Ans: Computers can be classified in three major categories. These are:
1. Based on Types
2. Based on Size
3. Based on Purpose

1. Based on Types

• Analog Computer – An analog computer is the one that uses the continuously changeable aspects of physical phenomena to model the problem to be solved. These include electrical, mechanical, or hydraulic quantities. They are extremely difficult to use. These are used in scientific and industrial applications. Examples – Thermometer, Operational Amplifiers, Electric Integrators, etc.

• Digital Computer – These computers help to solve problems in discrete format. It is only operated by data entered in binary language and can perform the dynamic function of managing large amounts of data and regulating the operations of the machine, Examples of Digital computers are Desktop, Laptop, Mobile Phones, etc.

• Hybrid Computer – These computers include features of both Analog and Digital computers. Logical operations are solved by the digital methods and the differential equations are solved using the analog methods. Some important examples of Hybrid Computers are – Space Flights, Food processing Plants, etc.

Types of Computers – Based on Size

• Micro Computers – This is the most affordable and smallest computer comprising a microprocessor and a Central Processing Unit (CPU). These are made with minimal circuitry mounting over a single circuit board. Examples – Desktop, Laptop, etc.

• Mini Computer – These were first developed in the mid-1960s. These are smaller than mainframe computers. They were developed keeping in consideration human interaction, control instrumentation and were cost-effective. For example, Smartphones, iPads, etc.

• Mainframe Computer – Computers used by large Organisations to manage bulk data are called Mainframe computers. Mainly used for managing customer statistics, census and other heavy data in a single device. For example, the system used at Trading companies.

• Super Computer – Computers used at Organisations dealing with Weather forecasting, Quantum Mechanics, Climate research, etc., where high level of performance has to be justified are called Super Computers.

Types of Computers – By Purpose

1. General Purpose – Based on General Purpose, there are these following functions which a device is expected to perform:
1. Basic Input/Output functions
2. Calculations
3. Data Saving on a smaller scale
4. General performing activities
Example – basic calculators, laptops, desktop computers, mobile phones, etc., which can help people with their basic necessary functions are included in the General-Purpose computer type.

2. Special Purpose – When a computer is designed specifically to perform a certain function, such type of computers is known as Special Purpose computer. These types may include:
1. Thermometers to test temperature
2. Generators to manage electricity
3. Devices used for analysing Climate Change
4. Large computers for IT Companies
5. Machines used at Manufacturing Units and the list goes on and on
Various Organisations use special-purpose computers for specific uses. Their applications are made in a way that makes the work easy and efficient.