Subject: System clock resolution and random numbers
To: None <current-users@NetBSD.ORG>
From: Rick Byers <rickb@iaw.on.ca>
List: current-users
Date: 04/30/1997 09:45:04
Hi,
I'm working on an application that needs as-random-as-possible values.
I've been using the tv_usec from gettimeofday as the seed. My question
is, what is the resolution of tv_usec? Is it possible to say that it will
only ever be a certain subset of possible values? I assume it's very
difficult to predict the exact value at any given time (because subsequent
calls return significantly different values).
Is there any better way to make a random number? I don't like the idea of
having a 32 bit seed because that limits the possible outcomes to 2^32.
Has their been any thought into putting a random number generator in the
kernel, and are there any patches to do this? I would think this would be
nearly perfect since it would be impossible to find the pattern unless you
had root/physical access.
Thanks,
Rick
=========================================================================
Rick Byers Internet Access Worldwide
rickb@iaw.on.ca System Administrator
Welland, Ontario, Canada (905)714-1400
http://www.iaw.on.ca/rickb/ http://www.iaw.on.ca/