From owner-freebsd-stable@FreeBSD.ORG Tue Jul 19 22:00:27 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 BD428106564A for ; Tue, 19 Jul 2011 22:00:27 +0000 (UTC) (envelope-from cswiger@mac.com) Received: from asmtpout023.mac.com (asmtpout023.mac.com [17.148.16.98]) by mx1.freebsd.org (Postfix) with ESMTP id A30968FC12 for ; Tue, 19 Jul 2011 22:00:27 +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 asmtp023.mac.com (Oracle Communications Messaging Exchange Server 7u4-20.01 64bit (built Nov 21 2010)) with ESMTPSA id <0LOL00LG9P4QY170@asmtp023.mac.com> for freebsd-stable@freebsd.org; Tue, 19 Jul 2011 15:00:27 -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-1107190185 From: Chuck Swiger In-reply-to: <20110719211039.GA16085@server.vk2pj.dyndns.org> Date: Tue, 19 Jul 2011 15:00:26 -0700 Message-id: <02D367A5-CA74-4E8A-BE3E-F81485B287A7@mac.com> References: <20110718234124.GA5626@icarus.home.lan> <20110719211039.GA16085@server.vk2pj.dyndns.org> To: Peter Jeremy 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 22:00:27 -0000 On Jul 19, 2011, at 2:10 PM, Peter Jeremy wrote: > On 2011-Jul-19 10:54:38 -0700, Chuck Swiger wrote: >> 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, > > Actually, Sun used customised CD-ROM drives that faked 512-byte > sectors to work around their lack of support for anything else. Hmm-- my brain could be fuzzy about things twenty-plus years ago. But I remember booting a Sun3_35 or _60 from a non-Sun or Sun OEM'ed SCSI CD-ROM drive, probably a Plextor? >> some of the early 1990's era SCSI hard drives supported low-level reformatting to a different sector size like 1024 or 2048 bytes. > > Did anyone actually do this? I wanted to but was warned against > it by the local OS rep (this was a Motorola SVR2). Worked fine with 250MB Seagate ST1280 drives, and also a a 1GB Micropolis 2112. It made a decent gain to available disk capacity (about 10-15%), and a smaller improvement to performance (about 5% IIRC). It wouldn't work with drives using a dedicated embedded servo for sector positioning (ie, Quantum and DEC), but other vendors like Seagate used a normal platter surface for servo positioning, and you could reformat it with a different sector size. Regards, -- -Chuck