[comp.unix.sysv386] Tape Backup Problems

stdtm@uokmax.ecn.uoknor.edu (Timothy A. Melton) (01/11/91)

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.  

Thanks in advance,

Tim


-- 
____________________________________________________________________________
Timothy A Melton                             University of Oklahoma
stdtm@uokmax.ecn.uoknor.edu            Department of Chemical Engineering

mschedlb@hawk.ulowell.edu (Martin J. Schedlbauer) (01/13/91)

In article <1991Jan11.034524.21413@uokmax.ecn.uoknor.edu> stdtm@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@ulowell.edu)
Institute for Visualization and Perception Research
Department of Computer Science
University of Lowell, Lowell, MA 01854		(Tel: (508) 934-3612)

john@karnak.cactus.org (John B. Meaders Jr.) (01/14/91)

In article <1701@ulowell.ulowell.edu> mschedlb@hawk.ulowell.edu (Martin J. Schedlbauer) writes:
>
>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:

Nice to see I am not the only person with problems.  I have an Archive
FT-60 that used to work under Esix.  Now it doesn't (I fear a bad controller).
It still reads (I have an old tape) and appears to write.  However, when
you read you get garbage.

>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.

I don't have /dev/rmt/c2s0.  I am using the Archive AT&T Unix drivers as
the Esix Everex drivers don't work properly with the FT-60.
I will check for interrupt bashing, but I am pretty sure that is not
the problem.
-- 
John B. Meaders, Jr.  510 Manchester Ct., Hopewell, VA  23860
Voice:  804-458-2983  Net: john@karnak.cactus.org or john@karnak.sigma.com
Uucp: ...!{sequoia,letni,ditka}!karnak!john        "Cowabunga dude" - TMNT

kdenning@pcserver2.naitc.com (Karl Denninger) (01/16/91)

In article <1991Jan14.052704.23339@karnak.cactus.org> john@karnak.cactus.org (John B. Meaders Jr.) writes:
>In article <1701@ulowell.ulowell.edu> mschedlb@hawk.ulowell.edu (Martin J. Schedlbauer) writes:
>>
>>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:
>
>Nice to see I am not the only person with problems.  I have an Archive
>FT-60 that used to work under Esix.  Now it doesn't (I fear a bad controller).
>It still reads (I have an old tape) and appears to write.  However, when
>you read you get garbage.

This is a REAL common failure mode.  I lost a disk and found my backups were
worthless on this one once.  Fortunately, I was able to recover the data off
the hard disk (another one of my horror stories).

The FT60s have this problem, and it would appear only this problem.  This is
the only failure mode I've EVER seen on that tape drive!

It's actually a controller problem -- get another controller.  The problem
will go away.  Unfortunately, you're hosed on the data you (thought) you
wrote to those tapes -- it isn't there.

Now I verify ALL tapes for readability.

--
Karl Denninger - AC Nielsen, Bannockburn IL (708) 317-3285
kdenning@nis.naitc.com

"The most dangerous command on any computer is the carriage return."
Disclaimer:  The opinions here are solely mine and may or may not reflect
  	     those of the company.

richard@pegasus.com (Richard Foulk) (01/20/91)

>This is a REAL common failure mode.  I lost a disk and found my backups were
>worthless on this one once.  Fortunately, I was able to recover the data off
>the hard disk (another one of my horror stories).


A backup without a verify is not a backup.



-- 
Richard Foulk		richard@pegasus.com