Basic Computer Knowledge

Master List of Questions General Computer Question 1: What is a computer? General Computer Question 2: How do we use computers? General Computer Question 3: How are computers used in Banking and Finance? General Computer Question 4: How are computers used in Education? General Computer Question 5: How are computers used in Medicine? General Computer Question 6: How are computers used in Business? General Computer Question 7: How are computers used in Entertainment and Recreation? General Computer Question 8: How are computers used in the workplace? General Computer Question 9: What is telecommuting? General Computer Question 10: What is ergonomics? General Computer Question 11: Are there privacy issues when using computers and the internet? General Computer Question 12: What can we do about computer crime? General Computer Question 13: What is a computer virus? General Computer Question 14: Is my data safe on a computer? How can it be protected? General Computer Question 15: What is backing up and why is it so important? General Computer Question 16: What is Software Piracy? General Computer Question 17: What is public domain and shareware? General Computer Question 18: What is Computer Ethics? General Computer Question 19: How can I improve my computer skills? General Computer Question 20: What types of computer jobs are available? General Computer Question 21: Are there health considerations when using computers? General Computer Question 22: What is computer-aided engineering (CAE)? General Computer Question 23: What is computer-aided manufacturing (CAM)? General Computer Question 24: What is computer robotics? General Computer Question 25: What is artificial intelligence? General Computer Question 26: What is an information system? General Computer Question 27: What is the system development cycle? Computer Hardware Question 1: What is Computer hardware? Computer Hardware Question 2: When was the computer developed? Computer Hardware Question 3: What is a first generation computer? Computer Hardware Question 4: What is a second generation computer? Computer Hardware Question 5: What is a third generation computer? Computer Hardware Question 6: What is a fourth generation computer? Computer Hardware Question 7: What types of computers will we use in the future? Computer Hardware Question 8: What is a mainframe? Computer Hardware Question 9: What is a supercomputer? Computer Hardware Question 10: What is a minicomputer? Computer Hardware Question 11: What is a microcomputer (PC, desktop computer)? Computer Hardware Question 12: What is a workstation? Computer Hardware Question 13: What is an embedded microprocessor? Computer Hardware Question 14: What is computer storage? Computer Hardware Question 15: What is input? Computer Hardware Question 16: What is an output device? Computer Hardware Question 17: What is the central processing unit (CPU)? Computer Hardware Question 18: What is a control unit? Computer Hardware Question 19: What is an arithmetic/logic unit (ALU)? Computer Hardware Question 20: What is the instruction cycle (I-Cycle) and the execution cycle (E-Cycle)? Computer Hardware Question 21: What is the CPU clock? Computer Hardware Question 22: What is main memory? Computer Hardware Question 23: What is a secondary storage system? Computer Hardware Question 24: What is disk storage? Computer Hardware Question 25: What is a hard disk (fixed disk) ? Computer Hardware Question 26: What is a diskette (floppy disk? Computer Hardware Question 27: What is tape storage? Computer Hardware Question 28: What is an optical disk? Computer Hardware Question 29: What is read-only memory (ROM)? Computer Hardware Question 30: What is a pointing devce? Computer Hardware Question 31: What is an image scanner? Computer Hardware Question 32: How does a display monitor work? Computer Hardware Question 33: What is an impact printer? Computer Hardware Question 34: What is a nonimpact printer? Computer Hardware Question 35: What is a line printer (also known as a chain, band, or drum printer)?

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Computer Hardware Question 36: What is a dot-matrix printer? Computer Hardware Question 37: What is a letter-quality printer? Computer Hardware Question 38: What is a laser printer? Computer Hardware Question 39: What is an ink-jet printer? Computer Hardware Question 40: What is a point-of-sale system? Computer Hardware Question 41: What is a plotter? Computer Software Question 1: What is software? Computer Software Question 2: What is systems software? Computer Software Question 3: What is applications software? Computer Software Question 4: What is programming software? Computer Software Question 5: What is an operating system? Computer Software Question 6: What is the binary number systemand how does it compare to the decimal number system? Computer Software Question 7: What is hexadecimal representation? Computer Software Question 8: What is ASCII? Computer Software Question 9: What is EBCDIC? Computer Software Question 10: What do the terms bit, byte, and word refer to? Computer Software Question 11: What is the human-computer interface (also known as the computer-user interface? Computer Software Question 12: What is optical character recognition (OCR)? Computer Software Question 13: What is a programming language? Computer Software Question 14: What is machine language? Computer Software Question 15: What is assembly language? Computer Software Question 16: What is a high-level language? Computer Software Question 17: What is a fourth-generation language? Computer Software Question 18: What is a fifth-generation language? Computer Software Question 19: What is object-oriented programming (OOP)? Computer Software Question 20: What is object-oriented authoring (OOA)? Computer Software Question 21: What is structured programming? Computer Software Question 22: What is an algorithm? Computer Software Question 23: What is a flowchart? Computer Software Question 24: What is pseudocode? Computer Software Question 25: What is debugging? Computer Software Question 26: What is beta testing? Computer Software Question 27: What is end-user documentation? Computer Software Question 28: What is an internet (web) browser? Computer Software Question 29: What is word processing? Computer Software Question 30: What is the cursor? Computer Software Question 31: What is a mouse? Computer Software Question 32: What is dragging? Computer Software Question 33: What is the scroll bar and the scroll box? Computer Software Question 34: What is a ruler line? Computer Software Question 35: What is background printing? Computer Software Question 36: What is a macro? Computer Software Question 37: What is desktop publishing? Computer Software Question 38: What is a spreadsheet? Computer Software Question 39: What is a computer graphic? Computer Software Question 40: What is a database? Computer Software Question 41: What are the types of databases? Computer Communications Question 1: What is data communications? Computer Communications Question 2: What does upload and download refer to? Computer Communications Question 3: What are the data communications options? Computer Communications Question 4: What is a modem? Computer Communications Question 5: What type of equipment do I need for computer communications? Computer Communications Question 6: What are the communications network types? Computer Communications Question 7: What is a bridge? Is it the same as a gateway? Computer Communications Question 8: What exactly is the internet? Is it the same as the world wide web? Computer Communications Question 9: What is email? Computer Communications Question 10: What is a fax? Computer Communications Question 11: What is Voice Mail? Computer Communications Question 12: What is a computer bulletin board? Computer Communications Question 13: What is computer teleconferencing? Computer Communications Question 14: What is file transfer protocol (FTP)?

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General Computer Questions General Computer Question 1: What is a computer? Answer: A common, somewhat simplified, definition is that the computer is an electronic device that can be used to process information. As we might expect from this definition, the fact that the computer is electronic means that it will be fast: it can operate at electronic speed. But what do we mean when we say the computer can process information? The answer to that question is not so simple. When computers were first used, they were used exclusively for calculating numbers. During that period, information processing was defined as calculating numbers. Today, computers are not only used for calculations, but also for creating and manipulating text and pictures. They are used to design bridges and spacecraft, to record a company's sales and to keep track of customers, to create a school newspaper, or to estimate the cost of a new school. If computers can do all these things, then it appears that we must define information processing in terms of what the current crop of computers can do, and that definition is constantly expanding. An illustration of a basic computer system is below.

A Basic Computer System.

In a remarkably short period of time the computer has changed our world. During the first half of the twentieth century, economic growth in the world's industrial societies was fueled by large-scale manufacturing processes. Back then, most manufacturing was involved in converting natural resources into products that were then sold to the public. During that period, the industrialized countries of the world developed factories with assembly lines that were designed to efficiently build everything from household appliances to automobiles, ships, and locomotives. The countries that were best able to adapt their societies to produce these kinds of products became the "industrialized" societies and they dominated the world's economy. But now, as we move into a new century, a relatively new invention, the computer, is leading to a shift in the world's power structure. Economic growth is now more likely to be fueled by the processing of information, the storage and delivery of facts and knowledge. We are now in the information age. While industrialized societies still build and sell the products of heavy industry - like automobiles and tractors - the computer has become an indispensable element in their design, manufacture, and distribution. Today, in the industrialized countries, much of the business and economic activity involves the computer. The computer is now involved in design work, the management of money, and the manufacture, marketing, and distribution of products. And, as the world's international markets become ever more competitive, the computer's role will continue to grow steadily (also see the General Computer Question #2 below: How do we use computers?)

