From: "Randy Brukardt" <randy@rrsoftware.com>
Subject: Re: is there a version of unix written in Ada
Date: Wed, 30 Sep 2020 17:42:01 -0500 [thread overview]
Message-ID: <rl31jv$cue$1@franka.jacob-sparre.dk> (raw)
In-Reply-To: rl2rqt$jdq$1@gioia.aioe.org
"Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> wrote in message
news:rl2rqt$jdq$1@gioia.aioe.org...
> On 30/09/2020 22:33, Paul Rubin wrote:
>> "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> writes:
>>> I want an OS protecting from compilers I do not trust without
>>> performance loss.
>>
>> That is not possible. Traditional OS's use memory protection hardware
>> for that, but that hardware introduces performance loss.
>
> I do not see why loss must be any bigger that other means of
> synchronization.
Synchronization is rather expensive, since it causes issues with prefetch
and caches and pretty much everything else that improves performance.
...
> P.S. Surely MS-DOS coordinated auxiliary processors, there exited lots of
> expansion cards with processors on them in MS-DOS times.
I suppose, that was done with device drivers and the like, below anything
visible. I don't remember every worrying about what was happening on cards,
anymore than one does nowdays on Windows or Linux.
> P.P.S. In MS-DOS processes were coordinated using glorious INT 21h. (:-))
Since there wasn't any extra processing (no cores back then), anything
working like a process was a hack. Janus/Ada used (and still uses)
cooperative multitasking to give the appearance of multiple processes, but
no such thing was actually happening. Given that MS-DOS itself wasn't
re-enterant, it was too risky to use any sort of conventional
interrupt-driven tasking. (Some people did it anyway, by trusting various
undocumented hacks; there even was a famous book about those - which came
out way too late to influnce the Janus/Ada design.)
Randy.
next prev parent reply other threads:[~2020-09-30 22:42 UTC|newest]
Thread overview: 105+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <e3c51e65-b71e-4623-bd58-c94cdbcc3ba6o@googlegroups.com>
2020-07-25 7:37 ` is there a version of unix written in Ada mockturtle
2020-07-26 19:45 ` Stéphane Rivière
2020-07-26 22:15 ` Jeffrey R. Carter
2020-07-27 7:40 ` Stéphane Rivière
2020-07-28 13:08 ` DrPi
2020-07-28 16:48 ` Simon Wright
2020-07-28 17:00 ` Fabien Chouteau
2020-07-29 9:21 ` DrPi
2020-07-29 9:28 ` Fabien Chouteau
2020-07-29 15:02 ` DrPi
2020-07-29 15:11 ` Fabien Chouteau
2020-07-29 20:41 ` DrPi
2020-07-29 9:20 ` DrPi
2020-07-29 16:53 ` Simon Wright
2020-07-29 20:42 ` DrPi
2020-07-25 8:47 ` Niklas Holsti
2020-07-25 9:36 ` Stéphane Rivière
2020-07-25 10:41 ` Luke A. Guest
2020-07-25 14:43 ` Jesper Quorning
2020-07-25 19:20 ` Andreas ZEURCHER
2020-07-27 7:40 ` Stéphane Rivière
