Message-ID: <000b01bf7136$1bbe6b20$94702ecb@sphinx>
From: "Johan Venter" <jventer AT writeme DOT com>
To: "Duane Atly" <aelp AT mail DOT com>
Cc: <djgpp AT delorie DOT com>
References: <PmTi4.8611$N36 DOT 414294 AT typhoon DOT austin DOT rr DOT com> <7c6p8sccsimi62b7el2pfkid1qd4dfvnrf AT 4ax DOT com> <Y0oj4.560$Ow2 DOT 5945 AT news DOT clear DOT net DOT nz> <3890db83_6 AT goliath DOT newsfeeds DOT com>
Subject: Re: Be passing Windows HDD driver (WAS Re: Boot sectors and partition tables)
Date: Sat, 5 Feb 2000 22:02:26 +1000
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Reply-To: djgpp AT delorie DOT com

> Is there a "good clean" way of going around Windows to look at the
partition
> table (or even issue Drive Cmds?)
>
> Just wondering.

Here's some code I wrote to read the partition table (a quick hack, so
forgive any minor errors, it works ok though). Note: this code also saves
the mbr into mbr.bin, and the partition table to pt.bin:

/* reads partition table on first hard disk and prints info */

#include <bios.h>
#include <stdio.h>

struct partitionEntry {
 unsigned char mediaByte   __attribute__ ((packed));
 unsigned char startHead   __attribute__ ((packed));
 unsigned short startCylSec  __attribute__ ((packed));
 unsigned char partitionType  __attribute__ ((packed));
 unsigned char endHead   __attribute__ ((packed));
 unsigned short endCylSec  __attribute__ ((packed));
 unsigned int sectorsToPartition  __attribute__ ((packed));
 unsigned int partitionSectors  __attribute__ ((packed));
};

struct partitionTable {
 struct partitionEntry partitions[4] __attribute__ ((packed));
} primaryPartitions;

unsigned char MasterBootRecord[512];

int readMBR(unsigned char *MBR);
struct partitionTable extractPartitionTable(unsigned char *MBR);

int main(void)
{
 int c;

 if (readMBR(MasterBootRecord)) {
  printf("error reading MBR.\n");
  exit(0);
 }

 primaryPartitions = extractPartitionTable(MasterBootRecord);

 printf("Partition Table/MBR reading example\n");
 printf("by Johan Venter (jventer AT writeme DOT com)\n\n");
 printf("number\t\ttype\t\tsize\t\tactive?\n");
 printf("======\t\t====\t\t====\t\t=======\n");
 for (c = 0; c < 4; c++) {
  printf("%d\t\t%d\t\t%d\t\t%s\n", c + 1,
primaryPartitions.partitions[c].partitionType,
     primaryPartitions.partitions[c].partitionSectors*512/1024/1024,
     primaryPartitions.partitions[c].mediaByte != 0 ? "Yes" : "No");
}
 return 0;
}

int readMBR(unsigned char *MBR)
{
 FILE *f = fopen("mbr.bin", "wb");

 if (biosdisk(2, 0x80, 0, 0, 1, 1, MBR))
  return 1;
 else {
  fwrite(MBR, 512, 1, f);
  fclose(f);
  return 0;
 }
}

struct partitionTable extractPartitionTable(unsigned char *MBR)
{
 FILE *f = fopen("pt.bin", "wb");
 struct partitionTable temp;

 memcpy(&temp, MBR + 0x1be, sizeof(struct partitionTable));
 fwrite(&temp, sizeof(struct partitionTable), 1, f);
 fclose(f);

 return temp;
}


Hope this helps. This won't work from Windows NT obviously, so I suggest you
make a Windows 95 or plain DOS bootdisk from someone elses machine.

Johan Venter
ICQ 3643877
jventer AT writeme DOT com
Binaries Servers ==-----