From owner-freebsd-current Tue Sep 9 15:53:04 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.7/8.8.7) id PAA12675 for current-outgoing; Tue, 9 Sep 1997 15:53:04 -0700 (PDT) Received: from usr02.primenet.com (tlambert@usr02.primenet.com [206.165.6.202]) by hub.freebsd.org (8.8.7/8.8.7) with ESMTP id PAA12555; Tue, 9 Sep 1997 15:51:23 -0700 (PDT) Received: (from tlambert@localhost) by usr02.primenet.com (8.8.5/8.8.5) id PAA02002; Tue, 9 Sep 1997 15:51:24 -0700 (MST) From: Terry Lambert Message-Id: <199709092251.PAA02002@usr02.primenet.com> Subject: Re: lousy disk perf. under cpu load (was IDE vs SCSI) To: se@freebsd.org (Stefan Esser) Date: Tue, 9 Sep 1997 22:51:23 +0000 (GMT) Cc: tlambert@primenet.com, mal@algonet.se, current@freebsd.org In-Reply-To: <19970909225733.44758@mi.uni-koeln.de> from "Stefan Esser" at Sep 9, 97 10:57:33 pm X-Mailer: ELM [version 2.4 PL23] Content-Type: text Sender: owner-freebsd-current@freebsd.org X-Loop: FreeBSD.org Precedence: bulk > Ahemm, the NCR driver was the first SCSI driver in FreeBSD > that handled tagged commands, back in, well, it existed in > the driver kit for FreeBSD-1.1.x as of spring 1994 ... But FAILSAFE is on in GENERIC. > Ahemm, you are sure you got a 53c810b ??? > Those were never built, AFAIK ;-) You're right. It's a rev 2. It was the "first, B, III" units mixup you see on situation comedies... 8-). > > I have gotten fabulous perforamnce figures on my NCR 53c810b under > > 3.0, but I've been using a 7200 RPM 9G IBM SCSI drive there lately, > > and a Quantum simply would not stack up to that (5.5ms avg access). > > Hmmm, you must have performed the tests on a file system, > that covered only a small fraction of the disk. Random > seeks will then cover only a small range of cylinders, and > in the case of a file system in the outer area, 1GB of 9GB > may restrict seeks to 1/15 to 1/20 of the tracks (because > of the larger capacity of outer tracks) ... I don't think so. But I could be wrong. It was a month ago... Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers.