The best OS to deal with Flash Cards

[Lennart Sorensen]

On Thu, Aug 25, 2005 at 12:47:21PM -0400, Christopher Browne wrote:
> It seems to me that a journalling filesystem is the very last thing I
> want to use on a flash card which has the vital property of limited
> numbers of writes that can be applied to it.
> 
> The journal is, by its nature, designed to be a "hot spot" on the disk
> that is updated extremely heavily, which will, by its design, shorten
> the lifespan of the flash device.

Do you think the journal is a problem compared to the superblock and
other meta data blocks of almost all normal filesystems?  Only things
like jffs that explicitly have rotating blocks used for the superblock
info are properly designed for flash use.

Of course since _most_ decent flash media does wear leveling in
hardware, you shouldn't have to worry about it to much.

I use ext3 on compact flash and certainly the reduced fsck problems in
case of a power failure far outweigh the issues of the journal.

> For a flash device, there are only three filesystems I'd consider:
> 
> 1.  VFAT - because so many kinds of devices understand it including my
> PalmOS device and even my digital camera
> 
> 2.  ext2 - because various OSes can mount it, including Linux,
> Windows, and *BSD.
> 
> 3.  minixfs - not as easily portable, but a very simple filesystem for
> what amounts to a "big floppy disk".  And there are "minitools" for
> DOS as well as a FreeBSD 4.x driver...
> 
> VFAT is at the top of that list, BTW...  I may despise it as a choice
> for use on one's "system hard drive," but as an extension of the CP/M
> filesystems originally created for use with small disks, there is
> actually a decent fit between design/purpose and use, for this
> application...

Well VFAT is common since everyone supports it, I wouldn't personally
consider either of the other two.

Lennart Sorensen
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