Has anyone seen any data on CF card reliability? Which technologies or brands are better/worse? We will be fielding BitsyXb which will be writing (on average) a small amount of data to the embedded CF card every 10 seconds for up to 10000 hours, or 3.6 million writes, I don't want this piece to become a maintenance/reliability problem.
Good thinking! Flash does wear out over time, and it's good to make sure that your app isn't going to prematurely wear out your storage medium.
We haven't looked into your question for commercial CF cards, but we did address it some time ago concerning our own onboard flash (ref: topic 189). The longevity of the flash will depend on the CF card controller's load-levelling algorithms (if any), as well as the size of the card and number of blocks.
Your best bet is to create an accelerated stress test that you can use to qualify the cards use in your systems. Perform continuous write-verify cycles, writing and erasing data in approximately the same proportions and data block sizes that you expect to use in your application. You should be able to simulate a lifetime of use within just a day or two. Keep this app around to validate new flash cards, as consumer devices have a very short product life cycle (six months is a ripe old age for most).
We've been working with the SanDisk CompactFlash 5000 industrial grade CF cards (4GB P/N 54-90-06421-4096) in a couple applications. We seen high reliability in both in-house testing and field use.