Read Only Memory (ROM)

READ ONLY MEMORY (ROM)

1)  ROM is an example of non-volatile memory.

2)  ROM is a class of storage medium used in Computers and other electronic devices.

3)  ROM is known as firmware, is an integrated circuit programmed with specific data when it is manufactured.

4)  Instructions for starting the computer are housed on Read Only Memory chip.

   Types of ROM

PROM(Programmable Read Only Memory)

1) A memory chip on which data can be written only once.

2) A program is written once on PROM  it remains there forever.

3) When the computer is turned off, PROM retains their contents.

4) To write data on a PROM chip, a special device PROM burner is needed.

EPROM(Erasable Programmable Read Only Memory)

1) EPROM is a special type of memory until it retains its content only

when it is exposed to ultraviolet light.

2) To write and Erase in EPROM a special device called PROM programmer

or PROM burner is needed.

EEPROM(Electrically Erasable Programmable Read Only Memory)

1) EEPROM is a special type of PROM  can be erased by exposing it to an

electric charge.

2) EEPROM retains its contents when the power is turned off.

3) EEPROM is not as fast as RAM.