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General Computer Question 2: How do we use computers? Answer: During the past few decades, computers and electronic technologies have been incorporated into almost every aspect of society. They now play a role in how we learn, how we take care of our money, and how we are entertained. Today, there is probably no better indication of how advanced a society is than how computerized it is. In our society, computers are now a fundamental component of our jobs, our schools, our stores, our means of transportation, and our health care. Our complex systems of banking and investment could not operated without computers. Essentially, all of our medical and scientific facilities now depend entirely upon incredibly complex computer-based systems. Almost all of our businesses now use the computer to maintain information about customers and products. Our schools use computers to teach and to maintain student records. Computers are now commonly used in medicine for diagnosis and treatment. In fact, every day it gets harder to find any type of business, educational institution, or government office that does not use computers in some way. A variety of new types of specialized hardware and software tools have made the computer valuable for everything from the most repetitive tasks, such as scanning items in a supermarket, to incredibly detailed and complex tasks, such as designing spacecraft. Because computers can store accurate information, they are used to help people make better decisions. Because computers can continue to operate day or night, 24 hours a day, they are now used to provide a level of services to humans that was unknown before their invention.

General Computer Question 3: How are computers used in Banking and Finance? Answer: Computers have become an indispensable tool in the handling of money and finances. Computerized ATM machines and credit card machines are now familiar throughout the United States and in many other countries in the world. Although they have only been in existence for a short while, many of us now take them for granted and expect our bank to provide these computerized services whenever and wherever we need them. Many do not realize that these machines are part of the huge electronic network that has been put in place in the banking and financial services industries. The ATM machines and the credit card machines provide our interface with the bank's computers. Computers are also used extensively in the world of stocks and investments. Around the world, investors, investment brokers, financial advisors, and the stock exchanges themselves rely on huge databases of information about world financial markets. Through a worldwide network of computers, this information can be quickly updated as financial events occur. This computerized financial network has created a global market for currencies and financial instruments. Today, a change in a stock on the Hong Kong stock market will be known instantly by everyone who has access to the computer network.

General Computer Question 4: How are computers used in Education? Answer: Today, computers can be found in every school. From kindergarten to graduate school, the computer is being used for learning, for record keeping, and for research. A variety of computer-assisted instruction ( CAI) programs are now being used to facilitate the learning of nearly every educational topic. Multimedia-based learning systems can deliver information to students in the form of sound and video in addition to text and pictures. Using these new tools, students can gain control over their own learning as the computer delivers the instruction at the student's desired pace, monitors their progress, and provides instantaneous feedback. And, because computers can now take over some of the instruction that used to take place in the classroom, teachers are free to work with students who need more concentrated attention.

General Computer Question 5: How are computers used in Medicine? Answer: Computers are now so widely used in medicine they are changing the very structure of our society's health care system. They are used extensively for basic tasks such as keeping track of patient appointments and they are used widely for diagnostic and treatment procedures. Diagnosis of illness can be aided through the use of databases that contain information on diseases and symptoms and laboratory tests on blood and tissue chemistry have become dependant on computer analysis. In addition, such computer-based technologies as computer tomography ( CAT) scans and magnetic resonance imaging (MRI), which allow the physician to see the organs of the body in three dimensions, can provide direct evidence of disease.

