From: jvd@cbnewsg.cb.att.com (john.a.van dyk)
Subject: PCTOOLS 8.0 SCSI Tape backup problems
Keywords: SCSI tape backup, fatal error, function not supported, quick erase
Organization: AT&T
Distribution: usa
Date: Sun, 3 Jan 1993 17:28:02 GMT

After using PCTOOLS CPBACKUP for about two weeks, and being in touch with
Technical Support, I've found what appears to be a serious problem.

Background info:  Adaptec 1542B, ASPI4DOS Ver 3.1, Wangtek 5150ES tape drive
                  SCSI HD.

Problem:  1)  Fatal errors during backup with "Compress = minimize time"
          2)  Tape Drive not responding (Verify=always - automatic compare)
 
I was using cpbackup, and trying out the various "compress" features, trying
to determine which backup would be the fastest.  I was backing up
approximately 130MB worth of data.  I found that the fastest backup time
was with "compress=minimize time", but the tape was left in an unsafe
state, which is explained below.

The cpbackup settings were:  High speed, verify=always, no data encryption,
                             CPS format, error correction=yes, compress=none,
                             backup and compare two DOS partitions.

"Tape Drive not responding" occurs when the option "verify=always" is used.
When a backup is finished, the tape starts rewinding to the beginning of the
backup set, and the compare software immediately starts up.  After about
20 seconds or so, while the tape is still rewinding, the message
"Tape Drive not responding" pops up, along with "OK" and "abort" buttons
(or something close to that).  If I wait for the tape to finish rewinding,
and then click on "OK", the compare starts up and everything seems to work.


The Fatal error occurs with the following settings:

The cpbackup settings were:  High speed, verify=always, no data encryption,
                             CPS format, error correction=yes,
                             compress=minimize time, backup and compare
                             two DOS partitions.


The backup and compare of the 1st DOS partition completes (with some 
"Tape Drive note responding" messages along the way).  Next, the backup
of the second DOS partition started.  When it was finished, CPBACKUP
started the compare of the second DOS partition.  At this time,
"ERROR: function not supported" appeared, and the only thing I could do was
abort the backup/compare.

After the tape rewound, I was able to manually start a compare of the
second DOS partition, and the compare succeeded.  But when I went to do
a "Quick Erase", which usually takes about 1 minute, I found that the tape
was left in an unsafe state.  The "Quick Erase" took approximately
22 minutes.  It took 19 minutes just to display the backup sets to be erased.
During this time, the tape was rewound/forwarded about 4 complete times,
with some short forward/reverse movements.  Once the backup sets to be
erased were displayed, it took another 3 minutes to erase the tape.

After talking with a person in technical support at Central Point, he
suggested that I set CPBACKUP to "Verify=when formatting" (no automatic
compare), Moderate speed, and add the "/N07" switch
(Bus-on time = 7 microseconds, default = 11) to the ASPI4DOS.SYS
driver for my Adaptec board.

The results of the additional testing were the same.  It seems that if
"compress=minimize-time" is specified, the tape is left in an unsafe state.

All of the other compression options (none, minimize space - moderate,
minimize space - maximum) worked for the most part.

With "Compress=minimize space-moderate", "verify=always", high speed, the
automatic compare of the second DOS partition failed with the following
message "ERROR: Function not supported".  I was able to manually start a 
compare, and the data on the tape was verified OK.  A quick erase took only
1 minute.

Has anybody else had problems like this?

I'm going to try to get in touch with Central Point's technical support
Monday afternoon, and I'll post a follow-up message on what answers/results
I've been able to obtain.


John Van Dyk
jvd@usl.com
Unix System Laboratories, Summit NJ 07901

Newsgroups: comp.periphs.scsi