Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!mips!spool.mu.edu!uwm.edu!ogicse!cvedc!gssc!bradd
From: bradd@gssc.UUCP (Brad Davis)
Newsgroups: comp.periphs.scsi
Subject: Re: Maxtor, Wangtek & WD FASST 7000 problem
Message-ID: <6639@gssc.UUCP>
Date: 16 Apr 91 19:03:35 GMT
References: <1991Apr12.150258.26918@qut.edu.au>
Organization: Graphic Software Systems, Inc. Beaverton, Or.
Lines: 44

In article <1991Apr12.150258.26918@qut.edu.au> lemon@qut.edu.au writes:
>The problem is that when a tape is placed in the tape unit the hard drive 
>makes chlunking sounds(well the same sounds it makes at power up, a reset?)
>and also after reading a number of blocks from the tape unit the hard drive
>does the same thing, which results in the software hanging. It also hangs
>when trying to write to the tape unit, the hard drive make the same sounds.
 
>Has anyone any idea as to what may be wrong ?
 
>PS : the SST software reports the correct ID's for the drive's. setup is on
>a 386 20Mhz, AMI bios. CHIPS chipset. 

This sounds something like a problem I'm having with an Adaptec 1540
and SCSI tape drives.  After a little experimentation, I found that it
worked fine on Compaqs and failed in the same way (hanging on reads) on
three out of three Chips & Technologies motherboards.

I believe the problem in my case, and possibly yours, is a bug in the
C&T chipset's DMA circuitry that shorts a couple of address lines together
at a crucial time.  C&T supposedly issued an errata sheet with work arounds,
but apparently all the motherboard OEMs ignored it.

It is also possible for a busmastering adapter to work around this bug,
but apparently Adaptec did not know how or did not realize that they should.
(My company makes a busmastering graphic adapter, and our hardware guys
ran into and solved this problem, so I know it can be done.)

In a couple of days I'll try again when my new Adaptec 1522 arrives.
This card doesn't use busmastering, and I'm hopefull it will clear up
the problem.

-Brad

P.S. I haven't been able to confirm any of the above with Adaptec because
Adaptec won't talk to me ("You're not a distributor.")  Why am I taking a
chance on another Adaptec product when their tech support is so non-existant?
Because after lurking here in comp.periphs.scsi for awhile, I get the
impression their products are perceived as the safest bets.  Go figure.
                                          _________
Random drivel from the keyboard of:      |       |.|
  Brad Davis, GSS Inc, Beaverton OR      | bradd |:|
  bradd@gssc         (503) 671-8431   ___|_______|_|___       _________
Disclaimer: The boss disavows        |[]gssc| _-_  _-_ |    @|#########|
  all knowledge of my actions.       |______|__________|@@@@ +---------+