Flash.

It's commonly used for MP3 players, computer BIOS code and "thumb" drives. Originally developed in Japan by Toshiba, it has become quite popular for products requiring non-volatile erasable memory. Flash devices have a limited number of erase cycles (typically 10,000 to 1,000,000 cycles) so they're not as good a choice for applications in which the data changes constantly. However, since it has no moving parts (unlike a hard disk) it is an excellent choice for storing the operating code for small personal electronics like PDAs, cell phones, digital cameras, and the data in items like MP3 players.