From mboxrd@z Thu Jan 1 00:00:00 1970 From: erik quanstrom Date: Tue, 4 Oct 2011 14:29:39 -0400 To: 9fans@9fans.net Message-ID: <54b82479e890b0938c81b9ab9251d075@chula.quanstro.net> In-Reply-To: <20111004182445.DC8C5B856@mail.bitblocks.com> References: <6e6d01007f08aaf2fd598115982645dc@chula.quanstro.net> <20111004182445.DC8C5B856@mail.bitblocks.com> 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: 328526d8-ead7-11e9-9d60-3106f5b1d025 On Tue Oct 4 14:25:29 EDT 2011, bakul@bitblocks.com wrote: > On Tue, 04 Oct 2011 12:45:58 EDT erik quanstrom wrote: > > > Writing 25000 4k records stepping by 8k takes > > > sector offset 1-7 mod 8: 27-30 sec > > > sector offset 0 mod 8: 14-17 sec > > > > > > Conclusion: WD10EARS has 4k byte physical sectors but is pretty > > > good at concealing it. > > Weren't there 4k sector disks that mapped the 1st 4k sector to > just the mbr? So the next four 512B sectors got mapped to the > next 4k sector and so on. that's not what they do. they offset the lba by one so that the mbr is actually at offset 512 in the first lba, and therefore sector 63 (where most of the action starts, is at (512*63 + 512)/4k offset (512*63 + 512)%4k which is physical sector 8, offset 0. i think the wd tool can change this alignment. i'm sure there's some magic set features commands. - erik