CLASSIFICATIONS OF COMPUTER

CLASSIFICATIONS OF COMPUTER

Computer can be classified based on the following ways:

1.     Computer type by different generation

2.     Computer type by size

3.     Computer type by device or kind of signal and data processed or mode of operation.

4.     Computer type by purpose

1.     CLASSIFICATION  BASED ON GENERATION  OF COMPUTER

There are various generations of computer that has been recorded. Five generations of computer have been produced between 1946 to date. The generations and some of their features are:

FIRST GENERATION OF COMPUTER

It was the first attempt made by man in building what is called computer. It was manufactured between 1946-1955.

It has the following features /characteristics:

·  It was developed with electronic valve “vacuum tubes” as its components.

·  It was too large in size and occupies a large space. Often occupied an entire room.

·  It was slow in operation.

·  It generates a lot of heat.

·  Very difficult to operate

·  Required cooling system since they generate a lot of heat

·  They use machine complex language, binary machine language.

·  They used punched cards

·  Programmed in languages such as COBOL (common Business oriented language)

·  They used magnetic disks and tapes.

 SECOND GENERATION COMPUTER

Scientist led by William Scholey at Bell laboratories invented a device called a transistor. This brought wonderful and significant changes in computer system by replacing vacuum tubes with the transistors. It was an improvement from the first generation of computer. It was manufactured between 1955-1964 and had the following features / characteristics

·  It was developed with a component called transistor.

·  It is smaller than the first generation computer

·  It is faster, more reliable and more efficient than the first generation computer

·  It makes use of high level language

·  It consumes less electricity

THIRD GENERATION OF COMPUTER

It was an improvement on the second generation computer. It makes use of a component called integrated circuit which consists of series of inter-connected transistors, resistors and capacitors, all attached on a single chip. As a result, computer became smaller as more components were squeezed unto ship.

          Another third generation developed includes the use of operating system that allows machine to run many different programs at once with a central program that monitored and co-ordinate the computer memory. So the third generation brings about the beginning of the modern computers. It was manufactured between 1964-1971. It has the following features /characteristics

·  It was developed with integrated circuit as its major component.

·  It gave rise to more development in hardware technology and it is the point of computer development in the standard form.

·  It is durable and faster

·  It produces less heat.

·  Keyboard and monitor introduced

·  Easily accessible to the masses.

·  Cheaper and smaller in size than their processor 

                                                        

FOURTH GENERATION OF COMPUTER

An Engineer called Dr. Hoff conceived the idea of converting the integrated circuit to a single central chip calledmicroprocessor.

This brought a radical change in the technological system by converting the entire component to the one known asmicroprocessor. It was manufactured between 1971 to early 1990’s.

Examples: Desktop computer, laptop computer, palmtop computer, breast/pocket size computer, notebook computer. It has the following features / characteristics

·  It makes use of chip (microprocessor) as memory

·  It led to the standard use of software

·  It is more compact and portable

·  It is faster in operation when compared to 3^rd generation computer.

·  It is smaller in size (micro) it is durable and cheap in price.

·  It is very powerful and efficient.

·  Network/ internet introduced.

·  Better operating system- windows was introduced.

FIFTH GENERATION COMPUTER

It is an advanced form of computer system. This form of computer makes use of higher manipulations and it is the standard form in the society. It is an advanced and sophisticated machine that reasons like human beings during operation (Artificial intelligence). The fifth generation computers are still being expected. It has the following feature / characteristics:

·        It makes use of logical inference and artificial intelligence

·        It processes data in million cycles per seconds.

2.     CLASSIFICATION ACCORDING TO SIZES OR COMPUTER TYPE BY SIZE AND WORK DONE

Presently, there are four (4) classes of computer type by size.

1.     SUPER COMPUTER

These are biggest and fastest of all computers. It is used in big organisations to nuclear power stations, space research laboratories etc.

These are largest type of computer in terms of size, highest in speed and more efficient and effective in usage. They are high capacity machine that require special air condition rooms and are the fastest calculating devices ever invented.

