From: Mark Murray <mark@grondar.za>
Date: Tue, 31 Oct 1995 02:42:16 +0800
To: "Theodore Ts'o" <tytso@MIT.EDU>
Subject: /dev/random for FreeBSD [was: Re: /dev/random for Linux]
Message-ID: <199510301816.UAA14080@grumble.grondar.za>
MIME-Version: 1.0
Content-Type: text/plain


>    > > On this same track, I suggest that "/dev/random" devices for unix are
>    > > an excellent idea. Ted Tso did one for Linux that steals all the bits
>    > > of semi-random timing information it can.
>    >
>    > Anyone know where I can find more information on this wonderful device?
> 
> I've just sent patches (versus the Linux 1.3.28 kernel) off to Linus.
> There's a fairly long exposition at the beginning of
> drivers/char/random.c which explain its theory of operation.

A colleague drew my attention to this, and I was so pleased with it that
I ported it to FreeBSD.

I kept the interface as close to the original as I could, but made some
changes for efficiency and ease:

1) I turned the huge comment at the top explaining the theory of operation
into a man page (random(4)).

2) We felt that hooking all interrupts might be dangerous. IDE drives can
interrupt at a heck of a rate, and so can some serial ports, and we felt
that in these cases _not_ using the interrupt was a good idea. So I
added an ioctl to allow the superuser to select his own set, appropriate
to the hardware in use. It is nearly impossible to do this automatically.

Gimme a yell if you want copies :-)

M
--
Mark Murray
46 Harvey Rd, Claremont, Cape Town 7700, South Africa
+27 21 61-3768 GMT+0200
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