From: cowan@mercury.ccil.org (John Cowan)
Subject: [TUHS] v6 RK05 bootloader question
Date: Wed, 30 Dec 2015 13:33:31 -0500 [thread overview]
Message-ID: <20151230183331.GA448@mercury.ccil.org> (raw)
In-Reply-To: <22302.1451498817@cesium.clock.org>
Erik E. Fair scripsit:
> Rather than memory-mapped I/O, the NOVA had I/O instructions, and
> six bits of device codes.
Same as the PDP-8, in fact. But all my PDP-8 work was with OS/8,
which runs with interrupts off: you can turn them on in userland if your
program wants to use them, but you have to shut them off before invoking
any system services. So I know little of these sixties sitcoms of
which you speak.
> Since "page zero" of the NOVA (the first 256 words of RAM) was a
> critical resource (direct reference from anywhere else in RAM rather
> than using space-expensive indirect addressing, plus, there were some
> autoincrement and autodecrement locations - reading them caused the
> stored value to change - handy for counters and pointers),
All exactly like the PDP-8.
--
John Cowan http://www.ccil.org/~cowan cowan at ccil.org
You are a child of the universe no less than the trees and all other acyclic
graphs; you have a right to be here. --DeXiderata by Sean McGrath
next prev parent reply other threads:[~2015-12-30 18:33 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-27 20:32 Norman Wilson
2015-12-29 20:55 ` Will Senn
2015-12-29 21:37 ` Ronald Natalie
2015-12-30 7:14 ` Wolfgang Helbig
2015-12-30 7:29 ` Will Senn
2015-12-30 18:06 ` Erik E. Fair
2015-12-30 18:33 ` John Cowan [this message]
2015-12-31 8:06 ` Wolfgang Helbig
-- strict thread matches above, loose matches on Subject: below --
2015-12-31 13:45 Noel Chiappa
2015-12-26 18:34 Will Senn
2015-12-26 19:15 ` Ronald Natalie
2015-12-26 19:26 ` Ronald Natalie
2015-12-26 20:34 ` Will Senn
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