A FIRST LOOK AT COMPUTERS

The feature common to all smart machines is their use of computer technology to supply "intelligence." A computer is a machine that stores and manipulates symbols using instructions from a human user. All computers are built around tiny pieces of silicon called computer chips, which utilize miniaturized electronic circuitry to carry out instructions from the user. When one of these computer chips is installed in a machine, such as a VCR or a fax machine, and is programmed to direct the machine's operations, the chip is referred to as a microprocessor.

We often encounter computers in the form of a terminal linked to a large centralized computer, or sitting on our desk in the form of a personal computer. Regardless of the form in which we find it, remember that the computer is a special type of tool—a very powerful mind tool that extends but does not replace the human mind. We have long used tools to ease our physical labors. In fact, the aim of the Industrial Revolution was to enhance production by using tools and machines to increase human physical productivity. Now the computer can do the same thing for our mental labors.

As examples of easing mental effort by using the computer, consider five tools commonly used in offices everywhere—the calculator, the typewriter, the file cabinet, the drafting table, and the telephone. All these tools are to some extent being replaced or enhanced by the computer; in the process, the human effort is reduced through the power of the computer.

Like a calculator, the computer can perform calculations. But the real power of the computer is its capability to allow the user to determine the effect of changes in the data or of changes in the assumptions underlying the calcu­lations. Similarly, computers can be used to create and revise documents with far greater ease than the standard typewriter. Computers can actually be used to develop professional-typeset-quality documents ready for publication. While it will be a long time before all storage of information on paper is ended, com­puters can now store information much more efficiently than filing cabinets, and computers allow the user to retrieve needed items of information without search­ing through many file folders. Drafting tables are also rapidly being replaced by computers that enable the user to either draw freehand or combine figures from a figure library to create a complete drawing. Finally, fax machines have now made it possible not just to talk over the telephone but also to send text and drawings over telephone lines to distant points.

Advantages and Limitations of the Computer

Two features of the computer strongly contribute to the rapid replacement of many "paper and pencil" tools. These are speed and accuracy. A computer is limited only by the speed at which electrical signals can be transmitted. This enables even personal computers to execute millions of operations per second in processing raw facts called data into a usable form known as information. The computer's speed enables it to carry out a desired operation in a fraction of the time needed to do the same thing manually. In terms of accuracy, a computer will do exactly what it is instructed to do without error. This enables the com­puter to repeat the same operations as many times as necessary, without error.

Of course, the computer does have limitations. A computer does not have reasoning capabilities. Rather, it must use instructions from the user to process the data the user inputs. If either the instructions or the data entered are incorrect, the results from the computer will also be incorrect. The fact that a computer can generate erroneous results has led to use of the term computer error. How­ever, this term is itself in error since the problem is not with the computer, but with the instructions or data given it by the human user. An acronym even exists to describe this process: GIGO—garbage in, garbage out! So when you receive an incorrect bill or are charged an incorrect amount by a computerized checkout system, remember it's not the computer that has caused the problem; it's the data or instructions input by a human user!

Since computers play such a large role in our lives, it is very useful to have at least a basic understanding of how they work and what they can and cannot do. In this section, we will look at what a computer can do, the parts of the com­puter and some ideas on computer use.

As mentioned earlier, a computer processes data into information. Recall that data are the raw facts that are entered into the computer for processing and that information is data that have been processed into a form that is useful to the user. Data can be in the form of numbers, letters of the alphabet, or any other type of symbols. On the other hand, information is the arrangement of data into tables, graphs, and reports. Because of this terminology, the operations that the computer performs are sometimes referred to as data processing.

Parts of the Computer

Processing data into information requires that the two primary elements of the computer—hardware and software—work together to accomplish the desired task. The computer's machinery is referred to as hardware and is made up of electronic devices and circuits. The human-provided logic and instructions to the computer are termed software. A common saying that helps to differentiate hardware from software is "If you bump into it, then it's hardware!"

A great deal has been written and said about the marvels of computer hard­ware, and hardly a week goes by without the introduction of a smaller, faster, or less expensive computer. However, hardware can do nothing without software to supply instructions. The software is made up of one or more lists of instruc­tions called programs. The process by which programs are developed is called programming. Many smart machines in everyday use have instructions already built into a computer chip so that all the user needs to do is press a button. Computer instructions in this form, known as firmware, blur the line between hardware and software.

Over the past 20 years, computers have become faster and smaller while also becoming much less expensive. Had the automobile industry undergone the same transformation, a Rolls Royce might cost $2.50 and get over 100 miles to the gallon! A computer that cost over $4,000 a few years ago can now be pur­chased for less than $1,000. However, while hardware costs have been dropping, software costs have not changed very much. The reason for this dichotomy is that hardware can be mass produced on a factory assembly line, but each piece of software must be created anew by individuals or groups of programmers. Developing software is a creative task similar to writing a novel or painting a portrait; as a result, the cost of software remains high compared to the cost of hardware.

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Date: 2015-02-03; view: 789