Date: Mon, 13 Dec 1999 00:08:38 -0700 From: "Kenneth D. Merry" <ken@kdm.org> To: Martin Welk <mw@theatre.sax.de> Cc: John <papalia@UDel.Edu>, mw@sax.de, David Bein <bein@pyramid.com>, freebsd-questions@FreeBSD.ORG Subject: Re: Adaptec/SCSI question ... Message-ID: <19991213000837.A26497@panzer.kdm.org> In-Reply-To: <19991213010953.I59717@theatre.sax.de>; from mw@theatre.sax.de on Mon, Dec 13, 1999 at 01:09:54AM %2B0100 References: <19991212234352.B59717@theatre.sax.de> <Pine.SOL.4.05.9912121836490.12806-100000@copland.udel.edu> <19991213010953.I59717@theatre.sax.de>
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On Mon, Dec 13, 1999 at 01:09:54AM +0100, Martin Welk wrote: > On Sun, Dec 12, 1999 at 06:39:05PM -0500, John wrote: > > > If I'm understanding what you're saying though, the AHA2930U2W and the > > AHA2940U2W now allow you to support devices off of all connectors, as > > opposed to needing to keep a linear configuration? Just want to make sure > > I'm understanding fully. > > That is what that AIC3660 SCSI bridge chip is doing. I don't know if the > AHA2940U2W has this chip on board, sorry, but the AHA2930U2W has it and > so I would expect it to do that job as this bridge does it on the P2B-S > motherboard. But to be true, I haven't read any ``genuine Adaptec > documentation'' promising that neither have I tried it yet. But as my > collegue said, it is possible to connect devices to each connector > (50 pin internal, 68 pin LVD internal, external ``high density'' > connector) and to use them parallel. I don't know about termination, > in the P2B-S based box all individual three SCSI chains have proper > termination at the one end and the rest is done by the motherboard. > > Neither I have checked the cable specifications - I don't know if each SCSI > chain can be seen as one individual SCSI chain with specification depending > on it's type or if there is something special. The 2940U2W includes a AIC-3860 bridge chip. The bridge chip, as well as allowing you to run at Ultra2 and non-Ultra2 speeds on the same bus, also makes it possible for you to use all the connectors on the board at the same time. By isolating the two segments of the bus, the bridge chip essentially gives you two linear configurations on the same logical SCSI bus. Adaptec's technical specs: http://www.adaptec.com/products/datasheets/aha2940u2w.html provide a reasonable description of what the card can do. Ken -- Kenneth Merry ken@kdm.org To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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