From owner-freebsd-hardware  Fri Sep 19 11:58:35 1997
Return-Path: <owner-freebsd-hardware>
Received: (from root@localhost)
          by hub.freebsd.org (8.8.7/8.8.7) id LAA01060
          for hardware-outgoing; Fri, 19 Sep 1997 11:58:35 -0700 (PDT)
Received: from iafnl.es.iaf.nl (uucp@iafnl.es.iaf.nl [195.108.17.20])
          by hub.freebsd.org (8.8.7/8.8.7) with SMTP id LAA01039;
          Fri, 19 Sep 1997 11:58:26 -0700 (PDT)
Received: by iafnl.es.iaf.nl with UUCP id AA07459
  (5.67b/IDA-1.5); Fri, 19 Sep 1997 20:59:38 +0200
Received: (from wilko@localhost) by yedi.iaf.nl (8.8.5/8.6.12) id UAA03014; Fri, 19 Sep 1997 20:45:49 +0200 (MET DST)
From: Wilko Bulte <wilko@yedi.iaf.nl>
Message-Id: <199709191845.UAA03014@yedi.iaf.nl>
Subject: Re: Warning! Sun archaeology [was Re: Is my NCR controller broken?]
To: Don.Lewis@tsc.tdk.com (Don Lewis)
Date: Fri, 19 Sep 1997 20:45:49 +0200 (MET DST)
Cc: mjacob@feral.com, Don.Lewis@tsc.tdk.com, freebsd-hardware@FreeBSD.ORG,
        freebsd-scsi@FreeBSD.ORG
In-Reply-To: <199709190125.SAA00739@salsa.gv.tsc.tdk.com> from "Don Lewis" at Sep 18, 97 06:25:48 pm
X-Organisation: Private FreeBSD site - Arnhem, The Netherlands
X-Pgp-Info: PGP public key at 'finger wilko@freefall.freebsd.org'
X-Mailer: ELM [version 2.4 PL24 ME8a]
Mime-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: owner-freebsd-hardware@FreeBSD.ORG
X-Loop: FreeBSD.org
Precedence: bulk

As Don Lewis wrote...
> 
> On Sep 18,  5:25pm, Matthew Jacob wrote:
> } Subject: Re: Is my NCR controller broken?
> } >(this stuff predates SCSI 1)
> } 
> } Wrong.
> 
> I may have misremembered on this point.
> 
> } > I believe the some Sun 3's actually
> } 
> } Wrong. It was actually the sun 4/110.
> 
> Looks like we're both right.  I was unaware that the 4/110 was
> similarly afflicted.  From my sun-managers archives:
> 
>   First, I was reminded about something which, while not directly impacting
>   my situation, is well worth repeating. This is the infamous design
>   decision(?) by Sun to ground the "termination power" SCSI pin on the 3/60
>   and 4/110 models, which means that a straight-through cable from either of
>   these models to a SCSI drive with termination power supplied tends to blow
>   the drive up! So while it's safe to plug an ex sun-3 drive onto a new
>   system, plugging a new drive onto a 3/60 is potentially a problem! It's ok
>   if you disable "termination power" on the drive, or cut the appropriate pin
>   of the SCSI cable.

The Sun thing is definitely a hardware bug. But drives should not die a
smoking death 'cause the TERMPOWER line should always be current-limited
(fused) of 1.5  amps per the ANSI SCSI standard. In addition a low-drop
(Schottky) diode is normally used to avoid powering switched-off devices
thru the SCSI bus.

Wilko
_     ____________________________________________________________________
 |   / o / /  _  Bulte  email: wilko@yedi.iaf.nl http://www.tcja.nl/~wilko
 |/|/ / / /( (_) Arnhem, The Netherlands - Do, or do not. There is no 'try'
----------------------------------------------------------------------Yoda