Re: lib/38883: Replace the algorithm used by random (3) by the Mersenne Twister (mertwist.c)

[Alan Barrett <apb%cequrux.com@localhost>]

The following reply was made to PR lib/38883; it has been noted by GNATS.

From: Alan Barrett <apb%cequrux.com@localhost>
To: gnats-bugs%NetBSD.org@localhost
Cc: netbsd-bugs%NetBSD.org@localhost
Subject: Re: lib/38883: Replace the algorithm used by random (3) by the
        Mersenne Twister (mertwist.c)
Date: Mon, 25 Aug 2008 12:22:56 +0200

 On Mon, 25 Aug 2008, David Holland wrote:
 >   > Thus, why not implement it as the standard algorithm for random (3)
 >   > group of calls?
 >  
 >  We can't (or at least shouldn't) do this because it would break the
 >  initstate() and setstate() interface to random(3).
 
 Do people really expect the kind of repatability offered by the
 initstate/getstate interface to persist across operating system
 upgrades?  In other words, do we guarantee that values returned by
 initstate befoer an upgrade may be passed to setstate after an upgrade?
 
 Even if we do need to retain this level of compatibility, there seem
 to be enough unused values in the first (int) of the state array that
 we could encode which algorithm is used.  Old algorithms would still
 have to work as if the old value of MAX_TYPES were retained, but it's
 nevertheless possible to add new algotithms.
 
 --apb (Alan Barrett)