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From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Newsgroups: comp.lang.ada
Subject: Re: Arbitrary Sandbox
Date: Sat, 18 Feb 2012 12:31:42 +0100
Organization: cbb software GmbH
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Date: 2012-02-18T12:31:42+01:00
List-Id: <comp.lang.ada>

On Sat, 18 Feb 2012 11:45:58 +0100, Yannick Duch�ne (Hibou57) wrote:

> Le Sat, 18 Feb 2012 09:26:42 +0100, Dmitry A. Kazakov  
> <mailbox@dmitry-kazakov.de> a �crit:
> 
>> On Fri, 17 Feb 2012 20:47:36 -0800 (PST), Shark8 wrote:
>>
>>> You know; I always wondered why they (developers, and OS designers)
>>> didn't take advantage of segments.
>>
>> Ineffective, complicated, generally useless?
> Why?

Presumably because of lack of address order. Comparing driver developing
for PDP-11/RSX-11 vs. 80286/Windows/DOS. The former was immensely simpler,
safer and also more effective (you could pass a buffer from the process
space to the driver). The latter was a pure horror.

I wonder what kind of architecture could require a safe implementation of
Ada, e.g. when private parts of packages and protected objects would be
mapped onto the memory physically inaccessible from public contexts.

Or, considering an implementation of an object-based OS without any I/O
when everything is just memory mapped. Maybe some sort of segments on top
of pages could be used for that...

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de