As the title says...

Self = fool, fool, fool
I was going to restore a CompactFlash drive image.

Was supposed to be writing to /dev/sda
Accidentally wrote to /dev/hda :: oops ::
Quickly hit Ctrl-C, but damage was already done.

MBR = gone
Partition table = gone
Windows partition = corrupt
Linux partition = up, running, fine... self-destruct on next reboot
Data = all backed up, ready to reboot

So, essentially... I could reboot and reinstall.
But can anyone recommend a way to determine
which partition table layout I booted with, and write this layout
back onto the drive?

Heh.
Had one idea:

Might the output of /proc/partitions... match my partition table's "state before disaster"?

:: goes to compare ::

maybe a program called " testdisk " can help you here. i heard it's good for repair.....
( google for it )

EDIT: i don't know , but if the partition-table is in the mbr (?) : there might be a file "/boot/boot.0300 " wich in fact is a copy of your mbr-before-storing-lilo-there.

egag

You should have a backup of the mbr at /boot/boot.0300

dd if=/boot/boot.0300 of=/dev/hda bs=1 count=512 skip=446 seek=446

then run lilo again to put lilo back on the mbr.

Explanation:
bs=1 <- 1 byte at a time
count=512 <- mbr=512 bytes
skip=446 <- first 446 bytes of boot.0300 are bootstrap code.
seek=446 <- that skips to the partition table.

NOTE: If you made any changes to your partition table since boot.0300 file was created then they will be lost. This could cause data loss if you don't know how to recreate the partition table exactly as before.

EDIT: i need new glasses

egag

Use TestDisk from www.cgsecurity.org. It should work.

If you recreate your partitions exactly as they were before, you should be fine. I've done this myself, but the partitioning scheme needs to be exact. In other words, the partition sizes as well as the partition order must be identical to how it was before.

To illustrate, if you had defined:

/dev/hda1 = 128Mg /boot
/dev/hda2 = 256Mg swap
/dev/hda3 = 6G /usr
/dev/hda5 = 6G /var
/dev/hda6 = 10G /
/dev/hda7 = (everything else) /home

then if you recreate those partitions in the same order, you should be OK. Good luck with it -- J.W.

try like /bin/bash says

as alternative try gpart (find it with google, it should be in the first list)

There is a HOWTO called "Partition-Rescue" that might be just the ticket. On my Slack system, it's located in /usr/doc/Linux-HOWTOs

Thank you for your kind recommendations.
In the end... I didn't run out of tools... but time.

I first looked at my output of "/proc/partitions", but found some oddities.
Did not dare to use -- copied into another machine (just in case).
Then I tried "gpart", but presence of extended partitions confused it.
It could not determine the original partition table layout.
Testdisk arrived at the same result.

Perhaps part of the problem was... that the data which overwrote
my partition table... was not random trash, but contained another parition table,
originating from a CompactFlash card.

In the end... I set the corrupted disk aside for analysis
(later extracted some source code from the Windows partition)
and started installing things onto a new disk (faster too).
Since everything I stored under Linux (read: most things)
were successfully evacuated, I obtained a working system reasonably fast
(and a new kernel too).

So things are... nearly back to normal.
And there's a CD-ROM on my bookshelf.
With double backups of my current partition table.