Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752935AbYJAK1k (ORCPT ); Wed, 1 Oct 2008 06:27:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751722AbYJAK1c (ORCPT ); Wed, 1 Oct 2008 06:27:32 -0400 Received: from ns.netcenter.hu ([195.228.254.57]:60181 "EHLO netcenter.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751538AbYJAK1b (ORCPT ); Wed, 1 Oct 2008 06:27:31 -0400 Message-ID: <409101c923af$c8092020$0400a8c0@dcccs> From: "Janos Haar" To: "Milton Miller" Cc: References: <200809301450.m8UEo5wT027331@sullivan.realtime.net> Subject: Re: How can i read really 512 byte? Date: Wed, 1 Oct 2008 12:23:32 +0200 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-2"; reply-type=original Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.3138 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3350 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1534 Lines: 47 ----- Original Message ----- From: "Milton Miller" To: "Janos Haar" Cc: Sent: Tuesday, September 30, 2008 4:50 PM Subject: How can i read really 512 byte? > On Tue, 30 Sep 2008 at 08:29:15 -0400 (EDT), Janos Haar wrote: >> Now i am working on recover some data from one defective drive. I >> am using dd_rescue, and dd, but both ready only 4K, i think, because >> the kernel's block size is 4K. >> >> I have tried to google for the solution, but only found this trick: >> >> losetup /dev/loop0 /dev/hdc >> blockdev --setbsz 512 /dev/hdc >> >> and after this set, trying to read the hdc... >> >> It looks like working on the first look, but not really. :-( The >> 512 size bad sectors still have 4K sizes, but the reading attempt >> takes more (8x ?) longer. >> >> Somebody can help me to set the reading block size to 512 byte? > > You need to add O_DIRECT to the open call in the flags parameter > (the second argument). (My brother tested this a year or so ago, > and it worked for him). > > milton Hello, Thank you for the information. Can you help me a little bit more? Where need to add this parameter? In the kernel, in the blocked's source, or in the dd_rescue's source? Thanks, Janos Haar -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/