From owner-freebsd-stable@FreeBSD.ORG Wed Feb 21 07:30:00 2007 Return-Path: X-Original-To: freebsd-stable@freebsd.org Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id F171316DE63 for ; Wed, 21 Feb 2007 07:30:00 +0000 (UTC) (envelope-from m.seaman@infracaninophile.co.uk) Received: from smtp.infracaninophile.co.uk (ns0.infracaninophile.co.uk [81.187.76.162]) by mx1.freebsd.org (Postfix) with ESMTP id 602B013C461 for ; Wed, 21 Feb 2007 07:30:00 +0000 (UTC) (envelope-from m.seaman@infracaninophile.co.uk) Received: from [IPv6:::1] (localhost.infracaninophile.co.uk [IPv6:::1]) by smtp.infracaninophile.co.uk (8.13.8/8.13.8) with ESMTP id l1L7TSVG040465; Wed, 21 Feb 2007 07:29:28 GMT (envelope-from m.seaman@infracaninophile.co.uk) Message-ID: <45DBF4D1.6000708@infracaninophile.co.uk> Date: Wed, 21 Feb 2007 07:29:21 +0000 From: Matthew Seaman Organization: Infracaninophile User-Agent: Thunderbird 1.5.0.9 (X11/20070120) MIME-Version: 1.0 To: Alan Amesbury References: <20070220215248.3C22216D23E@hub.freebsd.org> <45DB8B8D.6080706@umn.edu> In-Reply-To: <45DB8B8D.6080706@umn.edu> X-Enigmail-Version: 0.94.0.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="------------enigBE410E47035F0530B35EA1E7" X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-3.0 (smtp.infracaninophile.co.uk [IPv6:::1]); Wed, 21 Feb 2007 07:29:43 +0000 (GMT) X-Virus-Scanned: ClamAV 0.90/2614/Tue Feb 20 18:53:11 2007 on happy-idiot-talk.infracaninophile.co.uk X-Virus-Status: Clean X-Spam-Status: No, score=-2.3 required=5.0 tests=AWL,BAYES_00, DKIM_POLICY_TESTING,NO_RELAYS autolearn=ham version=3.1.8 X-Spam-Checker-Version: SpamAssassin 3.1.8 (2007-02-13) on happy-idiot-talk.infracaninophile.co.uk Cc: freebsd-stable@freebsd.org, Ivan Voras Subject: Re: getting garbage faster using FreeBSD? X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 21 Feb 2007 07:30:01 -0000 This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enigBE410E47035F0530B35EA1E7 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: quoted-printable Alan Amesbury wrote: > Ivan Voras wrote: >=20 >> The obvious question - why don't you burn the tapes and hammer the dis= ks? :) >=20 > Ah, low-tech. I know it well. Still, the last time I did any data > destruction, I found a 4 Tesla magnet does wonders. Downsides: >=20 > 1) Oxford's 90cm bore, helium-cooled magnets aren't that > common, perhaps because a 2000V/500A power source > is a bit expensive (solution doesn't scale). It ain't the PSU that's the expensive bit on a supercon magnet -- it's th= e liquid Helium. After all, once you've ramped the current in the coil up = to $bignum amps, it just keeps going so long as the superconductors aren't allowed to heat up. LHe costs about the same as good whiskey, and you nee= d gallons of the stuff every few weeks. > 2) The hard drive has a tendency to fly out of one's > hands while moving it through the lines of force > (solution requires some physical coordination). Hmmm.... a solenoid coil magnet has a field that is approximately dipolar= =2E Forces vary as the inverse *cube* of the distance away from the center of= the magnet. Move a centimeter too close and the drive will suddenly be ripped out of your hands harder than you can resist. And sticking lumps of magnetic material up the bore of a 4T magnet probably requires quenching the magnet in order to get it out without damaging the magnet... Can you feel your accounts department wincing yet? > It's primarily for item #1 that I hadn't mentioned this earlier, as mos= t > readers of -STABLE users are probably looking for a more scalable solut= ion. Everyone should have their very own NMR spectrometer in their living room= ! Cheers, Matthew --=20 Dr Matthew J Seaman MA, D.Phil. 7 Priory Courtyard Flat 3 PGP: http://www.infracaninophile.co.uk/pgpkey Ramsgate Kent, CT11 9PW --------------enigBE410E47035F0530B35EA1E7 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.2 (FreeBSD) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFF2/TX8Mjk52CukIwRCFsVAJ4qymkFzwHbDQALzM+6D8mcXnDfwACeLtzC QFZ+dIEV+YDOg4zXgJQU4Ow= =sju3 -----END PGP SIGNATURE----- --------------enigBE410E47035F0530B35EA1E7--