parkranger_dan <> [2011-05-15 17:37:04]:
> One question I had was in regard to the longevity of these little MicroSD
> cards, and their resilience to repeated power loss.
It depends on a lot of factors and unknown variables, but simply said, I
wouldn't trust them at all. I've seen quite a lot damaged SD cards. Well,
maybe if the whole rootfs on the SD card is R/O and some small R/W partition
for data, with sync() after each write. But even in this scenario I wouldn't
trust it much, because the corruption on the R/W partition could take down
whole SD card (don't ask me how and why, I didn't wrote the firmware of that
SD card, but it happens).
On the other end, with the pure NAND flash, you've almost everything under
your control, you can see the bottom layer, but with SD card, you see nothing,
nothing about NAND content, nothing about the firmware etc. So it's all just
guess and relying on some unpredictable.
> Customers will not have the ability to shutdown nicely, power will always be
> removed to turn off. I based my image from the latest.dd image available
> from the Technologic website, which if I remember correctly is formatted
> ext3.
Ext3, uh? Maybe something without journal, ext2 or so. But even then, nothing
much rock solid.
> Has anyone had any experience with a similar setup? How are the boxes
> holding up, and have the MicroSD cards been lasting?
Well, if you want such setup, use some kind of battery assisted graceful
shutdown with some kind of UPS, or something like ts-bat-3 or how it's called.
-- ynezz
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