"Cannot find file system superblock" error - how to recover?

[Sergey 'DoubleF' Zaharchenko]

On Tue, 6 Jan 2004 13:29:26 +1030
Malcolm Kay <malcolm.kay at internode.on.net> probably wrote:

> On Tue, 6 Jan 2004 10:59, Scott I. Remick wrote:
> > Sorry for the delay... holidays had me busy.

Me too:)

> > Hopefully you're still around
> > and interested in picking up where we left off. I think we're definitely
> > onto something...
> >
> 
> Looking back over some of your e-mails I find:
> QUOTE
> su-2.05b# disklabel -r /dev/ad6s1c
> # /dev/ad6s1c:
> 8 partitions:
> #        size   offset    fstype   [fsize bsize bps/cpg]
>   c: 156344517       63    unused        0     0         # "raw" part, don't
> edit
>   e: 156344517       63    4.2BSD     2048 16384    89
> partition c: partition extends past end of unit
> disklabel: partition c doesn't start at 0!
> disklabel: An incorrect partition c may cause problems for standard system
> utilities
> partition e: partition extends past end of unit
> 
> That doesn't look good.
> ENDQUOTE
> 
> The 63 offset is spurious. I've seen this before somewhere but can't
> remember the details -- i.e the value 63.

I know where you've seen this. The normal offset for the first *slice*
is 63 sectors, for some historical reasons (those extra sectors were to
be used for bad block replacement or something like that).

Not sure how the 63 made it into the disklabel, though.

> I wonder whether editing the label and setting both offsets to 0
> might solve the problem.

It definitely seems like that, as the actual offset of the partition is
0, as dd shows.

> You could always make a copy of the existing label 
> and put it back if the changes don't help.
> 
> You could in addition check the size for the partitions against the size given by 
> fdisk for the slice.
> 
> Malcolm Kay
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> 


-- 
DoubleF
Never settle with words what you can accomplish with a flame thrower.
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