[linux-mm-cc] [OFFTOPIC] SD wear-levelling (was: (no subject))

[Stefan Monnier]

> Wear leveling algorithms vary -- but as far as I know,  the majority
> are still based around the erase block.  (e.g.: When a group of
> sectors written are smaller than the size of an erase  block, the
> remaining sectors are read from the erase block, combined with the
> new data, and then written to a free block with the lowest amount
> of writes.)

AFAIK the SD cards don't support any kind of "tagged command queuing",
so after writing the first sector in a sequence, the card is supposed to
be in a state where the write is completed (even if power goes out at this
particular moment), so I wonder how they handle this while at the same
time being able to wait for the next write to see if it happens to be
to the next sector.


        Stefan