TYPES OF COMPUTERS

(1) Computers come in many sizes, shapes and capabilities.

Special-purpose computers are designed to perform specific tasks. Their operations are limited to the programs built into their microchips. These computers are the basis for electronic calculators and can be found in thousands of other electronic devices, including digital watches, cameras, televisions, and automobiles. Such computers are preprogrammed for a specific task, such as tuning to a particular television frequency, or keeping accurate time. They generally are “hard-wired”¹ – i.e. their programs are represented as circuits that cannot be re-programmed.

General-purpose computers, such as personal computers and business computers are much more versatile because they can accept new programs. Each new program enables the same computer to perform a different set of tasks. For example, one program instructs the computer to be a word processor, another instructs it to scan the hard drive for viruses, and yet another transforms it into a video game.

(2) Programmable computers differ greatly in their computational power, speed, memory capacity, and physical size. Some small computers can be held in one hand and are called personal digital assistants (See Figure 1). They are used as notepads, scheduling systems², and address books; if equipped with a cellular phone, they can connect to worldwide computer networks to exchange information regardless of location. Handheld television-game devices are also examples of small computers.

Figure 1