What is an EPROM or EEPROM?
EPROM (Erasable Programmable Read-Only Memory) was designed to allow changes to the ROM chips through the use of ultra-violet light. A window on the top of an EPROM chip allows you to reprogram the chip using a chip burner. This system works, but because outside equipment was required not many people used this system. The chip can be programmed with various types of information about the memory module, and the CPU uses this information when booting up to understand what kind of memory is in the system and adjust its settings accordingly. EEPROM (Electrically Erasable Programmable Read-Only Memory) allows technicians to flash an electric charge through the ROM chip to reprogram it’s code. Most current BIOS’s have EEPROMs, and can be flashed while still connected to the motherboard. This means that a simple software utility can re-write an entire BIOS.
