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Disk Parameter Code

I have some assembly used within Pascal to get the size of the hard disk as follows;

function GetGeometry(Drive: Byte; var cyls, heads, sects: Word): Integer;
var Regs: Registers;
begin
regs.ah := 8;
regs.dl :=Drive or $80;
Intr($13, regs);
cyls := (((regs.cl shl 2) and $300) or regs.ch) + 1;
heads := regs.dh + 1;
sects := regs.cl and $3F;
GetGeometry:=regs.ax and $FF00;
if regs.flags and 1 <> 0 then
GetGeometry:=-1;
end;

MB: (sect*heads*cyls)/2048

This unfortunatley only works upto 8gb, I've done some searching and found changing the interrupt 13
call to 48h should return me the information. I don't know how to access the informatin tho' as it is returned differently than above.

Can anyone post me some assembly/comment to help?

As It is quite urgent I am offering 500 points to a correct working solution.

Mike

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grg99

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MConnor

ASKER

Dos Boot Floppy, can be any version currently dos 6.22, I am using int13 as the disk might not be partitioned hence the calls to hardware directly.

Mike

SOLUTION

dimitry

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MConnor

ASKER

Thanks Dimitry, I had seen both links hence I know I need int13 ah=48h. The code I posted origonally uses int13 ah=8 and this works fine for disks <7.8gb this returns nice easy register entries for me to read.

ah=48h returns something else which I don't understand.

This essentially is my question, how do I read/interpret what int13h ah=48h returns?

If I can get an answer to that the points are yours (I don't hold points back like your last posted link).

Mike

SOLUTION

adg080898

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dimitry

Unfortunately I can't now write in Pascal, but the code C below shows how to use INT 13h, function 48h. It works properly for my computer, but I suspect that for different BIOSes it may work not properly. If you can't compile it, give me your e-mail, I'll send you executable.

/*-------------------------------------------------------*/
#include <stdio.h>
#include <dos.h>
/*-------------------------------------------------------*/
#define DISK 0x13
#define CF 1
typedef unsigned char BYTE;
typedef unsigned short WORD;
typedef unsigned long DWORD;
typedef struct {
DWORD lowSecNum;
DWORD highSecNum;
} QWORD;

typedef struct {
WORD bufSize; /* (001Ah for v1.x, 001Eh for v2.x, 42h for v3.0) */
WORD infoFlags; /* (see #00274) */
DWORD cylNum; /* number of physical cylinders on drive */
DWORD headNum; /* number of physical heads on drive */
DWORD secPerTrack; /* number of physical sectors per track */
QWORD secNum; /* total number of sectors on drive */
WORD bytesPerSec; /* bytes per sector */
/*---v2.0+ ---*/
DWORD confParam; /* -> EDD configuration parameters (see #00278) */
/*---v3.0 ---*/
WORD sign;
BYTE length;
BYTE reserved0[3];
BYTE nameBus[4]; /* ASCIZ name of host bus ("ISA" or "PCI") */
BYTE nameType[8]; /* ASCIZ name of interface type */
BYTE intPath[8];
BYTE devPath[8];
BYTE reserved1;
BYTE checksum;
} DevParam48;

DevParam48 devParam;
/*-------------------------------------------------------*/
int getDriveParam( unsigned short driveNo, void far *buf )
{ /* Send get Drive Parameters command to INT 13 */
struct REGPACK sreg;

sreg.r_ax = 0x4800; /* Get Drive Parameters */
sreg.r_dx = driveNo; /* Drive: 0x80 */
sreg.r_si = FP_OFF( buf );
sreg.r_ds = FP_SEG( buf );
intr(DISK, &sreg);
if( sreg.r_flags & CF )
return( 1 );
return( 0 );
}
/*-------------------------------------------------------*/
int main()
{
DWORD numOfMeg = 0L;

devParam.bufSize = 0x1A;
if( getDriveParam( 0x80, (void far *)&devParam ) != 0 ) {
printf("Error Get Drive Parameters\n");
return( 1 );
}
printf("Get Drive Parameters:\n");
numOfMeg = devParam.secNum.lowSecNum / 2048;
printf(" HD size = %ld Mb\n", numOfMeg);
return( 0 );
}

SOLUTION

Doors

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Okey

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DanRollins

ping

Okey

What's wrong with Borlands DriveSize?
It's really good assembly!
Try to throw an eye with a Debugger on it!

Make it Like this :

Uses {win}Dos;

...

Writeln('Size of actual Drive:',DiskSize(0):16);

...

DanRollins

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