The Palm Pilot personal digital assistant (PDA) was introduced in 1996.

 

(3) Desktop PCs as well as portable laptop and notebook computers refer to the class of microcomputers. They are designed for use in businesses and at home for word processing, calculating accounting information, Internet access, learning foreign languages, and for entertainment. They have large capacity internal memory to store hundreds of programs and documents. They are equipped with a keyboard; a mouse or other pointing device; and a video display monitor or liquid crystal display (LCD) to display information. Laptop and notebook computers usually have hardware and software similar to PCs, but they are more compact and have flat, lightweight LCDs rather than television-like video display monitors. Most people consider the terms “laptop” and “notebook” synonymous.

(4) Workstation is a combination of input, output, and computing hardware that can be used for work by an individual. More often, however, the term refers to a powerful, usually very expensive computer ($10,000 to $100,000). Workstations are used in computer-aided design and other applications, which require a machine with considerable calculating or graphics capability.

(5) Servers are fast, powerful computers that have greater data-processing capabilities than most PCs and workstations. They can be used simultaneously by many people. Often several PCs and workstations are connected to a server via a local area network. (LAN is a system that connects computers to each other within a building or organization so that people can use and work on the same information.) The server controls resources that are shared by the people working at the PCs and workstations. An example of a shared resource is a large collection of information called a database. Often all of the PCs at a business or university are connected to a central computer called a server.

(6) Mainframes are large, extremely fast, multi-user computers. They often contain several processors, each designed to perform a specific function. Because they can be shared by multiple users simultaneously, handle huge databases, and perform complex mathematical operations, they are used at large industrial businesses, scientific-research and university computing centers.

(7) The speed and power of supercomputers, the fastest class of computers, are almost beyond human comprehension, and their capabilities are being continually improved. They can perform many trillions of operations per second on some type of calculations and can do the work of thousands of PCs. Supercomputers achieve these speeds by means of the use of several advanced engineering techniques. For example, important circuitry is cooled to a temperature of nearly absolute zero so that electrons can move at the speed of light and many processing units are connected in such a way that they can all work on a single problem simultaneously. (See Figure 2)

 

Figure 2