Disk layout for XO-1.5

Walter Bender walter.bender at gmail.com
Mon Jul 27 19:17:49 EDT 2009


Why such a large system partition?

-walter

On Mon, Jul 27, 2009 at 6:17 PM, Mitch Bradley<wmb at laptop.org> wrote:
> This is a request for comments on a proposed disk layout for XO-1.5.
>
> XO-1.5 will have "managed NAND" instead of raw NAND, so we can use
> conventional filesystems instead of e.g. JFFS2.
>
> Proposal:
>
> The internal NAND storage will be partitioned with an FDISK partition
> map, into three partitions:
>
> /boot - 50 MB - FAT16
>    Contains olpc.fth, vmlinuz, initrd, and any other files that OFW
> needs to access during booting
>
> / - 2 GB - ext4
>    Contains system files
>
> /home - remainder of storage - ext4
>    Contains user files
>
> Dual-boot systems might have additional partitions for Windows.  That
> will probably require storage devices > 4GB.
>
> The partitions will be aligned to at least 1 MiB boundaries, ensuring
> that they do not split internal NAND erase blocks.
>
> The choice of FAT for /boot makes it usable for both Linux and Windows.
> The choice of FAT16 avoids any possible patent issues surrounding
> FAT32.  FAT16 works fine for 50 MB partitions, using a 1K cluster size.
> With larger cluster sizes, there are several factors of two of headroom
> - and large clusters are not a problem for /boot, which tends to contain
> mostly large files.
>
>
>
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>



-- 
Walter Bender
Sugar Labs
http://www.sugarlabs.org



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