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Article #625488Re: different architecture, was PDP 11/40 system manual
From: Rob Doyle
Date: Tue, 14 Aug 2018 23:15
Date: Tue, 14 Aug 2018 23:15
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2877 bytes
On 8/13/2018 2:23 PM, John Levine wrote: > In article <5b71ce88...@news.dslextreme.com> you write: >> Your so-called "categories" are arbitrary and mostly meaningless. Even before >> the advent of the 360, they were always "general purpose" computers. Meaning >> they could be used for any application, given the proper programming. The >> salient differences were in CPU speed, storage capacity, and data transfer >> rates. ... > > Yes and no. The architecture of the binary word addressed 704x/709x > scientific machines was rather different from the decimal word 7070 or > the character addressed 705/7080. Sure, they were all Turing > complete, but the 7080 was bad at floating point arithmetic and the > 7090 was bad at moving character strings around. > > We all think it's obvious to have byte/word addressing where the word > addresses are byte addresses with the low bits zero, but it wasn't > obvious at all before IBM invented it for the 360. Once they had a > memory architecture that could work either way, building the > instruction set wasn't so hard. ... and forgotten by the time that the DEC Alpha arrived on the scene. The first few versions of the DEC Alpha couldn't load or store 8-bit or 16-bit data to/from memory. Those instructions were added (EV5) when they realized how crazy that decision was. Oops. [snip] Rob.
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X-Received: by 2002:a24:b30f:: with SMTP id e15-v6mr9402731itf.48.1534288530205; Tue, 14 Aug 2018 16:15:30 -0700 (PDT) X-BeenThere: alt.folklore.computers@googlegroups.com Received: by 2002:a6b:7d46:: with SMTP id d6-v6ls15565ioq.21.gmail; Tue, 14 Aug 2018 16:15:29 -0700 (PDT) X-Received: by 2002:a6b:8f92:: with SMTP id r140-v6mr10465066iod.87.1534288529435; Tue, 14 Aug 2018 16:15:29 -0700 (PDT) Path: mbox-mo1.pugleaf.net!c189-v6ni605ith.0!nntp.google.com!border1.nntp.dca1.giganews.com!nntp.giganews.com!weretis.net!feeder6.news.weretis.net!feeder4.news.weretis.net!news.mixmin.net!aioe.org!.POSTED!not-for-mail From: Rob Doyle <radi...@gmail.com> Newsgroups: alt.folklore.computers Subject: Re: different architecture, was PDP 11/40 system manual Date: Tue, 14 Aug 2018 16:15:28 -0700 Organization: Aioe.org NNTP Server Lines: 29 Message-ID: <pkvnqe$3ft$1@gioia.aioe.org> References: <21aaeee8-c41a-4442-a4eb-ea6a29b1e4f1@googlegroups.com> <1769532633.555587539.250400.peter_flass-yahoo.com@news.eternal-september.org> <d62afda2-8a91-4665-88a4-cb16bc0f47ab@googlegroups.com> <5b71ce88.4681852@news.dslextreme.com> <pksssc$2p6c$1@gal.iecc.com> NNTP-Posting-Host: YwwfdajNdZzUWzTN6oSETA.user.gioia.aioe.org Mime-Version: 1.0 X-Complaints-To: ab...@aioe.org User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 X-Notice: Filtered by postfilter v. 0.8.3 Bytes: 2528 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit