Kevin Uhlir wrote:
Vfat..hmmm... well I could use that for the logs. Since log files would be somewhat "similar" to writing pictures sequentially, which is what the camera would do, it should fit their "possibly simple or non-existant leveling method".
I don't see vfat supporting anything like data=ordered for ext3. I'm left with the sync option. I'm still thinking I might beat the wear-out issue by simply scheduling copy and replacement once a year, then give away the old SD card to some unsuspecting person. Still I think I'll take the vfat advice in combination with scheduled replacement.
Ext3 is probably similar enough, and you'd get the journaling benefit as well.
But yea, I'd definitely schedule replacement--- and when picking the replacement
candidate buy two and abuse the daylights out of one first to see what happens.
I have seen a couple of SD/MMC controllers get completely hung up on an error,
to the point that you just pitch the card. Little postage-stamp-sized
doorstops, as I remember it.
I assume jffs2 would be the right choice for a rootfs on the nand flash on the board.
Yes, or perhaps yaffs. I haven't had time to look at the UBI stuff, maybe
there's something there too.
However if I mounted it read-only I could still choose ext2 for performance
reasons.
True, if you could create the image offline and then dd it into the device.
For read throughput, once you're mounted the performance difference might not be
all that different between ext* and the various *ffs*-en, because the kernel's
VFS stuff works to your advantage for both. JFFS has a reputation for slow
mounting, but "summary nodes" can speed that up if you enable that feature. If
your system even cold-boots at all, I mean--- most of my platforms are up so
long, the reboot time doesn't matter because it's only done a few times a year.
I'd probably go with one of the ffs-en rather than ext even in a presumed
read-only scenario. Because then if you changed your mind later about
read/write you wouldn't have to reconfigure the system--- just remount if
necesssary, and you're good to go.
b.g.