only be done in blocks or the entire chip.
In 1995 this relatively new technology started to replace
EPROMs because reprogramming could be done with the chip
installed. At that time FEPROMs could be rewritten about 1000
times.
Like
EAPROM and ferro-magnetic material, FEPROMs rely on
FNtunnelling. Some flash memory supports block erase.
(1995-04-22)