Re: Linux big bang theory....

[Vincent Archer <varcher () denyall com>]

On Sun, 2007-05-27 at 14:22 +0200, Pavel Kankovsky wrote:
> "All memory" involves any aspect of the system mutable by the software. If
> the microcode is mutable than the memory used to store it is a part of
> "all memory".

Yes. And for typical systems, that also includes all of the mass storage
(i.e. the file systems) attached to it: your software needs to require
every single byte of data storage. I think such a system would come
close to have a self-provable integrity, but such a system must be
extremely carefully designed for it, and notably is non-expandable. Any
expansion breaks down the proved state by introducing external
unvalidated states, and you're back to square one.

Being able to validate the integrity of a system requires *at least* the
entire potential system, which is why systems in general cannot
self-prove: they require more than themselves.

-- 
Vincent ARCHER
varcher () denyall com

Tel : +33 (0)1 40 07 47 14
Fax : +33 (0)1 40 07 47 27
Deny All - 23, rue Notre Dame des Victoires - 75002 Paris - France

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