Computer - Read Only Memory

On behalf of read-only memory ROM. From which we can only read, but can not write memory on it. This type of memory is non-volatile. In the manufacturing process information is permanently stored in memory such as. A ROM, such instructions needed to start the computer store. This operation is called bootstrapping. ROM chip is not only used in the computer, but also in other electronic items such as washing machines and microwave ovens.

The following are the various types of the ROM

MROM (masked ROM)

First ROM is hardwired contains program set of data or instructions means. These types of masked ROM is referred to as the ROM they are inexpensive.

PROM (Programmable Read Only Memory)

PROM is read-only memory can only be modified once the user. Users buy a blank and enter with the required PROM PROM programming content. PROM chip inside which opened a small fuse was burned when programming. It can be programmed only once, rather than erased

EPROM (Erasable and Programmable Read Only Memory)

The EPROM can be obtained by exposing it to ultraviolet light for up to 40 minutes duration is erased. Typically, an EPROM eraser implement this feature. During programming, charges are trapped in the insulated gate region. The charge holding more than ten years, because there is no charge leakage paths. Erase the charge, UV through a quartz window (cover). The exposure to ultraviolet light to dissipate the charge. In normal use quartz lid sealed with stickers.

EEPROM (Electrically Erasable and Programmable Read Only Memory)

The EEPROM programming and erasing electricity. It can be erased and reprogrammed about 10,000 times. Both the erase and programming, about 4 to 10ms (milliseconds). In the EEPROM, any position can be selectively erased and programmed. A byte erasable EEPROM time, rather than erase the entire chip. Thus, the process of reprogramming is flexible, but slower.