Table of Contents

Note: This API call is for DOS and Win16 personality only. Use Family API for portability.

2018/09/07 05:04 · prokushev · 0 Comments

Int 21H, AH=44H, AL=00H

Version

2 and higher

Brief

GET DEVICE INFORMATION

Family API

Input

      AX = 4400h
      BX = handle

Return

CF clear if successful

          DX = device information word (see #01423)
          AX destroyed
      CF set on error
          AX = error code (01h,05h,06h) (see #01680 at AH=59h/BX=0000h)

Macro

Notes

value in DH corresponds to high byte of device driver's attribute word if handle refers to a character device

Novell NetWare reportedly does not return a drive number in bits 5-0 for a disk file

this function was not supported by Digital Research's DOS Plus

Bitfields for device information word:

Bit(s) Description
character device
14 device driver can process IOCTL requests (see AX=4402h“DOS 2+”)
13 output until busy supported
11 driver supports OPEN/CLOSE calls
8 ??? (set by MS-DOS 6.2x KEYB)
7 set (indicates device)
6 EOF on input
5 raw (binary) mode
4 device is special (uses INT 29)
3 clock device
2 NUL device
1 standard output
0 standard input
disk file
15 file is remote (DOS 3.0+)
14 don't set file date/time on closing (DOS 3.0+)
11 media not removable
8 (DOS 4 only) generate INT 24 if no disk space on write or read past end of file
7 clear (indicates file)
6 file has not been written
5-0 drive number (0 = A:)

See also

AX=4401h,INT 2F/AX=122Bh, INT 29

Note

Text based on Ralf Brown Interrupt List Release 61

2018/09/04 17:23 · prokushev · 0 Comments