COMPUTER APPLICATIONS Learning Objective: Identify computer applications. Computer applications fall into a variety of broad categories. Information retrieval is one such application, or in a narrower sense, indexing or cataloging. Information is stored under a variety of key words or index headings. By calling up one of these headings, a listing of all or part of the information will be outputted by the computer. Another application is simulation. This involves simulating the operation of a new computer by using an older computer model. In this way, design deficiencies can be identified without going through the time-consuming and expensive process of building the newer unit. Real-time control of a production process is another application. For example, the petroleum and chemical industries put this process to good use. The computer can detect minute changes in the production process and initiate immediate corrective action. The advent of personal (home) computers has greatly expanded the computer-use horizon from the routine upkeep of a checkbook balance to the more complex functions of financial planning, home security, and computer video games. The application of the computer and its functions is virtually endless.    For this reason, there are some people who believe that the computer will soon control everything and everyone. This is not necessarily the case, however, as computers can do only what their creators have intended them to do. The computer enables people to do more than they have been able to do in the past. For example, computations that required years to calculate by human methods can now be accomplished in a matter of moments by modern computers. This has become particularly evident in our space program. The ability to put a man on the moon and send Voyager I and Voyager II on their journeys would have been impossible without the use of computers. Fears over job losses are, for the most part, needless. While some jobs may be eliminated, new ones are created. Thus, a worker may have to learn a new skill. For example, a laborer may have to be retrained as a computer programmer or operator. Rather than destroying jobs, the computer where none existed before. creates opportunities TYPES OF COMPUTERS Learning Objective: Identify the types of computers and the analytical processes used by each type. In general, there are two basic types of computers— analog and digital. ANALOG COMPUTERS The term analog, as applied to computers, pertains to representation by means of continuously variable physical quantities. For example, an analog computer can be a device that solves problems by setting up electrical circuits that represent the physical equivalents of certain phenomena. Then, measurements are made as these circuits are varied in accordance with changes in the phenomena. The analog computer is by no means restricted to electrical circuits as equivalents. The physical equivalents may be gear trains, gases, fluids, etc. Analog computers, because of their nature, have some inherent limitations. The use of physical equivalents limits their versatility. They are limited to performing only the tasks for which they were designed or, in certain instances, closely related tasks. DIGITAL COMPUTERS A digital computer is a device that solves problems by manipulating the numerical equivalents of phenomena in accordance with mathematical and logical processes. These numerical equivalents may be expressed as binary numbers, octal numbers, decimal numbers, etc. In an electronic digital computer, the numerical equivalents are generally expressed as binary numbers 1 or 0. Values of voltage and current are used to represent the 1s and 0s. The versatility of digital computers is based on the fact that they use numerical equivalents not only to represent the data to be processed, but also the instructions for processing the data. In other words, digital computers are generally provided with a wide variety of instructions. They are designed to respond in certain ways to the numerical equivalent of these instructions. Programming is merely a matter of modifying and/or arranging these instructions so that the computer will respond in a predictable manner to a given situation. While much more versatile than an analog system, digital systems are still limited as to 8-2