The Five Basics Operations of Computer System

1. Inputting: The process of entering data and instructions into the computer system.

2. Storing: Saving data and instructions to make them readily available for initial or additional processing whenever required.

3. Processing: Performing arithmetic operations (add, subtract, multiply, divide, etc.) or logical operations (comparisons like equal to, less than, greater than, etc.) on data to convert them into useful information.

4. Outputting: The process of producing useful information or results for the user such as a printed report or visual display.

5. Controlling: Directing the manner and sequence in which  all of the above operations are performed.


Input Unit:

An input unit of a computer system performs the

following functions:

1. It accepts (or reads) instructions and data from outside world.

2. It converts these instructions and data in computer

acceptable form.

3. It supplies the converted instructions and data to the

computer system for further processing.


Output Unit:

An output unit of a computer system performs the

following functions:

1. It accepts the results produced by the computer, which

are in coded form and hence, cannot be easily

understood by us.

2. It converts these coded results to human acceptable

(readable) form.

3. It supplies the converted results to outside world.


Storage Unit:

The storage unit of a computer system holds (or stores) the following :

1. Data and instructions required for processing (received from input devices).

2. Intermediate results of processing.

3. Final results of processing, before they are released to 

an output device.


Two Types of Storage

1. Primary Storage

2. Secondary Storage


 Primary storage

§ Used to hold running program instructions

§ Used to hold data, intermediate results, and

results of ongoing processing of job(s)

§ Fast in operation

§ Small Capacity

§ Expensive

§ Volatile (looses data on power dissipation)

    

 Secondary storage

§ Used to hold stored program instructions

§ Used to hold data and information of stored jobs

§ Slower than primary storage

§ Large Capacity

§ Lot cheaper that primary storage

§ Retains data even without power


Arithmetic Logic Unit (ALU)

Arithmetic Logic Unit of a computer system is the place where the actual executions of instructions takes place during processing operation.


Control Unit (CU)

Control Unit of a computer system manages and coordinates the operations of all other components of the computer system.


Central Processing Unit (CPU)

§ It is the brain of a computer system

§ It is responsible for controlling the operations of

all other units of a computer system


The System Concept

A system has following three characteristics:

1. A system has more than one element

2. All elements of a system are logically related

3. All elements of a system are controlled in a manner to

achieve the system goal

A computer is a system as it comprises of integrated components (input unit, output unit, storage unit, and CPU) that work together to perform the steps called for in the executing program.