What is a computer? A Computer is an electronic device that can receive a set ofinstructions, or program, and then carry out this program by performingcalculations on numerical data or by compiling and correlating other forms ofinformation. Thesis Statement:- The modern world of high technology could nothave come about except for the development of the computer. Different types andsizes of computers find uses throughout society in the storage and handling ofdata, from secret governmental files to banking transactions to privatehousehold accounts. Computers have opened up a new era in manufacturing throughthe techniques of automation, and they have enhanced modern communicationsystems.
They are essential tools in almost every field of research and appliedtechnology, from constructing models of the universe to producing tomorrow'sweather reports, and their use has in itself opened up new areas of conjecture.Database services and computer networks make available a great variety ofinformation sources. The same advanced techniques also make possible invasionsof privacy and of restricted information sources, but computer crime has becomeone of the many risks that society must face if it would enjoy the benefits ofmodern technology. Imagine a world without computers.
That would mean no propermeans of communicating, no Internet, no video games. Life would be extremelydifficult. Adults would have to store all their office work paper and thereforetake up an entire room. Teenagers would have to submit course-works and projectshand-written. All graphs and diagrams would have to be drawn neatly andcarefully.
Youngsters would never have heard of 'video-games' and will have tospend their free time either reading or playing outside with friends. But thanksto British mathematicians, Augusta Ada Byron and Charles Babbage, our lives aremade a lot easier. Later, on my investigation about the growth of computers overthe decades, I will be talking about types of computers, how and when computerswere first being developed, the progress it made, computers at present and plansfor the future. In types of computers, I will be talking about analogue anddigital computers and how they function. In the development of computers, I willbe mentioning about the very first electronic calculator and computer.
Underprogress made, I will only be mentioning about circuits. For computers of thepresent, I will be talking about networking, telecommunications and games. Andfinally, as for planning for the future, I will mention about new and recentideas, research and development of new computers heard and talked about innewspapers and on television. I. MAIN TYPES OF COMPUTERS There are two maintypes of computers which are in use today, analog and digital computers,although the term computer is often used to mean only the digital type. Analogcomputers exploit the mathematical similarity between physicalinterrelationships in certain problems, and employ electronic or hydrauliccircuits to simulate the physical problem.
Digital computers solve problems byperforming sums and by dealing with each number digit by digit. Hybrid computersare those which contain elements of both analog and digital computers. They areusually used for problems in which large numbers of complex equations, known astime integrals, are to be computed. Data in analog form can also be fed into adigital computer by means of an analog- to-digital converter, and the same istrue of the reverse situation.
a) What are analog computers and how do theywork? The analog computer is an electronic or hydraulic device that is designedto handle input in terms of, for example, voltage levels or hydraulic pressures,rather than numerical data. The simplest analog calculating device is the sliderule, which employs lengths of specially calibrated scales to facilitatemultiplication, division, and other functions. In a typical electronic analogcomputer, the inputs are converted into voltages that may be added or multipliedusing specially designed circuit elements. The answers are continuouslygenerated for display or for conversion to another desired form.
b) What aredigital computers and how do they work? Everything that a digital computer doesis based on one operation: the ability to determine if a switch, or"gate," is open or closed. That is, the computer can recognise onlytwo states in any of its microscopic circuits: on or off, high voltage or lowvoltage, or-in the case of numbers-0 or 1. The speed at which the computerperforms this simple act, however, is what makes it a marvel of moderntechnology. Computer speeds are measured in megahertz, or millions of cycles persecond. A computer with a "clock speed" of 10 MHz-a fairlyrepresentative speed for a microcomputer-is capable of executing 10 milliondiscrete operations each second. Business microcomputers can perform 15 to 40million operations per second, and supercomputers used in research and defenceapplications attain speeds of billions of cycles per second.
Digital computerspeed and calculating power are further enhanced by the amount of data handledduring each cycle. If a computer checks only one switch at a time, that switchcan represent only two commands or numbers; thus ON would symbolise oneoperation or number, and OFF would symbolise another. By checking groups ofswitches linked as a unit, however, the computer increases the number ofoperations it can recognise at each cycle. For example, a computer that checkstwo switches at one time can represent four numbers (0 to 3) or can execute oneof four instructions at each cycle, one for each of the following switchpatterns: OFF-OFF (0); OFF-ON (1); ON-OFF (2); or ON-ON (3).
II. WHERE IT ALLBEGAN a) The Mother of all Calculators The first adding machine, a precursor ofthe digital computer, was devised in 1642 by the French philosopher BlaisePascal. This device employed a series of ten-toothed wheels, each toothrepresenting a digit from 0 to 9. The wheels were connected so that numberscould be added to each other by advancing the wheels by a correct number ofteeth. In the 1670s the German philosopher and mathematician Gottfried Wilhelmvon Leibniz improved on this machine by devising one that could also multiply.
The French inventor Joseph Marie Jacquard , in designing an automatic loom, usedthin, perforated wooden boards to control the weaving of complicated designs.During the 1880s the American statistician Herman Hollerith conceived the ideaof using perforated cards, similar to Jacquard's boards, for processing data.Employing a system that passed punched cards over electrical contacts, he wasable to compile statistical information for the 1890 U.S.
census. b) The Motherof all Computers Also in the 19th century, the British mathematician andinventor Charles Babbage worked out the principles of the modern digitalcomputer. He conceived a number of machines, such as the Difference Engine, thatwere designed to handle complicated mathematical problems. Many historiansconsider Babbage and his associate, the British mathematician Augusta Ada Byron(Lady Lovelace, 1815-52), the daughter of the English poet Lord Byron, the trueinventors of the modern digital computer. The technology of their time was notcapable of translating their sound concepts into practice; but one of theirinventions, the Analytical Engine, had many features of a modern computer. Ithad an input stream in the form of a deck of punched cards, a "store"for saving data, a "mill" for arithmetic operations, and a printerthat made a permanent record.
c) Early Computers Analog computers began to bebuilt at the start of the 20th century. Early models calculated by means ofrotating shafts and gears. Numerical approximations of equations too difficultto solve in any other way were evaluated with such machines. During both worldwars, mechanical and, later, electrical analog computing systems were used astorpedo course predictors in submarines and as bombsight controllers inaircraft. Another system was designed to predict spring floods in theMississippi River Basin.
