CertiGuide to A+ (Core Hardware)  9  Chapter 0011:  System Memory       9  II  Memory Types

Erasable Programmable Read Only Memory (EPROM) 1 Random Access Memory (RAM)

EEPROMS were a significant advancement in ROM technology in that they allowed PC users to erase and reprogram their system ROM without the need of the special equipment used by PROM and EPROM chips.

A special software program that is often stored on a floppy disk controls the erasing and reprogramming routine.

This process of erasing and reprogramming an EEPROM chip is referred to as "flashing." A common implementation of this technology is used to upgrade the system BIOS program. In most new motherboards, the BIOS program is stored on an EEPROM, and can be updated by the user of the PC. The process is as follows:

The user gets a special program from the manufacturer of the motherboard, usually via the companies website.

The user runs this program in their OS environment. The program usually requires a blank, formatted floppy disk. It then writes a small operating system and the flashing program on the disk.

The user then reboots the computer with the disk in the floppy drive. The system boots the operating system from the floppy, bypassing the OS loaded on the hard drive of the PC.

The OS then executes the flashing program that erases and reprograms the ROM BIOS with a newer BIOS program.

The user then reboots the system without the floppy disk, and the process is complete.

Erasable Programmable Read Only Memory (EPROM) 1 Random Access Memory (RAM)