Md5sums and burning CDs

[Gary W. Swearingen]

Gabriel M Dragffy <dragffy at yandex.ru> writes:

> I can find out the MD5 of the .iso by doing md5sum foo.iso
> But finding out the MD5 of a written CD by doing,
> md5sum /media/dvdrecorder/*  gives me differing results.

There's a bit extra on the ISO CD (at the end) than in the ISO file.
Here's some script to figure amount of /dev/cdrom to check.

blockbytes=2048  ## Block size of ISO CDs. Nothing else will work (esp, in dd command).
filebytes=$(stat -f "%z" "${FILENAME}")
fileblocks=$(( ${filebytes} / ${blockbytes} ))
if [ $(( ${fileblocks} * ${blockbytes} )) != ${filebytes} ]; then
    echo "ERROR: '${FILENAME}' is not a multiple of the CD blocksize, ${blockbytes}. Nothing done."
    exit 3
fi

Add some "dd",etc.  BTW, IIRC, using "diff" should be better than
md5sum, if you've already checked the md5sum of the file.