In the 1940s, Howard Aiken, a Harvard Universitymathematician, created what is usually considered the first digital computer.This machine was constructed from mechanical adding machine parts. Theinstruction sequence to be used to solve a problem was fed into the machine on aroll of punched paper tape, rather than being stored in the computer. In 1945,however, a computer with program storage was built, based on the concepts of theHungarian-American mathematician John von Neumann.
The instructions were storedwithin a so-called memory, freeing the computer from the speed limitations ofthe paper tape reader during execution and permitting problems to be solvedwithout rewiring the computer. III. EARLY PROGRESS The rapidly advancing fieldof electronics led to construction of the first general-purpose all-electroniccomputer in 1946 at the University of Pennsylvania by the American engineer JohnPresper Eckert, Jr. and the American physicist John William Mauchly.
CalledENIAC, for Electronic Numerical Integrator And Computer, the device contained18,000 vacuum tubes and had a speed of several hundred multiplications perminute. Its program was wired into the processor and had to be manually altered.The use of the transistor in computers in the late 1950s marked the advent ofsmaller, faster, and more versatile logical elements than were possible withvacuum- tube machines. Because transistors use much less power and have a muchlonger life, this development alone was responsible for the improved machinescalled second-generation computers. Components became smaller, as didinter-component spacings, and the system became much less expensive to build. a)Integrated Circuits Late in the 1960s the integrated circuit, or IC, wasintroduced, making it possible for many transistors to be fabricated on onesilicon substrate, with inter- connecting wires plated in place.
The IC resultedin a further reduction in price, size, and failure rate. The microprocessorbecame a reality in the mid-1970s with the introduction of the large scaleintegrated (LSI) circuit and, later, the very large scale integrated (VLSI)circuit, with many thousands of interconnected transistors etched into a singlesilicon substrate. To return, then, to the "switch-checking"capabilities of a modern computer: computers in the 1970s generally were able tocheck eight switches at a time. That is, they could check eight binary digits,or bits, of data, at every cycle. A group of eight bits is called a byte, eachbyte containing 256 possible patterns of ONs and OFFs (or 1's and 0's). Eachpattern is the equivalent of an instruction, a part of an instruction, or aparticular type of datum, such as a number or a character or a graphics symbol.
The pattern 11010010, for example, might be binary data-in this case, thedecimal number 210 (see NUMBER SYSTEMS)-or it might tell the computer to comparedata stored in its switches to data stored in a certain memory-chip location.The development of processors that can handle 16, 32, and 64 bits of data at atime has increased the speed of computers. The complete collection ofrecognizable patterns-the total list of operations-of which a computer iscapable is called its instruction set. Both factors-number of bits at a time,and size of instruction sets-continue to increase with the ongoing developmentof modern digital computers. IV.
COMPUTERS OF THE 90'S a) Computer NetworksMajor changes in the use of computers have developed since it was firstinvented. Computers have expanded, via telephone lines, into vast nation-wide,or world-wide, networks. At each extremity of the network is a terminal device,or even a large computer, which can send jobs over the wire to the centralcomputer at the hub of the network. The central computer performs thecomputation or data processing and sends the results over the wire to anyterminal in the network for printing.
Some computer networks provide a servicecalled time sharing. This is a technique in which software shifts the computerfrom one task to the another with such timing that it appears to each user at aterminal that he has exclusive use of the computer. b) TelecommunicationsCertain telecommunication methods have become standard in the telecommunicationsindustry as a whole, because if two devices use different standards they areunable to communicate properly. Standards are developed in two ways: (1) themethod is so widely used that it comes to dominate; (2) the method is publishedby a standard-setting organisation. The most important organisation in thisrespect is the International Telecommunication Union, a specialised agency ofthe United Nations, and one of its operational entities, the InternationalTelegraph and Telephone Consultative Committee (CCITT). Other organizations inthe area of standards are the American National Standards Institute, theInstitute of Electrical Engineers, and the Electronic Industries Association.
One of the goals of these organizations is the full realisation of theIntegrated Services Digital Network (ISDN), which is projected to be capable oftransmitting through a variety of media and at very high speeds both voice andnon-voice data around the world in digital form. Other developments in theindustry are aimed at increasing the speed at which data can be transmitted.Improvements are being made continually in modems and in the communicationsnetworks. Some public data networks support transmission of 56,000 bits persecond (bps), and modems for home use are capable of as much as 56kbps. c) PCGames and Video CD's CD's have developed a lot over the past decade.
At first,they were used only for music. Now, there are CD's from which we can play PCgames and watch movies. The games at present are usually 3D. This means that thegame seems almost life-like or virtual.
One can spend hours playing a games onCD because they are addictive. This is one of the main disadvantage of computergames, because the person prevents themselves from doing anything educational orengaging themselves in any physical activities. Another common disadvantage isthat playing too much on the computer can cause bad eye-sight. But there are afew educational games for young children to help them learn and understandthings better. Games may not be all that good for an individual, but if seen howthey are programmed one will realise that it is not all easy to program a game.A few years ago, if one was bored, they would usually go to a video shop andrent a movie.
Now one can rent Movie CD's and play them on the computer andspecial Movie CD player's which are also installed in some new Hi-Fi Systems.
