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From: jmonroy@netcom.com (Jesus Monroy Jr)
Subject: Re: [FreeBSD 1.0R] DMA Problems?
Message-ID: <jmonroyCJ5JwH.EzE@netcom.com>
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References: <CHCErs.G5w@genesis.nred.ma.us> <2dj25i$1ga@u.cc.utah.edu> <2encotINN3sq@bonnie.sax.de> <CIDrrv.3MJ@sneaky.lonestar.org>
Date: Wed, 5 Jan 1994 10:31:29 GMT
Lines: 42
Posted as a curtiousy(sp?) to David.
=========================================================================
Subject: Re: [FreeBSD 1.0R] DMA Problems?
From: David Greenman <davidg@implode.rain.com>
Date: Tue, 04 Jan 94 05:34:25 -0800
>I'm sorry for this reply... but
>
>Sagitarius (sp?) won't align with the moon for at least
>four days.... Can I give you an answer then?
>
>What is this "cosmic ray" stuff?
>Somebody please tell me if I should take this seriously?
You most certainly should; John knows what he's talking about. It's
interesting about the cosmic ray stuff - cosmic rays are a major source of
alpha particles. In the early days of DRAM designs, alpha particles were the
primary failure mode for DRAM - they were such a problem that nobody would
seriously consider a DRAM design that didn't implement ECC. The 256k DRAMs were
where the problem really became serious - some engineers were sure that
smaller micron technologies would be impossible because of the alpha particle
problems. ...But then there was improved die 'coating' materials that
dramtically reduced the problem. Cosmic rays aren't the only cause of alpha
particles, in fact I think that the plastic package that contains the die is
actually a greater source of them then cosmic rays (but I'm fuzzy on this).
Please post this to the net - I can't post at the moment.
-DG
David Greenman
FreeBSD development team
--
Jesus Monroy Jr jmonroy@netcom.com
Zebra Research
/386BSD/device-drivers /fd /qic /clock /documentation
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