Why NAND and NOR flash

PDO
Hello,
I just have a small question that bother me since I've got this card : why
is there 2 kinds of flash memory (NAND and NOR) on the mini2440 ?
Thanks in advance for the answer,
Pascal

davef
Wikipedia has a nice concise description.
http://en.wikipedia.org/wiki/Flash_memory

PDO
Davef,
Thanks for the answer. I should have started with Wikipedia, as usual :-)