General Computer Question 6: How are computers used in Business? Answer: Business was one of the first areas to incorporate the computer. Because of its powerful capability to store and retrieve vast amounts of information, computers are now a vital component of almost every type of business. They are used to record sales, maintain information about inventories, maintain payroll records, and generate paychecks. Business workers now

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use computers to keep track of meetings, write letters and memos, create charts and presentation graphics, create newsletters, and examine trends. All of us have by now experienced how the point-of-sale ( POS) product scanning systems in stores have speeded up the checkout process and made it more accurate by eliminating the need for checkers to punch in the price for each individual item. These point-of-sale systems not only make it more convenient for shoppers, but they also provide an accurate inventory of product availability for the store's management.

General Computer Question 7: How are computers used in Entertainment and Recreation? Answer: Computers can be found throughout the entertainment industry. They are behind much of the glitz and excitement that we encounter every time we turn on the television, attend a professional basketball game, or risk our money in the slot machines of Las Vegas. Computers are used to create the special effects used in television advertisements, the colorful displays on the score boards at sports arenas, and the cards that are displayed on the screen if we play a game of video poker. Computer games are becoming more and more lifelike as the computer's capability to portray graphics is constantly improved. In the motion picture industry, the time required to create animation has been greatly reduced through the use of computers and special graphics software. The movie industry also uses computers routinely for a variety of special effects and specialized computer programs have even made it possible to "colorize" old black-and-white films. Musicians are also taking advantage of advances in technology by using computerized electronic synthesizers to store, modify, and access a wide variety of sounds. Special word processing software has been created for scoring music and other applications give musicians a way to actually cut and paste stored sounds to create compositions.

General Computer Question 8: How are computers used in the workplace? Answer: With the proliferation of computers throughout our society, there has been a resultant discussion about what their role should be. Although almost everyone recognizes the presence of computers in today's workplaces, not everyone welcomes them. Some employees fear that they may be replaced by computers. And although it may be true that in some areas such as manufacturing where robots have taken over the job of human workers, overall, the employment of computers has not resulted in a net loss of jobs. What computers have often caused is a need for people to be retrained so that they can fill the jobs that have been created by computers and new related technologies. In some cases the retraining is minimal, as when typists learn to apply their typing skills to word processing but, in other cases, significant retraining is necessary. In some jobs, for example, where assembly-line workers have been displaced by robots, employees have to be totally retrained. New technology-based manufacturing systems often require an entirely new set of worker skills and people who have habituated to doing their work in a particular way often find it difficult to make the changes necessary to fit in. Many of us are afraid of change, until we learn more about what it means. Fear of technology is known as technophobia, and there are a fair number of people suffering from it these days. However, many people feel that as new generations grow up with computers and learn to use them in a variety of environments they will feel more comfortable with the technology and will not suffer the discomfort of this transitional period.

General Computer Question 9: What is telecommuting? Answer: While some people fear the change that computers represent, others are taking advantage of the new capabilities they offer. Using computers and communications technologies, some people are working out agreements with their employers wherein they do their work in their homes. These workers can communicate with the office and access information from the company's computer system by using a computer and modem attached to the phone line. In addition, many workers are establishing computer systems in their homes of the same type as they use at work. That way, they can install the same programs at home as they use in the office and then carry files back and forth between the two locations. Using one of these methods, if employees have to work overtime, at least they can do so in the comfort of their own home. Parents can be available for their children at home and still get some work done. Disabled workers can have jobs and not have to face the difficulties of commuting by car or public transportation. By telecommuting, employees can do the work when they are most productive. As a result, because the computer never sleeps, night owls can work all night.

General Computer Question 10: What is ergonomics?

