Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sun-barr!lll-winken!unixhub!shelby!agate!sprite.Berkeley.EDU!elm From: elm@sprite.Berkeley.EDU (ethan miller) Newsgroups: comp.arch Subject: Re: Historical architectural advances?? Message-ID: <1990Oct16.234455.17743@agate.berkeley.edu> Date: 16 Oct 90 23:44:55 GMT References: <8139@scolex.sco.COM> <1990Oct13.035313.174@ingres.Ingres.COM> <1990Oct13.200414.3523@motaus.sps.mot.com> <61266@masscomp.ccur.com> Sender: usenet@agate.berkeley.edu (USENET Administrator) Reply-To: elm@sprite.Berkeley.EDU (ethan miller) Organization: Berkeley--Shaken, not Stirred Lines: 29 In article <61266@masscomp.ccur.com>, hank@masscomp.ccur.com (Hank Cohen) writes: %In article aglew@crhc.uiuc.edu (Andy Glew) writes: %> %>And the MC68000 didn't have virtual memory. Not all instructions %>could handle page faults, etc. It took a while before the 68000 was %>suitable for use as a "real machine". %> %>I trust everyone knows about the twinned 68000s used in early Apollos? %>One a cycle behind the other, so that it could pick up at a page fault? % %Not early Apollos early Masscomps. ( Of course Masswho or Whatcomp %always suffered from a lack of recognition.) [description of Masscomps omitted...] Perhaps it is true that Masscomp used two 68000s, but I *know* Apollo used dual 68000s in their DN300s. I used them as an undergrad at Brown, and learned a lot about their hardware. The CPU that was a cycle ahead would suffer the unrecoverable bus errors, and the trailing CPU would know to stop at that point, load the necessary page (via token ring net that slowed down really terribly with 50 active users :-), and continue after making sure the leading CPU was in the right place with the correct state. This was also the first time I saw virtual memory for the display. If a page wasn't present, the area was black. ethan ================================= ethan miller--cs grad student elm@sprite.berkeley.edu #include {...}!ucbvax!sprite!elm Witty signature line condemned due to major quake damage.