INT 21 - DOS 2+ - IOCTL - SET DEVICE INFORMATION

Input

 DOS1 N DOS2 Y

DOS4

 Y DOS5 Y

Output

AX

 44h 01h Error Code AX

BX

  File Handle     BX

CX

         CX

DX

  00h Device Info     DX

ES:DI

   Set if Error CF 
        Can only be used to set info for Character Devices
Device Info for Character Devices
Bit Dec Hex  Description
0 1 0001h  Standard Input Device
1 2 0002h  Standard Output Device
2 4 0004h  NUL Device
3 8 0008h  CLOCK$ Device
4 16 0010h  Special Device (Supports INT 28h)
5 32 0020h  Binary (RAW) Mode
6 64 0040h  Not EOF for Input
7 128 0080h  1
8 256 0100h  Reserved
9 512 0200h
10 1024 0400h
11 2048 0800h
12 4096 1000h  Network Device
13 8192 2000h  Reserved
14 16384 4000h  Can process IOCTL (Can't Set)
15 32768 8000h  Reserved
 


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