From: Clem cole <firstname.lastname@example.org> To: Bakul Shah <email@example.com> Cc: The Eunuchs Hysterical Society <firstname.lastname@example.org> Subject: Re: [TUHS] dmr streams & networking [was: Re: If not Linux, then what?] Date: Fri, 30 Aug 2019 22:46:57 -0400 Message-ID: <88242A0D-D08E-47EB-84DC-A7205780A417@ccc.com> (raw) In-Reply-To: <20190831011359.E9F491570CE9@mail.bitblocks.com> There was most definitely a TLB or as Dave called it ‘The TB’ *** Remember Dave Cane (Masscomp hw lead) was part of the 780, led the 750 and designed the BI before he left dec. He was a bus and memory specialist *** west coast VS east coast training - calling it a TB vs a TLB. Sent from my PDP-7 Running UNIX V0 expect things to be almost but not quite. > On Aug 30, 2019, at 9:13 PM, Bakul Shah <email@example.com> wrote: > >> On Fri, 30 Aug 2019 20:58:13 -0400 Clem Cole <firstname.lastname@example.org> wrote: >> >> Actually not in lock step. They were independent. One was called the >> executor and the other the fixer. When a fault was detected the executor >> was sent wait stated while the fixer handled the fault and refilled the >> TLB. Once the TLB was set to instruction was allowed to complete. Btw >> when the 68010 was released the pals on the board were changed to allow the >> executor to actually take the fault and do something else while the fixer >> replaced the TLB entry > > As I remember, the issue with 68000 was that instructions were > not restartable so in case of accessing memory that didn't > exist, you couldn't take a segfault and do anything useful. > This is why you needed a second processor to deal with an > external MMU. There would have been no TLB unless you actually > added an external TLB -- but an external CAM would've been > very expensive. May be a direct map? > > What we did at Fortune was to utilize a 4 entry external map: > text, data, extra and stack. When a new function was invoked > it would do a 'probe'. If the probe caused a segfault, stack > was extended in the handler. The probe didn't have to be > restartable. So we didn't need a second 68k. This logic may > have been in the V7 port we started from.
next prev parent reply other threads:[~2019-08-31 2:47 UTC|newest] Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-08-30 20:21 Norman Wilson 2019-08-30 20:28 ` Larry McVoy 2019-08-30 20:39 ` Clem Cole 2019-08-30 21:52 ` Larry McVoy 2019-08-31 0:58 ` Clem Cole 2019-08-31 1:13 ` Bakul Shah 2019-08-31 2:46 ` Clem cole [this message] 2019-08-31 2:57 ` Clem cole 2019-08-31 3:14 ` Gregg Levine 2019-08-31 3:47 ` Clem cole 2019-08-31 3:38 ` Bakul Shah 2019-08-31 5:37 ` Dave Horsfall 2019-08-31 19:03 ` Clem Cole 2019-09-05 5:11 ` Al Kossow 2019-09-02 8:28 ` Peter Jeremy 2019-09-02 23:26 ` Dave Horsfall 2019-08-31 3:19 ` Bakul Shah -- strict thread matches above, loose matches on Subject: below -- 2019-09-01 2:36 [TUHS] dmr streams & networking [was: Re: If not Linux, then what? Rudi Blom 2019-09-01 2:16 [TUHS] dmr streams & networking [was: Re: If not Linux, then what?] Rudi Blom 2019-08-31 9:43 Rudi Blom 2019-08-31 15:41 ` Clem Cole 2019-08-28 18:41 Doug McIlroy 2019-08-28 18:49 ` arnold 2019-08-28 19:03 ` Chet Ramey 2019-08-28 19:05 ` Larry McVoy 2019-08-29 14:58 ` Jason Stevens 2019-08-29 16:25 ` arnold 2019-08-29 16:38 ` Ralph Corderoy 2019-08-29 17:35 ` arnold 2019-08-28 21:55 ` Rob Pike 2019-08-28 22:29 ` George Michaelson 2019-08-28 22:36 ` William Pechter 2019-08-28 23:02 ` Arthur Krewat 2019-08-29 0:11 ` Clem cole 2019-08-29 0:18 ` George Michaelson 2019-08-29 6:27 ` Lars Brinkhoff 2019-08-28 17:57 Doug McIlroy 2019-08-28 18:05 ` Adam Thornton 2019-08-28 18:08 ` arnold 2019-08-28 18:27 ` Warner Losh 2019-08-28 18:34 ` Warner Losh 2019-08-28 21:54 ` Rob Pike 2019-08-29 6:43 ` arnold 2019-08-29 7:39 ` Rob Pike 2019-08-29 16:26 ` arnold 2019-08-29 3:29 ` Lawrence Stewart 2019-08-29 4:10 ` Larry McVoy 2019-08-28 9:17 Paul Ruizendaal 2019-08-28 10:44 ` Angelo Papenhoff
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