Date: Tue, 9 Sep 2014 02:29:54 +0200 From: Bernd Walter <ticso@cicely7.cicely.de> To: freebsd-arm@freebsd.org Cc: Bernd Walter <ticso@cicely7.cicely.de> Subject: Re: Crochet partition alignment Message-ID: <20140909002954.GB24276@cicely7.cicely.de>
next in thread | raw e-mail | index | archive | help
[67]wandboard# gpart list Geom name: mmcsd0 modified: false state: OK fwheads: 255 fwsectors: 63 last: 61497343 first: 63 entries: 4 scheme: MBR Providers: 1. Name: mmcsd0s1 Mediasize: 52416000 (50M) Sectorsize: 512 Stripesize: 4194304 Stripeoffset: 30208 Mode: r1w1e1 attrib: active rawtype: 12 length: 52416000 offset: 8418816 type: !12 index: 1 end: 118817 start: 16443 2. Name: mmcsd0s2 Mediasize: 31425805312 (29G) Sectorsize: 512 Stripesize: 4194304 Stripeoffset: 2114560 Mode: r1w1e2 rawtype: 165 length: 31425805312 offset: 60834816 type: freebsd index: 2 end: 61497343 start: 118818 Consumers: 1. Name: mmcsd0 Mediasize: 31486640128 (29G) Sectorsize: 512 Stripesize: 4194304 Stripeoffset: 0 Mode: r2w2e5 Geom name: mmcsd0s2 modified: false state: OK fwheads: 255 fwsectors: 63 last: 61378525 first: 0 entries: 8 scheme: BSD Providers: 1. Name: mmcsd0s2a Mediasize: 31425757184 (29G) Sectorsize: 512 Stripesize: 4194304 Stripeoffset: 2162688 Mode: r1w1e1 rawtype: 7 length: 31425757184 offset: 48128 type: freebsd-ufs index: 1 end: 61378525 start: 94 Consumers: 1. Name: mmcsd0s2 Mediasize: 31425805312 (29G) Sectorsize: 512 Stripesize: 4194304 Stripeoffset: 2114560 Mode: r1w1e2 There are 63 sectors per track in MBR table. s1 starts at sector 16443 in track 261. This is an uneven 512 byte sector number, so it starts at 512 Byte alignment only. Leaves the question why 261 tracks are left out when it still isn't aligned? s2, which is what I care most about, starts at 118818. This is even, but only once divideable by 2. It is at a 1024 alignment - still not the needed >= 4k for SD cards. Inside s2 the a partition starts at 48128 (+118818 from provider). Again lost space. By itself it would be a 512k alignment - more than perfect, though I don't think it requires such a big waste, but with the mmcsd0s2 provider alignemt it's still only 1k. -- B.Walter <bernd@bwct.de> http://www.bwct.de Modbus/TCP Ethernet I/O Baugruppen, ARM basierte FreeBSD Rechner uvm.
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20140909002954.GB24276>