Date: Wed, 24 Apr 1996 01:45:47 -0700 From: "Amancio Hasty Jr." <hasty@rah.star-gate.com> To: current@FreeBSD.ORG Cc: hackers@FreeBSD.ORG Subject: Re: Intelligent Debugging Tools... Message-ID: <199604240845.BAA00464@rah.star-gate.com> In-Reply-To: Your message of "Wed, 24 Apr 1996 01:32:35 PDT." <199604240832.BAA04088@GndRsh.aac.dev.com>
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I hope that all this useful information about scsi goes into the FreeBSD
Handbook 8)
Cheers,
Amancio
>>> "Rodney W. Grimes" said:
> > >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
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