On Fri, Oct 09, 2009 at 04:23:17PM -0700, S Page wrote: > On Tue, Oct 6, 2009 at 3:10 AM, Mitch Bradley <w...@laptop.org> wrote: > > > b) If you must construct a fixed partition layout for use on multiple > > different devices, align each partition on at least a 4MiB boundary. > > That means that you "waste" 4M for the partition map (one 512-byte > > sector padded out to a 4 MiB boundary, but oh well). > > [...] > > 1. > Do the F11 / SoaS "overwrite your USB/SD device" XO images follow this > guideline? > cat soas??xo.2gremovable.tar.lzma | lzma -dc - | tar xf - -O > > /dev/sdX
Nope (SoaS) - that'll waste your partition table in favour of whatever I copied from my dsd-inspired "make-fake-device" partition table script[1]. I'd love patches. Actually, I even had a try[2] at getting it right a while ago, based on what I understood from T'so's post[3] and Mitch's warning page[4]: --- Do this for ext3 (omit -j for ext2): fdisk -H 224 -S 56 /dev/sdb [partition as normal] mke2fs -j -E stripe-width=32,resize=500G /dev/sdb1 [etc.] ...or this for ext4: fdisk -H 224 -S 56 /dev/sdb [partition as normal] mke2fs -t ext4 -E stripe-width=32,resize=500G /dev/sdb1 [etc.] --- ...but if anyone can correct / enlighten me as to The True Partition... > (The way a boot image is created and distributed as multiple > monolithic 379+ MB files seems crazy -- surely it's just a collection > of files, tweaks to the existing MBR, and some disk partitioning and > FS layout requirements. But that's a different discussion. ;-) ) Err, I call Q.E.D. on why that's the easiest way to distribute a workable image :). But we burn a lot of disk space distributing .ISOs, NAND-ready JFFS2 images, tar'ed directory trees, and even xdeltas of the tar'ed directory trees (or something), so hopefully anyone who can write a better set of instructions than that cat pipeline you quoted won't be stopped by the lack of a set of bytes to kick the process off. > (I have a cheap USB flash drive that has "gone crazy" after two > /dev/sdb reblastings; often usb-creator leaves it in a bizarre state > and dosfsck reports hundreds of errors it can't repair. Weird.) Indeed...sorry to hear it. I have a cheap 4GB USB drive that's been "re-blasted" a hundred or so times and is still going. > =S Page Martin 1. http://cgit.sugarlabs.org/soas/mainline/tree/make_fake_device.sh#n55 2. http://www.martindengler.com/ , scroll down to "2009-03-07 : Formatting SD cards as ext2, ext3, or ext4" 3. http://thunk.org/tytso/blog/2009/02/20/aligning-filesystems-to-an-ssds-erase-block-size/ 4. http://wiki.laptop.org/go/How_to_Damage_a_FLASH_Storage_Device
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