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Since the earliest days of civilization man has been preoccupied with mathematics and logic, and the attempts to create a machine to carry out calculations on numbers – additions, subtractions, multiplications, divisions – began in the days of the great thinkers of Asia, Greece and Egypt.
The abacus and later mechanical implements were developed, but until the twentieth century no machine has been invented which could “store” a sequence of calculations and repeat them as required. Every calculation needed to be carried out afresh.
It was a Victoria gentleman called Babbage who invented, in the late nineteenth century, the first “programmable” computer. That was a machine built of thousands of intricate geared cylinders interlocked in incredibly complex ways which could carry out instructions under the control of a “program” contained in the holes in punched cards – an idea inspired by the jacquard loom, a card-controlled loom (weaving machine) which wove extremely complex patterns.
Early in the twentieth century, the idea was developed of storing the instructions electronically, instead of mechanically, using valves. That was so successful that the first “real” computers were built; but the number, complexity and size of their components were so great that the machine were enormous in size and cost.
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Until the mid-1950’s, computer development and use were largely confined to a few universities in Britain and the United States of America, here their main use was the rapid solution of mathematical and scientific problems.
Gradually computers came to be used more for government administration and business purposes, but their huge size, cost and complexity limited their use to only the largest enterprises and institutions.
As transistors replaced valves as the essential components of computers, medium-size businesses and industries found the sizes and costs of computers more suited to their needs and resources. As the new computers were still designed primarily for complex mathematical and engineering problems, however, operators of the computers still had to be specially trained to use them, and highly skilled programmers were needed to produce the results required by the “users”.
Soon “thin-film” technology was able to etch many transistorized components on a single chip of silicon – the “silicon chip” – giving use the integrated circuit.
Rapid developments in the 1970’s provided vast increases in the density of such circuits which could be packed on to a single silicon chip, with dramatic improvements in speed, reliability and versatility – and immense reduction in costs. The power and capabilities of a computer, which would once have filled a whole room and would have hundreds of thousands of pounds, could now be held in a microcomputer capable of being housed on a desk and costing well within the financial resources of the average small business.
In addition to the developments in the size and cost of computes, clear changes have taken place over the years in the manner of usage of such computers, and each stage can be clearly defined.
The first generation of modern electronic computers was, as has been described, remote, large, difficult, expensive and – usually – single-purposed, capable of carrying out just one “user task” at a time.
The Second Generation of computers was, however, characterized by being less large, difficult and expensive, and general-purpose rather than being dedicated to a particular objective. But such computers were still somewhat remote, with very scientifically-minded and trained programmers being needed to write the instructions for them and highly skilled operators being needed to control the running of them. Most importantly, they were still capable of carrying out a succession of single user tasks (often described as operating in a ‘batch processing mode’). Such equipment became known generally as mainframe computers.
The third generation of computers became known as mini-computers.
(Smaller and cheaper than the huge mainframe, )They continued the trend, too, of making the actual programming part of getting the machine to perform something useful – which is, after all, the whole purpose of computers and computing – much more “approachable”. Gradually programming languages were developed which became more easily available for many people who were not trained computer scientists to learn; and computer programming became a skill, which many people with the necessary level of ability could learn and use.
The fourth generation (Microcomputers) in this family of decreasing size and increasing power. They were, in fact, a development in concept from the hand-held calculator, which in its early days had the disadvantage of not being able to store and repeat complex instructions (or programs). At first the microcomputer appealed only to the “hobbyist”, who purchased it in “kit” form to build, smaller to hi-fi, radio and television equipment.
Then the fascinating of programming – of actually being able to instruct this electronic machine to do something useful and variable – began to take hold. It was very soon realized that here was a means of carrying out “personal” or even “small business’ computing applications at a price affordable for the first time by a whole range of people who never before had been given that opportunity.
As micro-computers became more generally available, the demand for less complex, more easily usable programs grew, and there has been a steady increase in the number of generalized programs which can, within limits, be adapted to meet the requirements of individual businesses. Use of these program packages, avoids the very high costs of writing programs for each user.
The microcomputer, originally produced by International Business Machines (IBM), but imitated – and is some cases improved upon – by many other computer manufacturers, has established a ‘standard’ throughout the business world. Within a relatively short period of time, PC-compatible micros have appeared on managers’ desks, offering a wide range of facilities never before available in such variety and breadth. Equipment and programs compatible the “PC standard” have proliferated, taking full advantage of the ease of transfer now available between one PC-compatible computer and another.
The speed of developments in the computer industry is so breath-taking that it is almost impossible to keep up to date with it. Every month new and exciting inventions and enhancements are being announced, and explored and developed.
