Main circuit board of computer. Contains all connector’s ports and slots for connecting different things. Motherboard’s chipset. An analogy of a human nervous system.


used to store and run information.


Main Memory:

  • Referred to as primary memory.
  • Primary storage space.
  • Randomly accessible
  • Stores instruction and data for current execution.

Types of Primary Storage:


1-stands for Random Access Memory

2-use to run data and then send it to secondary memory.


1-Dynamic RAM (DRAM)

2-Static RAM (SRAM)

3-Magneto Resistive RAM


1-more commonly used.

2-needs to refreshed again and again




1-do not need to be refreshed

2-Faster as compared to DRAM


Magneto Resistive RAM:

1-Uses magnetic charges.

2-Unlike DRAM and SRAM it retains it’s contents.


Read Only Memory as it’s name implies data can only be read from this memory and cannot be written on it. It’s content remain even power is switch off.

There are three types of ROM



1-Programmable Read Only Memory.

2-Can be programmed only once.

3-Retains its contents.

4-Manufactured as a blank memory.

5-PROM burner is required to program.


1-Erasable Read Only Memory

2-Can be programmed many times as per user requirements.

3-Contents are erased by exposing the EPROM to Ultraviolet Rays.


1-Electrically Erasable Programmable Read Only Memory.

2-Can be programmed many times.

3-Programmed through electric pulses.

4-Circuitry for programming EEPROM can be integrated into computer.

->Cache Memory:

1-is a small high speed RAM buffer present between CPU and main memory.

2-Cache holds a copy of instructions presently used by CPU.

3-main purpose is to accelerate computer.


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