On 01/01/2021 16:14, Chris Bell via GLLUG wrote:
Hello Mark
Knoppix appears to show sda as a 2TB disk partitioned using GPT which will
install a GPT partition immediately after the space normally used by the DOS
MBR to provide more space for information about multiple main partitions, not
just the maximum of 4 physical partitions in the old MS-DOS. Most computers
search for the MBR, so it is used to re-direct the BIOS to the GPT partition.
The main boot sequence is then controlled from the GPT partition, and none of
the other partitions will be labelled as bootable.
I often see some unallocated space at either end of the disc space, usually
less than 1 sector, but most of sda appears to be a single partition, possibly
using a swap file instead of a swap partition.
Perhaps the disc was re-partitioned as a GPT disc, which would overwrite the
original MS-DOS system, but then just left not further partitioned or
formatted.
There appears to be more information about sdb and its partitions without
mention of corruption.
If sda is corrupted do not try to alter it. There was a package "photorec"
designed to recover deleted photos which was later enhanced to recover almost
anything and may be re-named "testdisk". It is not a quick and easy recovery,
but can examine, list, recover, and copy as many directories and files as
possible to another formatted disc.
Hi all,
Just an update to this thread.
I found the information posted by Chris above and John Edwards
previously very useful. I also found the web-page
https://help.ubuntu.com/community/DataRecovery helpful. I took my time
to back up the unallocated hard drive in various ways using two 4TB
external hard drives, before using scalpel to obtain the spreadsheet
files I was really interested in (see
https://stackoverflow.com/questions/22542527/recovering-odt-file-using-scalpel
for an example of how to do this). Then I used gparted to restore the
partition table on the actual hard drive itself.
I tried to reboot the hard drive but this failed due, I think, to the
lack of a /boot/EFI. I could see all the files on the various other
partitions though using Knoppix. So, I resorted to trying various Linux
distributions such as Debian, Mint, and eventually Red Hat. All from
various Linux Magazine or Linut Format CDs. The Red Hat CD was useful in
that it appeared to put the EFI file in a 130GB partition that I had
created for a new "home" directory. Nevertheless it still wouldn't boot
for some reason. However, after that I was able to use Linux Mint (which
hadn't worked previously) to get a bootable system. Eventually I was
able to transfer the EFI directory to a much smaller partition, and use
the 130GB partition as a new home partition.
Currently the disk looks like this:
root@mark-H97-HD3:/home/mark# parted -l
Model: ATA ST2000DX001-1CM1 (scsi)
Disk /dev/sda: 2000GB
Sector size (logical/physical): 512B/4096B
Partition Table: msdos
Disk Flags:
Number Start End Size Type File system Flags
2 1049kB 538MB 537MB primary fat32
1 539MB 149GB 149GB extended
8 539MB 12.0GB 11.5GB logical ext4
5 12.0GB 13.0GB 1023MB logical linux-swap(v1)
6 13.0GB 130GB 117GB logical ext4
7 130GB 149GB 18.8GB logical linux-swap(v1) boot
3 149GB 2000GB 1851GB primary ext4
Number 8 is /dev/sda8 the / directory, and number 3 is /dev/sda3 which
is now my "backup" partition and holds all the files that were in my
previous home directory. The /dev/sda6 partition contains the new home
directory. I'm not too sure what number 1 (/dev/sda1) is doing at the
moment. My guess is not a lot, or why the linux-swap(v1) has the boot
label, but at least the system is up and running, and the HMRC basic
tools is also working. Anyway, thank you GLLUG.
--
Regards,
Mark Preston
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