Special Purpose Computers:

The computers that are built for a specific operation usually for a single customer,

are called special purpose computers. Such computers may incorporate many of the features of a general purpose machine. It’s applicability to a particular problem is a function of design and not of the program. Computers used for the collection of highway tools, air traffic control, railway reservation, data communication, tracking etc. fall in the category of special purpose computers.

These dedicated systems may reduce the processing load on large

Classification Base on Capacity

A)MICRO COMPUTER

B)MINI COMPUTER

C)MAIN FRAME COMPUTER

D)SUPER COMPUTER

MICRO COMPUTER:

Micro computers are the computers commonly used everywhere. They 

are the smallest type of computers. Micro computers have generally a keyboard, 

a monitor and one or two floppy drives on its system unit. Micro computer is 

the smallest in size and it is cheap too. The computers that we use in our schools, office, and homes are Micro Computers.

A micro computer’s CPU is a microprocessors. They are typically used as 

single user computer although present day microcomputers are very powerful. 

They support highly interactive environmental specially like graphical user 

interface like windows. These computers are popular for home and business applications. The microcomputer originated in late 1970’s. The first microcomputers were built around 8-bit data microprocessor chips. What do we mean by an 8bit chip? It means that the chip can retrieve instruction/data from storage, manipulate, and process an 8-bit data at a time or we can say that the chip has a built - in 8-bit data transfer path.

MINI COMPUTER:

Mini computers are at least five times faster than Micro computers. Compared to Micro Computers, mini compute is bigger in size and it has larger memory. An important feature of minicomputer is that same time. Several input and output 

devices such as light pen, micro mouse, graphics plotter etc. can be used with 

mini computers.

MAIN FRAME COMPUTER:

Main Frame computers are more powerful than the Mini computers, but smaller 

than the super computers. Since Main Frame computers have many terminals, 

they can be used by many users. These machines are used in big organizations. 

They have all the input and output devices. Due to their higher cost Main Frame computers are not commonly used as Micro or Mini computers.

SUPER COMPUTER:

 Super computer are the fastest computers. They are the biggest type of computers present in the world today. The highest speed and the and the greatest capacity of storage in memory make super computers the most powerful computer in the world. Super computers are used for scientific invention, weather forecasting, space technology and in other important sectors. The main memory of super computer 

is minimum 256 Megabytes. It has all the input and output devices also lot of terminals.

WHAT IS FUNCTIONS OF A COMPUTER

All computers perform at least five functions or basic operation. They are 

inputting, storing, processing, outputting, and controlling.

Inputting: Computer needs instruction to perform any task. It is the collection 

of letters, numbers and images. They task of feeding data in computer by 

any input device, such as keyboard, mouse, light pen, scanner etc are 

called inputting.

Storing: Computer can store data and instruction, which we (Computer 

Operator’s) feed in computer its storage device. So we can read or write 

our data any time as we need. So the process of saving data in computer is 

called storing.

Processing: The operator of computer data as per given instruction by user 

is called process. And the method of process is called processing. It is totally 

internal process of the computer system.

Outputting: By processing the given instruction of user (Inputs) it gives 

meaningful information. The given information is called output and the method 

of it called outputting. Output is also called as result. We can save these 

results in the storage devices for the future use. Some examples of outputs are 

printing playing a sound in a sound system, playing a move in your desktop

screen.

Controlling: There cannot be proper order in a country if there is the absence 

of a good leader. If there is an important function, and we want everything to 

go on well then there should be an organizer to see to every detail and 

give instructions. In the same manner in computer system also there is a part which direct the process of inputting, storing, processing and outputting.

BLOCK DIAGRAM OF A COMPUTER