From owner-freebsd-questions Wed Jun 12 09:36:37 1996 Return-Path: owner-questions Received: (from root@localhost) by freefall.freebsd.org (8.7.5/8.7.3) id JAA15597 for questions-outgoing; Wed, 12 Jun 1996 09:36:37 -0700 (PDT) Received: from ns2.clever.net (root@[207.15.222.252]) by freefall.freebsd.org (8.7.5/8.7.3) with ESMTP id JAA15588 for ; Wed, 12 Jun 1996 09:36:32 -0700 (PDT) Received: from localhost (root@localhost) by ns2.clever.net (8.7.3/8.6.9) with SMTP id MAA02297; Wed, 12 Jun 1996 12:43:53 -0400 (EDT) Date: Wed, 12 Jun 1996 12:43:52 -0400 (EDT) From: Sam Brown To: "Jacob M. Parnas" cc: Bob Loftus , "Aaron D. Gifford" , freebsd-questions@freebsd.org, bsdi-users@BSDI.COM Subject: Re: Adaptec2940UW vs. BusLogicBT-958 (opinions?) In-Reply-To: <199606121235.IAA12473@jparnas.cybercom.net> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-questions@freebsd.org X-Loop: FreeBSD.org Precedence: bulk I've yet to quite understand why with all the problems induced with one large scsi-bus You would want wide/fast. Consider: The NCR PCI SCSI (ncr53C810) costs $45/qty 1, this is not a symbios clone, but a real ncr chip. We usually start with two , one per spindle, and the io transfers are multiplexed more than the ability of the same two drives on one card. Most noticable during fscheck's during boot. Also a scsi-bus hang, if one ever occurs, doesn't kill the primary drive either. I can't imagine why one would go out of the way to spend a ton of more money on a non-raid controller running wide/ultra. When you still have the weak link of the single controller card and single scsi-cable to impede your reliability. On Wed, 12 Jun 1996, Jacob M. Parnas wrote: > > In message you write: > >I believe that Paul Vixie has expounded quite masterfully on this topic > >in the past, check the bsdi-users archive @ nexial.nl as I recall it > >doesn't really matter, and you can't possibly keep the scsi bus busy > >enough to warrant it. "Wide SCSI is just for those suffering from > >spec-envy." "Wide SCSI has lovely marketing, I guess. Everybody wants it, > >nobody needs it." -- Paul Vixie > >Have fun... > > Would you please elaborate a bit on the logic? I don't see why with up to > 15 devices, you couldn't fill up 40MB/sec for a fast/wide/ultra SCSI III bus? > Especially with some raids counting as one large SCSI device? > > Trying to understand, Jacob >