Types of computers

We can categorize computer in two ways:

on the basis of data handling capabilities and size.

On the basis of data handling capabilities, the computer is of three types:

• Analogue Computer
• Digital Computer
• Hybrid Computer

1) Analogue Computer

Analogue computers are designed to process analogue data. Analogue data is continuous data that changes continuously and cannot have discrete values. We can say that analogue computers are used where we don't need exact values always such as speed, temperature, pressure and current.

Analogue computers directly accept the data from the measuring device without first converting it into numbers and codes. They measure the continuous changes in physical quantity and generally render output as a reading on a dial or scale. Speedometer and mercury thermometer are examples of analogue computers.

Advantages of using analogue computers:

• It allows real-time operations and computation at the same time and continuous representation of all data within the rage of the analogue machine.
• In some applications, it allows performing calculations without taking the help of transducers for converting the inputs or outputs to digital electronic form and vice versa.
• The programmer can scale the problem for the dynamic range of the analogue computer. It provides insight into the problem and helps understand the errors and their effects.

2) Digital Computer

Digital computer is designed to perform calculations and logical operations at high speed. It accepts the raw data as input in the form of digits or binary numbers (0 and 1) and processes it with programs stored in its memory to produce the output. All modern computers like laptops, desktops including smartphones that we use at home or office are digital computers.

Advantages of digital computers:

• It allows you to store a large amount of information and to retrieve it easily whenever you need it.
• You can easily add new features to digital systems more easily.
• Different applications can be used in digital systems just by changing the program without making any changes in hardware
• The cost of hardware is less due to the advancement in the IC technology.
• It offers high speed as the data is processed digitally.
• It is highly reliable as it uses error correction codes.
• Reproducibility of results is higher as the output is not affected by noise, temperature, humidity, and other properties of its components.

3) Hybrid Computer

Hybrid computer has features of both analogue and digital computer. It is fast like an analogue computer and has memory and accuracy like digital computers. It can process both continuous and discrete data. It accepts analogue signals and convert them into digital form before processing. So, it is widely used in specialized applications where both analogue and digital data is processed. For example, a processor is used in petrol pumps that converts the measurements of fuel flow into quantity and price. Similarly, they are used in airplanes, hospitals, and scientific applications.

Advantages of using hybrid computers:

• Its computing speed is very high due to the all-parallel configuration of the analogue subsystem.
• It produces precise and quick results that are more accurate and useful.
• It has the ability to solve and manage big equation in real-time.
• It helps in the on-line data processing.

On the basis of size, the computer can be of five types:

1   1. Super computers

• Definition: The fastest, most powerful computers used for complex simulations and calculations.
• Applications: Climate modeling, quantum mechanics, nuclear research, cryptography, and large-scale simulations.
• Examples: Summit, Fugaku, and Titan.
• Key Features: Massive parallel processing, high speed, high memory capacity, and specialized hardware for computation-intensive tasks.

2. Mainframe Computers

• Definition: Large, powerful computers primarily used by large organizations for critical applications, bulk data processing, and large-scale transaction processing.
• Applications: Banking systems, insurance companies, government data management, and enterprise resource planning (ERP).
• Examples: IBM zSeries, Unisys ClearPath.
• Key Features: High reliability, scalability, security, and support for thousands of users simultaneously.

3. Minicomputers (Mid-Range Computers)

• Definition: Multi-user computers that fall in between mainframes and microcomputers in terms of size and processing power.
• Applications: Business and academic applications, scientific research, and process control.
• Examples: IBM AS/400, DEC VAX.
• Key Features: Smaller and less powerful than mainframes but capable of supporting multiple users and processes.

4. Microcomputers (Personal Computers)

• Definition: Small, affordable computers intended for individual use.
• Applications: Everyday computing tasks, such as browsing the web, gaming, office productivity, and multimedia consumption.
• Examples: Desktops, laptops, tablets, and smartphones.
• Key Features: Single-user systems, affordability, portability (in the case of laptops and tablets), and ease of use.