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

Input

 DOS1 N DOS2 Y

DOS4

 Y DOS5 Y

Output

AX

 44h 00h Error Code AX

BX

  File Handle     BX

CX

         CX

DX

     Device Info DX

ES:DI

   Set if Error CF

 

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 strings
15 32768 8000h  Reserved

 

Device Info for File Devices
Bit Dec Hex  Description
0 1 0001h  Block Device Number (0=A,1=B,etc).
1 2 0002h
2 4 0004h
3 8 0008h
4 16 0010h
5 32 0020h
6 64 0040h  File has not been written
7 128 0080h  0
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 Strings
15 32768 8000h  File is Remote
 


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