From owner-freebsd-hackers@FreeBSD.ORG Tue Aug 10 19:05:39 2010 Return-Path: Delivered-To: hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 64350106566B; Tue, 10 Aug 2010 19:05:39 +0000 (UTC) (envelope-from bakul@bitblocks.com) Received: from mail.bitblocks.com (mail.bitblocks.com [64.142.15.60]) by mx1.freebsd.org (Postfix) with ESMTP id 468008FC12; Tue, 10 Aug 2010 19:05:39 +0000 (UTC) Received: from bitblocks.com (localhost.bitblocks.com [127.0.0.1]) by mail.bitblocks.com (Postfix) with ESMTP id 21FED5B5A; Tue, 10 Aug 2010 11:48:53 -0700 (PDT) To: =?utf-8?Q?Dag-Erling_Sm=C3=B8rgrav?= In-reply-to: Your message of "Tue, 10 Aug 2010 19:44:48 +0200." <86wrry1hwv.fsf@ds4.des.no> References: <86wrry1hwv.fsf@ds4.des.no> Comments: In-reply-to =?utf-8?Q?Dag-Erling_Sm=C3=B8rgrav?= message dated "Tue, 10 Aug 2010 19:44:48 +0200." Date: Tue, 10 Aug 2010 11:48:53 -0700 From: Bakul Shah Message-Id: <20100810184853.21FED5B5A@mail.bitblocks.com> Cc: geom@freebsd.org, hackers@freebsd.org Subject: Re: Support for WD Advanced Format disks X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 10 Aug 2010 19:05:39 -0000 On Tue, 10 Aug 2010 19:44:48 +0200 =?utf-8?Q?Dag-Erling_Sm=C3=B8rgrav?= wrote: > I'm looking into a clean, permanent solution for WD Green drives that > use 4096-byte physical sectors. To summarize the information I've > collected so far: > > - There are several types of WD Green disks. I am primarily interested > in the 1+ TB models: EARS and EADS. > > - According to WD's own documentation, EARS disks are Advanced Format > while EADS disks are not; furthermore, EARS disks have 64 MB cache > while EADS disks have only 32 MB. http://www.wdc.com/en/library/2579-001028.pdf gives an explanation of what the drive letters mean but they don't talk about 4k sector size. > - There is at least one source that provides model and serial numbers > for two EADS disks that seem have the performance characteristics of > an Advanced Format disk. One of them actually reports 4096-byte > sectors, the other does not. I am not entirely certain that source > is reliable. See below. > - Advanced Format disks should have a label that clearly describes them > as such: > > http://media.bestofmicro.com/U/O/238272/original/Western-Digital-WD10EARS-top.jpg >From http://www.wdc.com/en/products/advancedformat/ What models utilize Advanced Format technology? Some models of the WD Caviar Green and WD Scorpio Blue product families are built using Advanced Format technology. Over time more models and capacities will be added. WD drives with Advanced Format technology include special installation information on the drive label so be sure to read the label on your drive before installing it. ^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ So it seems that only the label distinguishes 4k sector drives.