del@fnx.UUCP (Dag Erik Lindberg) (09/26/90)
How can I append files to an archive tape? I am trying to archive
binaries and sources to an Archive 2150S streamer under ISC 2.0.2
The only utility I can find to add a file to the end of a tape is
'tar', and it will only do so if the blocking factor is 1. The
trouble with that is that the tape starts/stops for (apparently)
every block. Besides the phenomenal amount of time it would take
to read to the end of data if the tape already has 100 meg or so
on it, the wear and tear on the drive is far too great. The tape
will (mostly) stream with a high blocking factor, but when giving
the 'append' switch to tar it bombs out unless the blocking factor
is 1.
What I would like is a utility that would seek to end of tape (by
reading it into /dev/null if necessary) at full speed, then append
the new data. I tried to write a program to experiment with this,
but whenever I close the tape device the system freezes (this must
be a bug in the driver, there is no way a common user account should
*ever* be able to kill the system, no matter what they do).
Can anybody help?
--
del AKA Erik Lindberg uunet!pilchuck!fnx!del
Who is John Galt?jik@athena.mit.edu (Jonathan I. Kamens) (09/26/90)
Well, I don't know about the particular architecture you're working on, but under for versions of Unix, most tape-like devices have a corresponding non-rewinding device that doesn't rewind when it's closed (you didn't mention this in your posting, so I don't know whether or not you know about it). For example, one of our machines has an exabyte tape drive hooked up to it as /dev/mt0. The raw device name is /dev/rmt0. And the non-rewinding device is /dev/nrmt0. Last night, I wrote a tape that contained a label at the beginning and then a tar archive. I used: mt -f /dev/rmt0 rewind dd if=/tmp/label of=/dev/nrmt0 tar cvf - [files I was saving] | dd of=/dev/nrmt0 mt -f /dev/rmt0 rewind So, if the device you're using has a corresponding non-rewinding device, you can use that. Hope this helps. -- Jonathan Kamens USnail: MIT Project Athena 11 Ashford Terrace jik@Athena.MIT.EDU Allston, MA 02134 Office: 617-253-8495 Home: 617-782-0710