Date: Fri, 19 Sep 1997 20:45:49 +0200 (MET DST) From: Wilko Bulte <wilko@yedi.iaf.nl> To: Don.Lewis@tsc.tdk.com (Don Lewis) Cc: mjacob@feral.com, Don.Lewis@tsc.tdk.com, freebsd-hardware@FreeBSD.ORG, freebsd-scsi@FreeBSD.ORG Subject: Re: Warning! Sun archaeology [was Re: Is my NCR controller broken?] Message-ID: <199709191845.UAA03014@yedi.iaf.nl> In-Reply-To: <199709190125.SAA00739@salsa.gv.tsc.tdk.com> from "Don Lewis" at Sep 18, 97 06:25:48 pm
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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
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