On Sun, Mar 25, 2007 at 11:48:57AM +0100, Paul Smith wrote: > On 3/25/07, Charles Curley <charlescurley@xxxxxxxxxxxxxxxxx> wrote: > >> I am getting the errors below when I execute the command > >To answer your other email, you can validate a freshly minted DVD > >similarly. > > Thanks, Charles. Yes, it was the error regarding dd that was causing > the md5sums mismatch (reported in the other post of mine). However, > the method that you suggest works fine, and my problem is solved. The > command dd is not very reliable, indeed. The dd command is quite reliable. It does exactly what you tell it to do, not what you think you told it to do. Had you given it a count of sectors to read (calculated to match exactly the size of the ISO), it would have read only those sectors. E.g.: dd bs= count= if=/dev/dvd of=dvd1.iso The CD burning software pads the ISO with blank data to round its size up to a multiple of sectors. (I'm not sure why; perhaps someone more familiar with CDs can explain this.) So what you got back was larger than the original ISO. So of course the MD5 sums were different. However, giving dd an exact count of sectors would not have helped. Apparently CD burning software also mucks with a field in the CD header as it burns the CD/DVD. So I would say that dd is quite reliable, it just wasn't appropriate for what you wanted to do. -- Charles Curley /"\ ASCII Ribbon Campaign Looking for fine software \ / Respect for open standards and/or writing? X No HTML/RTF in email http://www.charlescurley.com / \ No M$ Word docs in email Key fingerprint = CE5C 6645 A45A 64E4 94C0 809C FFF6 4C48 4ECD DFDB
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