Path: csiph.com!news.mixmin.net!eternal-september.org!reader01.eternal-september.org!.POSTED!not-for-mail From: Anne & Lynn Wheeler Newsgroups: alt.folklore.computers Subject: Re: TOPS-20 Boot Camp for VMS Users 05-Mar-2022 Date: Sun, 25 Dec 2022 09:12:31 -1000 Organization: Wheeler&Wheeler Lines: 53 Message-ID: <87wn6fs3fk.fsf@localhost> References: <5H6UJ.233887$Rza5.134368@fx47.iad> <1480498945.668113352.883426.peter_flass-yahoo.com@news.eternal-september.org> <87fsnxl8dt.fsf@nightsong.com> <1585529182.668284324.850327.peter_flass-yahoo.com@news.eternal-september.org> <871qopg8qi.fsf@localhost> <20221223214212.a86c268e81b03fd2dd00430e@eircom.net> <80deqhlgr5kccskhpqo5rqfqqrc2j18ptm@4ax.com> MIME-Version: 1.0 Content-Type: text/plain Injection-Info: reader01.eternal-september.org; posting-host="371d055dc63f07fb66ea95d87635f7ad"; logging-data="3017811"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1+T27YhtAXR1XFL/jwY9+m67oDLSqIIhLQ=" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.1 (gnu/linux) Cancel-Lock: sha1:9x4aCmokUkkJhnIGXHXKpbZuS+E= sha1:KjzXGXFVnr6Jcptbk+cOMWtTJ+A= Xref: csiph.com alt.folklore.computers:223266 D.J. writes: > The Cray YMP-2 had a non-conductive fluid that flowed across the > circuit boards, then out to a head exchanger. IBM water cooled machines had flow sensor on inboard fluid side but not on outboard side of heat exchanger ... and a customer machine outboard side lost water flow ... by the time the thermal sensor registered temperature was increasing (and shutoff power) ... it was too late and circuits fried. All heat exchangers were then retrofitted with flow sensor on the outboard side. as periodically mentioned, during Future System project (in first half of 70s), 370 projects were being shutdown (FS was going to completely replace 370s and completely different). When FS imploded there was mad rush to get stuff back into the 370 product pipelines, including kicking off quick&dirty 3033 & 3081 in parallel. http://www.jfsowa.com/computer/memo125.htm The 370 emulator minus the FS microcode was eventually sold in 1980 as as the IBM 3081. The ratio of the amount of circuitry in the 3081 to its performance was significantly worse than other IBM systems of the time; its price/performance ratio wasn't quite so bad because IBM had to cut the price to be competitive. The major competition at the time was from Amdahl Systems -- a company founded by Gene Amdahl, who left IBM shortly before the FS project began, when his plans for the Advanced Computer System (ACS) were killed. The Amdahl machine was indeed superior to the 3081 in price/performance and spectaculary superior in terms of performance compared to the amount of circuitry.] ... snip ... the enormous number of circuits for 3081 helped motivate TCMs ... to pack them in reasonable sized physical volume https://www.ibm.com/ibm/history/exhibits/vintage/vintage_4506VV2137.html ... note above marketing respinning the enormous number of circuits, also the increased heat density significantly exacerbated sensitivity to loss of cooling. Note initial 3081D was two processor claiming 5mips/processor (although several benchmarks were slower than 4.5mips 3033). IBM then doubled the cache size for 3081K claiming 7mips/processor (aka from improved cache hit rate, with some of those benchmarks now equivalent to 4.5mips 3033 or slightly better, see previous post increasingly machine throughput was becoming increasingly sensitive to cache miss and wating on memory) ... or two processor aggregate of 14mips claimed. By comparison, the single processor Amdahl benchmarked at around 13mips. shutdown of ACS/360 https://people.cs.clemson.edu/~mark/acs_end.html -- virtualization experience starting Jan1968, online at home since Mar1970