Jukka Marin <jmarin@pyy.jmp.fi>  wrote:
 > The CF controller "circulates" the write around the entire disk space to
 > prevent failing of one FLASH sector.  At least SanDisk CF manuals say so.

Do they also optimize writes?  ie: if an address contains 0xf4 and the data
to be written is 0xc4, this can be done by clearing 2 bits and doesn't require
an erase cycle. Thereby preserving a write cycle for 3 bits.