File systems for SD cards

I don't think that there is any limitation what file system to use on an
SD-Card. So why not do NTFS <g>.

-Michael

cards

Thats not the way I see it. SD Cards require the SD File System otherwise
they aren't SD cards anymore.

Peter

Right ! No chance to exchange them with other systems.

-Michael

With Linux you can use just about any file system you want. Choose one
that's native to Linux -- ext3, reiser, etc..

So long as you don't care about non-linux portability, then any
linux-supported fs should do. However, I'd stay away from journalling
filesystems (flash memory has a large but limited number of write
cycles, and journals add to the # of writes), and look at low-overhead
filesystems. My personal choice would likely be the Minix fs (for
general portability) or one of the memory filesystems (ramfs?)
specifically designed for these sorts of devices.

HTH

Acutally non-portable is good (security through obscurity is a good
thing, no? :-) )

Seriously, I am trying to fix some performance issues - very slow access
with multiple processes accessing the SD card - and I am trying to
experiment with different file systems for SD to see if they are more
suitable for this than vfat.  The SD card seems to bog down seriously
with different processes accessing it at once....

I'm going to try ext2 but I will give minix fs a try.  I tried to use
jffs but it doesn't work with SD cards all as they emulate scsi devices,
and the kernel doesn't see them as mtd.

Something like jffs for scsi would be good to try...

--Yan

access

Just FYI,

I have a Sharp Zaurus (CL-3000 Japanese-only model from importer).  It's a
linux-based PDA/micro-laptop. I found a HUGE improvement in speed of
access when I reformatted my external SD cards to EXT2.  I don't do a lot
of writing to them, primarily readback of datafiles and .oggs for music.
As a rough estimate, I'd say write-speed is 2-3X faster and readback is
easily 5-10x faster, especially with multiple processes accessing files on
the card.

YMMV,
-S

:-)  I have  a 3100, bought in Japan last X-mas.  Ain't it great?  I
wish they brought them here.



OK, thanks.  I'll give it a try.  Any special mounting options?

I figure async,noatime,rw should be enough for me...

--Yan

Ask Uncle Bill Gates......

Dave

I think minix fs would cause as many problems as it would seem to solve,
such as filname limitations and (IIRC) fragmentation vulnerability.  I
don't know about the utility of ramfs for this, but I've used ext2 on an
sd card for years.

If it is used in a camera, then you had better use the same file system the
camera uses (usually vfat). If not, put whatever you want on it, but if you
want both linux and windows to use it, better stick with vfat.