biosdisk

Syntax

#include <bios.h>

int biosdisk(int cmd, int drive, int head, int track,
	     int sector, int nsects, void *buffer);

Description

This function interfaces with the BIOS disk sevice (interrupt 0x13). Please refer to a BIOS reference manual for detailed information about the parameters of this call. All known calls are supported. A sector size of 512 bytes is assumed.

0 - reset disk subsystem

1 - get disk subsystem status

2 - read one or more sectors

3 - write one or more sectors

5 - format a track

6 - format back track

7 - format drive

8 - get drive parameters

9 - initialize drive parameters

10 - read long sectors

11 - write long sectors

12 - seek to cylinder

13 - alternate fixed disk reset

14 - read test buffer

15 - write test buffer

16 - test for drive ready

17 - recalibrate drive

18 - controller RAM diagnostic

19 - controller drive diagnostic

20 - controller internal diagnostic

15 - read fixed disk type

22 - read disk change line status

23 - set DASD type (pass dasd in nsects)

24 - set media type for format

The first request with more sectors than will fit in the transfer buffer will cause a DOS buffer to be allocated. This buffer is automatically freed when your application exits. Since this buffer is big enough to hold 18 sectors, requests for more sectors than that will fail.

Request eight returns values in buffer as follows:

byte 0 = sectors per track (bits 0..5) and top two bits of cylinder (in bits 6..7)

byte 1 = cyliders (bits 0..7)

byte 2 = number of drives

byte 3 = number of heads

Return Value

The value of AH returned by the BIOS.

Portability

not ANSI, not POSIX

Example

char buffer[512];
if (biosdisk(2, 0x80, 0, 0, 0, 1, buffer))
  error("disk");

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