Fh - M

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