Computer

The first electronic computer, the ENIAC, was developed at the University of Pennsylvania in 1946. It used vacuum tubes and weighed thirty tons. Remington Rand Corporation produced the first commercial computer, the Univac, in 1951, which also used transistors (Long and Long, 1999). Transistors replaced vacuum tubes, were far smaller, and used less power than tubes. Transistors were shortly thereafter replaced by integrated circuits, which further minimized size and lessened power requirements. The availability of integrated circuits made the first personal computer possible in 1977 when Stephen Jobs and Steve Wozniak introduced the "Apple II" (Long and Long, 1999). IBM offered their first microcomputer in 1981, and Apple's Macintosh was introduced in 1984. The Macintosh was the first popular computer with a graphical user interface (GUI), and it also had a laser printer that could combine text and pictures (Long and Long, 1999). A GUI operating system receives input from both the keyboard and a pointing device (mouse). This type of system was a boon to computer users who were not proficient or comfortable with keyboarding, and today most personal computers require the use of a mouse.

Classifications and Definitions of Computers

There are three main classifications of computers: mainframe, minicomputer, and microcomputer. The major categories can only be used as general guidelines because of the huge variety in product lines. Computer "servers" have also been included in this discussion because of their important role in networking and Internet applications.

A mainframe computer is any large computer system, such as that used by the Internal Revenue Service. Another typical use of a mainframe computer would be for an airline ticketing system, which can have thousands of users connected to one computer. The next smaller-sized computer is termed a minicomputer. It is of medium scale and can serve up to several hundred users. The microcomputer is the smallest in size and power, and the term is "generally synonymous with personal computer, such as a Windows PC or Macintosh, but it can refer to any kind of small computer" (CMP Net Online Encylopedia). Microcomputers can also be portable, and some have Pentium processors, fourteen-inch color screens, and multi-gigabyte hard drives. Very small computers include hand-held units and pen computers that store information the user enters with a stylus rather than a key board (Hutchinson and Sawyer, 1998).

A "server" computer is one that is used to connect a cluster of personal computers through using a local area network (LAN). World Wide Web pages are also stored on a "Webserver," which is typically a dedicated personal computer.

Bibliography

CMP Net Online Encyclopedia. (1999). http://www.techweb.com/encyclopedia/.

Forcier, R. (1996). The Computer as a Productivity Tool in Education. Boston: Merrill.

Hutchinson, S., and Sawyer, S. (1998). Computers, Communications, and Information. Boston: Irwin/McGraw-Hill.

Long, L., and Long, N. (1999). Computers. Upper Saddle River, NJ: Prentice-Hall.

[Article by: ARMAND SEGUIN; CYNTHIA SHELTON SEGUIN]