problem with partition manager

[NO2]

i was previously using ubuntu x64 and windows xp
i tried pcbsd which removed my c drive(windows).
i used the live cd and formatted sda1 to fat32.
i had sda8 as ext3 and sda9 as swap but ihad to change their sizes so sda8 became swap and sda9 ext3.
i installed xp again to sda1.
i used the live cd, but now the partition manager was showing my hard disk as unallocated, showing no partitions at all.
what could be the problem?

[Partyboi2]

Can you boot the live cd and open a terminal (Applications>Accessoires>Terminal) and post the output to

sudo fdisk -l

[caljohnsmith]

Often when the partition editor shows your entire drive as unallocated, that's a sign that the HDD's partition table is corrupt. In order to check, please post the output of:

sudo fdisk -lu
sudo sfdisk -d
Be sure to include the "u" option with fdisk so I can see the start/stop points as sectors, not cylinders.

[NO2]

ubuntu@ubuntu:~$ su
Password:
root@ubuntu:/home/ubuntu# fdisk -l
omitting empty partition (5)

Disk /dev/sda: 80.0 GB, 80026361856 bytes
255 heads, 63 sectors/track, 9729 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x8f800000

Device Boot Start End Blocks Id System
/dev/sda1 * 1 1244 9992398+ b W95 FAT32
/dev/sda2 1245 9728 68147730 f W95 Ext'd (LBA)
/dev/sda3 2551 5100 20482843+ b W95 FAT32
/dev/sda5 1245 1505 2096419+ 82 Linux swap / Solaris
/dev/sda6 1506 2550 8393931 83 Linux
/dev/sda7 5101 7650 20482843+ b W95 FAT32
/dev/sda8 7651 9728 16691503+ b W95 FAT32
root@ubuntu:/home/ubuntu# fdisk -lu
omitting empty partition (5)

Disk /dev/sda: 80.0 GB, 80026361856 bytes
255 heads, 63 sectors/track, 9729 cylinders, total 156301488 sectors
Units = sectors of 1 * 512 = 512 bytes
Disk identifier: 0x8f800000

Device Boot Start End Blocks Id System
/dev/sda1 * 63 19984859 9992398+ b W95 FAT32
/dev/sda2 19984860 156280319 68147730 f W95 Ext'd (LBA)
/dev/sda3 40965813 81931499 20482843+ b W95 FAT32
/dev/sda5 19984986 24177824 2096419+ 82 Linux swap / Solaris
/dev/sda6 24177888 40965749 8393931 83 Linux
/dev/sda7 81931563 122897249 20482843+ b W95 FAT32
/dev/sda8 122897313 156280319 16691503+ b W95 FAT32
root@ubuntu:/home/ubuntu# sfdisk -d
# partition table of /dev/sda
unit: sectors

/dev/sda1 : start= 63, size= 19984797, Id= b, bootable
/dev/sda2 : start= 19984860, size=136295460, Id= f
/dev/sda3 : start= 40965813, size= 40965687, Id= b
/dev/sda4 : start= 0, size= 0, Id= 0
/dev/sda5 : start= 19984986, size= 4192839, Id=82
/dev/sda6 : start= 24177888, size= 16787862, Id=83
/dev/sda7 : start= 81931563, size= 40965687, Id= b
/dev/sda8 : start=122897313, size= 33383007, Id= b

[caljohnsmith]

root@ubuntu:/home/ubuntu# fdisk -lu
omitting empty partition (5)

Disk /dev/sda: 80.0 GB, 80026361856 bytes
255 heads, 63 sectors/track, 9729 cylinders, total 156301488 sectors
Units = sectors of 1 * 512 = 512 bytes
Disk identifier: 0x8f800000

Device Boot Start End Blocks Id System
/dev/sda1 * 63 19984859 9992398+ b W95 FAT32
/dev/sda2 19984860 156280319 68147730 f W95 Ext'd (LBA)
/dev/sda3 40965813 81931499 20482843+ b W95 FAT32
/dev/sda5 19984986 24177824 2096419+ 82 Linux swap / Solaris
/dev/sda6 24177888 40965749 8393931 83 Linux
/dev/sda7 81931563 122897249 20482843+ b W95 FAT32
/dev/sda8 122897313 156280319 16691503+ b W95 FAT32


Unfortunately your partition table is corrupt; right now your sda3 primary partition is inside of your sda2 extended partition, so sda3 should be a logical partition instead. Fortunately it doesn't look like the problem will be difficult to correct, so how about first downloading the attached "partition_table.txt" file to your Ubuntu desktop, and then do:

sudo sfdisk --no-reread -f /dev/sda -O ~/Desktop/sda_sectors_modified.save < ~/Desktop/partition_table.txt
And please post the output. The above command will create a backup of the few sectors being modified as a small "sda_sectors_modified.save" file on your desktop, so if for some reason anything were to go wrong, we can easily restore your original partition table with that file. Therefore, be sure to copy that file to a different drive, or you could for instance save it to your email account or something like that. In case anyone is interested, for convenience here is the contents of the partition_table.txt file:

# partition table of /dev/sda
unit: sectors

/dev/sda1 : start= 63, size= 19984797, Id= b, bootable
/dev/sda2 : start= 19984860, size=136295460, Id= f
/dev/sda3 : start= 0, size= 0, Id= 0
/dev/sda4 : start= 0, size= 0, Id= 0
/dev/sda5 : start= 19984986, size= 4192839, Id=82
/dev/sda6 : start= 24177888, size= 16787862, Id=83
/dev/sda7 : start= 40965813, size= 40965687, Id= b
/dev/sda8 : start= 81931563, size= 40965687, Id= b
/dev/sda9 : start=122897313, size= 33383007, Id= b

So basically all I did was move primary partition sda3 so it will become logical partition sda7, and then delete sda3 by zeroing all its fields. Fortunately all the logical partitions have free sectors between them where the EBRs (Extended Boot Records) can reside, so it is not necessary to resize any of the partitions to accommodate the partition change. Next reboot, and please post the new output of:

sudo fdisk -lu
sudo sfdisk -d
sudo parted /dev/sda print
And we can work from there.

[NO2]

gparted is detecting the partitions now.
Thank You very much caljohnsmith.

[caljohnsmith]

Glad that worked OK; cheers and have fun with Ubuntu.