[Arm-netbook] Must watch video of GK802

[Gordan Bobic]

 On Fri, 11 Jan 2013 09:12:21 +0000, jm <joem at martindale-electric.co.uk> 
 wrote:

> This kind of thing should now be possible for all
> these matchbox computers because of f2fs.
> F2fs (flash friendly file system http://en.wikipedia.org/wiki/F2FS )
> merged into the kernel that allows ordinary flash to be used
> 
> http://www.h-online.com/open/news/item/F2fs-flash-friendly-filesystem-integrated-into-Linux-1773746.html
>
> F2fs keeps writing files to new locations and then cycle
> back to the beginning allowing even wear levelling.

 1) How is this different / better than nilfs2?
 nilfs is fully log structured and always appends
 to the end, with a garbage collection thread that
 starts from the head of the log (block device), and writes
 the de-garbaged data back to the tail of the log.

 Is f2fs more clever and less write-intensive (due to
 the nature of nilfs2's garbage collection)?

 Either way, this is by no means a pre-requisite for
 using such devices. Many existing ARM machines
 have been happily running off eMMC and SD devices long
 term without any issues regarding media wear-out.

 My SheevaPlugs run off an SD card, and have been for
 at least a couple of years without any issues, as
 have my Toshiba AC100s. It's really not a problem.
 Performance on random-writes is a much bigger issue,
 which is one place where something like nilfs2 helps
 a great deal by making all writes always linear,
 this making your random write MB/s the same as your
 linear write MB/s. Reads are extremely quick on
 SD cards regardless of whether they are sequential
 or random so potential de-linearization of them
 isn't problem.

> The great thing is that you can now yank out the OS
> and put a new OS in seconds. No way to brick a device.

 There are several other devices that work this way.

 Gordan