2020-07-27 15:00 ` nobody in particular
2020-07-27 14:58 ` nobody in particular
2020-07-27 20:28 ` Shark8
2020-07-30 0:57 ` gdotone
2020-07-31 14:01 ` Shark8
2020-09-23 17:39 ` Olivier Henley
2020-09-25 15:06 ` DrPi
2020-09-25 17:31 ` Andreas ZEURCHER
2020-09-26 8:50 ` DrPi
2020-09-27 18:55 ` Luke A. Guest
2020-09-27 19:07 ` Luke A. Guest
2020-09-27 18:53 ` Luke A. Guest
2020-09-27 14:25 ` Shark8
2020-09-27 15:01 ` Dmitry A. Kazakov
2020-09-27 20:59 ` DrPi
2020-09-28 7:41 ` Dmitry A. Kazakov
2020-09-28 13:48 ` Olivier Henley
2020-09-28 14:48 ` Dmitry A. Kazakov
2020-09-28 16:28 ` Olivier Henley
2020-09-28 20:30 ` Dmitry A. Kazakov
2020-09-28 21:06 ` Shark8
2020-09-28 17:47 ` Paul Rubin
2020-09-28 20:27 ` Dmitry A. Kazakov
2020-09-29 23:54 ` Paul Rubin
2020-09-30 8:18 ` Dmitry A. Kazakov
2020-09-30 17:27 ` Paul Rubin
2020-09-30 19:42 ` Dmitry A. Kazakov
2020-09-30 20:33 ` Paul Rubin
2020-09-30 21:03 ` Dmitry A. Kazakov
2020-09-30 22:42 ` Randy Brukardt [this message]
2020-10-01 9:28 ` Dmitry A. Kazakov
2020-10-01 9:59 ` J-P. Rosen
2020-10-01 10:21 ` Dmitry A. Kazakov
2020-10-01 11:38 ` Niklas Holsti
2020-10-01 11:52 ` Niklas Holsti
2020-10-01 12:51 ` Dmitry A. Kazakov
2020-10-01 14:18 ` J-P. Rosen
2020-10-01 15:44 ` Dmitry A. Kazakov
2020-10-01 22:10 ` Randy Brukardt
2020-10-02 5:36 ` J-P. Rosen
2020-10-02 6:56 ` Dmitry A. Kazakov
2020-10-02 7:42 ` J-P. Rosen
2020-10-03 3:14 ` Randy Brukardt
2020-10-01 15:38 ` Niklas Holsti
2020-10-01 16:06 ` Dmitry A. Kazakov
2020-10-01 17:01 ` Niklas Holsti
2020-10-01 17:37 ` Dmitry A. Kazakov
2020-10-01 22:13 ` Randy Brukardt
2020-10-01 11:48 ` J-P. Rosen
2020-10-01 12:54 ` Dmitry A. Kazakov
2020-10-01 7:57 ` Paul Rubin
2020-10-01 9:26 ` Dmitry A. Kazakov
2020-10-01 9:46 ` Paul Rubin
2020-10-01 10:35 ` Dmitry A. Kazakov
2020-10-01 19:02 ` DrPi
2020-10-01 23:12 ` Paul Rubin
2020-10-01 21:54 ` Randy Brukardt
2020-10-01 23:14 ` Paul Rubin
2020-10-01 21:36 ` Brian Drummond
2020-10-02 6:56 ` Dmitry A. Kazakov
2020-10-02 18:34 ` Brian Drummond
2020-10-02 21:24 ` Paul Rubin
2020-10-06 23:54 ` Brian Drummond
2020-10-03 6:54 ` Dmitry A. Kazakov
2020-10-05 14:03 ` Shark8
2020-10-07 11:56 ` Olivier Henley
2020-10-09 12:35 ` Olivier Henley
2020-10-09 14:41 ` Brian Drummond
2020-09-28 18:40 ` Vincent Marciante
2020-09-28 20:28 ` Dmitry A. Kazakov
2020-09-28 17:04 ` DrPi
2020-09-28 17:30 ` Olivier Henley
2020-09-28 18:05 ` Olivier Henley
2020-09-28 19:36 ` Shark8
2020-09-03 10:32 ` c+
2020-09-12 4:30 ` sumde121
2020-09-19 14:09 ` erchetan33
2020-10-01 22:21 Randy Brukardt
2020-10-02 6:55 ` Dmitry A. Kazakov
2020-10-03 3:09 ` Randy Brukardt
2020-10-03 6:42 ` Dmitry A. Kazakov
2020-10-03 7:44 ` Niklas Holsti
2020-10-03 8:16 ` Dmitry A. Kazakov
2020-10-03 10:44 ` Niklas Holsti
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