Personal Computer

I

Introduction

Personal Computer (PC), computer in the form of a desktop or laptop device designed for use by a single person. PCs function using a display monitor and a keyboard. Since their introduction in the 1980s, PCs have become powerful and extremely versatile tools that have revolutionized how people work, learn, communicate, and find entertainment. Many households in the United States now have PCs, thanks to affordable prices and software that has made PCs easy to use without special computer expertise. Personal computers are also a crucial component of information technology (IT) and play a key role in modern economies worldwide.

The usefulness and capabilities of personal computers can be greatly enhanced by connection to the Internet and World Wide Web, as well as to smaller networks that link to local computers or databases. Personal computers can also be used to access content stored on compact discs (CDs) or digital versatile discs (DVDs), and to transfer files to personal media devices and video players.

Personal computers are sometimes called microcomputers or micros. Powerful PCs designed for professional or technical use are known as work stations. Other names that reflect different roles for PCs include home computers and small-business computers. Laptops are compact and portable personal computers that have many of the same capabilities as desktop computers but with reduced data storage capacity. Netbooks are small, very lightweight laptop computers that rely on an Internet connection to perform most applications rather than on stored software. The PC is generally larger and more powerful than handheld computers, including personal digital assistants (PDAs) and gaming devices.

II

Parts of a Personal Computer

The different types of equipment that make a computer function are known as hardware; the coded instructions that make a computer work are known as software.

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A

Types of Hardware

PCs consist of electronic circuitry called a microprocessor, such as the central processing unit (CPU), that directs logical and arithmetical functions and executes computer programs. The CPU is located on a motherboard with other chips. A PC also has electronic memory known as random access memory (RAM) to temporarily store programs and data. A basic component of most PCs is a disk drive, commonly in the form of a hard disk or hard drive. A hard disk is a magnetic storage device in the form of a disk or disks that rotate. The magnetically stored information is read or modified using a drive head that scans the surface of the disk.

Removable storage devices—such as floppy drives, compact disc (CD-ROM) and digital versatile disc (DVD) drives, and additional hard drives—can be used to permanently store as well as access programs and data. PCs may have CD or DVD “burners” that allow users to write or rewrite data onto recordable discs. Other external devices to transfer and store files include memory sticks and flash drives, small solid-state devices that do not have internal moving parts.

Cards are printed circuit boards that can be plugged into a PC to provide additional functions such as recording or playing video or audio, or enhancing graphics (see Graphics Card).

A PC user enters information and commands with a keyboard or with a pointing device such as a mouse. A joystick may be used for computer games or other tasks. Information from the PC is displayed on a video monitor or on a liquid crystal display (LCD) video screen. Accessories such as speakers or headphones allow audio to be listened to. Files, photographs, or documents can be printed on laser, dot-matrix, or inkjet printers. The various components of the computer system are physically attached to the PC through the bus. Some PCs have wireless systems that use infrared or radio waves to link to the mouse, the keyboard, or other components.

PC connections to the Internet or local networks may be through a cable attachment or a phone line and a modem (a device that permits transmission of digital signals). Wireless links to the Internet and networks operate through a radio modem. Modems also are used to link other devices to communication systems.

B

Types of Software

PCs are run by software called the operating system. Widely used operating systems include Microsoft’s Windows, Apple’s Mac OS, and Linux. Other types of software called applications allow the user to perform a wide variety of tasks such as word processing; using spreadsheets; manipulating or accessing data; or editing video, photographs, or audio files. Software for different applications is generally installed on a PC’s hard drive. However, a connection to the Internet means that application software, as well as document and data storage, can also be accessed online as needed from a powerful system of computers, reducing the need to store large amounts of software and data on a single PC.

Drivers are special software programs that operate specific devices that can be either crucial or optional to the functioning of the computer. Drivers help operate keyboards, printers, and DVD drives, for example.

Most PCs use software to run a screen display called a graphical user interface (GUI). A GUI allows a user to open and move files, work with applications, and perform other tasks by clicking on graphic icons with a mouse or other pointing device.

In addition to text files, PCs can store digital multimedia files such as photographs, audio recordings, and video. These media files are usually in compressed digital formats such as JPEG for photographs, MP3 for audio, and MPEG for video.

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