On Fri, Aug 10, 2001 at 08:21:21AM -0600, Herb Peyerl 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.

I'm not sure.  FLASH can't be erased byte-by-byte (but one sector at a time)
and I guess it's quite unlikely that you can write a complete disk block
without erasing a single byte.  If you need to change one bit or a sector
from "0" to "1", you must erase the whole sector.

The SanDisk manuals tell more, but I can't locate mine right now..

  -jm