computer

A programmable machine. The two principal characteristics of a computer are:

It responds to a specific set of instructions in a well-defined manner.

• It can execute a prerecorded list of instructions (a program).

Modern computers are electronic and digital. The actual machinery -- wires, transistors, and circuits -- is called hardware; the instructions and data are called software.

All general-purpose computers require the following hardware components:

memory : Enables a computer to store, at least temporarily, data and programs.

mass storage device : Allows a computer to permanently retain large amounts of data. Common mass storage devices include disk drives and tape drives.

input device : Usually a keyboard and mouse, the input device is the conduit through which data and instructions enter a computer.

output device : A display screen, printer, or other device that lets you see what the computer has accomplished.

central processing unit (CPU): The heart of the computer, this is the component that actually executes instructions.

In addition to these components, many others make it possible for the basic components to work together efficiently. For example, every computer requires a bus that transmits data from one part of the computer to another.

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. In addition to the microprocessor, a personal computer has a keyboard for entering data, a monitor for displaying information, and a storage device for saving data.

workstation : A powerful, single-user computer. A workstation is like a personal computer, but it has a more powerful microprocessor and a higher-quality monitor.

minicomputer : A multi-user computer capable of supporting from 10 to hundreds of users simultaneously.

mainframe : A powerful multi-user computer capable of supporting many hundreds or thousands of users simultaneously.

supercomputer : An extremely fast computer that can perform hundreds of millions of instructions per second.

Also see the The Five Generations of Computers and the Computer Science category in the Did You Know...? section of Webopedia.

•E-mail this definition to a colleague•

For internet.com pages about computer . Also check out the following links!

Building Your Own PC
What hard-core techies and companies like Dell and Compaq have been doing for years is what any computer user can learn how to do - build a computer from scratch. Let SE take you on a stroll through the park and ease the pain of building a DIY PC.

Getting Started With Green Computing
Going green means operating in a way that uses the least amount of resources for the greatest gain; it's about introducing practices that focus on conservation, reuse and the reduction of a company's carbon footprint.

Microprocessor Comparison Chart
A cut-to-the-chase guide that compares and contrasts popular processing chips.

Webopedia Did You Know - From AT to BTX: Motherboard Form Factors
You've probably heard the term motherboard a thousand times, but do you know what it really means and how it relates to the rest of your computer?

Webopedia Quick Reference: Common Windows PC Issues
Tips to Diagnose and fix a slow running computer.

Webopedia: How to Clean Computer Parts and Devices
From dusty computer fans to fingerprints on compact discs, computer parts and devices can get awfully dirty from normal everyday use or when left sitting unused.

Webopedia: What Is CPU Overclocking?
Basically overclocking means to run a microprocessor faster than the clock speed for which it has been tested and approved.

Webopedia's "Did You Know... Preventative Maintenance Tips for Your PC"
The following tips will serve as a basic guideline to keep your PC maintained to run efficiently, increase component lifespan and also will help lessen the likelihood of PC failure.

Webopedia's Did You Know... Different Types of Memory Cards
Memory cards are a popular storage medium for many of today's consumer electronics devices, including digital cameras, cellphones, handheld devices and other small electronic devices. Flash memory is nonvolatile, that is the memory card will not lose its data when removed from the device, and the cards can also be erased or reformatted and reused.

What Is 64-bit Computing?
When reading about PCs and servers, you'll often see the CPU described by the number of bits (e.g., 32-bit or 64-bit), here's a little info about what that means.

IEEE's Computer magazine
Monthly magazine received by all members of the IEEE Computer Society. Offers articles of interest to computing professionals, computer scientists and engineers.