SCSI Woes.
2007-12-25 11:35:00
Many thanks to all who responded! Your names precede your replies below.
-fp
========================================================================
THE QUERY
The system is an upgraded Sparc IPC, with a Cycle-5 motherboard. The
'uname -a' output is: 'SunOS admin 5.4 generic sun4m sparc'.
The tape drives are nothing special; on a different machine, where I was
able to run 'mt status' on them, this is how they identified themselves:
Exabyte EXB-8200 8mm tape drive
Archive Python 4mm Helical Scan tape drive
Symptoms range from being unable to boot at all, to getting messages
during the boot about how the transfer speed of the internal hard disk
was lowered.
========================================================================
THE RESPONSES
........................................................................
From: tkevans@eplrx7.es.dupont.com (Tim Evans)
I presume you've checked all the SCSI target ID's and don't have any
conflicts. CD players are normally target 6, while tapes are usually
4 and/or 5. You also need to do 'boot -r' to get the system to look
for new devices.
........................................................................
From: Wis Macomson <wis@sequent.com>
I suspect termination problems, but maybe cabling:
A) is the terminator at the end of the SCSI bus?
B) does/do the tape drive/s have internal termination that
must be disabled if they are not the last one on the bus?
there may be a jumper or switch to deal with this.
C) my favorite: crappy cables. I spent hours trying to get
a tape drive working, only to find that with a decent cable
there were no problems.
You might try running with just a tape drive (i.e., no CD ROM).
'tar -cvf' a 5 or 10MB file, then rewind and 'tar -tvf' to convince
yourself that it actually works.
........................................................................
From: bismark@alta.jpl.nasa.gov (Bismark Espinoza)
The 8mm drive and the 4mm drive seem to be
old scsi-1, 3.2 MB/s. The sparc 5 probably has a FAST
scsi-2 interface, 10MB/s. Your scsi master will negotiate
the lowest speed of your old devices.
You may have to disable tagged-command queuing and/or
synchronous transfers.
........................................................................
From: "Alfredo Sola" <asola@intelideas.com>
Sounds like a cable/termination problem. Did you double check that
you have an ACTIVE termination? There are situations in the SCSI buses
where they can work with a little thing out of specs, but begin to do weird
things when you push them. You must have an active termination at the end
of the bus and no termination on the remainder (this may seem obvious, but
my experience says that a lot of hours might be lost just because of
forgetting about a very basic thing)
........................................................................
From: DAN MCHUGH <MCHUGHD@osstf.on.ca>
SCSI Woes can be a direct result of termination and cable quality. If you
had a working External CD ROM before, I would target SCSI cable or
Termination. I saw from this list you get better termination on the scsi
chain if you use a active terminator at the end of the chain. This makes
ultimate sense. It's expensive but you have probably spent that much
money trying to figure it out what the problem is. If your not using
Sun/HP/Adaptec SCSI cables I'd suggest cutting open one of the new
cables you have added into the chain to determine that:
1) There must be a foil wrap that goes completely around all the wires.
2) There must be braided wire around all the wires.
3) The wires should be twisted in pairs of two.
If one of these items is not true buy new cables. A proper cable should
cost about $70 dollars canadian. US and other places I'm not sure about.
After cutting the cable you will not be able to use it. If the cables works
with just one SCSI device in the chain it is not enough to say the cable is
good enough to be used with two or more devices.
........................................................................
From: Brad Young <bbyoung@amoco.com>
Check cabling and termination. Make certain that cabling does not exceed 5
meters total length. Check that your tape drives do not have internal
terminators if you are using an external terminator ( You _are_ using an
external terminator, aren't you?..). Use an active or a SLICK external
terminator.
........................................................................
From: Kent Clarstroem <kent@syd.dimension.se>
I think you are suffering from no or poor termination. Get an active
terminator.
........................................................................
From: blymn@awadi.com.au (Brett Lymn)
What speed cycle board do you have? I had all sorts of problems with
a 125MHz board, the supplier told me to diddle some switches to change
the speed of the clock down to 120MHz the board worked fine.
........................................................................
From: "Ken Picard" <Ken.Picard@ska.com>
Answer can vary from long SCSI cables, to a bad connector. I have
similar intermitten problems with my 8mm tape drive. on my IPC.
........................................................................
From: Richard Cooper <rich@desdbx.com>
It sounds like you have a buss length problem. Although the SCSI spec says
single-ended SCSI will go 6 meters (18 feet), don't believe it!!! The 6
meter limit only applies to 5 MB transfer rate. What you are seeing is the
driver lowering the transfer rate until reliable SCSI communication is
possible. If you assume a maximum length of ten feet for the SCSI from
terminator to terminator, you'll be better off. Don't forget to allow for
ribbon cable length inside cdrom and tape enclosures.
