From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rogier Wolff Subject: Driver retries disk errors. Date: Mon, 30 Aug 2004 18:39:31 +0200 Sender: linux-ide-owner@vger.kernel.org Message-ID: <20040830163931.GA4295@bitwizard.nl> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from users.linvision.com ([62.58.92.114]:7914 "HELO bitwizard.nl") by vger.kernel.org with SMTP id S268541AbUH3Qje (ORCPT ); Mon, 30 Aug 2004 12:39:34 -0400 Content-Disposition: inline List-Id: linux-ide@vger.kernel.org To: linux-kernel@vger.kernel.org Cc: linux-ide@vger.kernel.org Hi, We encounter "bad" drives with quite a lot more regularity than other people (look at the Email address). We're however, wondering why the IDE code still retries a bad block 8 times? By the time the drive reports "bad block" it has already tried it several times, including a bunch of "recalibrates" etc etc. For comparison, the Scsi-disk driver doesn't do any retrying. So, why do we still do this? - The driver may still work for MFM drives and less "intelligent" controllers? - Someone has recently seen that this actually helps? In fact we regularly are able to recover data from drives: we have a userspace application that retries over and over again, and this sometimes recovers "marginal" blocks. This could be considered "good practise" if there is a filesystem requesting the block. On the other hand, when this happens, the drive is usually beyond being usable for a filesystem: if we recover one block this way, the next block will be errorred and the filesystem "crashes" anyway. In fact this behaviour may masquerade the first warnings that something is going wrong.... So, I'm arguing for: We remove the retry code alltogether, OR we make an option to re-enable the retry code for MFM era drives(*) (Note: those are more than 10 years old, so almost (but not quite) extinct). Roger. (*) Note: Tested last month: The driver still works for MFM drives. However, the initialization apparently is not enough anymore. The drive did not work when the BIOS didn't think there was a drive. -- +-- Rogier Wolff -- www.harddisk-recovery.nl -- 0800 220 20 20 -- | Files foetsie, bestanden kwijt, alle data weg?! | Blijf kalm en neem contact op met Harddisk-recovery.nl!