Fundamentals of Computer

The term 'Computer' is derived from the Latin word 'Computar' which means to calculate.

Computer is an electronic machine, that process the input data according to the given instruction & gives output as a result. It also saves the result for future use.

Central Processing Unit (CPU)

The most essential part of the computer that perform the various operations provided. It is also called the brain of the computer. It is mainly divided into three categories:

Arithmetic & logic Unit : It performs all arithmetical as well as logical operations such as addition, subtraction, multiplication & division. Also it performs the comparison between the entities & thus help in decision making to the computer.

Control Unit : It controls the flow of instruction within the system. CU gets the program instruction from memory & executes them one after another.

Memory Unit : It saves the instructions that are being executed for the future use. Each instruction takes certain memory for its proper execution.

Components of the CPU


Hard disk




SMPS & Connecting wire


Floppy Drive


Graphics Card

Sound Card


Storage Devices

The storing capacity of computer expressed in bytes. Bytes store one character of data. There are mainly two types of memory:

Primary Memory:

This is the main memory of the computer. This memory is used frequently by the CPU for execution of the instructions. There are again two types of Primary Memory:

RAM : RAM stands for Random Access Memory. Initially every task is stored in RAM & then executed or stored in Hard disk. It is volatile, it stores data temporarily. So no data will remain when the power is switched off. It ranges from 64 MB to 16 GB.

ROM : ROM stands for Read Only Memory. It is a programming chip, where all the system information are recorded & can't be changed. Its types are PROM, EPROM, EEPROM, etc. It is non-volatile.

Secondary Memory

These are the storage devices & are used to save the programs files permanently. There are different types of Secondary Memory:

Hard disk (ranges from 40 GB to 1 TB)

Floppy disk (1.44 MB)

CD (720MB), DVD (4.7 GB, 8.5 GB)

Blue ray Disc (25 GB, 40 GB)

Pen Drive (ranges from 128 MB to 256 GB)

Magnetic Tapes, Zip disk, etc.