Hello,
We are developing a Linux based embedded system that will use CompactFlash.
Should we prefer ext2 or ext3? How should we think about the trade- offs?
What is your experience using either in a fielded system?
Thanks.
Jim
I tend to use ext2 or even minix filesystems for this purpose.
You could also consider loopback-mounting the filesystem on top of fat which will enable customers to update the Software using M$ Operating Systems.
Linux _does_ have very a very good Journaling Flash Filesystem (jffs2), but unfortunately the block device emulation of common flash devices like CompactFlash or SD-cards does not allow us to use this filesystem in conjunction with such devices.
Sven
--
"Every time you use Google, you're using a Linux machine"
(Chris DiBona, a programs manager for Google)
/me is giggls@ircnet, http://sven.gegg.us/ on the Web
I would recommend not using CF in any way. They are for consumer electronics and where data security is not important.
Don't use CF! If you want to interrupt the power supply at any point of time you can clobber your CF and any filesystem on it. In such a case also ext3 does not help. If you buy today some cards it might work, and if you will buy the next cards in six month it fails badly (and no chance to find out why). Instead try to work an bare NAND or NOR flash. In this case you have the control about the devices and the required wear leveling. And if you mount some partitions readonly it is really readonly!
JB
Correct. But even if it _could_ be done it would not help, as the internal wear leveling the card does on it's own behalf can destroy the data it powered off after any simple write access. And there is no hint by the manufacturers about how long the wear leveling can take.
-Michael
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