Re: input/output error on hd

On Sat, Feb 24, 2007 at 06:12:39PM +1100, Ian Smith wrote:

On Fri, 23 Feb 2007, Jerry McAllister wrote:

Jerry, just on a couple of points:

Me to Marty:
> > Does the above result mean that my boot sector is ok?
>
> I think maybe you might be getting some of your terminology shuffled
> around. Your boot sector is not at question here. It doesn't
> affect the ability to read the disk partition.

I was talking about sector 0 on ad1. If the disk were bootable it would
be the 'boot sector', but it's not bootable. It still contains the DOS
partition table though. boot0cfg -v <drive> shows this info too.

OK. Yes, he already worked on the sector 0 earlier.
The DOS partition table is what is called the slice table in FreeBSD.
That seems to be OK - as I noted.

////jerry


> Secondly, it looks like the slice table - which is what fdisk mucks
> with - is OK.

Luckily .. though with only one slice on the disk, easily recreatable.

> What seems to be messed up is either the slice 1 label which contains
> the partition table. In fact, with one of your postings, it looked
> like it thinks it is slice 4, but I don't remember what you did to
> get that.

Try 'fdisk ad0sY' where Y is any freebsd slice, and you'll get that (or
at least, I do on both my ad0 freebsd slices). Maybe fdisk should barf
or at least whinge rather than reporting the first sector of any slice
specified as if it were a sector 0 / MBR / boot sector?

Probably should barf or make some other error message. Anyway, one
shouldn't run fdisk on a slice, but on the device, so that accounts for
the weird message I suppose.

////jerry


> If none of this helps at all, then the problem is past the label and
> in to the filesystem structure itself. Then I think you are stuck with
> tracing superblocks as I pointed out before. That is going to take some
> study but it might work.

Yep, it depends on how precious this data is, but no learning is wasted.

Cheers, Ian

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