Read: ProdManualSDCardv1.9.pdf I never saw any such commands or status, 2009/3/26 Bobby Clark <bcl...@airmail.net>
> There were a number of patents issued to SanDisk starting in the early > 90's for flash wear leveling. One of the more recent ones is 6,985,992. > The methods disclosed are simple counts of usage and block or byte moves. > Most of it centers around pointers. I suspect that the wear leveling > happens in a few machine cycles after the write command is given. It is > highly unlikely that the wear leveling mechanism could be causing data > corruption unless the power is cut right after the command is given to write > the data. Even then it would need to happen very quickly to effect the > write. Again one way to prove it would be to run a series of test. Knowing > the patent contents we could most likely determine what method they were > using. There is also most likely a debug interface in to the system. One > can probably get access to the written block data and replacement cells > available counts. > > Bobby > > > ----- Original Message ----- > *From:* Bobby Clark <bcl...@airmail.net> > *To:* uClinux development list <uclinux-dev@uclinux.org> > *Sent:* Thursday, March 26, 2009 9:26 AM > *Subject:* Re: [uClinux-dev] SD card corruption upon reboot and de-power > > Based on a 4MB zone and a 3 % reserve block there would be 120k bytes of > reserve bytes per 4MB zone. According to the doc the pool is a random > assortment per zone. It all comes down to how fast 120k bytes wear out. > Modern hard drives have a reserve pool and replace sectors or tracks that > are predicted to fail or have failed automatically. The SanDisk method > seems to be a good compromise to extend life for a simple system like the > flash cell. I suspect that the implementation is fairly simple. A search > of the patent office might reveal the raw details. > > Bobby > > > ----- Original Message ----- > *From:* Michael Schnell <mschn...@lumino.de> > *To:* uClinux development list <uclinux-dev@uclinux.org> > *Sent:* Thursday, March 26, 2009 7:05 AM > *Subject:* Re: [uClinux-dev] SD card corruption upon reboot and de-power > > > If this is true for a current card the OS would have a direct influence > on life > > Right ! > > FAT is abysmal. > > -Michael > > ------------------------------ > > _______________________________________________ > uClinux-dev mailing list > uClinux-dev@uclinux.org > http://mailman.uclinux.org/mailman/listinfo/uclinux-dev > This message was resent by uclinux-dev@uclinux.org > To unsubscribe see: > http://mailman.uclinux.org/mailman/options/uclinux-dev > > ------------------------------ > > _______________________________________________ > uClinux-dev mailing list > uClinux-dev@uclinux.org > http://mailman.uclinux.org/mailman/listinfo/uclinux-dev > This message was resent by uclinux-dev@uclinux.org > To unsubscribe see: > http://mailman.uclinux.org/mailman/options/uclinux-dev > > > _______________________________________________ > uClinux-dev mailing list > uClinux-dev@uclinux.org > http://mailman.uclinux.org/mailman/listinfo/uclinux-dev > This message was resent by uclinux-dev@uclinux.org > To unsubscribe see: > http://mailman.uclinux.org/mailman/options/uclinux-dev >
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