Department of Computer Scien

ce and Information Engineering

National Cheng Kung University

HANEL

SEMI-

CONDUCTOR MEMORY

ROM

Flash Memory EPROM (cont’)

‰It is believed that flash memory will replace part of the hard disk as a mass storage medium

¾The flash memory can be programmed while it is in its socket on the system board

ƒWidely used as a way to upgrade PC BIOS ROM

¾Flash memory is semiconductor memory with access time in the range of 100 ns compared with disk access time in the range of tens of milliseconds¾Flash memory’s program/erase cycles must become infinite, like hard disks

ƒProgram/erase cycle refers to the number of times that a chip can be erased and programmed before it becomes unusableƒThe program/erase cycle is 100,000 for flash and EEPROM, 1000 for UV-EPROM