Messages in this thread | | | Date | Tue, 20 Sep 2005 18:11:03 +0400 | From | "Artem B. Bityutskiy" <> | Subject | Re: data loss on jffs2 filesystem on dataflash |
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Jörn Engel wrote: > Still can't. Block devices have the attribute that writing AAA... to > a block containing BBB... gives you one of three possible results in > case of power failure: > > 1. BBB...BBB all written > 2. AAA...AAA nothing written > 3. AAA...BBB partially written. > > Flash doesn't have 3, but two more cases: > 4. FFF...FFF erased, nothing written > 5. AAA...FFF erased, partially written > > Plus the really obnoxious > 6. FFF...FFF partially erased. Looks fine but some bits may flip > randomly, writes may not stick, etc. > > Now try finding a filesystem that is robust if 4-6 happens. ;) Don't underastand this. If you mean the atomicity, CRC may help here. And no problems. Or may be you missed the the fact that we have eraseblock size = writeblock size?
>>JFFS2 orients to "classical" flashes. They have no "write page with >>built-in erase" operation. > What does this thing do? It erases individual page, then writes there. To put it differently, in your terminology, eraseblock size = writeblock size.
P.S. I actually missed the mailing list, this should have gone to the MTD ML. So let's move there please.
-- Best Regards, Artem B. Bityuckiy, St.-Petersburg, Russia.
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