Writing program to Unhide the Partition
The program to unhide the hidden partition works just opposite to the program which hides the program. In this program we subtract 16 (0x10) from the value of file system indicator byte of the hidden partition.
The coding of the program in as follows:
/* Program to unhide the partition hidden by the previous program */
#include <bios.h>
#include <stdio.h>
int main(void)
{
struct diskinfo_t dinfo;
int result, tohide;
int i;
static char dbuf[512];/* Data buffer */
clrscr();
dinfo.drive = 0x80; /* drive number for
First Hard Disk */
dinfo.head = 0; /* disk head number */
dinfo.track = 0; /* track number */
dinfo.sector = 1; /* sector number */
dinfo.nsectors = 1; /* sector count */
dinfo.buffer = dbuf; /* data buffer */
result = _bios_disk(_DISK_READ, &dinfo);
if ((result & 0xff00) == 0)
{
printf("The Partition Codes of Four Partition
Entries are, 0x%02x, 0x%02x, 0x%02x And 0x%02x.\n",
dbuf[450] & 0xff, dbuf[466] & 0xff,
dbuf[482] & 0xff, dbuf[498] & 0xff);
textcolor(15);
gotoxy(5,5);
cprintf("Partition Entry in MBR is as follows:");
gotoxy(10,7);cprintf("1. "); showtype(dbuf[450] & 0xff);
gotoxy(10,8);cprintf("2. "); showtype(dbuf[466] & 0xff);
gotoxy(10,9);cprintf("3. "); showtype(dbuf[482] & 0xff);
gotoxy(10,10);cprintf("4. "); showtype(dbuf[498] & 0xff);
/* Get the Use input to unhide the partition */
gotoxy(1,15);printf("Enter The partition no., Which to
unhide, Or Press any other key to
Exit... ");
tohide=getche();
switch(tohide)
{
/* Unhide first partition of partition table */
case '1':
dbuf[450] = dbuf[450] -16;
result = _bios_disk(_DISK_WRITE, &dinfo);
break;
/* Unhide second partition of partition table */
case '2':
dbuf[466] = dbuf[466]-16;
result = _bios_disk(_DISK_WRITE, &dinfo);
break;
/* Unhide third partition of partition table */
case '3':
dbuf[482] = dbuf[482] -16;
result = _bios_disk(_DISK_WRITE, &dinfo);
break;
/* Unhide fourth partition of partition table */
case '4':
dbuf[498] = dbuf[498]-16;
result = _bios_disk(_DISK_WRITE, &dinfo);
break;
default:
exit(0);
}
if ((result & 0xff00) == 0)
{
printf("\n\nThe New Partition Codes of Four Partition
Entries are, 0x%02x, 0x%02x, 0x%02x And 0x%02x.\n",
dbuf[450] & 0xff, dbuf[466] & 0xff,
dbuf[482] & 0xff, dbuf[498] & 0xff);
getch();
}
else
{
printf("Cannot Change the Byte, status = 0x%02x\n",
result);
getch();
}
}
return 0;
}
Comments on Program
Be careful while giving the partition number to unhide. If the number of partition is entered wrong by mistake, the file system information of that partition will be changed and partition may become inaccessible. However the program previously discussed to hide the partitions, may help you to cure the file system indicator byte of that partition.
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