[GLLUG] reading a goofy CD-ROM

[Nathan Thern]

Hi all-
Is there a linux tool that can help me with this problem?

I have an important (to me) CD-ROM filled with pdf files and executables that I burned a couple of
weeks ago. The first few times I accessed it, the files were fine. Now, however, the files in the
root directory show up just fine in a directory listing and the file sizes appear to be right, but
most of the files are corrupted. I looked at a few in binary format and the corrupted files have
data from the end of one file prepended to the beginning of the file and data missing from the
end. Between the truncated end of one file and the data that shows up on the next file are a lot
of missing bits that I can't find anywhere.

In summary, it appears that the info for the root directory of the CD somehow has an offset error
causing it to point to the wrong spot for the beginning of each file. (BTW, the several flavors of
windows that I tried had the same problem with the CD, and solaris was completely unable to mount
it)

Solution possibilities that I can think of are:
1) Read the CD with a utility that can recognize and correct the error
  (the cdparanoia home page said that cdparanoia can correct corrupted data, but after reading the
manual page it seems that only means _audio_ data)

2) dump the entire CD as an image and pick out the bits for each file by hand
  Is there a way to do this with dd or cpio? AND will the data for each file be contiguous?

3) mount the CD with options to correct the offset error
  I couldn't find anything in the mount man page, but it did refer to separate executables that
mount certain devices.

any help would be much appreciated

Nate Thern


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