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From: "H. Peter Anvin" <hpa@zytor.com>
To: Peter Monta <pmonta@pmonta.com>
Cc: garzik@havoc.gtf.org, linux-kernel@vger.kernel.org
Subject: Re: Continuing /dev/random problems with 2.4
Date: Fri, 01 Feb 2002 17:50:05 -0800	[thread overview]
Message-ID: <3C5B45CD.5060401@zytor.com> (raw)
In-Reply-To: <20020201031744.A32127@asooo.flowerfire.com> <1012582401.813.1.camel@phantasy> <a3enf3$93p$1@cesium.transmeta.com> <20020201202334.72F921C5@www.pmonta.com> <20020201153346.B2497@havoc.gtf.org> <20020201205605.ED5111C5@www.pmonta.com> <3C5B1CBB.6080802@zytor.com> <20020201232723.12F3E1C5@www.pmonta.com>

Peter Monta wrote:

>>The point with the tests that have been mentioned is to derive such a
>>conservative estimate, and to raise a red flag if the output suddenly
>>becomes predictable.
>>
> 
> Ah, I see; I was misled by the "truly random" remark, sorry.  So a reasonable
> sanity test for a block of audio samples might be a standard deviation
> greater than a few LSB; this will catch constant or close-to-constant
> output.
> 


However, those aren't the main failure modes you need to be concerned 
with.  Antenna effects may actually be your biggest problem -- picking 
up deterministic signals from other parts of the system.

However, I believe this is a solved problem.  It would definitely be 
interesting taking rngd and figuring out a way to drive it from /dev/dsp 
-- probably not too difficult a modification.

	-hpa




  reply	other threads:[~2002-02-02  1:50 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-02-01  9:17 Continuing /dev/random problems with 2.4 Ken Brownfield
2002-02-01 16:36 ` Andreas Dilger
2002-02-01 17:00   ` Ken Brownfield
2002-02-01 16:53 ` Robert Love
2002-02-01 17:01   ` Ken Brownfield
2002-02-04  9:28     ` Sean Hunter
2002-02-01 18:40   ` H. Peter Anvin
2002-02-01 19:38     ` Ken Brownfield
2002-02-01 19:50       ` Robert Love
2002-02-01 19:52         ` Ken Brownfield
2002-02-01 19:57       ` Andreas Dilger
2002-02-01 20:22         ` Ken Brownfield
2002-02-01 19:43     ` Andreas Dilger
2002-02-01 20:12       ` H. Peter Anvin
2002-02-01 20:28         ` Jeff Garzik
2002-02-02  1:33           ` David Wagner
2002-02-02  8:01             ` Jeff Garzik
2002-02-02  8:54           ` Kai Henningsen
2002-02-02 11:13             ` Andreas Dilger
2002-02-04 22:13         ` Bill Davidsen
2002-02-04 22:37           ` Roland Dreier
2002-02-04 22:45             ` Robert Love
2002-02-05 23:02               ` Bill Davidsen
2002-02-05 23:17                 ` Robert Love
2002-02-06 16:16                   ` Bill Davidsen
2002-02-06 16:31                     ` Need a clew WRT fig2dev Kirk Reiser
2002-02-06 16:42                       ` Adrian Bunk
2002-02-06 20:40                       ` Jeff Garzik
2002-02-09 19:45                     ` Continuing /dev/random problems with 2.4 Nix N. Nix
2002-02-03 12:51       ` Henning P. Schmiedehausen
2002-02-01 20:23     ` Peter Monta
2002-02-01 20:27       ` H. Peter Anvin
2002-02-01 20:36         ` Jeff Garzik
2002-02-01 20:33       ` Jeff Garzik
2002-02-01 20:40         ` H. Peter Anvin
2002-02-01 20:54           ` Jeff Garzik
2002-02-01 20:56         ` Peter Monta
2002-02-01 22:54           ` H. Peter Anvin
2002-02-01 23:27             ` Peter Monta
2002-02-02  1:50               ` H. Peter Anvin [this message]
2002-02-02  2:05       ` David Wagner
2002-02-02  3:30         ` Peter Monta
2002-02-02 21:02         ` Martin Dalecki
  -- strict thread matches above, loose matches on Subject: below --
2002-02-04 21:53 Ishan O. Jayawardena

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