Gary Ayala
New member
Similar question came up on a difference forum. This was the definative response:
"The amount of data written to by a format is less than 256k, it resets the
FAT table (64k) and clears the root directory (128k). This is done only once
per format, but an entry in the FAT table is written with every shot, so the
card will wear out much more from normal usage than by formatting. The
controller on quality CF cards also does cell mapping so that the cells on
the card are evenly used. For example in you case if you only were to only
ever use 2/3 of the card then the 1/3 cells not used in one session may be
mapped into use in the next, also cells are retired when they go bad so
slowly you may find that the card holds fewer images as it gets older. CF
cards that are manufactured using the MLC (multi level Cell) construction
are claimed to be rated over 10,000 write/erase cycles per cell whereas SLC
(single level Cell) construction are good for over 100,000 write/erase
cycles so in theory these will out last the 20D shutter by 2x. Also SLC
cards are faster than MLC so in general faster cards should last longer than
slower ones."
"The amount of data written to by a format is less than 256k, it resets the
FAT table (64k) and clears the root directory (128k). This is done only once
per format, but an entry in the FAT table is written with every shot, so the
card will wear out much more from normal usage than by formatting. The
controller on quality CF cards also does cell mapping so that the cells on
the card are evenly used. For example in you case if you only were to only
ever use 2/3 of the card then the 1/3 cells not used in one session may be
mapped into use in the next, also cells are retired when they go bad so
slowly you may find that the card holds fewer images as it gets older. CF
cards that are manufactured using the MLC (multi level Cell) construction
are claimed to be rated over 10,000 write/erase cycles per cell whereas SLC
(single level Cell) construction are good for over 100,000 write/erase
cycles so in theory these will out last the 20D shutter by 2x. Also SLC
cards are faster than MLC so in general faster cards should last longer than
slower ones."