[3388] in linux-scsi channel archive
Re: CD-ROM resets SCSI bus on Buslogic BT-958
daemon@ATHENA.MIT.EDU (Jeff Collins)
Mon Feb 23 13:58:38 1998
Date: Mon, 23 Feb 1998 10:37:01 -0800 (PST)
From: Jeff Collins <collinsj@ece.ucdavis.edu>
To: Brendan Miller <brmiller@wco.com>
cc: linux-scsi@vger.rutgers.edu
In-Reply-To: <19980222181410.52486@wco.com>
On Sun, 22 Feb 1998, Brendan Miller wrote:
> Okay, can anyone give me a clue about what might cause this? I get
> SCSI bus resets whenever I read the CDROM, and apparantly, there
> is some kind of CDROM read error. I have tried this with different
> CDROMs, and while it doesn't happen while trying to read *every* file,
> it will always happen if I try something like:
<snip>
> # ID:0 Vendor: SEAGATE Model: ST31230N Rev: 0170
> # ID:1 Vendor: QUANTUM Model: XP34550W Rev: LXY4
> # ID:2 Vendor: HP Model: C3725S Rev: 6039
> # ID:4 Vendor: TOSHIBA Model: CD-ROM XM-5701TA Rev: 0167
> # ID:5 Vendor: IOMEGA Model: ZIP 100 Rev: D.09
>
> The Quantum is the only wide device, is connected to the 68pin header on
> the Buslogic, and is terminated. All the other drives are connected to
> the internal 50pin header in this order: CD-ROM, Seagate, HP, ZIP.
> Termination is only on the ZIP.
I was having somewhat similar problems when I attempted to add a CDROM
burner and a SCSI tape drive to my system (a Buslogic 946 w/ 2 SCSI
disks). My problem turned out to be that I had been using passive
termination on one end of the bus. With only the 3 existing devices, I
didn't notice any problems. However, on trying to extend the bus, things
must have gotten out of spec and I started getting command timeouts and
the like. So, is your narrow bus passively (with resistors) or actively
(by jumpering to "enable termination") terminated? --jw
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
Jeff Collins, collinsj@ece.ucdavis.edu, Computer Engineering Research Lab
Electrical and Computer Engineering, The University of California, Davis
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