The following message is a courtesy copy of an article that has been posted to bit.listserv.ibm-main as well.
[email protected] (Scott T. Harder) writes: > Very cool. Funny, though... I remember first logging onto TSO on what > I thought was a 3082 (although I didn't know what even DASD was at the > time). Then, when I finally got my hands on a mainframe in MCO, it > was a 3084. This slideshow shows a 3083, which I don't have any > recollection of. Looks like a 3084, from what I can remember, though. 308x were going to be multiprocessor only ... 3081 was two-processor machine, 3084 was pair of 3081s ganged together for four-processor machines. traditional 370 cache machines slowed the processing cycle down by 10% to allow for cross-cache chatter in a two-processor configuration (and four-processor was even slower) ... that is addition to the actual cache processing overhead of handling cross-cache signals (two-way met that there was signals from one other cache, four-way resulted in signals from three other caches). TPF/ACP was an important market segment at the time ... but didn't have SMP (tightly-coupled, shared memory, multiprocessor) support. 3083 was 3081 with some of the hardware removed for a single processor and the single machine running nearly 15% faster (cross-cache chatter slowdown disabled). Prior to 3083, TPF/ACP operation on 3081 was under vm/370 (handling multiprocessor hardware) providing multiple (single processor) virtual machines for TPF/ACP operator (TPF/ACP did have loosely-coupled, cluster support ... so the multiple TPF/ACP virtual machines could be coordinated ... as opposed to say, production vis-a-vis test). Although there were some TPF/ACP 3081 operations where the 2nd processor would sit mostly idle. 3083 was primarily introduced to address TPF/ACP market. web reference: http://www-03.ibm.com/ibm/history/exhibits/mainframe/mainframe_PP3081.html prior to 308x, a 370 multiprocessor had fully replicated hardware ... and a two processor system could be split and run as two independent single processors. for the 3081, the term "dyadic" was introduced to differentiate that while it had two execution processors ... all the hardware was not fully duplicated and so a 3081 couldn't be split and operated as two independent uniprocessors (although a 4-processor 3084 could be split into two 3081s). 3082 waas the "service processor". One of the issues was that field engineering required a "boot-strap" diagnostic process ... which started with scoping failed components and going up from there. TCMs in 308x were not "scope'able" ... so things started with a service processor that was simpler technology and was scope'able ... then a "working" service processor had all sorts of diagnostices instrumentation into the TCMs. There were lots of issues with developing a roll-your-own operating system and diagnostic applications for the service processor in the 308x ... so for the 3090 ... it was decided to go with a standard (low-end, "scope' able") 370 for the service process. The 3090 effort started out with 4331 running a customized version of vm370 release six and all the service screens implemented in cms ios3720. by the time, the 3090 shipped, the "service processor" had been upgraded to a pair of 4361s (effectively replicated units in lieu of having to scope the service processor for diagnostic process). misc. past posts mentioning 3083: http://www.garlic.com/~lynn/99.html#103 IBM 9020 computers used by FAA (was Re: EPO stories (was: HELP IT'S HOT!!!!!)) http://www.garlic.com/~lynn/2000b.html#65 oddly portable machines http://www.garlic.com/~lynn/2000d.html#9 4341 was "Is a VAX a mainframe?" http://www.garlic.com/~lynn/2000f.html#69 TSS ancient history, was X86 ultimate CISC? designs) http://www.garlic.com/~lynn/2001b.html#37 John Mashey's greatest hits http://www.garlic.com/~lynn/2001c.html#13 LINUS for S/390 http://www.garlic.com/~lynn/2001j.html#17 I hate Compaq http://www.garlic.com/~lynn/2002c.html#9 IBM Doesn't Make Small MP's Anymore http://www.garlic.com/~lynn/2002i.html#83 HONE http://www.garlic.com/~lynn/2002m.html#67 Tweaking old computers? http://www.garlic.com/~lynn/2002o.html#28 TPF http://www.garlic.com/~lynn/2002p.html#58 AMP vs SMP http://www.garlic.com/~lynn/2003g.html#30 One Processor is bad? http://www.garlic.com/~lynn/2003p.html#45 Saturation Design Point http://www.garlic.com/~lynn/2004.html#7 Dyadic http://www.garlic.com/~lynn/2004c.html#35 Computer-oriented license plates http://www.garlic.com/~lynn/2004e.html#44 Infiniband - practicalities for small clusters http://www.garlic.com/~lynn/2005.html#22 The Soul of Barb's New Machine (was Re: creat) http://www.garlic.com/~lynn/2005j.html#16 Performance and Capacity Planning http://www.garlic.com/~lynn/2005m.html#55 54 Processors? http://www.garlic.com/~lynn/2005o.html#44 Intel engineer discusses their dual-core design http://www.garlic.com/~lynn/2005s.html#7 Performance of zOS guest http://www.garlic.com/~lynn/2005s.html#38 MVCIN instruction http://www.garlic.com/~lynn/2006d.html#5 IBM 610 workstation computer http://www.garlic.com/~lynn/2006l.html#30 One or two CPUs - the pros & cons http://www.garlic.com/~lynn/2006n.html#16 On the 370/165 and the 360/85 http://www.garlic.com/~lynn/2007.html#44 vm/sp1 http://www.garlic.com/~lynn/2007g.html#16 What's a CPU second? http://www.garlic.com/~lynn/2007o.html#37 Each CPU usage http://www.garlic.com/~lynn/2008c.html#83 CPU time differences for the same job http://www.garlic.com/~lynn/2008e.html#40 Fantasy-Land_Hierarchal_NUMA_Memory-Model_on_Vertical http://www.garlic.com/~lynn/2008g.html#14 Was CMS multi-tasking? http://www.garlic.com/~lynn/2008i.html#38 American Airlines http://www.garlic.com/~lynn/2008i.html#57 Microsoft versus Digital Equipment Corporation -- 40+yrs virtualization experience (since Jan68), online at home since Mar1970 ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