........................................................................
From: James.E.Coby.Jr@cdc.com (James Coby)
You probably have checked these things but a couple things
come to mind with the addition of the tapes.
1. Check the cable pins themselves. I have seen strange problems
on scsi busses when the small scsi2 connectors such as the
python had bent pins. The connector will still snap on and
hook.
2. Is there any chance the scsi ID of the cdrom and tapes are the same?
3. Check you are not exceeding the cable length of approx 12-15 ft
total.
4. Is it possible that all 3 devices have terminators on them
internally?
........................................................................
From: hxktb0@nfs1.supervalu.com (Kris Briscoe)
Do you have conflicting target address's? Also, remember that speed on a chain
is limited to the slowest device on the chain.
========================================================================
ARCHIVED SUMMARIES
My original post said I had no luck digging in the archives at
http://www.latech.edu/sunman.html; wrong! A slower and more careful dig
turned up over a dozen items on similar topics. Here are the headings,
for those of you who want to read them.
Subject: SUMMARY: SCSI reconnect/reset error
From: beattie@poincare.mskcc.org (Bradley Beattie)
Date: Wed, 3 May 95 10:23:24 EDT
Subject: SUMMARY: SCSI sync/async operation
From: "Dr. D.C. Williams" <dcwill@ee.unr.edu>
Date: Tue, 7 Mar 1995 23:05:00 -0800 (PST)
Subject: SUMMARY: SCSI terminators: What's the diff?
From: daniel@sar3.CANR.Hydro.Qc.CA (Daniel Hurtubise)
Date: Thu, 9 Mar 1995 10:28:55 -0500
Subject: SUMMARY: SCSI TERMINATRS and TIMEOUT ERRORS
From: Paul Woods <woodsp@smtplink.indigo.co.il>
Date: Sat, 13 May 95 01:23:07 IST
Subject: SUMMARY: SCSI errors
From: Veselin Terzic <terzic@deneb.mda.ca>
Date: Tue, 14 Feb 1995 17:53:56 -0800
Subject: SUMMARY Command Tag Queuing
From: Luis Vallejo <vallejo@osg.emc.com>
Date: Wed, 15 Mar 1995 07:53:57 -0500
Subject: SUMMARY: set scsi_options=0x3f8 in /etc/system
From: Anchi Zhang <anchi@starbase.neosoft.com>
Date: Tue, 15 Nov 1994 09:55:23 -0600 (CST)
Subject: Summary: SCSI transport "reset" errors
From: art@infinity.com (Art Hebert)
Date: Tue, 18 Jul 95 14:48:32 PDT
Subject: SUMMARY: SS5 SCSI-Problems with IBM 0663-E12 Disks
From: zdv123@zam092.zam.KFA-Juelich.de (V.Sander)
Date: Thu, 20 Apr 1995 08:57:48 +0200
Subject: SUMMARY: question: solaris 2.4 scsi problems
From: michaelm@citenet.net (Michael Moscovitch)
Date: Thu, 20 Jul 1995 11:59:08 -0400 (EDT)
Subject: SUMMARY: SCSI transport failed
From: gianolio@sunvlsi.cern.ch (Elena Gianolio)
Date: Mon, 21 Aug 95 11:32:35 +0200
Subject: SUMMARY: Disk Drive Problems with 4.1.4 and 2.4. (LONG)
From: murff@nicimg.com (Jim Murff)
Date: Fri, 23 Jun 95 18:01:35 PDT
Subject: SUMMARY: SCSI Drive reports: "incomplete write- retrying"!
From: Lawrence Houston <houston@felix.geog.mcgill.ca>
Date: Sat, 24 Jun 1995 15:35:00 -0400 (EDT)
Subject: SUMMARY - SCSI Bus Errors
From: Ralph Howard <rahjr@orca.tpsinc.com>
Date: Fri, 25 Nov 1994 14:18:16 -0500
Subject: SUMMARY:SCSI hang
From: rashad@ii.uni.wroc.pl (Rashad Al-Yawir)
Date: Tue, 28 Mar 1995 08:40:30 --100
Subject: SUMMARY: scsi errors on 9.0Gb drive
From: Travis <tehoyt01@msuacad.morehead-st.edu>
Date: Fri, 30 Jun 95 12:46:20 EDT
========================================================================
--
Frank Pardo <fpardo@tisny.com>
The scholar's ink outlasts the martyr's blood. -- Irish proverb
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