COMPUTER HARDWARE

When computers first began moving into the business world in the late 1950s and early 1960s, the computing environment was best described as centralized, host-based computing. In this environment, the typical organization had a large mainframe computer (the centralized host) connected to a number of ‘‘dumb’’ terminals scattered throughout the organization or at remote sites. These terminals were labeled ‘‘dumb’’ because they had no native ‘‘intelligence’’ (i.e., they had no built-in central processing units [CPUs] that were capable of processing data). The main frame did all the data processing for all the user terminals connected to it.

In the mid-1960s, Digital Equipment Corporation (DEC) announced the development of the mini computer. Smaller than the mainframe, the minicomputer ushered in the era of distributed data processing (DDP). In this new processing environment, an organization could connect one or more minicomputers to its mainframe. Typically, the minicomputers were located in an organization’s regional offices, from which they were connected to the mainframe in corporate headquarters. This, the organization’s data-processing function was no longer localized in a single, centralized computer (the mainframe) but, rather, distributed among all the computers.

The commercial introduction of the personal computer by IBM in the early 1980s revolutionized organizational data processing. The personal computer carried the distributed processing concept even further within organizations it brought data processing to the desktop. Also, it eclipsed the dumb terminal as the terminal of choice by users. The commercial success of the IBM personal computer led other computer manufacturers to develop their own personal computers that were compatible with the IBM PC (these are usually described as IBM clones or IBM-compatible computers). One notable exception is Apple Computers, Inc., which developed its own line of non-IBM-compatible computers, namely the Apple and Macintosh line of computers.

The all inclusive term microcomputer is sometimes used to encompass all makes and models of desktop computers, including the IBM PC (and its clones) and the Apple/Macintosh computers.

It is important to note that, despite their proliferation and ubiquity, personal computers have not replaced minicomputers or mainframes. A large number of organizations still rely on these larger computers for significant aspects of their day-to-day operations.