Describe the composition of computer hardware

The computer hardware consists of the following –
1. The Central Processing Unit (CPU) – In general terms, the CPU is referred to as the brain of the computer as it operates and controls the various other parts of the computer system. CPU acts as the stage for carrying out various important activities like manipulating numbers, letters, symbols etc. The CPU further consists of two very vital units:-

a. The Arithmetic Logic Unit (ALU) – This unit of the CPU is responsible for performing the arithmetic operations as well as the logical operations.

The ALU is responsible for adding, multiplying, subtracting and dividing by understanding the nature of the numbers i.e. whether a number is positive or negative or is a whole number (a zero).

The ALU is not only responsible for determining the difference between the numbers and the letters on logical basis but is also responsible for knowing the differences between the various quantities i.e. which quantity is greater or smaller or equal to some other quantity.

b. The Control Unit (CU) – The CU is blessed with registers along with a decoder, which allows this unit of the CPU to select and also interpret the programs instructions and then being able to check them in their execution.

The decoder consists of the circuitry in order to decode and then interpret the ever instruction, which is supported by the CPU. The control unit interprets the instructions which it receives from the program i.e. stored in the main memory, then issues signals, leading to their execution by the other units of the system.

The control unit, because of all these properties is referred to as the central nervous system of the computer.

2. Input Unit – For any computation to take place, the entry of the data and the instructions in to the computer system is a very major necessity. This function of entering the data and the instructions is done by the Input Unit. The input devices are responsible for the conversion of the input data into the binary codes the input unit first of all receives (reads) the data and the instructions and then change them in the form, which the computer will accept and at last these changed instructions are send to the computer system so that further work or processing can be followed.

Examples of the input devices are:-
a. Computer Mouse
b. Keyboard
c. Touch Screen
d. Source Data Automation

3. Output Unit – The main and the most essential responsibility of this unit is to receive coded form of the results, formed by the computer and then further change them into such a form that can be read by the humans. This unit’s function is exactly the reverse of the function that the input unit performs.

Examples of the output devices are:-
a. Printers
b. Plotters
c. Audio Output
d. Video Display Unit/Monitor

4. Storage Device
a. Primary Storage
(1.) acts as the main or the core memory.
(2.) stores data/instructions for a temporary period only.
(3.) Devices are the Register, the Cache and the RAM.

The Data bus, the Address bus and the Control bus provide or act as a bridge between the CPU, the primary storage device and the various other devices.

b. Secondary Storage
(1.) also called as the Auxiliary memory.
(2.) is cheaper.
(3.) stores large volume of data on permanent basis.
Some of the Secondary storage devices are the Hard Disk, High Density Diskette, Magnetic Tape, Optical Disk etc.