[wellylug] Creating data CD's accurately.

Nigel Walters nigel.walters at ihug.co.nz
Thu Aug 7 17:45:31 NZST 2003


Richard,

Tried this readcd gave the same results as dd. They both produce the
saMe MD5 checksum, which of course is not the same as the original image
MD5 checksum

Thanks
Nigel 


On Wed, 2003-08-06 at 20:20, Richard Hector wrote:
> On Thu, Aug 07, 2003 at 01:16:14AM +1200, Nigel Walters wrote:
> > Hi,
> > 
> > I download iso images and then check the MD5 checksum. So far so good.
> > Then I burn the image to CD using the following command
> > 
> > cdrecord -v dev-0,0,0 image.iso
> > 
> > I attempt to verify that the image is correct by reading the image back.
> > 
> > dd if=/dev/scd0 of=newimage.iso
> > 
> > I always get an error on the readback but newimage.iso seems
> > functionally ok.
> > 
> > Unfortunately when I perform the md5sum on the final image it is
> > incorrect.
> 
> I've heard that dd sometimes doesn't do everything right when reading a CD.
> 
> In particular, I think it reads past the end, or something like that - so
> the image might work OK, but the md5sum doesn't match.
> 
> I think the preferred way to read cds is with readcd - comes with cdrecord
> AFAIK, so you should have it (I do - not that I've used it yet).
> 
> Let us know how it goes.
> 
> Richard
-- 
Nigel Walters <nigel.walters at ihug.co.nz>




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