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From: "Rodney W. Grimes" <rgrimes@GndRsh.aac.dev.com>
Message-Id: <199604240832.BAA04088@GndRsh.aac.dev.com>
Subject: Re: Intelligent Debugging Tools...
To: davidg@Root.COM
Date: Wed, 24 Apr 1996 01:32:35 -0700 (PDT)
Cc: hasty@rah.star-gate.com, scrappy@ki.net, current@FreeBSD.ORG,
        hackers@FreeBSD.ORG
In-Reply-To: <199604240134.SAA02806@Root.COM> from David Greenman at "Apr 23, 96 06:34:47 pm"
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> >5. make sure that one of the drives is sending the termination power
> 
>    For external termination, this is normally done by the controller, not any
> of the drives.

True.

> Most people terminate the last drive with the drive's termination

I would disagree with that, most people use an external terminator on
an external chain.  Turning terminators on inside of external scsi
enclosures is a no no in my book, it often leads to multiple termination
when someone not so informed adds something to a chain.  Or middle
termination with a floating end when a chain gets swapped around.

> and configure that drive to supply it's on termination power
                                          ^^ own
For external scsi chains of any length > 3 feet I would _strongly_ encourage
the use of drive supplied termination power (preferably from the last
drive on the chain) to the scsi bus.  

> (which is usually the factory default).

With the advent of the SCSI PnP spec this and other defaults are rapidly
changing, the SCSI PnP spec requires that drives ship with no termination
enabled, the use of on drive termination is verboten, you are suppose to
use cable end terminators both internally and externally.  I don't seem
to recally anything about term power though :-(.

-- 
Rod Grimes                                      rgrimes@gndrsh.aac.dev.com
Accurate Automation Company                 Reliable computers for FreeBSD