Suggestions for Raw Tape Reading Under Linux?

From: "William von Hagen" <vonhagen(a)vonhagen.org> Hi. I've been trying to read in a variety of old backup cartridge tapes as raw data so that I can write some tools to parse them (or port the old backup software used to write them). This seems to be the easiest way to explore old backup data from a variety of old machines without having to fire up the machines themselves. Since I'm trying to do this from a Unix (Linux) box, 'dd' was the obvious first choice, but I don't know things like the block size at which the tapes were originally written. Ideally, I'd just like to read raw data from the media, period. I've tried reading the tapes using 'dd' with a variety of block sizes, but still get zero-length input files. The drives I'm using to read the data are capabable of the densities at which they were written, and I understand the Unix/Linux device numbers - you can hear that the drives are working at the correct density, but I'm still not getting data. I even wrote a little program to just read data directly from the raw device, but don't seem to be getting anything there either.The drives whir and whine, but I get nada. Any suggestions? Any utilities you'd suggest rather than 'dd'? Many of these are non-Unix systems, so 'tar' and 'cpio' aren't appropriate. Thanks! Bill