What is a Computer?

A computer is a programmable machine. The two principal characteristics of a computer are: It responds to a specific set of instructions in a well-defined manner and it can execute a prerecorded list of instructions (a program).

Modern Computers Defined

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

Computer System

All general-purpose computers require the following hardware components:

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.

Computer Classification: By Size and Power

Most people associate a personal computer (PC) with the phrase computer. A PC is a small and relatively inexpensive computer designed for an individual use. PCs are based on the microprocessor technology that enables manufacturers to put an entire CPU on one chip.

Personal computers at home can be used for a number of different applications including games, word processing, accounting and other tasks.

Computers are generally classified by size and power as follows, although there is considerable overlap. The differences between computer classifications generally get smaller as technology advances, creating smaller and more powerful and cost-friendly components.

  • 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.
  • An emerging trend that attempts to go beyond the binary limitations of traditional computing is quantum computing

    Webopedia Stuydy Guide Recommended Reading: Webopedia’s Computer Architecture Study Guide is an introduction to computer system basics.

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    Kaiti Norton
    Kaiti Norton is a Nashville-based Content Writer for TechnologyAdvice, a full-service B2B media company. She is passionate about helping brands build genuine connections with their customers through relatable, research-based content. When she's not writing about technology, she's sharing her musings about fashion, cats, books, and skincare on her blog.

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