Verifying a DVD

[Matthias Apitz]

El día Sunday, May 23, 2010 a las 03:23:26PM -0700, Doug Hardie escribió:

> I am periodically backing up a bunch of files to DVD.  I use mkisofs to create the original image and growisofs to write it to a real DVD.  However, at that point I want to verify that the write was successful.  I tried using dd to read back in the DVD to a file.  Its interesting that the bs parameter must be at least 2048 or dd complains about a parameter error.  However, the big issues is that the original image file is shorter than the read file.  The difference is 10240  bytes.  This difference is the same for bs 2048, 10240, or 102400.  It appears that dd is adding one last block.  Is there a way to prevent this or remove that block?_______________________________________________

I think it isn't important how many blocks are on the DVD, but more
important that a) all files area readable on the DVD and b) are MD5
identically with the original on the hard disk. That's why after burning
a tree of files for backup to some DVD I use a combination of 
find+md5+sort+diff to verify the result.

HIH

	matthias
-- 
Matthias Apitz
t +49-89-61308 351 - f +49-89-61308 399 - m +49-170-4527211
e <guru at unixarea.de> - w http://www.unixarea.de/
¡Ya basta! ¡Tropas de OTAN, fuera de Afghanistan!
There's an end of it! NATO troups out of Afghanistan!
Schluss jetzt endlich! NATO raus aus Afghanistan!