[lug] proper way to MD5SUM a cdrom?

[David Anselmi]

Paul E Condon wrote:
>>>On Sat, Jun 12, 2004 at 06:39:41PM +0000, D. Stimits wrote:
>>>
>>>>Just a question on verifying CD-R's. I have the ISO, and have run md5sum 
>>>>on it, it looks good. Then I burn it with cdrecord. How do I verify the 

You can do md5sum /dev/cdrom (or whatever the right device is).

> Suggestion: Don't do an MD5SUM check. Instead, read the whole CD with:
> dd if=/dev/scd8 of=cpybak
> and then use 
> cmp cpybak original.iso
> to check byte by byte the copy against the original

Why do you say that?  Hmm, probably cmp is faster than md5sum but:

cmp original.iso /dev/cdrom

should be faster than recopying the CD, don't you think?

I once was copying CDs in a duplicating machine and then comparing them 
(with diff, but same idea as cmp).  Interestingly all the copies were 
identical (and good, as far as I could tell) but differed from the 
original.  Perhaps the duplicator changed some metadata.

Dave