WHAT ARE COMPUTERS?

UNIT 2. HARDWARE AND OPERATING SYSTEM

What are computers?

Computers are machines that perform tasks or calculations according to a set of instructions, or programs.

Computers work through an interaction of hardware and software. Hardware refers to the parts of a computer that you can see and touch, including the case and everything inside it. The most important piece of hardware is a tiny rectangular chip inside your computer called the central processing unit (CPU), or microprocessor. It's the "brain" of your computer. Hardware items such as your monitor, keyboard, mouse, printer, and other components are often called hardware devices, or devices.

Software refers to the instructions, or programs, that tell the hardware what to do. A word processing program that you can use to write letters on your computer is a type of software. The operating system (OS) is software that manages your computer and the devices connected to it. Two well-known operating systems are Windows and Macintosh operating system.

Types of computers

Computers can be generally classified by size and power as follows, though there is considerable overlap:

• Personal computer: A small, single-user computer based on a microprocessor.
• Workstation
• Minicomputer
• Mainframe.
• Supercomputer.

The personal computer, or PC, is designed to be used by one person at a time. This section describes the various kinds of personal computers: desktops, laptops, handheld computers, and Tablet PCs.

Desktop computers

Desktop computers are designed for use at a desk or table. They are typically larger and more powerful than other types of personal computers. Desktop computers are made up of separate components. The main component, called the system unit, is usually a rectangular case that sits on or underneath a desk. Other components, such as the monitor, mouse, and keyboard, connect to the system unit.

Laptop computers

Laptop computers are lightweight mobile PCs with a thin screen. They are often called notebook computers because of their small size. Laptops can operate on batteries, so you can take them anywhere. Unlike desktops, laptops combine the CPU, screen, and keyboard in a single case. The screen folds down onto the keyboard when not in use.

Handheld computers

Handheld computers, also called personal digital assistants (PDAs), are battery-powered computers small enough to carry almost anywhere. Although not as powerful as desktops or laptops, handhelds are useful for scheduling appointments, storing addresses and phone numbers, and playing games. Some have more advanced capabilities, such as making telephone calls or accessing the Internet. Instead of keyboards, handhelds have touch screens that you use with your finger or a stylus (a pen-shaped pointing tool).

Tablet PCs

Tablet PCs are mobile PCs that combine features of laptops and handhelds. Like laptops, they're powerful and have a built-in screen. Like handhelds, they allow you to write notes or draw pictures on the screen, usually with a tablet pen instead of a stylus. They can also convert your handwriting into typed text.

EXERCISE.

1. WHAT ARE COMPUTERS?

2. WHAT IS THE DIFFERENCE BETWEEN HARDWARE AND SOFTWARE? GIVE AN EXAMPLE OF EACH.

3. CLASSIFY THE 5 TYPES OF COMPUTERS, FROM SMALLEST TO LARGEST.

4. NAME 3 TYPES OF PERSONAL COMPUTERS.

5. WHAT ARE THE MAIN COMPONENTS OF A DESKTOP COMPUTER?

6. WHAT IS THE DIFFERENCE BETWEEN A LAPTOP AND A NOTEBOOK?

7. WHAT ARE HANDHELD COMPUTERS USED FOR?

8.HOW ARE HANDHELD COMPUTERS DIFFERENT FROM LAPTOPS?