Computer Memory

Main/Primary memory

Main memory is temporary storage area built into the computer hardware. Instruction and data of a program reside mainly in this area when CPU is executing the program. This memory directly accessible to the CPU. Physically primary memory consists of some I C chip, on a small circuit board attached to the motherboard of computer system.

Types of Main/Primary Memory are:


RAM (Random access memory). It is temporary in nature. The memory can be accessed for the information transfer from any random location. It is a rid/write memory. This memory is volatile in nature. RAM consists of some I C chip, on a small circuit board attached to the motherboard the additional RAM chip. Which plug into special socket in the motherboard are also know as single-in-line memory modules (SIMMS.

Dynamic RAM :- DRAM is type of RAM. That used an external circuitry to periodically “regenerate”.

Static RAM :- Static RAM is type of RAM. That hold its data with external refresh for as ling as power supplied to the circuit.


ROM (Read only memory). ROM is a non-volatile memory chip, in which data is stored permanently ans cannot be altered the programmer. The data stored in ROM chop can only be read and used they cannot be changed. ROM are mainly used to store program and data. Also used “system boot program.


PROM are programmed to recored information using a special device know as PROM-programmer. Once the chip have been programmed to recorded information cannot be changed. It is only possible to read the store information. PROM is also non-volatile.


It is possible to erase information stored in a E PROM chip and the chip can be reprogram to store new information. When E PROM is in use information store in it can only be read.


E E PROM chip in which stored information is erased by using high voltage pulses. Also know as flash memory.

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