[5718] in linux-scsi channel archive
Re: Adaptec 2940UW controller driver for Linux
daemon@ATHENA.MIT.EDU (doctor@fruitbat.org)
Wed Jan 27 15:52:29 1999
From: doctor@fruitbat.org
To: BOB.allison@qwest.com (Allison Bob)
Date: Wed, 27 Jan 1999 12:05:56 -0800 (PST)
Cc: david.c.hoos.sr@ada95.com, mhuff@colltech.com,
linux-scsi@vger.rutgers.edu
In-Reply-To: <597F8A30943CD21185CC00104BC6BCF67CE0E4@duntx005> from "Allison, Bob" at Jan 27, 99 00:27:09 am
Allison, Bob said ...
>
> AFAIK, the 274x/284x/294x driver in Linux supports all of the 294x family,
> including the 2940U2W (at least, it was recognized on my system).
>
> The 2940U2W uses UltraSCSI signal levels (LVD=Low Voltage Differential).
> Although the documentation indicates that it can drive single-ended as well
> as differential devices, I found that it would not drive my older SCSI-2
> drives. This is because they require a higher signal voltage.
Untrue. The controller has a fall back mode in which it will switch to
SCSI-II signal levels to support non-LVD devices on the U2 bus. However,
mixing LVD and non-LVD on the same bus will reduce the through-put to
SCSI-II levels. I've a mix of devices on the LVD bus and this is the
results I get. Perhaps you didn't have proper termination?
> Unless you have LVD devices, you better stick to the 2940UW for SE devices
> and 2944UW for FWD devices.
Na. The 2940U2W does quite well for either.
--
Peter A. Castro (doctor@fruitbat.org) or (pcastro@us.oracle.com)
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