Tape Backup Problems (cpio read errors)

[Martin J. Schedlbauer]

In article <1991Jan11.034524.21413 at uokmax.ecn.uoknor.edu> stdtm at uokmax.ecn.uoknor.edu (Timothy A. Melton) writes:
>I have just installed a Wangtech QIC-60 Tape drive and controller on my
>ESIX rev. D system.  The drive seems to work fine under DOS, but when I
>use cpio (or /usr/bin/backup) to write a tape and then read it back in, I
>get numerous "Out of sync.  Searching for magic number/header" messages.
>What could be the problem?  I believe that the drive and controller are
>fine (they seem to work great under DOS).  Why am I getting these errors?
>Am I losing files for each error?  I have recovered the last file from a
>backup tape, but I was wondering if I might be losing other files on the
>tape.  Sorry if this has been hashed over before, but I haven't seen an FAQ
>posting in the last month or 2.  
>

Finally somebody who also has that problem!! You can still make backups
but use /dev/rmt/c2s0 instead of /dev/rmt/c0s0. The problem may be caused
by several factors:

1. You have another device that uses the same IRQ as teh tape controller.

2. If you have a VGA card disable it's use of the IRQ2 for EGA compatibilty.

3. You motherboards DMA chip is hosed, most likely it can't handle more
than one open DMA channel at one time.

You can still read ALL tapes with the fast /dev/rmt/c0s0, but you should
write them only with /dev/rmt/c2s0. I also recomment using GNU tar and
cpio, but be sure you rename GNU cpio to soemthing likegnu-cpio as 
installpkg will barf otherwise.

	...Martin

Martin Schedlbauer				(mschedlb at ulowell.edu)
Institute for Visualization and Perception Research
Department of Computer Science
University of Lowell, Lowell, MA 01854		(Tel: (508) 934-3612)