Fwd: Re: Please help. Can't see HD
malcolm.kay at internode.on.net
Sun Dec 28 20:27:19 PST 2003
On Mon, 29 Dec 2003 14:39, Francisco Reyes wrote:
> On Mon, 29 Dec 2003 14:27:01 +1030, Malcolm Kay wrote:
> >This is likely your problem source!!!
> >/dev/rad[n] is an alias of /dev/ad[n]; that is it refers to IDE drive n.
> >(Historically they had somewhat different meanings but even then still
> >refered to the same physical device -- the 'r' means raw)
> >If n was 2 you have over written the beginning of ad2.
> Well I guess the good news is that the HD is probably ok then.
Yes; should be.
> In FAT I seem to recall there are two copies of the boot sector.
> Does FreeBSD has anything like that?
I seem to recall some options or utilities under MS-DOS that did
something like that, but think this was mainly for floppies.
Certainly there are duplicate copies of the FAT allocation tables,
but these are next to one another on the disk so don't really protect
against this sort of calamity.
I guess the nearest thing in FreeBSD is mutiple copies of the
superblocks within the file system, but unless you can reconstruct
the slice table(partition in MS terms) I don't believe it will help.
> If what I did trashed the first sectors would that have affected
> all mount points?
How big was the image you copied to the disk? -- that should tell
you how much of your drive is overwritten.
It is probable your disklabel has also disappeared, so you
probably need to reconstruct both the slice table in the MBR and
the disklabel in the first slice. With some vague recollections of
what you did originally to install FBSD it is possible that some
lucky guesses might work.
If you can find the first sector of a slice carrying an installed file
system then this might hold a copy of the slice table allowing
reconstruction of the original MBR with some confidence.
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