From owner-freebsd-stable@FreeBSD.ORG Tue Jul 19 18:55:03 2011 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 62990106564A for ; Tue, 19 Jul 2011 18:55:03 +0000 (UTC) (envelope-from cswiger@mac.com) Received: from asmtpout029.mac.com (asmtpout029.mac.com [17.148.16.104]) by mx1.freebsd.org (Postfix) with ESMTP id 428CD8FC13 for ; Tue, 19 Jul 2011 18:55:03 +0000 (UTC) MIME-version: 1.0 Content-transfer-encoding: 7BIT Content-type: text/plain; CHARSET=US-ASCII Received: from cswiger1.apple.com ([17.209.4.71]) by asmtp029.mac.com (Oracle Communications Messaging Exchange Server 7u4-20.01 64bit (built Nov 21 2010)) with ESMTPSA id <0LOL00877DR3V660@asmtp029.mac.com> for freebsd-stable@freebsd.org; Tue, 19 Jul 2011 10:54:39 -0700 (PDT) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:5.4.6813,1.0.211,0.0.0000 definitions=2011-07-19_05:2011-07-19, 2011-07-19, 1970-01-01 signatures=0 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 ipscore=0 suspectscore=0 phishscore=0 bulkscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx engine=6.0.2-1012030000 definitions=main-1107190136 From: Chuck Swiger In-reply-to: Date: Tue, 19 Jul 2011 10:54:38 -0700 Message-id: References: <20110718234124.GA5626@icarus.home.lan> To: Kevin Oberman X-Mailer: Apple Mail (2.1084) Cc: "freebsd-stable@freebsd.org Stable" Subject: Re: Status of support for 4KB disk sectors X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 19 Jul 2011 18:55:03 -0000 On Jul 18, 2011, at 11:04 PM, Kevin Oberman wrote: > I just wish FreeBSD had some decent documentation on such a fundamental > operation. Fortunately there are some pretty good articles folks have > written, but they did leave me with several questions. Is there something in FreeBSD which is preventing you from using the drive's native DEV_BSIZE of 4096 bytes, or is it that the drive claims to have a physical block size of 512 bytes when it is really 4k? Except for a PC BIOS maybe wanting a 512-byte boot sector, there shouldn't be anything magical about that sector size. Unix operating systems like SunOS 3 and NEXTSTEP would happily run with a DEV_BSIZE of 1024 or larger-- they'd boot fine off of optical media using 2048-byte sectors, for example, and some of the early 1990's era SCSI hard drives supported low-level reformatting to a different sector size like 1024 or 2048 bytes. Regards, -- -Chuck