From owner-freebsd-questions Wed Mar 1 23:06:12 1995 Return-Path: questions-owner Received: (from majordom@localhost) by freefall.cdrom.com (8.6.9/8.6.6) id XAA24702 for questions-outgoing; Wed, 1 Mar 1995 23:06:12 -0800 Received: from gndrsh.aac.dev.com (gndrsh.aac.dev.com [198.145.92.241]) by freefall.cdrom.com (8.6.9/8.6.6) with ESMTP id XAA24487; Wed, 1 Mar 1995 23:04:15 -0800 Received: (from rgrimes@localhost) by gndrsh.aac.dev.com (8.6.8/8.6.6) id XAA13606; Wed, 1 Mar 1995 23:00:12 -0800 From: "Rodney W. Grimes" Message-Id: <199503020700.XAA13606@gndrsh.aac.dev.com> Subject: Re: Questions about support for NCR 53c825???? To: olsenc@ichips.intel.com Date: Wed, 1 Mar 1995 23:00:12 -0800 (PST) Cc: questions@FreeBSD.org, hardware@FreeBSD.org In-Reply-To: <9503020625.AA30072@dtt030.intel.com> from "olsenc@ichips.intel.com" at Mar 1, 95 10:25:31 pm X-Mailer: ELM [version 2.4 PL23] Content-Type: text Content-Length: 1666 Sender: questions-owner@FreeBSD.org Precedence: bulk > > > Hello: > > I posted on the net and got no response on this. Is there > support, or plans for support, for the NCR fast-wide SCSI > II chipset? > > I've read the FAQ, and I saw the generic 810 support. There is already support in the driver for the 53C825 chip: hookturn# dmesg FreeBSD 2.1.0-Development #0: Sun Feb 26 13:00:35 PST 1995 rgrimes@hookturn.aac.dev.com:/usr/src/sys/compile/HOOKTURN ... ncr0 int a irq 11 on pci0:17 reg20: virtual=0xf28fc000 physical=0xf0000000 I currently don't have any wide devices so I can't actually say that it works with wide devices, but it works just fine with fast scsi-ii devices. I am also running the same controller under 2.0R without problems. > Would fast-wide really be necessary? If you are using very fast disk drives wide can be a payoff. Note that drives like the Quantum Empire 2100S are capabile of 5MB/sec transfer rates, so 2 of them on a fast scsi-ii bus pretty much kill the scsi bus. And these are only 5400 RPM drives, now image what happens if you are running a couple of Quantum Grand Prix 4301 7200 RPM drives, these should do close to 6.7MB/sec. For that you would really want to go with a wide controller and wide drives. > Opinions would be very appreciated. If you want top performance the premium for fast wide scsi disks can bring some real benifits. For a single user system it is probably not worth it, but for a server or multiuser system it can be money very well spent. > -Clint -- Rod Grimes rgrimes@gndrsh.aac.dev.com Accurate Automation Company Custom computers for FreeBSD