History of the computer Essay Example For Students

History of the computer Essay Generally, a computer is any device that can perform numerical Calculations even an adding machine, an abacus, or a slide rule. Currently, however, the term usually refers to an electronic device that can use a list of instructions, called a program, to perform calculations or to store, manipulate, and retrieve information. Todays computers are marvels of miniaturization. Machines that once weighed 30 tons and occupied warehouse-size rooms now may weigh as little as three pounds (1. lograms) and can be carried in a suit pocket. The heart of todays computers are integrated circuits (ICs), sometimes called microchips, or simply chips. These tiny silicon wafers can contain millions of microscopic electronic components and are designed for many specific operations: some control an entire computer (CPU, or central processing unit, chips); some perform millions of mathematical operations per second (math oprocessors); others can store more than 16 million characters of information at one time (memory chips). In 1953 there were only about 100 computers in use in the entire world. Today hundreds of millions of computers form the core of electronic products, and more than 110 million programmable computers are being used in homes, businesses, government offices, and universities for almost every conceivable purpose. Computers come in many sizes and shapes. Special-purpose, or dedicated, computers are designed to perform specific tasks. Their operations are limited to the programs built into their microchips. These computers are the basis for electronic calculators and can be found in thousands of other electronic products, including digital watches (controlling timing, alarms, and displays), cameras (monitoring shutter speeds and aperture settings), and automobiles (controlling fuel injection, heating, and air conditioning and monitoring hundreds of electronic sensors). General-purpose computers, such as personal computers and business computers, are much more versatile because they can accept new sets of instructions. Each new set of instructions, or program, nables the same computer to perform a different type of operation. For example, one program lets the computer act like a word processor, another lets it manage inventories, and yet another transforms it into a video game. Although some general-purpose computers are as small as pocket radios, the smallest class of fully functional, self-contained computers is the class called notebook computers. These usually consist of a CPU, data-storage devices called disk drives, a liquid-crystal display (LCD), and a full-size keyboardall housed in a single unit small enough to fit into a briefcase. Todays desktop personal computers, or PCs, are many times more powerful than the huge, million-dollar business computers of the 1960s and 1970s. Most PCs can perform from 16 to 66 million operations per second, and some can even perform more than 100 million. These computers are used not only for household management and personal entertainment, but also for most of the automated tasks required by small businesses, including word processing, generating mailing lists, tracking inventory, and calculating accounting information. Minicomputers are fast computers that have greater datamanipulating capabilities than personal computers and can be used simultaneously by many people. These machines are primarily used by larger businesses to handle extensive accounting, billing, and inventory records. Mainframes are large, extremely fast, multi-user computers that often contain complex arrays of processors, each designed to perform a specific function. Because they can handle huge databases, can simultaneously accommodate scores of users, and can perform complex mathematical operations, they are the mainstay of industry, research, and university computing centers. The speed and power of supercomputers, the fastest class of computer, are almost beyond human comprehension, and their capabilities are continually being improved. The most sophisticated of these machines can perform nearly 32 billion calculations per second, can store a billion characters in memory at one time, and can do in one hour what a desktop computer would take 40 years to do. Supercomputers attain these speeds through the use of several advanced engineering techniques. For example, critical circuitry is supercooled to nearly absolute zero so that electrons can move at the peed of light, and many processors are linked in such a way that they can all work on a single problem simultaneously. Because these computers can cost millions of dollars, they are used primarily by government agencies and large research centers. Computer development is rapidly progressing at both the high and the low ends of the computing spectrum. On the high end, by linking together networks of several small computers and programming them to use a language called Linda, scientists have been able to outperform the supercomputer. This technology is called parallel processing and helps avoid hours of idle computer time. A goal of this technology is the creation of a machine that could perform a trillion calculations per second, a measure known as a teraflop. On the other end of the spectrum, companies like Apple and Compaq are developing small, handheld personal digital assistants (PDAs). The Apple Newton, for example, lets people use a pen to input handwritten information through a touch-sensitive screen and to send mail and faxes to other computers. Researchers are currently developing microchips called digital signal rocessors, or DSPs, to enable these PDAs to recognize and interpret human speech. This development, which will permit people in all professions to use a computer quickly and easily, promises to lead to a revolution in the way humans communicate and transfer information. Communication. Computers make all modern communication possible. They operate telephone switching systems, coordinate satellite launches and operations, help generate special effects for movies, and control the equipment in all phases of television and radio broadcasts. Local-area networks (LANs) link the computers in separate departments of businesses or universities, and larger networks, such as the Internet, permit modemstelecommunication