Date: Tue, 9 Sep 1997 22:51:23 +0000 (GMT) From: Terry Lambert <tlambert@primenet.com> To: se@freebsd.org (Stefan Esser) Cc: tlambert@primenet.com, mal@algonet.se, current@freebsd.org Subject: Re: lousy disk perf. under cpu load (was IDE vs SCSI) Message-ID: <199709092251.PAA02002@usr02.primenet.com> In-Reply-To: <19970909225733.44758@mi.uni-koeln.de> from "Stefan Esser" at Sep 9, 97 10:57:33 pm
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> 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.
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