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INTRODUCTION TO TODAY'S COMPUTERS
A computer is an electronic device used to process information. It is this function of the computer that placed it at the center of our transition from the industrial period of our society to the information age. Today, we encounter computers in almost every aspect of society. Computers are higly visible in such professions as education, science, medicine, and business, but they also can be found behind-the-scenes at the grocery store, in our automobiles, microwave ovens, and VCRs.
Computers have evolved through several generations. Each new generation is based on technological innovations and new methods of processing data. The first generation began with the development of the earliest large mainframe computers. These room-sized computers, such as the UNIVAC 1, were based on electromechanical devices and vacuum-tube technology. Computers based on the transistor, which was invented in the late 1950s, mark the beginning of the second generation of computers. Transistors brought about the development of smallest, faster, and more efficient computers.
The third generation of computers used integrated circuits that opened the door for the creation of even smaller and faster computers. These smaller computers were known as minicomputers and were the first to incorporate operating systems that automated many of the computer's operational tasks, tasks that had been formerly handled by humans.
The fourth generation of computers is characterized by large-scale integration of computer circuitry and small microprocessors. Microcomputer (also called personal computers or PCs) were based on these microprocessors and they put computing power into the hands of individual users. In the future, computers that utilize artificial intelligence technologies will be able to make decisions based on accumulated evidence.
Although the technologies innovations that mark the different generations in the evolution of the computer are generally concerned with the central processing capabilites of the computer, a computer system is actually an integrated set of computing components. A computer system requires input devices (keyboard, mouse, scanners, etc.) to get information into the computer and output devices (monitor, printer, etc.) to get information out of the computer.
These physical components of the computer are known as hardware. The set of instructions or programs that are created by programmers to control the computer's response to user input is known as software.
There are several types of software: system software, which refers to the programs used to operate the computer itself applications software, which refers to programs used to perform various tasks such as word processing, database management, and record keeping; and programming software, which refers to programs used to create software.
Programming languages have evolted through a series of generations, just as computer hardware has. Machine languages give the programmer precise control over all of the computer's activities using programming commands that are closely related to hardware capabilities. Assembly languages use easier-to-understand code words rather than the binary code used in machine languages. High-level languages, which utilize Enlish-like instructions, made the programming process much easier.
Today, nonprocedural languages, object-oriented languages, and natural-language approaches provide much more flexibility to programmers by eliminating the need for many of the special syntax rules of earlier languages. Just as the personal computer gave computing power to the individual, today's new authoring tools are providing a way for nonprogrammers to create their own programms.
COMPUTERS IN EDUCATION, SCIENCE AND MEDICINE
In the past, many might have questioned the need to know about computers. Computers were complex, mysterious devices that were managed by computer professionals in computer centres that were hidden away in specially designed, climate-controlled rooms. But today, we use computers and computerized devices every day. And while there is still a tremendous need for computer programmers and other computer professionals in our society, there is an even grater need for knowledgeable computer users. From word processing to medical imaging, today's computers give us new capabilities and new ways to accomplish our daily tasks. Today's users need to know what computers and computer programs are capable of and how to take advantage of those capabilities.
In education, personal computers have given teachers new ways to individualize instruction. New types of computerized learning programs can combine text, graphics, and even on-screen digitised video to give students more realistic, motivational lessons. Programs that provide practice and feedback about basic concepts have now been supplemented with tutorials and simulations that present students with information about real-world situations.
Today, elementary and secondary schools as well as colleges and universities provide a variety of courses about using computers. Many high schools and colleges are now requiring all students to take at least one course on using computers and some states now require all teachers to be knowledgeable about computers and computer programs before they can acquire teaching credentials.
Reseraches in science and medicine have used computers since they were invested, but today new, more powerful computers and more sophisticated computer programs have made them indispensable to scientists. Scientific instrumentation for research and analysis has now become thorougly computerized. And medical diagnostic technologies and computer-based medical imaging represent one of the fastest-growing areas in the computer field.
COMPUTER-BASED COMMUNICATIONS SYSTEMS
Computer-based communications systems have significantly enhanced our ability to communicate with each other. In the last few decades, computer-based technologies led to a redesign of our telephone systems, and new technologies have created new ways to convey information.
FAX machines and computers that can communicate with FAX machines now quickly send copies of documents across the country or across the world.
Even our traditional methods of sending mail have changed because of the computer. Computers are now used to prepare memos, letters, and business information. New programs can create much more attractive documents that include graphics and varieties of text styles and sizes.
In additiom, many computer users now send mail electronically. Electronic mail (e-mail) systems are computer-based systems that provide individual computer users with an "address" to which computer messages can be sent. Once sent by the computer, the e-mail message will arrive almost instantaneously at its destination, where it will be stored until the addresses uses a computer to access it. Individuals can also send of the fastest-growing uses of computers. Today, they are becoming common in business and in education.
Over the last few decades, almost business, whether large or small, has "computerized." And every aspect of business - from sales to product delivery - now involves the use of a computer. In marketing, the computer is used to maintain information about customers and accounts. In manufacturing, the computer is used to keep track of raw materials, production, and inventory. Computers are now so common in business that they are used to track a company's products from their design to their delivery. And most large businesses now have a special department to manage the computers and the flow of computerized business information. In computers and computer programs to use often closely related to the overall success of the company.
Our private homes represent one of the last places in our society to be significantly changed by the computer. While government offices, schools, hospitals and businesses have found advantageous applications for computers, many homes have not. Some have predicted that the next great surge in new computer applications will be for our homes.
They say we will soon be ordering our groceries, our auto service, our cable TV programs, or our Sunday papers simply by choosing an option from a menu of choices on the computer's screen.
Today, there are already computerized security systems in many homes. Some homebuilders have installed systems in houses that use a computer to control the lights, the heat, and ever the electric appliances. In some homes, these computerized systems can be controlled by calling the house from any phone and typing in number sequences using the phone's numbered dialling buttons.
Now, many computer experts believe that the computer will finally find its way into our homes as part of a unifield information and entertainment system. If the technologies of television, computers, and electronic games come together, they will provide a new form of interactive video entertainment. This may take the form of continually available television broadcasts that can be stored inside your computerized entertainment centre, letting you determine what you want to see when you want to see it.