Newsgroups: comp.periphs.scsi, comp.unix.sysv386, comp.sys.ibm.pc.hardware
Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!think.com!unixland!bill
From: bill@unixland.uucp (Bill Heiser)
Subject: (LONG) problem with multiple scsi devices on ESIX machine
Message-ID: <1991Apr13.211855.4730@unixland.uucp>
Follow-Up-To:  comp.periphs.scsi
Organization: The Think_Tank BBS & Public Access Unix
Date: Sat, 13 Apr 91 21:18:55 GMT


This feels like a hardware configuration problem, but I seem to be 
overlooking something ...  My old configuration was as follows:

---on internal connect on Adaptec <----                --> on external connect
CDC Wren IV HD --- Archive Viper Tape --- Adaptec 1542b --- Toshiba MK-156FB HD
  id 1                 id 4                id 7                   id 0

There is a termination at the CDC end and at the Toshiba end.  Everything
worked just fine.


I just got my Maxtor 8760S back from warranty repair, and have added it
as follows:

---on internal connect on Adaptec <----                --> on external connect
CDC Wren HD --- Archive Tape --- Adaptec 1542b --- Toshiba  --- Maxtor
  id 1                 id 4           id 7           id 2        id 0

There is a termination at the CDC end and at the Maxtor end.

I am not able to boot from my Esix floppies with this configuration.
When I do, it gets to the secnd boot disk, then the machine hangs.
There is a little disk activity for a minute after starting to read the
second boot disk, but then nothing.  By removing either the Toshiba or
Maxtor, and adjusting the termination/drive ids appropriately, everything
is fine.    Also, with both drives in place, if I run SCSICNTL v5.5,
it tells me "drive failed to respond to read capacity command" or some
such thing.  The Toshiba is the culprit, it doesn't show up in the 
"select device menu" in SCSICNTL.  Without the Maxtor in place, the
Toshiba responds just fine!  The Maxtor responds either with or without
the Toshiba in place.

By removing a drive a ta time, I was able to format, partition, newfs, etc
eeach drive.  Right now, they are both up and running on the system. 
Obviously, though, there is something wrong.  If I need to boot from floppy,
I have to reconfigure the hardware!  If I want to boot and run SCSICNTL,
again I need to reconfigure the hardware!

One side issue here is that I had a dos floppy infected with the Stone
virus.  (THANKS to all in this conference who alerted me to that as being
the source of the "Your PC is now Stoned" message I was getting)  By booting
with that floppy, I wiped out my Esix boot disk and to re-install
Esix.  Esix is booting just fine, so I guess that is OK now.  The dos
boot disk I use now is CLEAN according to "virx.exe".  In any case, I 
don't see how that would cause the SCSI problem outlined above (would it?)

My first guess was a termination problem - but as shown above, I have
termination at each end of the chain.  I'm a little fuzzy about whether
each of the units should have parity-checking enabled/disabled, and
termination power supplied to drive/bus, etc, ...  I've played with
those a bit, and haven't seen a difference.  Maybe I haven't hit on 
the right combination of configuration parameters???

Thanks very much in advance for advice on how to cure this situation.

Thanks!

Bill

-- 
bill@unixland.uucp                 The Think_Tank BBS & Public Access Unix
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