Re: CONFIG_RANDOM option for 1.99.2

Ulrich Windl (Ulrich.Windl@rz.uni-regensburg.de)
Sat, 18 May 1996 12:59:57 +0200


On 17 May 96 at 9:44, Martin.Dalecki wrote:

I could resist a long toiome no replying, but this was too much...
>
> No definitly false. Monte Carlo methods are based on *equally distributed*
> sequences. They are not based on *random* sequences. That's a subtile
> difference! The get_random routine in random.c is sequentializing
> pseudo random numbers in the range of 0..255 into bigger ones. This is in
> generall somehow dangerous in respect of the stochstical properties.

If you have random bytes concatenated to word, they are still random.
That's why a single bit random generator is enough. Also "equally
distributed" and "random" are completely independent; a genarator can
have both properties.

>
> It would interrest me if anybody did some serious testing on this topic?.
>
> And finally random.c is not as random as You may beleve. Start it on an
> otherwise not busy machine to see why! Yust do cat /dev/random and see
> the random numbers coming precisely after any keybord hit. This isn't
> acceptable for any number cruching, since those are mostly programms
> which are supposed to run in core and on otherwise idle machines.

What you are examining are not the random values, but the time when a
value comes out; that's something completely different.

>
> In fact it was a Montecarlo integration, which made me sceptical
> about /dev/random or /dev/urandom.
>
> Marcin

Please rethink some of your statements!
Ulrich