ROM:

ROM-Read Only Memory, as we are all using computers now and most of as doesn't know about ROM. Here i explained ROM and its types. ROM is permanently in-uilt in the computer. It is also called as "Firmware". It stores a set of instructions permanently, which instructs the computer to how to work. The permanent programs like operating system and supporting programs are stored in ROM. It performs the BIOS functions. The ROM chips uses only less power. It is a non volatile memory. It is available in high storage capacity. The processing speed is low when compared to RAM.

Types Of ROM:

There are five different types of ROM's available. They are

1.Masked ROM

2.PROM

3.EPROM

4.EEPROMS

5.Flash ROM

1.Masked ROM:

Masked ROM is  a hand wired device and it contains a pre-programmed set of data or instructions.

2.PROM:

PROM-Programmable Read Only Memory, in other words it is called as Programmable ROM. The manufacturer supply it with blank and the user must write the desired program into it once by a special process. It is one time programmable.

3.EPROM:

EPROM- Erasable Programmable ROM. As the name indicates the program can be written more than once. So it solve the problem of PROM.

4.EEPROMS:

EEPROM-Electrically Erasable Programmable ROM. It can be easily reprogrammed by the application of a small voltage. It can be erased and reprogrammed repeatedly. It is more expensive then PROM. The contents in EEPROM are erased by part by part.

5.Flash ROM:

It is also called "Flash Memory". It is a non volatile memory. It is used in digital cellular phones, digital cameras, and in many devices. The data can be erased and reprogrammed into it, flash memory is used to hold control code such as BIOS in a computer.

I am sure this article is very useful.