Brasero Or: How I Learned To Stop Burning Coasters And Love K3B

Thursday, February 12, 2009

Whenever I burn a CD from an ISO, I md5sum the CD to confirm the data was written correctly. Using the beauty of Linux, I can md5sum the cdrom device directly using "md5sum /dev/cdrom".

One day I was trying to burn OpenSolaris 2008.11 to check out the awesomeness of ZFS. After I burned the disk using Brasero, I tried to md5sum it. I was greeted with a rather strange error: "md5sum: /dev/cdrom: Input/output error". Input/output error? Is my drive going bad? I presumed it was the media. I put in another CD of the same brand and tried again. Nope. The batch of media was pretty old, so I decided to try another brand/batch. Maybe it's my drive? Five coasters later...

At this point I'm starting to think this is a software issue. Was there an update in 8.10 that made this not work? No, it worked on other disks. Googling, I came to this page at BigAdmin which describes the symptoms perfectly.

As it turns out, Brasero was burning the ISO using track-at-once. The problem with this is, as quoted from BigAdmin:

"the last block may be confused with the lead out area, and some drives will not read it properly. Thus your MD5 checksums will fail. You can pad the last blocks using the -pad option of cdrecord, but your checksums still might not match as you have added additional data to the CD that was not present in the original ISO image."

The solution? Make sure to set the record mode to disc-at-once (session-at-once may also work) in your CD burning software. I simply could not find this setting in Brasero, so I installed K3B and found it easily under "Writing Mode". Lesson learned.

Has this ever happened to you? Leave a comment!

Posted by Craig Younkins at 9:08 PM  

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