From mboxrd@z Thu Jan 1 00:00:00 1970 From: Oleg Drokin Subject: Re: 'let the hdd remap the bad blocks' Date: Mon, 19 Aug 2002 19:59:06 +0400 Message-ID: <20020819195906.A19984@namesys.com> References: <5.1.1.6.2.20020819155611.01ff7af0@pop.tvnet.hu> Mime-Version: 1.0 Return-path: list-help: list-unsubscribe: list-post: Errors-To: flx@namesys.com Content-Disposition: inline In-Reply-To: <5.1.1.6.2.20020819155611.01ff7af0@pop.tvnet.hu> List-Id: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Newsmail Cc: reiserfs-list@namesys.com Hello! Basically uyou'd better search for this on HDD vendors sites. What's going on is simply can be described this way: You write some block to HDD, if HDD decides the block is bad for some reason and remapping is allowed (usually by tiurning on SMART), block is written to different on-platter location and drive adds one more entry to its remaped-blocks list. Next time you read this block, drive consults its remapped blocks list and if block is remapped, reads it from new location with correct content. Described mechanism works for writing. Actually I've seen something that looks like remapping on read, though I have no meaningful explanation for that (except that they may have some extra redundant info stored when you write data to disk, so that if sector cannot be read, its content is restored with that redundant information and sector is then remapped.). And this process takes a lot of time. Bye, Oleg On Mon, Aug 19, 2002 at 03:58:30PM +0100, Newsmail wrote: > Hello Hans and Oleg, > maybe its an offtopic question, but Hans always talks about leaving the > hard disk to remap the bad blocks by itself. could you explain it in some > words, how all this works, what happens after, and since when it exists, or > do you have any special URL explaining this? > thx in advance, > greg > > >