Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!munnari.oz.au!uhccux!virtue!hamish
From: hamish@waikato.ac.nz
Newsgroups: comp.sys.amiga.tech
Subject: Re: Memory Protection!
Message-ID: <1248.26cbc22c@waikato.ac.nz>
Date: 16 Aug 90 22:08:44 GMT
References: <13756@cbmvax.commodore.com> <900816.150215.CDT.C506634@UMCVMB.MISSOURI.EDU>
Organization: University of Waikato, Hamilton, New Zealand
Lines: 65

In article <900816.150215.CDT.C506634@UMCVMB.MISSOURI.EDU>, C506634@UMCVMB.MISSOURI.EDU (Eric Edwards) writes:
> On 10 Aug 90 19:56:24 GMT Valentin Pepelea said:
>>Another problem is that even if you provide the possiblity for new applications
>>to run protected within the environment, the fact that older programs cann
>>still
>>jog around the address space and wreak havoc, defeats the initial purpose.
>>Either you provide memory protection to everybody simultaneoulsy, or you
>>don't at all.
> Obviously we can't provide memory protection to everybody simultaneously.  For
> the forseable future there will always be old programs that will not work
> properly with memory protection and people that want to run them.  However,
> memory protection is too valuable to just write off.
> 
> As has been mentioned before (I beleive) The operating system and unprotected
> programs could be lumped together.  Protected programs would, of course, be
> isolated from each other and the OS.
>

  I believe it too!
 
> Now, what happens when an unprotected program tries to step on a protected.
> program?  I'd call that a task held.  It's not very nice but at least it stops
> the errant program from doing real damage.
>

  Definitly nicer that "The GURU!"
 
> Is this as good as "real" memory protection?  No.  But it's better than we have
> now and starts the process going toward "real" memory protection.  In the
> beginning it wouldn't be much differnt than now becuase protected programs
> be few.   But if the memory in protected programs is larger than the OS then
> errant programs will usually be stopped by protection violations.  This *would*
> be more stable.  And as time progressed it would only get better.
>

 All I can say, is that people who use code hunks for data ought to be
punished severly. (Especially Commodore Employees). Excuses are no
longer good enough. Was it Valentine who said everybody does it including
him. Well I DON'T do it. CODE is CODE and DATA is DATA! Using a bad programming
practice doesn't make it good or acceptable. I find now that I might have
to think twice before laying out hard cash for an unprotected system, where
I need security.

 (Appologies to Valentine if it wasn't you who said that, but it tends to
  get my goat when a bad programming practice is used and the defended by
  saying "But everbody else does it!". Sounds like my little sister caught
  painting on the carpet with oil based paint)
 
> Eric Edwards: c506634 @    "The 3090.  Proof that by applying state of the
> Inet: umcvmb.missouri.edu   art technology to an obsolete architecture,
> Bitnet: umcvmb.bitnet       one can achieve mediocre performance."

Just my 0.02c worth!

-- 
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|  Hamish Marson                        |  Internet  hamish@waikato.ac.nz    |
|  Computer Support Person              |  Phone  (071)562889 xt 8181        |
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|  University of Waikato                |                                    |
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|Disclaimer:  Anything said in this message is the personal opinion of the   |
|             finger hitting the keyboard & doesn't represent my employers   |
|             opinion in any way. (ie we probably don't agree)               |
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