Messages in this thread | | | From | "Janos Haar" <> | Subject | Re: How can i read really 512 byte? | Date | Wed, 1 Oct 2008 12:23:32 +0200 |
| |
----- Original Message ----- From: "Milton Miller" <miltonm@bga.com> To: "Janos Haar" <janos.haar@netcenter.hu> Cc: <linux-kernel@vger.kernel.org> 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
| |