Every computer system has the following three basic components :
1. Input Unit
2. Central Processing Unit
3. Output Unit
1. Input Unit :
This unit helps users to enter data and commands into a computer system. Data can be in the form of numbers, words, actions, commands, etc. The main function of input devices is to direct commands and data into computer. Computer then uses its CPU to process data and produce output.
For example,
a keyboard is an input device that enters numbers and characters. Similarly, even a mouse can be an input device for entering directions and commands. Other examples include barcode reader, Magnetic Ink Character Reader (MICR), Optical Character Reader (OCR), etc.
2. Central Processing Unit (CPU) :
After receiving data and commands from users, a computer system has to process it according to the instructions provided. Here, it has to rely on a component called the Central Processing Unit. The CPU further uses these three elements :
a) Arithmetic and Logic Unit : This part of the CPU performs arithmetic operations. It does basic mathematical calculations like addition, subtraction, division, multiplication, etc. Further, it can even perform logical functions like the comparison of data.
b) Control Unit : This unit is the back bone of computers. It is responsible for coordinating tasks between all components of a computer system. The control unit collects data from input units and sends it to processing units depending on its nature. Finally, it further transmits processed data to output units to facilitate users.
c) Memory Unit : Once a user enters data using input devices, the computer system stores this data in its memory unit. This data will now remain here until other components of CPU process it. The memory unit uses a set of pre-programmed instructions to further transmit this data to other parts of the CPU.
3. Output Unit :
The third and final component of a computer system is the output unit. After processing of data, it is converted into a format which human can understand. After conversion, the output unit displays this data to users. Examples of output devices include monitors, screens, printers and speakers etc. Thus, output units basically reproduce the data formatted by the computer for user's benefit.
