From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: To: 9fans@9fans.net From: Richard Miller <9fans@hamnavoe.com> Date: Fri, 30 Sep 2011 09:31:04 +0100 In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Subject: Re: [9fans] copying fossil filesystem to a bigger disk Topicbox-Message-UUID: 2d5a618c-ead7-11e9-9d60-3106f5b1d025 > inquiry WDC WD20EARS-00MVWB0 > ... > The new drive is completely blank. It has 4096 byte sector size, and > disk/mbr fails. > > su# disk/mbr -m /386/mbr /dev/sdE1/data > mbr: secsize 4096 invalid Interesting. I have a WD10EARS which lies about its sector size - it reports 512 although it's really 4096. On that drive disk/mbr works as normal, but after fdisk and prep I had to readjust some partitions by hand because the "cylinder" size is 255*63*512, not a multiple of 4096. Plan 9 fdisk aligns things to a "cylinder" boundary, but the partitions need to be aligned to a multiple of 8 512-byte sectors from the beginning of the disk, or else every write would require a read-modify-write cycle. I suspect disk/mbr isn't the only place in Plan 9 where sector size is assumed to be 512. Has anyone else had experience with these "advanced format" drives?