Class 9 Computer Second Chapter - Types of computer

Intro to types of computer

Nowadays, various types of computers are available. These computers are different from each other on the basis of their purpose, capacity, size, working principle, brand, etc.

On the basis of their purpose

On the basis of purpose, digital computers are classified into two types.

i. Special Purpose Digital Computer

These types of digital computers are designed to perform a single specific task. The program is loaded during manufacturing time in this type of digital computer which the user cannot change. Digital thermometers, digital watches, self-driven vehicles, washing machines, digital television, etc. are the example of special-purpose digital computers.

Ii. General Purpose Digital Computer

These types of digital computers are designed to perform more than one task. The user can load programs into the computer as per requirement to perform a different task. Desktop computers, laptops, notebooks, etc. are the example of general-purpose digital computers.

On the basis of data types, they operate (on the basis of work)

Computers can be categorized into three types according to the working principle (data type they operate). They are:

i. Analog computer

ii. Digital computer

iii. Hybrid computer

I. Analog Computer: Analog computers are special-purpose computers that can measure continuously changing data such as pressure, temperature, voltage, etc. It can perform a single task. For example, a speedometer which displays the speed of vehicles, a voltmeter, an analog watch, a seismograph, etc.

The features of analog computers are given below: 

1. Cheaper than other devices.

2. Works on continuous data.

3. Storage capacity is low.

4. Works in real-time. 

5. Gives output in the form of graphs and signals.

II. Digital Computer: Digital computers are general-purpose computers that solve problems by computing discrete data. It works on digital values, and binary digits (0 or 1). It can perform many tasks according to user requirements. Computers in school, home, and office are examples of digital computers.

1. Feature of digital computer:  works on discontinuous.

2. highly accurate and reliable.

3. used for general purposes.

4. based on discrete data (digits 0 and 1).

III. Hybrid Computer: The computer designed with combined features of an analog computer and a digital computer is called a hybrid computer. These computers are designed for a special purpose. They are used in hospitals for Ultra Sound, ECG (Electro Cardio Graph), CT scan (Computed Tomography scan), etc., in airplanes for air pressure, temperature, speed, and weight, in scientific labs, in ships, large industries, etc.

Feature of hybrid computer:

1. Expensive

2. designed for special purpose

3. works on both continuous and discrete value 

4. more complex and limited storage

Classification of digitals computers

On the basis of size, digital computers are classified into four types. They are

i. Microcomputer

ii. Minicomputer

iii. Mainframe computer and

iv. Supercomputer

i. Microcomputer: Microcomputer is also called PC (Personal Computer) because it is used by a single person at a time. The microprocessor is used as the main processing unit (CPU). IBM-PC was the first microcomputer designed by IBM (International Business Machine) company. Microcomputers are used in the home, school, college, hospital, offices, etc. for data processing purposes. These microcomputers are further divided into the following categories:

1. Desktop computer

2. Laptop computer/Notebook computer

3. Palmtop computers (Handheld computers)

4. Tablet computer

1. Desktop computer: Desktop computers are a special type of single-user computer. They are designed to be fitted on a desktop. These computers are specially designed for desktop work such as book designing, graphics designing, desktop publishing, etc.

2. Laptop Computer: A laptop computer is also known as a notebook computer. It is small in size and can fit inside a briefcase. So we can carry it anywhere we go. A laptop computer operates on a special rechargeable battery and it does not have to plug in like desktop computers. It is a portable and fully functional microcomputer. It is mostly used during the journey. It can be used on the lap of an airplane. So, it is referred to as a laptop computer. The memory, storage capacity, and processing speed of a laptop computer are almost equivalent to powerful personal computers. It has a built-in keyboard built in a touchpad as a pointing device. Laptop computers are more expensive than desk computers. Nowadays laptop computers are very popular.

3. Handheld Computers: Nowadays we can see many new types of small personal computing devices in the market. These are referred to as handheld computers. These computers are also referred to as palmtop computers or sometimes called Mini- Notebook computers. This type of computer is named a handheld computer because it can fit in one hand and we can operate it with the other hand. Because of its reduced size, the screen of handheld computers is quite small. Similarly, it also has a small keyboard. Mobile employees, such as meter readers, use these computers.

ii. Mnicomputer: Minicomputer is more powerful and expensive than a microcomputer but less powerful and costly than a mainframe computer. So, the capabilities of a minicomputer are in between a microcomputer and a mainframe computer. Minicomputer is used in scientific research, banking system, telephone switch, etc. These computers work on a multiprocessing system and about two hundred of PCs can be connected to the network. PDI-1 was the first minicomputer designed by DEC (Digital Equipment Crop) company in 1960. Time-sharing, batch processing, online processing, etc. are the services provided by minicomputers. IBM-System/3, Honeywell 200, etc. are some examples of minicomputers.

iii. Mainframe Computer: Mainframe computers are more powerful, have large storage capacity, and are more expensive than minicomputers but less powerful and costly than supercomputers. These computers allow multi-user and have multi-processor and support more than 200 PCs. These computers are used as a server on WWW (World Wide Web) and also used in large organizations such as a bank, telecommunication, airlines, and universities for large data processing. IBM is the major manufacturer of mainframe computers. IBM 1401 mainframe computer was brought to Nepal for the first time to process census data in a year. IBM-2 series, system 210 servers, CDC (Control Data Cyber) 6600, etc. are popular examples of the mainframe computer.

Iv. Super Computer: Supercomputers are the most powerful, most expensive, and have the highest processing speed than other computers. It has parallel processing for performing any task. These computers are mainly used in weather forecasting, nuclear energy research, national security, space-related research, etc. Nowadays, the most powerful supercomputer is Sunway Taihulight from National Super Computing Centre, Wuxi, China. Supercomputers can perform more than one trillion calculations per second. Piz Daint, Tianhe-z, Titan, Seq voie, Cori, ETA-10, etc. are popular examples of supercomputers. Supercomputers are mainly used for:

1. Weather forecasting

2. Online banking

3. Nuclear energy research

4. Aircraft design

5. To control industrial units.

Note of Unit-1 of Class Nine: Computer Basics

Chapter 4: Computer Hardware