Mini2440 and Wear Leveling for Flash Memory.

Hi to all.

I was wonder if Mini2440 has Wear Leveling for Flash Memory. My application
has a SQLite database for storing log data. This data base is a single file
within the application directory. As you know log records is generated very
often, and normally are readed and erased once per day. My concern is if
Mini2440 hardware or WinCE6.0 OS have some kind of feature to prevent
premature Flash memory damage, or how many write/erase cycles can give the
memory chip.


Thanks in advance, and best regards.

Built into the file system.  Read JFFS2 here:
http://en.wikipedia.org/wiki/JFFS2

Then look for YAFFS2

Hi davef.

Thanks for your response. If I understood, I have to format the NAND Flash
(Supervivi's option "f") with the YAFFS2 filesystem before download the OS
Image (Supervivi's option "w"), in order to ensure the NAND memory
leveling?

Thanks for your help.

Hi Ferite.

Why not use an SD card? If I was running SQLite on the Mini I would
definitely find a way to use SD and monitor to see if I needed a
maintenance and card copy/swap schedule to avoid loss of data.

How do you monitor wear in a SD memory?. An external memory was not my
first option because it make our product enclosure bigger, and we should
add an extra cost.

I'm sad to find out how few info there is in Internet for this important
subject.

All flash filesystems have wear-leveling, some better then others. 

The standard linux images from friendly arm are already in yaffs format. so
no need to do anything special.

Its always a good idea to keep in mind that you are using a flash storage
(for NAND or sd). like mounting /var/log, /var/tmp and others on a ram
filesystem, or disable the system logger completely.

Remco

Hi Remco.

If I understood well, wear-leveling is not implemented by the hardware but
by the software?. I wonder if the Windows CE file system implements a
equivalent protection.

Thanks.

I dont know anything about winCE, but it *must* implement it. 

if you buy a 128meg flash chip, its actually a few megs bigger. and it
comes with badblocks from the factory (they guarantee that the first meg
orso is badblock-free), and the number of badblocks will grow slowly over
the lifetime of the chip. the 10,000 cycle limit usually stated in the
datasheet of the chip, normaly means that is reached 1% badblocks at that
point.

Remco

Ferite,

You could use a mini sd card if you are using the mini or micro 2440.  It
has the connector built on the board and the card only extends about 1/8
inch (2 or 3mm).

John