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Re: OT: protection in SASOS
From: |
Jonathan S. Shapiro |
Subject: |
Re: OT: protection in SASOS |
Date: |
Thu, 11 May 2006 10:00:34 -0400 |
On Thu, 2006-05-11 at 15:36 +0200, Tom Bachmann wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> Marcus Brinkmann wrote:
> > At Wed, 10 May 2006 08:54:41 -0700,
> > Thomas Bushnell wrote:
> >> Still, he is essentially right. The conclusion is--dare I say
> >> it--right as well. The best computer systems *are* single address
> >> space systems. Of this, I have absolutely no doubt.
> >
> > But this just replaces the war on the best kernel with a war on the
> > best memory-safe programming language...
> >
>
> OT: Why implies sasos a memory-safe language?
It does not.
However, I don't agree with Thomas. The SASOS idea is a very attractive
idea, but its attraction derives from a fundamental abandonment of
encapsulation. A SASOS is easier to implement for the kernel developer,
but without fully separate address spaces there are interactions between
processes that the developer cannot control.
Fundamentally, a SASOS abandons the idea of a process-private namespace,
and reduces all addresses to global names.
Contrast this with the current situation in L4, where an *overwhelming*
effort is being made to *eliminate* global names because of severe
security issues.
> If you have a look at e.g. mungi or nemesis, they show that other
> mechanisms (virtual memory) can be used.
Yes. They also demonstrate (in both cases) that fault isolation and
security are harder to achieve in such a system.
shap
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?, 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, 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, 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