Paul Eggert wrote:
>
> > Date: Wed, 23 May 2001 18:15:08 -0700 (PDT)
> > From: Dave Dittrich <[EMAIL PROTECTED]>
>
> > > I'm not sure, though, that dd is the right place for this; perhaps it
> > > would be better to have a separate tool? dd tends to suffer from the
> > > kitchen-sink problem. Maybe it's better to put this into md5sum
> > > instead?
> >
> > md5sum just reads stdin and checksums it. It doesn't have any of the
> > other features of dd, like byte swapping, alternate output blocking
> > for efficiently filling streaming media buffers, etc.
>
> But if you add one simple options to md5sum to control the location of
> the checksum output, and to make a copy to standard output, you can
> get all the above. For example, you could do the following:
>
> dd if=/big/input/device ibs=whatever |
> md5sum -C checksum.txt |
> dd of=/big/output/device obs=whatever
>
> where '-C FOO' means "put a copy of the checksums in FOO and output a
> copy of the input to standard output".
I think you snipped out and are not addressing the
essential point of his method which a gave a checksum
on every byte so that one bad byte could not invalidate an
entire hard drive.
I don't know where you get your md5sum. I have
the latest GNU textutils installed and that
md5sum --version == 2.0.13
and I don't have and -C filename.txt option.
I think your example would compute only one checksum,
but I can't check, so why not tell us, hmmmm?
Regards,
Matthew
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