Flash is frightening. I wrote a transactional flash file system (well, object store) in the early 90s. It used NOR flash, which allows you slam individual bits

Flash is frightening. I wrote a transactional flash file system (well, object store) in the early 90s. It used NOR flash, which allows you slam individual bits from 1 to zero in any order. Basic strategy for doing a write: Write the payload, verify it, then clear some "commit" bits, and have enough infrastructure bits around that you can handle commit failure from stuck-at-1 errors. My failure model was probably pretty stupid, but it seemed to work well and I never heard of someone losing data. Of course, flash parts were a lot clunkier back then. Fast-forward 20 years and they're playing terrifying games with those flash cells. I worry that the people writing the firmware are willing to trade off reliability for capacity or speed. Or they make crazy risks ("Hey, this window is only for ten milliseconds, what are the chances?"). I know too many lame firmware engineers to be really comfortable. The failure modes are not block-by-block now, either. The whole device can go dead just because the firmware lost a lookup table to a bad bit. Something like this very clearly happened to Intel a couple years ago, and I know of other manufacturers who weren't very careful with their firmware quality (along the lines of "If we bump the version number on every fix, this will just make our customers nervous." Wow). I'd love to see an eMMC spec that: - Allows raw access to the underlying flash (useful for data recovery, in any event) - Provides metadata describing the treatment of that flash (how many reads / erases, leveling requirements, geometry info, etc.) - Provdes access to ECC engines, buffers and other support hardware (to reduce bus traffic and host computation) ... then we could push the data management into a FOSS layer in the host, where people can inspect it, fix it, and improve it. The combination of a hot commodity, pressure to make it perfom, complex management algorithms and opacity of implementation do not make me feel very happy about flash. [edit: typos]