I was wondering if anyone has a definitive answer as to why my md5sum never matches after I burn to disk. I use md5sum /Dev/sr0 and get a different value than the iso I burned it from. I relive checking the iso is what matters and that is fine but it annoys me the Burned disk is different. I have read that burning programs add empty space to the end sometimes and this can make the md5 value different but the weird thing is I tried brasero and then k3b and they produced disks with equal values to each other but still different from the original iso. Also both k3b and brasero were set to verify image and it successfully passed those tests. Any ideas. It's a rewritable DVD and I did a full blanking no quick both times.

Use 'cmp' to compare the iso to the burned image, it should say EOF on the iso. You are right that the burned disk is padded with zeros at the end, and this alters the md5sum.

Thanks for the response. I did read about using cmp somewhere but it seemed a little odd the way it was done as it used ls -ltr *.iso to get the length then the next command was length=<length> and finally cmp was used with with a variable $length somehow and involved a block size=512 along with dd utility or something I forget exacat syntax. Didn't work for me though because the $length/512 gave me an error in bash.
Are you saying just use it like this: cmp /dev/sr0 /path/to/*.iso
Because wouldn't that include those zeros also for /dev/sr0
I guess I could try cmp with the -n switch and the size from ls-l *.iso for the argument. Is that right?

Just run “cmp file.iso /dev/sr0” already… You are making things overly complicated.