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Article #625519Re: PDP 11/40 system manual
From: Kerr-MuddJohn
Date: Sat, 18 Aug 2018 18:40
Date: Sat, 18 Aug 2018 18:40
31 lines
3233 bytes
3233 bytes
On Sat, 18 Aug 2018 04:27:07 GMT, Anne & Lynn Wheeler <ly...@garlic.com> wrote: > Peter Flass <peter...@yahoo.com> writes: >> Cable length was the big problem. If you put the core too far from >> the CPU you had to go with slow memory. Each <mumble>K of core needed >> its own frame. One of the larger machines had the boxes of core >> arranged in an "X" around the CPU to try to reduce cable length. I'm >> not sure about core, but I think some large shops put disk >> controllers one floor down from the CPU and dropped the channel >> cables thru the floor to reduce distance. > > packaging distance ... happened for 3090 ... plus some 3880 disk > controller channel overhead. 3880/3380 increased transfer speed but > also doubled max. channel cable distance (by expanding number of bytes > transferred in single handshake). however they went from a very fast > horizontal microcode controller for 3830 to a very slow verticial > microcode controller for 3880 ... with a hardware side-path for data > transfer. The increased data transfer reduced channel busy, but the > increased 3880 controller overhead more than offset the increased > transfer speed. When I started there was an old chap, nearing retirement, whose main job (it seemed) was juggling bits of paper on a plan of the computer room to get a new piece of kit and the existing stuff reconfigured for best performance. -- Bah, and indeed, Humbug.
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X-Received: by 2002:a1c:9e42:: with SMTP id h63-v6mr3583655wme.10.1534617602503; Sat, 18 Aug 2018 11:40:02 -0700 (PDT) X-BeenThere: alt.folklore.computers@googlegroups.com Received: by 2002:a1c:6a11:: with SMTP id f17-v6ls2383329wmc.11.gmail; Sat, 18 Aug 2018 11:40:01 -0700 (PDT) X-Received: by 2002:a1c:3f8e:: with SMTP id m136-v6mr3612986wma.2.1534617601734; Sat, 18 Aug 2018 11:40:01 -0700 (PDT) MIME-Version: 1.0 Path: mbox-mo1.pugleaf.net!w16-v6ni10602wmw.0!nntp.google.com!proxad.net!feeder1-2.proxad.net!news.mixmin.net!eternal-september.org!feeder.eternal-september.org!reader02.eternal-september.org!.POSTED!not-for-mail From: "Kerr-Mudd,John" <nots...@invalid.org> Newsgroups: alt.folklore.computers Subject: Re: PDP 11/40 system manual Date: Sat, 18 Aug 2018 18:40:01 -0000 (UTC) Organization: dis Lines: 31 Message-ID: <XnsA942C818F2D4Aadmin127001@85.214.115.223> References: <21aaeee8-c41a-4442-a4eb-ea6a29b1e4f1@googlegroups.com> <mdd7ekzl6pr.fsf@panix5.panix.com> <pki8ae$ca0$1@dont-email.me> <1028478389.555543171.735142.peter_flass-yahoo.com@news.eternal-september.org> <pkl2h6$abc$2@gal.iecc.com> <715eff9f-01d8-439d-98a2-5e199e66ddc7@googlegroups.com> <72800c64-b531-477d-aa16-b30ff7c2d70e@googlegroups.com> <38853659.556223633.740467.peter_flass-yahoo.com@news.eternal-september.org> <87ftzcz4dg.fsf@localhost> Injection-Date: Sat, 18 Aug 2018 18:40:01 -0000 (UTC) Injection-Info: reader02.eternal-september.org; posting-host="e01f0d375b2767c40db8111d5c15adab"; logging-data="27964"; mail-complaints-to="ab...@eternal-september.org"; posting-account="U2FsdGVkX1+641KnUDbbTCWjkcm5QVyVgL7hms4/M8o=" User-Agent: Xnews/5.04.25 Cancel-Lock: sha1:jJX9frPWoD1MXrsT1CqyPwmi4yo= Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit