From: "H. Peter Anvin" <hpa@zytor.com>
To: Bill Davidsen <davidsen@tmr.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>,
Neil Brown <neilb@suse.de>, Eyal Lebedinsky <eyal@eyal.emu.id.au>,
Christian Pernegger <pernegger@gmail.com>,
linux-raid@vger.kernel.org
Subject: Re: mismatch_cnt questions
Date: Thu, 08 Mar 2007 20:20:36 -0800 [thread overview]
Message-ID: <45F0E094.4060809@zytor.com> (raw)
In-Reply-To: <45F0BFBA.5010201@tmr.com>
Bill Davidsen wrote:
>
> When last I looked at Hamming code, and that would be 1989 or 1990, I
> believe that I learned that the number of Hamming bits needed to cover N
> data bits was 1+log2(N), which for 512 bytes would be 1+12, and fit into
> a 16 bit field nicely. I don't know that I would go that way, fix any
> one bit error, detect any two bit error, rather than a CRC which gives
> me only one chance in 64k of an undetected data error, but I find it
> interesting.
>
A Hamming code across the bytes of a sector is pretty darn pointless,
since that's not a typical failure pattern.
-hpa
next prev parent reply other threads:[~2007-03-09 4:20 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-03-04 11:22 mismatch_cnt questions Christian Pernegger
2007-03-04 11:50 ` Neil Brown
2007-03-04 12:01 ` Christian Pernegger
2007-03-04 22:19 ` Neil Brown
2007-03-06 10:04 ` mismatch_cnt questions - how about raid10? Peter Rabbitson
2007-03-06 10:20 ` Neil Brown
2007-03-06 10:56 ` Peter Rabbitson
2007-03-06 10:59 ` Justin Piszcz
2007-03-12 5:35 ` Neil Brown
2007-03-12 14:26 ` Peter Rabbitson
2007-03-04 21:21 ` mismatch_cnt questions Eyal Lebedinsky
2007-03-04 22:30 ` Neil Brown
2007-03-05 7:45 ` Eyal Lebedinsky
2007-03-05 14:56 ` detecting/correcting _slightly_ flaky disks Michael Stumpf
2007-03-05 15:09 ` Justin Piszcz
2007-03-05 17:01 ` Michael Stumpf
2007-03-05 17:11 ` Justin Piszcz
2007-03-07 0:14 ` Bill Davidsen
2007-03-07 1:37 ` Michael Stumpf
2007-03-07 13:57 ` berk walker
2007-03-07 15:01 ` Bill Davidsen
2007-03-05 23:40 ` mismatch_cnt questions Neil Brown
2007-03-07 0:22 ` Bill Davidsen
2007-03-08 6:39 ` H. Peter Anvin
2007-03-08 13:54 ` Martin K. Petersen
2007-03-09 2:00 ` Bill Davidsen
2007-03-09 4:20 ` H. Peter Anvin [this message]
2007-03-09 5:20 ` Bill Davidsen
2007-03-08 6:34 ` H. Peter Anvin
2007-03-08 7:00 ` H. Peter Anvin
2007-03-08 8:21 ` H. Peter Anvin
2007-03-13 9:58 ` Andre Noll
2007-03-13 23:46 ` H. Peter Anvin
2007-03-06 6:27 ` Paul Davidson
2008-05-12 11:16 ` Bas van Schaik
2008-05-12 14:31 ` Justin Piszcz
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