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Path: ...!eternal-september.org!feeder3.eternal-september.org!news.iecc.com!.POSTED.news.iecc.com!not-for-mail From: John Levine <johnl@taugh.com> Newsgroups: comp.arch Subject: Re: The Seymour Cray Era of Supercomputers Date: Tue, 20 May 2025 19:59:48 -0000 (UTC) Organization: Taughannock Networks Message-ID: <100imvk$26fg$1@gal.iecc.com> References: <100apst$hsll$1@dont-email.me> <20250519165549.000026d1@yahoo.com> <100ggin$1sbnn$2@dont-email.me> <20250520134518.0000531e@yahoo.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Injection-Date: Tue, 20 May 2025 19:59:48 -0000 (UTC) Injection-Info: gal.iecc.com; posting-host="news.iecc.com:2001:470:1f07:1126:0:676f:7373:6970"; logging-data="72176"; mail-complaints-to="abuse@iecc.com" In-Reply-To: <100apst$hsll$1@dont-email.me> <20250519165549.000026d1@yahoo.com> <100ggin$1sbnn$2@dont-email.me> <20250520134518.0000531e@yahoo.com> Cleverness: some X-Newsreader: trn 4.0-test77 (Sep 1, 2010) Originator: johnl@iecc.com (John Levine) Bytes: 3206 Lines: 44 According to Michael S <already5chosen@yahoo.com>: >At time of introduction CDC 6600 was undoubtedly much faster both than >older [more expensive] IBM 7030 and than contemporary [significantly >less expensive] S/360 Model 50. But it was not "orders of magnitude >faster". Not even one order of magnitude faster, except, may be, vs >Model 50 in artificial very memory-light floating-point intensive >scenarios. >High end S/360 (Model 65) came about half a year later. I would imagine >that for non-floating-point code it had about the same speed as 6600. Those 360 models seem wrong. The 360/50 was a midrange machine that shipped in August 1965, the /65 was a large machine that shipped in November 1964, and the 360/75 was a high end machine that shipped in January 1966. They were all announced at the same time, give or take IBM's replacing the paper 60 and 70 with the faster 65 and 75. STRETCH was about 1.2 MIPS, the /50 was 0.133 scientific, 0.169 commercial, the /65 was .563 and .567, and the /75 was .940 and .670, so only the /75 was a plausible replacement. The high end machine was the /91 which shipped late and over budget in Oct 1967 and was much faster, 1.9 MIPS scientific and 1.8 MIPS commercial. (I think the 91's actual commercial performance was much lower since it simulated decimal arithmetic in software, but nobody ran RPG programs on a /91.) For concrete numbers a double precision floating point memory to register add on the /50 took 9.7us, /65 took 2.5us, /75 took .92us Floating multiply was 47us, 7.7us, 4.1us. The numbers for the /91 depended on whether the operands were available but if they were adds were 120ns, multiply 180ns. The 6600 was reported to be three times faster than STRETCH which would have been 3.6 MIPS, a lot faster than any 360 of the time and well over an order of magnitude faster than the not particularly fast 360/50. -- Regards, John Levine, johnl@taugh.com, Primary Perpetrator of "The Internet for Dummies", Please consider the environment before reading this e-mail. https://jl.ly