From owner-freebsd-stable Tue Apr 2 01:21:35 1996 Return-Path: owner-stable Received: (from root@localhost) by freefall.freebsd.org (8.7.3/8.7.3) id BAA25527 for stable-outgoing; Tue, 2 Apr 1996 01:21:35 -0800 (PST) Received: from dilbert.oasysinc.com ([199.165.197.21]) by freefall.freebsd.org (8.7.3/8.7.3) with ESMTP id BAA25512 for ; Tue, 2 Apr 1996 01:21:32 -0800 (PST) Received: from seyma ([199.165.197.181]) by dilbert.oasysinc.com (post.office MTA v1.9.1 **** trial license expired ****) with SMTP id AAA357 for ; Tue, 2 Apr 1996 01:18:15 -0800 Received: by seyma with Microsoft Mail id <01BB2033.F2720440@seyma>; Tue, 2 Apr 1996 01:30:16 -0800 Message-ID: <01BB2033.F2720440@seyma> From: Zeki@Dilbert.Oasysinc.com (Zeki Basbuyuk) To: "'Stable'" Subject: RE: SCSI Performance under -stable/-current Date: Tue, 2 Apr 1996 00:38:28 -0800 MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Sender: owner-stable@Freebsd.org X-Loop: FreeBSD.org Precedence: bulk ---------- From: Tom Samplonius[SMTP:tom@uniserve.com] Sent: Saturday, March 30, 1996 8:27 AM To: Marc G. Fournier Cc: stable@freebsd.org Subject: Re: SCSI Performance under -stable/-current The ncr results should be higher, unless your drives are slow. On a=20 -stable system with a 2940 and a Quantum Fireball, I see over 6MB/sec on = file I/O. How do you get this speed? I thought there is a physical limitation on = how much speed you can get for a hard drive. The calculation is as = follows. 120 rps (revs per sec assuming 7200 rpm drive) X 40 sectors per = track (average or above average) X 512 bps (bytes per sector) =3D 2.4 MB = /sec. To get 6 MB either spt needs to increase to 100 or so or rotation = needs to be increased. Tom