Re: Trashed partition table
On Fri, 08 Nov 2002 20:49:07 +0100, Michael Naumann
<mnaumann@giga-stream.de> wrote:
>08.11.2002 18:01:57, Jorge Santos <jsf@ciencias.unam.mx> wrote:
>
>>Hello,
>>
>>I installed some other OS and id overworte the MBR, to make a long
>>story short, I booted with ethe second woody disc and went for the
>>rescue option at which point I was surprised to find out that fsck
>>claimed one of the partitions had a bad superblock (it had an ext3 fs,
>>and the kernel was 2.2.x, but I was under the impression that it would
>>just mount it as an ext2 fs, so I don't think that was the problem),
>>no problem, just a few hundred megs of mp3s there so I went on to run
>>grub-install, but it didn't find stage2, so i made some floppies with
>>grub-floppy and booted with that, they didn't work, to make another
>>long story short, I booted into the install system and in a console I
>>found that fdisk stated this about my partition table:
>>
>>Device Boot Start End Blocks Id System
>>/dev/hda1 ? 20682 154408 1074152739 0 Empty
>>
>>Partition 1 does not end on cylinder boundary:
>>phys(637, 190, 61) should be (637, 254, 63)
>>
>>
>>So I gather the partition table is trashed. So for my question:
>>
>>Is there any way to fix this mess?
>>
>>TIA
>>
>>Jorge Santos
>
>I vaguely remember, there is a tool that guesses the partition table.
>I've never had the need to use it, so I don't know exactly.
>
>As a last resort, you can use
>cfdisk -z
>Which starts on an empty partition table.
>
>Your problem sounds more like you've changed something in the settings for your disk.
>I can imagine that something alike happens if you switch from head/sector/cylinder to LBA
>or vice versa. I'd be surprised if the other OS is the reason.
>
>Michael
I think the numbers would be more different than 637/190/61 and
637/254/63 if this was a CHS/LBA screwup. Windoze does attack the MBR
during installation and has been known to trash it.
A DOS boot floppy with Norton Utilities on it will get you working
(slowly). If someone else can post details of what "signature data"
you'd expect to find at the start of an ext3fs partition, cos I don't
know, you can scan the disk with NU until you find it, then
recalculate the partition table by hand. Tedious but probably worth
it.
NU can also scan the disk looking for what it thinks are different
partitions, but I don't think it recognises other than DOS ones.
Generally, don't let it repair anything automatically. In particular,
don't run Norton Disk Doctor, which will convert a dodgy but
recoverable HD into a totally trashed one.
Pigeon
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