From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964828AbWHCS1G (ORCPT ); Thu, 3 Aug 2006 14:27:06 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964829AbWHCS1F (ORCPT ); Thu, 3 Aug 2006 14:27:05 -0400 Received: from thebsh.namesys.com ([212.16.7.65]:59094 "HELO thebsh.namesys.com") by vger.kernel.org with SMTP id S964828AbWHCS1E (ORCPT ); Thu, 3 Aug 2006 14:27:04 -0400 Message-ID: <44D231DF.1080804@namesys.com> Date: Thu, 03 Aug 2006 11:26:55 -0600 From: Hans Reiser User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.13) Gecko/20060417 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Edward Shishkin CC: Matthias Andree , ric@emc.com, Alan Cox , Adrian Ulrich , "Horst H. von Brand" , bernd-schubert@gmx.de, reiserfs-list@namesys.com, jbglaw@lug-owl.de, clay.barnes@gmail.com, rudy@edsons.demon.nl, ipso@snappymail.ca, lkml@lpbproductions.com, jeff@garzik.org, tytso@mit.edu, linux-kernel@vger.kernel.org Subject: Re: the " 'official' point of view" expressed by kernelnewbies.org regarding reiser4 inclusion References: <200607312314.37863.bernd-schubert@gmx.de> <200608011428.k71ESIuv007094@laptop13.inf.utfsm.cl> <20060801165234.9448cb6f.reiser4@blinkenlights.ch> <1154446189.15540.43.camel@localhost.localdomain> <44CF9BAD.5020003@emc.com> <44CF3DE0.3010501@namesys.com> <20060803140344.GC7431@merlin.emma.line.org> <44D219F9.9080404@namesys.com> In-Reply-To: <44D219F9.9080404@namesys.com> X-Enigmail-Version: 0.93.0.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Edward Shishkin wrote: > Matthias Andree wrote: > >> On Tue, 01 Aug 2006, Hans Reiser wrote: >> >> >>> You will want to try our compression plugin, it has an ecc for every >>> 64k.... >> >> >> >> What kind of forward error correction would that be, > > > > Actually we use checksums, not ECC. If checksum is wrong, then run > fsck - it will remove the whole disk cluster, that represent 64K of > data. How about we switch to ecc, which would help with bit rot not sector loss? > > > and how much and > >> what failure patterns can it correct? URL suffices. >> > > Checksum is checked before unsafe decompression (when trying to > decompress incorrect data can lead to fatal things). It can be > broken because of many reasons. The main one is tree corruption > (for example, when disk cluster became incomplete - ECC can not > help here). Perhaps such checksumming is also useful for other > things, I didnt classify the patterns.. > > Edward. > >