There seems to be a small amount of software available for recovering data from tape.
I need to recover compressed UNIX data from DDS2 and would like to know if anyone can recommend some competent software for this.
It would have to be able to handle a variety of formats - client doesn't know what was originally used to back up to tape.

I am no expert in data recovery and I have no idea if such a tool ( a swiss army knife kind of thing) exists, but I played with this kind of tapes in the past while UNIX system administrator. In UNIX you have all kinds of tools and in general every tool does only one thing and tries to do it well.
dd is a standard UNIX command that can read a bit stream and copy it anywhere you want it to be. It can also do some conversions. Lately I came accross a similar tool called dd_rescue (check the GNU web site).

Once the data is copied from the tape, you can try to guess the format of it (tar, dump, proprietary, etc) and if it is compressed or not (Compress, gzip, bzip2, lzh, etc). In general, 'file' command would tell you what it is. If you need a hex editor, hexdump (or even emacs) is there for you.

In general you can end up with one single shell command, something like:
zcat <filename> | tar tvf -
to inspect the data.

Thanks, iraklion

I finally managed a solution using either Unix or Linux, plus the Macintosh and sometimes also the PC.