devices that transmit data through telephone linesto link individual computers to other computers anywhere in the world. Journalists and writers now use word processors to write books and articles, which they then submit to publishers on magnetic disks or through telephone lines. The data may then be sent directly to computer-controlled typesetters, some of which actually design the layout of printed pages on computer screens. Science and research. Computers are used by scientists and researchers in many ways to collect, store, manipulate, and analyze data. Running simulations is one of the most important applications. Data representing a real-life system is entered into the computer, and the computer manipulates the data in order to show how the natural system is likely to behave under a variety of conditions. In this way scientists can test new theories and designs or can examine a problem that does not lend itself to direct experimentation. Computer-aided design, or CAD, programs enable engineers and architects to design three-dimensional models on a computer screen. Chemists may use computer simulation to design and test molecular models of new drugs. Some simulation programs can generate models of weather conditions to help meteorologists make predictions. Flight simulators are valuable training tools for pilots. Industry. Computers have opened a new era in manufacturing and consumer-product development. In the factory, computer-assisted manufacturing, or CAM, programs help people plan complex production schedules, keep track of inventories and accounts, run automated assembly lines, and control robots. Dedicated computers are routinely used in thousands of products ranging from calculators to airplanes. Government. Government agencies are the largest users of mainframes and supercomputers. The United States Department of Defense uses computers for hundreds of tasks, including research, breaking codes, interpreting data from spy satellites, and targeting missiles. The Internal Revenue Service uses computers to keep track of tens of millions of tax returns. Computers are also essential for taking the census, maintaining criminal records, and other tasks. Education. Computers have proved to be valuable educational tools. Computer-assisted instruction, or CAI, uses computerized lessons that range from simple drills and practice sessions to complex interactive tutorials. These programs have become essential teaching tools in medical schools and military training centers, where the topics are complex and the cost of human teachers is extremely high. Educational aids, such as some encyclopedias and other major reference works, are available to personal-computer userseither on magnetic disks or optical discs or through various Telecommunication networks. Arts and Entertainment. Video games are one of the most popular applications of personal computers. The constantly improving graphics and sound capabilities of personal computers have made them popular tools for artists and musicians. Personal computers can display millions of colors, can produce images far clearer than those of a television set, and can connect to various musical instruments and synthesizers. Painting and drawing programs enable artists to create realistic images and animated displays much more easily than they could with more traditional tools. Native Americans and Aztecs EssayMagnetic-tape storage devices are usually used together with hard disk drives on large computer systems that handle high volumes of onstantly changing data. The tape drives, which access data very slowly, regularly back up, or duplicate, the data in the hard disk drives to protect the system against loss of data during power failures or computer malfunctions. magnetic-drum memories store data in the form of magnetized spots in adjacent circular tracks on the surface of a rotating metal cylinder. They are relatively slow and are rarely used today. Optical discs are nonmagnetic auxiliary storage devices that developed from compact-audio-disc technology. Data is encoded on a disc as a series of pits and flat spaces, called lands, the lengths of which correspond to different patterns of 0s and 1s. One removable 43/4-inch (12-centimeter) disc contains a spiral track more than 3 miles (4. 8 kilometers) long, on which can be stored nearly a billion bytes (gigabyte) of information. All of the text in this encyclopedia, for example, would fill only one fifth of one disc. Read-only optical discs, whose data can be read but not changed, are called CD- ROMs Recordable CD-ROM drives, called WORM (write-once/read-many) drives, are used by many businesses and universities to periodically back up changing databases and to conveniently distribute massive amounts of information to customers or users. Output devices let the user see the results of the computers data processing. The most common output device is the video display terminal (VDT), or monitor, which uses a cathode-ray tube (CRT) to display characters and graphics on a television-like screen. Modems (modulator-demodulators) are input-output devices that allow computers to transfer data between each other. A modem on one computer translates digital pulses into analog signals (sound) and then transmits the signals through a telephone line or a communication network to another computer. A modem on the computer at the other end of the line reverses the process. Printers generate hard copya printed version of information stored in one of the computers memory systems. The three principal types of printers are daisy-wheel, dot-matrix, and laser. Other types of printers include ink-jet printers and thermal printers. A computers operating system is the software that allows all of the dissimilar hardware and software systems to work together. It is often stored in a computers ROM memory. An operating system consists of programs and routines that coordinate operations and processes, translate the data from different input and output devices, regulate data storage in memory, allocate tasks to different processors, and provide functions that help programmers write software. Computers that use disk memory-storage systems are said to have disk operating systems (DOS). MS-DOS is the most popular microcomputer operating system. UNIX, a powerful operating system for larger computers, allows many users