From: "Ken Hirsch" <kenhirsch@myself.com>
To: "Chris Wedgwood" <cw@f00f.org>, "John Alvord" <jalvo@mbay.net>
Cc: "Daniel Phillips" <phillips@bonn-fries.net>,
"Alan Cox" <alan@lxorguk.ukuu.org.uk>,
"Andrew Morton" <andrewm@uow.edu.au>,
"Andreas Dilger" <adilger@turbolinux.com>,
"Albert D. Cahalan" <acahalan@cs.uml.edu>,
"Ben LaHaise" <bcrl@redhat.com>,
"Ragnar Kjxrstad" <kernel@ragnark.vestdata.no>,
<linux-fsdevel@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<mike@bigstorage.com>, <kevin@bigstorage.com>,
<linux-lvm@sistina.com>
Subject: Re: [PATCH] 64 bit scsi read/write
Date: Sun, 15 Jul 2001 09:16:09 -0400 [thread overview]
Message-ID: <005501c10d30$54e0e260$7c853dd0@hppav> (raw)
In-Reply-To: <Pine.LNX.4.20.0107142304010.17541-100000@otter.mbay.net> <20010715180752.B7993@weta.f00f.org>
Chris Wedgwood <cw@f00f.org> wrote:
> On Sat, Jul 14, 2001 at 11:05:36PM -0700, John Alvord wrote:
>
> In the IBM solution to this (1977-78, VM/CMS) the critical data was
> written at the begining and the end of the block. If the two data
items
> didn't match then the block was rejected.
>
> Neat.
>
>
> Simple and effective. Presumably you can also checksum the block, and
> check that.
The first technique is not sufficient with modern disk controllers, which
may reorder sector writes within a block. A checksum, especially a robust
CRC32, is sufficient, but rather expensive.
Mohan has a clever technique that is computationally trivial and only uses
one bit per sector: http://www.almaden.ibm.com/u/mohan/ICDE95.pdf
Unfortunately, it's also patented:
http://www.delphion.com/details?pn=US05418940__
Perhaps IBM will clarify their position with respect to free software and
patents in the upcoming conference.
next prev parent reply other threads:[~2001-07-15 13:15 UTC|newest]
Thread overview: 71+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-07-01 4:53 [RFC][PATCH] first cut 64 bit block support Ben LaHaise
2001-07-03 4:53 ` Ragnar Kjørstad
2001-07-04 2:19 ` [PATCH] 64 bit scsi read/write Ben LaHaise
2001-07-04 7:11 ` Alan Cox
2001-07-05 6:34 ` Ragnar Kjørstad
2001-07-05 7:35 ` Ben LaHaise
2001-07-13 18:20 ` Albert D. Cahalan
2001-07-13 20:41 ` Andreas Dilger
2001-07-13 21:07 ` Chris Wedgwood
2001-07-13 22:04 ` Andreas Dilger
2001-07-14 0:49 ` Jonathan Lundell
2001-07-14 12:27 ` Paul Jakma
2001-07-14 14:48 ` Chris Wedgwood
2001-07-14 15:42 ` Paul Jakma
2001-07-14 17:18 ` Chris Wedgwood
2001-07-20 17:03 ` Stephen C. Tweedie
2001-07-16 18:53 ` Andreas Dilger
2001-07-16 19:13 ` Ragnar Kjørstad
2001-07-13 21:14 ` Alan Cox
2001-07-14 3:23 ` Andrew Morton
2001-07-14 8:45 ` Alan Cox
2001-07-14 14:50 ` Chris Wedgwood
2001-07-14 20:11 ` Daniel Phillips
2001-07-15 1:21 ` Andrew Morton
2001-07-15 1:53 ` Daniel Phillips
2001-07-15 3:36 ` Chris Wedgwood
2001-07-15 6:05 ` John Alvord
2001-07-15 6:07 ` Chris Wedgwood
2001-07-15 13:16 ` Ken Hirsch [this message]
2001-07-15 14:50 ` Chris Wedgwood
2001-07-15 22:14 ` Daniel Phillips
2001-07-17 0:31 ` Juan Quintela
2001-07-15 13:44 ` Daniel Phillips
2001-07-15 14:39 ` Chris Wedgwood
2001-07-15 15:32 ` Alan Cox
2001-07-15 15:33 ` Chris Wedgwood
2001-07-15 16:24 ` Chris Wedgwood
2001-07-15 15:06 ` Jonathan Lundell
2001-07-15 15:22 ` Chris Wedgwood
2001-07-15 17:44 ` Jonathan Lundell
2001-07-15 17:47 ` Justin T. Gibbs
2001-07-15 23:14 ` Rod Van Meter
2001-07-16 0:37 ` Jonathan Lundell
2001-07-16 15:11 ` Rod Van Meter
2001-07-16 8:56 ` Chris Wedgwood
2001-07-16 13:19 ` Daniel Phillips
2001-07-16 1:08 ` Albert D. Cahalan
2001-07-16 8:49 ` Chris Wedgwood
2001-07-21 19:18 ` Alexander Griesser
2001-07-22 3:52 ` Albert D. Cahalan
2001-07-23 14:41 ` Daniel Phillips
2001-07-24 4:29 ` Albert D. Cahalan
2001-07-24 11:45 ` Daniel Phillips
2001-07-14 15:41 ` Jonathan Lundell
2001-07-14 17:00 ` Chris Wedgwood
2001-07-14 17:33 ` Jonathan Lundell
2001-07-15 4:02 ` Chris Wedgwood
2001-07-15 5:46 ` Jonathan Lundell
2001-07-15 17:10 ` Chris Wedgwood
2001-07-15 17:39 ` Jonathan Lundell
2001-07-26 2:18 ` Ragnar Kjørstad
2001-07-26 16:24 ` Andreas Dilger
2001-08-10 19:42 ` Ben LaHaise
2001-08-10 19:51 ` Ragnar Kjørstad
2001-08-10 20:02 ` Ben LaHaise
2001-08-11 0:18 ` Steve Lord
2001-08-11 21:44 ` Matti Aarnio
2001-07-04 10:16 ` [RFC][PATCH] first cut 64 bit block support Chris Wedgwood
2001-07-04 16:59 ` Ben LaHaise
2001-07-14 15:08 [PATCH] 64 bit scsi read/write Ed Tomlinson
2001-07-19 7:35 [PATCH] 64 bit SCSI read/write Andre Hedrick
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