I've got a physical burnt CD and the original ISO image of it. No reference checksum files were provided for the CD contents. How do I check the actual CD is correct (corresponds to the original image) and fully readable?
First, you rip your CD to a temporary file:
Then you check if
If the size is identical, it's easy:
But I noticed that in certain cases the size can be slightly different because there are trailing zeroes in either the copy or the original image. For example, if
Of course you should also check that the trailing bytes are just zeroes:
The first line, except for the offset, should be zeroes only. The second line should be an asterisk. The asterisk is to avoid showing consecutive identical lines.
If you still have the ISO, you can compare them byte by byte using
Possible outcomes on success:
Possible outcomes on failure:
If the ISO file is the same one used to burn the CD, then here are my two favourites:
Compares the recorded image against the image file. If you feel a bit more masochistic, you could try something like this:
and compare the signatures. This one's more useful if you already have the SHA1 sum somewhere. Both commands will read the medium to the end.
If you want to do it the way @Marki555 suggests, you'll want to mount both optical drive and image first. Here's a complete script: (you can, of course, dispense with the
You can check that CD is fully readable by using
So you can only mount the CD, mount the ISO image and compare it at filesystem level by using some kind of directory comparison tool (sorry, I didn't use any yet on linux).