Re: [PATCH] (0/4) Entropy accounting fixes

From: Oliver Xymoron (
Date: Sun Aug 18 2002 - 10:08:31 EST

On Sun, Aug 18, 2002 at 11:30:05AM +0100, Alan Cox wrote:
> Its probably true there are low bits of randomness available from such
> sources providing we know the machine has a tsc, unless the I/O APIC is
> clocked at a divider of the processor clock in which case our current
> behaviour is probably much saner.

I actually looked at this a bit for embedded applications - there's a
technique for pulling entropy from free-running clock skew.

Unfortunately with modern chipsets, just about all clocks are
generated from a single source these days. This is even true in the
non-x86 world now. Any extra clocks you have are likely to be out in
peripheral-land and too slow (serial port) or too inaccessible (VGA
dot clocks) to be interesting.
> With modern systems that have real RNG's its a non issue.


 "Love the dolphins," she advised him. "Write by W.A.S.T.E.." 
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