is there an fsck for .iso disk images?

Question

I have an iso file on a hard drive that's been having problems. Is there any way to check that the file didn't get corrupted, like an fsck for iso file systems?

score 9 · Accepted Answer · answered Nov 07 '11 at 11:36

I've got an isovfy utility. From the man page:

isovfy is a utility to verify the integrity of an iso9660 image. Most of the tests in isovfy were
added  after  bugs  were discovered in early versions of mkisofs. It isn't all that clear how useful
this is anymore, but it doesn't hurt to have this around.

Maybe that will help?

score 3 · Answer 2 · answered Nov 07 '11 at 11:42

The usual way to check an .ISO image is an MD5 checksum, depending on where it came from. If it was downloaded, most sites have the MD5 available to compare against. You run md5 or md5sum against what you downloaded and compare the results and if it is different, there's corruption.

This entirely depends on where you got the .ISO file, though, and the availability of the MD5 checksum "known good" versus the one you have. Or if you have file integrity checkers (part of intruder detection) they should know if something changed in a file. Again, depends on how you had things set up.

If you have good backups, compare your first version of the ISO's MD5 with the current MD5 to see if things changed.

score 0 · Answer 3 · answered Nov 07 '11 at 11:43

0

My understanding of the High Sierra filesystem might be rusty by now but if you can list the files in there then.. that's it. There is nothing really to verify aside from the list of files. If blocks in there went bad, there's no checksum in the image. The really powerful Reed-Solomon error correction codes are only used on the CD not in the High Sierra FS.

answered Nov 07 '11 at 11:43

chx

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HSF was the predecessor to ISO-9660 prior to 1986... It was only used between '84 and '86, succeeding the Yellow Book Data format... – Chris S Nov 07 '11 at 13:58
AFAIK Yellow Book described how things are layed down on a CD but the file system is still HS. – chx Nov 07 '11 at 18:45

score -1 · Answer 4 · answered Nov 07 '11 at 14:58

I know this doesn't really answer the question, but here are some additional options:

If you want to see if files can still be extracted from the iso, WinRAR or a similar app can be used to extract the files and you could compare them to your source or see if they function properly. Also, I think WinRAR will alert you if the iso file is damaged.

You could also mount the iso with DaemonTools to access the files.

is there an fsck for .iso disk images?

4 Answers4