and many different programs to gain access to a computers processor at the same time. Visual operating systems called GUIs (graphical user interfaces) were designed to be easy to use, yet to give UNIX-like power and flexibility to home and small-business users. Future operating systems will enable users to control all aspects of the computers hardware and software simply by moving and manipulating their corresponding objects, or graphical icons displayed on the screen. Sometimes programs other than the operating system are built into the hardware, as is the case in dedicated computers or ROM chips. Most often, however, programs exist independently of the computer. When such software is loaded into a general-purpose computer, it automatically programs the computer to perform a specific tasksuch as word processing, managing accounts and inventories, or displaying an arcade game. By the mid-1970s, microchips and microprocessors had drastically reduced the cost of the thousands of electronic components required in a computer. The first affordable desktop computer designed specifically for personal use was called the Altair 8800 and was sold by Micro Telemetry Systems in 1974. In 1977 Tandy Corporation became the first major electronics firm to produce a personal computer. They added a keyboard and CRT to their computer and offered a means of storing programs on a cassette recorder. Soon afterward, a small company named Apple Computer, founded by engineer Stephen Wozniak and entrepreneur Steven Jobs, began producing a superior computer. IBM introduced its Personal Computer, or PC, in 1981. As a result of competition from the makers of clones (computers that worked exactly like an IBM-PC), the price of personal computers fell drastically. Todays personal computer is 400 times faster than ENIAC, 3,000 times lighter, and several million dollars cheaper. In rapid succession computers have shrunk from tabletop to lap-top and finally to palm size. With some personal computers, called pen-pads, people can even write directly on an etched-glass, liquid-crystal screen using a small electronic stylus , and words will appear on the screen in clean typescript. In the early 1990s, manufacturers began producing inexpensive CD-ROM drives that could access more than 650 megabytes of data form a single disc. This development started a multimedia revolution that may continue for decades. The term multimedia encompasses the computers ability to merge sounds, video, text, music, animations, charts, maps, etc. into colorful, interactive presentations, a business advertising campaign, or even a space-war arcade game. Faster computers and the rapid proliferation of multimedia programs will probably forever change the way people get information. The computers ability to instantly retrieve a tiny piece of information from the midst of a huge mass of data has always been one of its most important uses. Since video and audio clips can be stored alongside text on a single CD-ROM disc, a whole new way of exploring a subject is possible . By using hyperlinksa programming method by which related terms, articles, pictures, and sounds are internally hooked togethermaterial can be presented to people so that they can peruse it in a typically human manner, by association. For example, if you are reading about Abraham Lincolns Gettysburg Address and you want to read about the battle of Gettysburg, you need only click on the highlighted hyperlink battle of Gettysburg. Instantly, the appropriate text, photos, and maps appear on the monitor. Pennsylvania is another click away, and so on. Encyclopedias, almanacs, collections of reference books, interactive games using movie footage, educational programs, and even motion pictures with accompanying screenplay, actor biographies, directors notes, and reviews make multimedia one of the computer worlds most exciting and creative fields. A computer network is the interconnection of many individual computers, much as a road is the link between the homes and the buildings of a city. Having many separate computers linked on a network provides many advantages to organizations such as businesses and universities. People may quickly and easily share files; modify databases; send memos called E-mail, or electronic mail; run programs on remote mainframes; and get access to information in databases that are too massive to fit on a small computers hard drive. Networks provide an essential tool for the routing, managing, and storing of huge amounts of rapidly changing data. The Internet is a network of networks: the international linking of tens of thousands of businesses, universities, and research organizations with millions of individual users. It is what United States President Al Gore first publicly referred to as the information superhighway. What is now known as the Internet was originally formed in 1970 as a military network called ARPAnet (Advanced Research Projects Agency network) as part of the Department of Defense. The network opened to non-military users in the 1970s, when universities and companies doing defense-related research were given access, and flourished in the late 1980s as most universities and many businesses around the world online. In 1993, when commercial providers were first permitted to sell Internet connections to individuals, usage of the network exploded. Millions of new users came on within months, and a new era of computer communications began. Most networks on the Internet make certain files available to other. These common files can be databases, programs, or E-mail from the individuals on the network. With hundreds of thousands of international sites each providing thousands of pieces of data, its easy to imagine the mass of raw data available to users. The Internet is by no means the only way in which computer users can communicate with others. Several commercial online services provide connections to members who pay a monthly connect-time fee. CompuServe, America OnLine, Prodigy, Genie, and several others provide a tremendous range of information and services, including online conferencing, electronic mail transfer, program downloading, current weather and stock market information, travel and entertainment information, access to encyclopedias and other reference works, and electronic forums for specific users groups such as PC us