Path: news.eternal-september.org!eternal-september.org!feeder3.eternal-september.org!i2pn.org!i2pn2.org!.POSTED!not-for-mail From: mitchalsup@aol.com (MitchAlsup1) Newsgroups: comp.arch Subject: Re: The Seymour Cray Era of Supercomputers Date: Mon, 26 May 2025 18:01:56 +0000 Organization: Rocksolid Light Message-ID: References: <100apst$hsll$1@dont-email.me> <20250518113330.00003889@yahoo.com> <5e2ce293484d3e69e84c6d84d687a271@www.novabbs.org> <20250519163537.00005e7c@yahoo.com> <8fcf1025f7684b064397b7b444e3b1d6@www.novabbs.org> <101260d$23dmo$1@dont-email.me> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Info: i2pn2.org; logging-data="2035460"; mail-complaints-to="usenet@i2pn2.org"; posting-account="o5SwNDfMfYu6Mv4wwLiW6e/jbA93UAdzFodw5PEa6eU"; User-Agent: Rocksolid Light X-Rslight-Site: $2y$10$fICwjpyiFWG8iJCJmryYTOb8au28iyoYHhhKGxQVjxOim9oPv482q X-Rslight-Posting-User: cb29269328a20fe5719ed6a1c397e21f651bda71 X-Spam-Checker-Version: SpamAssassin 4.0.0 On Mon, 26 May 2025 16:48:13 +0000, Brian G. Lucas wrote: > On 5/19/25 2:14 PM, MitchAlsup1 wrote: >> On Mon, 19 May 2025 13:35:37 +0000, Michael S wrote: >> >>> On Sun, 18 May 2025 22:01:19 +0000 >>> mitchalsup@aol.com (MitchAlsup1) wrote: >>> >>>> On Sun, 18 May 2025 8:33:30 +0000, Michael S wrote: >>>> >>>>> On Sat, 17 May 2025 21:27:04 +0000 >>>>> mitchalsup@aol.com (MitchAlsup1) wrote: >>>>> >>>>>> Did the book relate the story of why CRAY-1 presented a DC-load to >>>>>> the power supply:: that is, the ECL gates were all of the form >>>>>> where they would switch 20 ma into either the true or the >>>>>> complement out- put and thus have no AC energy at the power supply >>>>>> level ?? >>>>>> >>>>>> During the CDC 7600 reign, when performing vector calculations, >>>>>> (even though CDC 7600 was not a vector machine, it could stream >>>>>> calculations through its execution window at impressive rates); >>>>>> Certain data bit-patterns in CDC 7600 would cause more Gnd bounce >>>>>> and Vdd drop than the gates cols accommodate and the machine would >>>>>> take a data-dependent hard crash. >>>>>> >>>>> >>>>> Which voltage, current and frequency are we talking about? >>>> >>>> Vdd and Gnd which fed the integrated logic gates. >>>> >>> >>> My question was about absolute numbers. Volts, amperes, nanoseconds. >> >> CDC 6600 was built with (effectively) RTL logic using individual parts >> {transistors, resistors, capacitors, ...} well documented in "design >> of a computer" Thornton. >> >> CDC 7600 was built with some kind of integrated circuits, but not >> TTL or ECL. I don't remember which (its been too long). >> > Could it have been DTL (Diode-Transistor-Logic). Candidates:: RTL, DTL, CML > In 1966 I worked > on an aerospace computer implemented with DTL, in flatpacks made > by Westinghouse (could that be?). The computer was interesting > in that it had sine and cosine instructions (implemented by the > cordic algorithm). > > Brian > > >>> >>>>> >>>>>> So, Cray got rid of the problem by presenting a DC-load to the >>>>>> power supply.