The portable computer, which fits into a briefcase or on a lap, with its own screen, keyboard and mini-printer, is available in a variety of forms. Many micro-computers use a “mouse” – a hand-held remote control box, to move an arrow around the screen to instruct the computers are a reality, with only the cost of these newer features limiting their wider popularity. Modern microcomputers can produce pictures, graphs, charts, play tunes, as well as undertake many necessary administrative and clerical functions.
The fifth generation of computers is often mentioned in the news. Major research in the field of artificial intelligence is continuously under way, and it will not be too long before computers will be developed which can “think” more like a human brain. These will be used to make very complex decisions, based on a huge number of factors, and will eventually come to the aid of those such as doctors and lawyers, researchers and all those others who have need to rely on intuition and experience.
Whole areas of uses for computers have yet to be opened up, and the manager who thinks ahead and who wishes to harness the latest contributions of technology for the better service of his enterprise, will do well to keep in touch with the rapid developments of the computer world.
1.2 Characteristics of Computers
This following summary will give you an insight into many ways in which the use of computers can improve the efficiency of management in the Armed Forces, and of many businesses, whatever their sizes.
Speed – Computers work at incredible speeds, performing hundreds, thousands, even millions of calculations in a second. The speed at which electrical signals pass within the computer’s “brain” is approximately the speed of light. It is this speed, measured in terms of microseconds (millionths of a second), or even in nanoseconds (thousand-millionths of a second), which enables the provision of instant information, for example, on tomorrow’s weather, today’s flight bookings, this year’s sales by department – answers within seconds whereas previously considerable research and manual documentation might have been necessary.
Storage and Retrieval of Information – Computers can store vast quantities of information, which they can “sift” through when so instructed. They can then present relevant details of that information, exactly in the format required, within seconds.
Diligence – Computers, unlike frail human beings, do not become bored or tired or lose concentration when performing highly repetitive work. If a computer has to perform a certain calculation on a million numbers, it will calculate the first and the last with equal diligence. This enables trust to be placed in the results generated by computers, and confidence to be replaced in their ability – neither of which can always be replaced in humans!
Accuracy – The computer is capable of doing only what it is told to do. If the human beings who design a given application make a mistake, in invoicing customers for example, then it is hardly fair to “blame” the computer, when correctly programmed computers are far more accurate than human beings. It must be remembered always that computers are only machines to be used by humans, as are typewriters, calculators, etc., and the results produced by computers are only as good as the skills of those who designed and operate them.
There is a phrase well known to computer users: “GIGO”, which means “garbage in, garbage out”. In other words, if rubbish is fed into the computer, the results will be rubbish too. It is therefore, for the user to ensure:
It cannot be emphasized enough that computer is NOT a replacement for human competence. It is an office machine, an aid to administration and management, and as such it is only as good as the people who use it.
1.3 Various Areas of Computer Applications
In this section you will learn:
2.0 Definition Of A Computer
A computer is an electronic machine or device that accepts data (raw facts) from an input device, performs arithmetical and logical operations (processing) in accordance with a stored pre-defined program and finally transfers the processed data (information) to an output device.
The above definition will be understood excellently when we come to illustrate how a computer system works later in this section.
2.1 Classification of Computers
All electronic computers are basically the same in their functional design. The main essential differences are in four categories:
This refers to the initial and maintenance cost which is determined by the technology involved and the accompanying facilities, e.g. the power of processing.
This refers to the capability of the CPU to handle input data and instructions to generate information to the recipients.
This is influenced by the computer generation.
The storage facility is influenced by the type of media that the computer supports and/or information to be stored.
2.2 Types of Computers
Basically, there are three main types of computers. These are:
Mainframes are large computers with almost unlimited power allowing many users access to them simultaneously. They have large storage capacity and can perform calculations at very high speeds.
As technology improved, it was possible to design smaller computers especially after the invention of integrated circuits. Minicomputers were designed for use in a normal office environment, providing extensive processing power, adequate for medium sized organizations.
Microcomputers (commonly called personal computers, PCs) are the smallest computers and were intended for use in an office, fitting on a desktop. Their design is based on large-scale circuit integration that confines several physical components to a small element. Their internal memory is smaller than the mini and mainframe computers and they support limited backing storage media. They are relatively cheaper and are the most commonly used computers in offices today.
There are two basic parts of a computer system namely:
Computer Hardware Components.
The computer hardware comprises of the physical and tangible components. They are the parts of the computer that you can see when it is displayed. If it is visible, then that is hardware.
The hardware is again divided into two basic parts namely: –
| CPU |