When doing a level 0 backup, the script does a quick erase of
the tape, then does the retension, then does the backup. When
doing an incremental backup, it seeks to the end of recorded
medium, then does the backup. The script works with the
no-rewind device, /dev/nsa0.
The script always used to fail with EINVAL attempting to run a
quick erase, ``mt erase 0''. After a bit of experimenting, it
turned out that `erase' only works if I rewind the tape (either
through by using the rewind device, or by running the `rewind'
or `retension' commands in advance).
Here is my question. Is this always the case that MTERASE only
works with a rewinded tape, or is this device-dependent? If the
former, what would be an appropriate way to document it? (I am
reluctant to find myself where this EINVAL is coming from, and
there is a plenty of them under sys/cam/.)
Ruslan Ermilov Sysadmin and DBA,
ru...@sunbay.com Sunbay Software AG,
ru...@FreeBSD.org FreeBSD committer,
+380.652.512.251 Simferopol, Ukraine