A computer is a programmable machine. The two principal characteristics of a computer are: This 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 electric and digital. The actual machinery - wires, transistors, and circuits - is known as hardware; the instructions and data are called software.
All general-purpose computers need the following hardware components:
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Memory: enables a computer to store, at least temporarily, data as well as programs.
Mass storage device: allows a computer to permanently retain large amounts of data. Typical mass storage devices include solid state drives (SSDs) or disk turns and tape drives.
Input device: usually a keyboard and mouse, the actual input device is the conduit through which data and instructions enter a computer.
Outcome device: a display screen, printer, or other device that lets you see what the personal computer has accomplished.
Central processing unit (CPU): the heart of the computer, this is the element that actually executes instructions.
In addition to these components, many others make it possible for the basic components to operate together efficiently. For example , every computer requires a bus that transmits data in one part of the computer to another.
Computer Classification: By Size and Power
Most people relate a personal computer (PC) with the phrase computer. A PC is a small and not too expensive computer designed for an individual use. PCs are based on the microprocessor technology that enables producers to put an entire CPU on one chip.
Personal computers at home can be used for a number of different programs including games, word processing, accounting and other tasks.
Computers are generally classified through size and power as follows, although there is considerable overlap. The differences between computer system classifications generally get smaller as technology advances, creating smaller and more effective and cost-friendly components.
Personal computer: a small, single-user computer based on a microprocessor. Besides the microprocessor, a personal computer has a keyboard for entering data, a monitor with regard to displaying information, and a storage device for saving data.
Workstation: a powerful, single-user laptop or 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 countless users simultaneously.
Mainframe: a powerful multi-user computer capable of supporting many hundreds or thousands associated with users simultaneously.
Supercomputer: an extremely fast computer that can perform hundreds of millions of directions per second.
