On Wed, 11 Mar 1998 mvanloon@MindBender.serv.net wrote:

> There has been an on-going discussion in the FreeBSD lists that this is
> a problem with the Seagate firmware incorrectly supporting
> tagged-command-queuing, in conjunction with how the ahc sequencer works.
> Evidently, the problem is reproducible in NetBSD, FreeBSD, and Linux,
> all OS' that use tagged-commands in their SCSI driver with the 2940.
> 
> You might surf the mailing list archives at http://www.freebsd.org/ .

Perhaps I shall - thanks.
> 
> I have had some problems myself.  I "resolved" them by using an older
> drive on my NetBSD machine, and using my DDS-3 drive only on my NT
> boxes.  Not exactly the fix I would prefer, but it allows me to get
> backups for the time being.  Other proposed fixes are to disable
> AHC_TAGENABLE in the kernel, or try a different SCSI controller (such as
> a SymBIOS/NCR 53c8xx-based board).  However it sounds like you tried the
> NCR route without success?

I will add to what I said below : >
We have 3 tape drives at the moment on different machines, each with
different motherboards/CPUs memory etc. We are using NCR controllers too.

Every piece of hardware has been substituted or switched - especially on the
"amon" box. We are also using a Sony DDS3. All behave more or less
the same way: Sooner or later the box requires a cold boot or we can't read or
write to tape... Occasionally the entire bus locks up and NO drives are
accessible, but this has not happened with the 2940 yet. Generally its been
better behaved than the NCR.

> 
> You can also try complaining to tapesupport@seagate.com.
> 
I could but I doubt its a Seagate problem as we get the same results with other
tape drives DDS, DDS2, && DDS3. Archive Pythons whatever...

Im starting to think that tape drives are like cheap modems - they lose their
marbles from time to time and have to be power cycled..

> > -----Original Message-----
> > From:	Gerryt [SMTP:gerryt@portal.ca]
> > Sent:	Wednesday, March 04, 1998 2:33 PM
> > 
> > Arch: i386
> > 
> > We have occasional backup problems with 4 mm DATS. What happens is we
> > see this
> > message:
> > Mar  1 12:56:28 amon /netbsd: st0(ahc1:4:0):  Check Condition on
> > opcode 0x1
> > Mar  1 12:56:28 amon /netbsd:     SENSE KEY:  Unit Attention
> > Mar  1 12:56:28 amon /netbsd:      ASC/ASCQ:  Power On, Reset, or Bus
> > Device
> > Reset Occurred
> > 
> > When you see this message only a cold boot clears up the problem as
> > tapes are
> > no longer accesible.
> > 
> > This is using an Adaptec 2940 UW controller. In the past we have tried
> > changing:
> > 
> > controller NCR to AHA
> > scsi cable
> > DAT drives
> > OS upgrades from 1.2.1 to 1.3
> > 
> > In short everything but the motherboard has been swapped out with
> > different H/W
> > or S/W. Still we see the above message at random times - approximately
> > every
> > 7-14 days. 
> > 
> > Are all scsi tape drives this screwy? Do they work better if we say,
> > give it
> > its OWN controller?
>