incorrect super block

[lee slaughter]

>
>
>
>There is no filesystem support for mounting gzipped tar files as
>filesystems, so you'll have to use it as a raw device.
>     tar -xzf /dev/acd1
>should extract the data.
>
no, i tried it with tar file. it got maybe 20% of way thru with 
unexpected eof.

with tar.gz:
  tar:  /dev/acd1: Cannot read: Input/output error
  tar: At beginning of tape, quitting now
  tar: Error is not recoverable: exiting now

i just want to back up to a cd.