Date: Sat, 06 Sep 1997 23:58:22 -0700 (PDT) From: Simon Shapiro <Shimon@i-Connect.Net> To: dyson@FreeBSD.ORG Cc: current@FreeBSD.ORG, mal@algonet.se, sos@sos.freebsd.dk, (Michael L. VanLoon -- HeadCandy.com) <michaelv@MindBender.serv.net> Subject: Re: lousy disk perf. under cpu load (was IDE vs SCSI) Message-ID: <XFMail.970906235822.Shimon@i-Connect.Net> In-Reply-To: <199709070512.AAA00465@dyson.iquest.net>
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Hi "John S. Dyson"; On 07-Sep-97 you wrote: What you are all running into is the fact that, for a smoothly run system, you need a certain balance between I/O, memory (capacity & bandwidth, both), and CPU. If you compare a 14" disk pack from the mid-seventies (SMDE) to a disk drive of today, you see that capacity climbed nicely (about 30x), performance has barely moved (I am NOT talking about 5MB Shugart 5.25"!), being that a good SMDE drive could do about 5MB/sec or even better, while CPU's jumped almost 300x! Now many of you have machines with more processing power (cached loops) than any old machine, but memory bandwidth sucks and disk I/O is pittyful. Some of us make a nice living stretching what disks can do, but they are about the speed of a good paper-tape punch on an IBM 360. Much slower than a card reader (in relative terms). BTW, the architecture (in realizable terms) of the typical disk controller has not changed at all since the IBM-PC, and even the best caching SCSI controller is primitive when compared to a 1963 IBM mainframe, and not much faster. The young ones amoung you, I have a challenge for you (old folks like me can think no more :-): Don't bellyache about disk performance. It will just get worst (at 50%/year, last I checked). Come up with a new I/O ARCHITECTURE. Totally new. The first one to come up with a truely random storage device with capacity of 1GB and performance of (sustained) 100MB/Sec will make more money than BG thought exists. Be good and prosper! --- Sincerely Yours, (Sent on 06-Sep-97, 23:35:32 by XF-Mail) Simon Shapiro Atlas Telecom Senior Architect 14355 SW Allen Blvd., Suite 130 Beaverton OR 97005 Shimon@i-Connect.Net Voice: 503.643.5559, Emergency: 503.799.2313
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