General-purpose computers capable of handling a variety of task can be found in a range of shapes, from cube-shape to U-shaped to cylindrical to notebook-shaped. However, the most distinguishing characteristic of any computer system is its size--not its physical size, but its computing power. Loosely speaking, size, or computing power, is the amount of processing that can be accomplished by a computer computer system in a certain amount of time, usually a second.
At one end of the power spectrum is the low-end personal computer that costs less than $500 and at the other is the powerful supercomputer that may cost more than an office building. The personal computer, as name implies, is designed to serve one person at a time. In contrast, a supercomputer can handle the processing needs of thousands of users at a time or perform processing that would take thousands of PCs.
Over the past five decades computers have taken on as many handles as there were niche needs. Terms like mainframe computer and minicomputer were popular in the 1970s and 1980s. Today, computers are generally grouped in these categories: notebook PCs, desktop PCs, wearable PCs, handheld computers, thin clients, workstations, server computers, and supercomputers. Give desktop PCs a slight edge in power over notebook PCs, but, generally, the two types offer similar computing capabilities. Wearable PCs are worn by the user, about the waist or on the arm, providing the ultimate in mobile processing. The workstation is a notch above the top desktop PCs, offering individuals the performance they need for demanding scientific and graphics applications. In most computer networks, one or more central computers, called sever computers, manage the resources on a network, called client computers. PCs, workstations, and thin clients are linked to the server computer to form the network. Thin clients are somewhat less than full-featured PCs(thin) and they are clients of (dependent on) server computers for certain resources, such as storage and some processing.
