1. The types of computers and their functionalities

2. What are the different types of computers? When most people hear the word computer, they think of a personal computer such as a desktop or laptop. However, computers come in many shapes and sizes, and they perform many different functions in our daily lives.

3. Machines and their size Microcomputers Minicomputers Mainframes Supercomputers

4. Microcomputer A microcomputer is a computer that has a microprocessor chip as its CPU. They are often called personal computers because they are designed to be used by one person at a time. Personal computers are typically used at home, at school, or at a business. Popular uses for microcomputers include word processing, surfing the web, sending and receiving e-mail, spreadsheet calculations, database management, editing photographs, creating graphics, and playing music or games. Personal computers come in two major varieties, desktop computers and laptop computers.

5. Desktop computers Many people use desktop computers at work, home, school, or the library. They can be small, medium, or large in style, and they usually sit on a desk. Once you add a monitor, mouse, and keyboard, you have what is typically known as a desktop computer.

7. Most desktop computers are easy to upgrade and expand or add new parts. Another benefit of desktop computers is their cost. If you compare a desktop and laptop with the same features, you will most likely find that the desktop is less expensive.

8. Laptop computers The second type of computer you may be familiar with is a laptop computer, or a notebook. Laptops are battery- or AC-powered personal computers that are more portable than desktop computers, allowing you to use them almost anywhere. Because a laptop is smaller than a desktop, it's more difficult to access its internal components. This means you may not be able to upgrade them as easily as a desktop.

10. Tablet computers Tablet computers—or tablets—are handheld computers that are even more portable than laptops. Instead of a keyboard or touchpad, tablets use a touch-sensitive screen for typing and navigation. The iPad is an example of a tablet. Tablets can't necessarily do anything a laptop or a desktop can do, so you may still want a desktop or laptop to run programs or create documents. But if you just want to be able to play games, check email and social media, or stream music and videos, a tablet may be a good computer replacement.

12. Minicomputers A minicomputer is a multi-user computer that is less powerful than a mainframe. This class of computers became available in the 1960’s when large scale integrated circuits made it possible to build a computer much cheaper than the then existing mainframes (minicomputers cost around $100,000 instead of the $1,000,000 cost of a mainframe).

13. Mainframe A mainframe computer is a large, powerful computer that handles the processing for many users at the same time (up to several hundred users). The name mainframe originated after minicomputers appeared in the 1960’s to distinguish the larger systems from the smaller minicomputers. Mainframes typically cost several hundred thousand dollars. They are used in situations where a company wants the processing power and information storage in a centralized location. Mainframes are also now being used as high-capacity server computers for networks with many client workstations.

15. Servers A server is a computer that serves up information to other computers on a network. Many businesses have file servers employees can use to store and share files. A server can look like a regular desktop computer, or it can be much larger. Servers also play an important role in making the Internet work: They are where webpages are stored. When you use your browser to click a link, a web server delivers the page you requested.

17. Supercomputers A supercomputer is a mainframe computer that has been optimized for speed and processing power. The most famous series of supercomputers were designed by the company founded and named after Seymour Cray. The Cray-1 was built in the 1976 and installed at Los Alamos National Laboratory. Supercomputers are used for extremely calculation-intensive tasks such simulating nuclear bomb detonations, aerodynamic flows, and global weather patterns. A supercomputer typically costs several million dollars.

18. Other types of computers Today, there are many everyday devices that are basically specialized computers, even though we don't always think of them as computers. Here are a few common examples: Mobile phones: Many mobile phones can do a lot of things computers can do, such as browsing the Internet and playing games. These phones are often called smartphones. Game consoles: A game console is a specialized kind of computer that is used for playing video games. Although they are not as fully featured as desktop computers, many newer consoles allow you to perform nongaming tasks like browsing the Web.

19. PCs and Macs Personal computers come in two main styles: PC and Mac. Both are fully functional, but they have a different look and feel, and many people prefer one or the other. PC: This type of computer began with the original IBM PC that was introduced in 1981. Other companies began creating similar computers, which were called IBM PC Compatible (often shortened to PC). Today, this is the most common type of personal computer, and it typically includes the Microsoft Windows operating system. Mac: The Macintosh computer was introduced in 1984, and it was the first widely sold personal computer with a graphical user interface, or GUI (graphical user interface). All Macs are made by one company, Apple Inc., and they almost always use the Mac OS X operating system.