
Fundamentals of Computers I-23
amount of time. Note that an EPROM eraser is not selective; it will erase the entire EPROM. Although
EPROM is more expensive than PROM, its ability to be reprogrammed makes it more useful.
• Electrically erasable programmable ROM (EEPROM): This type of ROM can be erased by an
electrical charge and then written to by using slightly higher-than-normal voltage. EEPROM can
be erased one byte at a time, rather than erasing the entire chip with ultraviolet light. Hence, the
process of re-programming is flexible, but slow. Also, changing the contents does not require any
additional committed equipment. As these chips ...