I also was doing a backup to a scsi tape and got the signal 31.

The cause: none of the above. :-)

You (and I) mis-spelled the name of the output file and so were backing up the hard drive to a file in /dev. When it hits the filesystem limit, you get the signal.

In your case, you added a "-" to the filename. In my case, I thought there was a link (named tape) in the /dev directory, and there wasn't.

Yeah, I know this response is later than you wanted, but I put it here so that the next time I do it myself, I'll see my own response.

---dcm