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Re: Linus replies. Re: Computer: Can We Make Operating Systems Reliable
From: |
Niklas Klügel |
Subject: |
Re: Linus replies. Re: Computer: Can We Make Operating Systems Reliable and Secure?// SAS |
Date: |
Thu, 11 May 2006 21:21:18 +0200 |
User-agent: |
Debian Thunderbird 1.0.7 (X11/20051017) |
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>
> Consider:
>
> 1. The measured performance of the best JVM sucks. 2. There is no
> possibility of hard real-time in a garbage-collected runtime. 3.
> The amount of code needed to implement a decent JVM (or similar
> system) is approximately 10x the amount of code needed to implement
> a protected microkernel.
>
that was not my point. it was an example that software-based
memory protection is already practicable at acceptable costs.
there are probably many ways of making memory protection
software based with less overhead. i could also argue that in
some fields of application program-verification works, so
(leaving inconsitencies caused by concurrency aside)
there is no overhead at all added and the operating
system environment is unequally simpler than anything
beyond DOS :)
to make a clear conculsion: all that i am saying is, that the
complexity introduced by highly modular OSes in order
to adapt to former/common principles of OS-Development/Design/etc
might be a sign that these former/common principles
are wrong for the aims of such highly modular OSes.
> Next time your life depends on the software being right, which one
> would you rather depend on?
>
>> today the programming languages and its environments allow a much
>> finer granularity of modularity.
>
>
> You also mentioned sharing. Sharing isn't the solution to
> robustness. It's the *problem*.
i didnt say that either. i said that sharing is more complex in
non-SAS environments and that there are no
restrictions in SAS-environments about what entity shares which objects.
> Shared-memory concurrency is known to be a completely
> non-engineerable approach.
>
> Finer granularity is not always better. The trick is to discover
> the finest granularity that real programmers can manage
> successfully. Unfortunately, there seem to be different answers for
> program structure (the object boundary) than for protection
> structure (the subsystem boundary).
true.
So long...
niklas
>
>
> shap
>
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- Re: Linus replies, (continued)
- Re: Linus replies. Re: Computer: Can We Make Operating Systems Reliable and Secure?, Thomas Bushnell BSG, 2006/05/11
- Re: Linus replies. Re: Computer: Can We Make Operating Systems Reliable and Secure?, Marcus Brinkmann, 2006/05/11
- OT: protection in SASOS, Tom Bachmann, 2006/05/11
- Re: OT: protection in SASOS, Jonathan S. Shapiro, 2006/05/11
- Re: OT: protection in SASOS, Espen Skoglund, 2006/05/11
- Re: OT: protection in SASOS, Jonathan S. Shapiro, 2006/05/11
- Re: Linus replies. Re: Computer: Can We Make Operating Systems Reliable and Secure?, Jonathan S. Shapiro, 2006/05/11
- Re: Linus replies. Re: Computer: Can We Make Operating Systems Reliable and Secure?// SAS, Niklas Klügel, 2006/05/11
- Re: Linus replies. Re: Computer: Can We Make Operating Systems Reliable and Secure?// SAS, Jonathan S. Shapiro, 2006/05/11
- Re: Linus replies. Re: Computer: Can We Make Operating Systems Reliable and Secure?// SAS,
Niklas Klügel <=
- Re: Linus replies. Re: Computer: Can We Make Operating Systems Reliable and Secure?// SAS, Jonathan S. Shapiro, 2006/05/11
- Re: Linus replies. Re: Computer: Can We Make Operating Systems Reliable and Secure?// SAS, Bas Wijnen, 2006/05/11
- Re: Linus replies. Re: Computer: Can We Make Operating Systems Reliable and Secure?// SAS, Jonathan S. Shapiro, 2006/05/11
- Re: Linus replies. Re: Computer: Can We Make Operating Systems Reliable and Secure?, Ludovic Courtès, 2006/05/18
Re: Linus replies. Re: Computer: Can We Make Operating Systems Reliable and Secure?, Marco Gerards, 2006/05/11