Re: [Yaffs] Mounting time

> -----Original Message-----
> From: yaffs-bounces@lists.aleph1.co.uk [mailto:yaffs-
> bounces@lists.aleph1.co.uk] On Behalf Of alex z
> Sent: Tuesday, 29 July 2008 2:53 PM
> To: Charles Manning
> Cc: yaffs@lists.aleph1.co.uk
> Subject: Re: [Yaffs] Mounting time
>
> mini-UPS is impossible, my system is a handheld product. :)

If it's a handheld product (battery powered, I assume), then how can an
unexpected shutdown happen? A battery is the simplest UPS there is :)

> Is it possible that don't call yaffs_ScanBackwards after not clear
umount?
> It really kills time.
>
That's the bit that works out where the files are, so no.

> Can I use this solution to reduce the mounting time (after normal
umount or
> not clear umount):
> 1) assume the size of yaffs2 partition is 3G, it's called mypartition.
> 2) create a file which is called myfile and its size is 2.9G into
> mypartition
> 3) after mount mypartition, then mount myfile as vfat filesystem.
> 4) read and write files from/to vfat filesystem.
>
> Any comment?
>
You're trying to use YAFFS as a Flash Translation Layer there - you'll
end up with the mount speed of YAFFS and the reliability of VFAT.

The reason YAFFS (or any other filesystem designed for Flash) mounts
slowly and FAT mounts quickly is because FAT assumes that it can keep
the File Allocation Table in a fixed location and rewrite it often.
That's true for a hard disk, but you can't do that with NAND Flash.
Every update has to go in a new location.

What YAFFS has to do during mount is work out which blocks hold the
latest versions of each file/node - and that would include FAT loopback
containers too :)

James