2.     MAIN FRAME COMPUTER

This type of computer is of high size and it is only owned by large organization. It cannot be used by private or individuals. This class of computer is capable of doing calculation in large quantities. It also occupies large space because of its size.

This class of computer cannot be placed on top of desk or table, instead on a floor. It has a world length ranging from 32 to 64 bits and can be operated with the range of 50 personas doing different things at the same time.

CHARACTERISTICS/ FEATURES OF MAINFRAME COMPUTER

·  It operates at high speed

·  It has large storage capacity

·  It is multi users

·  It is used in large networks

·  It is very expensive to procure and maintain.

·  Specialized training for operators

·  It is used in universities and big business organization.

            

3.     MINI COMPUTERS

This is a sub-computer which is deducted from the mainframe or it can be considered as a scaled down version of mainframe computer. It is capable of doing the same thing as that of a mainframe but now in a lower speed. It handles arithmetic work and being operated by 20 persons. This class of computer is bigger than the micro computer but it serves many users with many display units called terminals connected to it. They have world length of 16 to 32 bits.

CHARACTERISTICS / FEATURES OF MINI COMPUTER

·  It can support multi users up to 20 persons.

·  It is medium scaled computers.

·  It can allow single and multi users.

·  It is less expensive than mainframe

4.                             MICRO COMPUTERS

This is known as personal computer (P.C). It is the type of computer we can see in offices and business centres. They are small computers that have small parts called the micro processor in the central processing unit (C.P.U.). The components are in a single case. They have a world length of about 8 to 16 bits.

Examples of micro computers are: Desktop computers, palmtop computers, breast/pocket, size computers, and notebook computers.

CHARACTERISTICS /FEATURES OF MICRO COMPUTERS

·  It is faster than the above mentioned types of computer

·  It is durable and portable

·  It is cheap, easy to operate and generate less heat.

·  It has mostly single processor.

·  It is commonly single user computer

·  It is the commonest computer

TYPES OF MICRO COMPUTERS

·  DESKTOP MICRO COMPUTER

It is the type of computer that is usually placed on the desk while operating. It has three parts which includes monitor, keyboard and central processing unit (C.P.U.).

·  LAPTOP MICRO COMPUTER

It is the type of computer that is usually kept on the laps while operating. This type of computer has the keyboard, mouse and C.P.U. joined together. The screen or monitor is equally attached together so that one can read from the screen. It is small enough to fit into a briefcase. Which can be carried about or any where you go.

·  PALMTOP MICRO COMPUTER

It is the type of computer that is usually placed on the palm while operating.

·  NOTE BOOK MICRO COMPUTER

This is the type of computer that has the structure of notebook.

It is small enough to be helped with one hand and operated with the other hand.

3. COMPUTER TYPE BY DEVICE OR KIND OF SIGNALS AND DATA   PROCESSED    OR MODE OF OPERATION.

·              ANALOGUE COMPUTERS

This kind of computers is used for measuring things. It measures changes in current, temperature or pressure and translates these into electrical current. Examples of such computers are thermometer, barometer, speedometer etc. They are used in every day life and hospital and medical laboratories.

·              DIGITAL COMPUTERS

These concentrate one of the bases of counting numbers of digits. They often help us to add, subtract, multiply, divide and help to know the difference between things.

This kind of computer is usually used in schools, offices, and factories and even in banks where they are used for administrative and commercial purposes.

·        HYBIRD COMPUTER

These are computers that can be used for both counting and measuring. This combines the features of both the digital and analogue computers. It is used in specialized applications such as industrial process control where both kinds of information needed to be processed.

4. COMPUTER TYPE BY PURPOSE

They are: Special purpose computer and General purpose computer

·  SPECIAL PURPOSE COMPUTER

 This is a type of computer designed for a particular job e.g. computer designed for air traffic control.

·  GENERAL PURPOSE COMPUTER

These are computer designed to solve wide varieties of problems and is used to carry out different jobs e.g. desktop computer etc.