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Re: Building packages three times in a row

On Mon, Sep 24, 2007 at 08:35:50PM +0200, Goswin von Brederlow wrote:
> Martin Uecker <muecker@gmx.de> writes:

> > I think it would be really cool if the Debian policy required
> > that packages could be rebuild bit-identical from source. 
> > At the moment, it is impossible to independly verify the
> > integricity of binary packages.
> >
> >
> > Greetings,
> > Martin
> Some tools use randomization to get out of worst case situations or
> general optimization. For example when you look for an optimal
> allocation of register usage you can do a search by picking a random
> register allocation and repeat that a few thousand times to find a
> suitable minimum. Or a randomized heap that gives you O(1) time for
> all operations instead of O(lg n).

I do not know of any compiler which does register allocation
like that. This would be a debugging nightmare!
> By requiring bit-to-bit identical results you eliminate all such
> randomness and could seriously hinder the algorithm available for
> tools.

Such algorithms would certainly use a pseudo-random number generator
which could be seeded identically in each build.

Do you actually know about any tool wich produces different output
each time because of the use of a randomized algorithm?


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