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Answer: Ergonomics is the study of how humans interact with all kinds of machines, not just computers. But today, with so many using a computer as an everyday part of their jobs, there is considerable focus on the ergonomic issues that are related to the use of the computer. As health concerns arise, the computer industry and others are attempting to solve the problems related to continual use of computers. Special attention has been focused on ergonomic factors that can improve the design of input and output devices in order to reduce fatigue and other work-related problems. Knowing that there are potential problems associated with computer use, businesses and other organizations are now paying more attention to the work environment, making sure that desks and chairs are adjustable and that there are appropriate light levels. Many companies are now purchasing special devices that are designed to improve the working conditions for their employees who use computers. In addition to giving consideration to physical ergonomic issues, the computer industry is also trying to improve the way we interface with the computer by making the computer easier and more intuitive to use. New software designs utilize standard ways to carry out common computer tasks. If the computer-user interface employed in software programs is the same or very similar from one program to the next, the user can generalize from skills they have previously learned. This approach helps to relieve some of the stress related to having to learn a new program. Because today's input and output devices provide the interface between human users and the computer, ergonomic analysis often focuses on these devices.

General Computer Question 11: Are there privacy issues when using computers and the internet? Answer: With the increased use of computers for storing large databases of information about individuals, the problem of privacy has become a real concern. The government, as well as a number of businesses and organizations, have compiled databases containing a variety of personal information about each of us. The collection of information begins at the moment of our birth and continues throughout our lives. Almost any activity that requires the use of a computer, including registering to go to a school, applying for a job, applying for a loan or credit card, entering a contest, or getting a marriage license can result in your name ending up in somebody's computer data file. The government itself has a variety of agencies that collect information on its citizens: the Internal Revenue Service has an electronic record of all of our tax returns, the Civil Service Department has records on hundreds of thousands of government employees, and the Department of Health, Education and Welfare keeps records on anyone who has received social security, medicaid, medicare, or welfare benefits. Most people understand the benefits derived from electronic databases. For example, they understand that there must be a computerized record if they are to receive their Medicare payment. But some fear that this information could be misused. More and more personal information is now accessible via the internet. There are occasionally reports that agencies sell personal information for use as mailing lists by sales organizations. Would you be concerned if, for example, the motor vehicle department in your state began selling descriptive information gleaned from your driver's license application? In some states, this type of information is already available to businesses who specialize in putting together mailing lists based on personal characteristics and preferences of value to businesses who want to market their goods and services. Nongovernmental agencies, such as credit bureaus, also maintain databases that contain personal information about us. Recently, some of these agencies have come under fire for selling our personal information to businesses for marketing purposes. Businesses are always looking for mailing lists that target people with particular characteristics, and there is often some company or group willing to sell this type of information. If you subscribe to a particular type of magazine, say a computer magazine, you can almost bet you'll receive a subscription offer for every other computer magazine that comes along. Or, if you enter a contest to win a car, don't be surprised if you receive a phone call telling you about a new condominium development in your area. Although, some of these agencies have decided that a person's right to privacy takes precedence over a company's right to make money, many agencies are still selling this kind of information. Some people are also concerned that by pulling together information from a variety of databases, it is possible for individuals to obtain comprehensive information about us. Many feel that it is one thing for someone to have information about our credit record, but it is another thing altogether if someone is able to collect all of the personal data that is available in all of the various databases and gather it into one computer record. In response to problems related to privacy issues and computers, a number of laws have already been passed. The Freedom of Information Act, passed in 1970, requires that government agencies allow citizens to know what information is filed on them. The Fair Credit Reporting Act, also passed in 1970, requires credit bureaus to allow people to inspect and challenge any information in their credit records. The Privacy Act of 1974 makes it illegal for government agencies to collect information on citizens for illegitimate reasons. The Comprehensive Crime Control Act of 1984 made it a crime to access computers without authorization in order to obtain classified information and protected financial information. The Electronic Communications Privacy Act of 1986 provides privacy protection for computer communications, including electronic mail. This act makes it a federal crime to intercept these kinds of computer-based transmissions. Since these original laws were enacted, a number of other follow-up acts have been introduced to expand and clarify them at both the national and state level.

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General Computer Question 12: What can we do about computer crime? Answer: Along with the potential for the misuse of personal information stored in computer databases, there are a number of areas where there is potential for criminal activity related to the use of computers. For example, because many computers are both valuable and transportable, they are frequently targeted by criminals who steal them for their personal use or to sell. When computers are stolen, it can be devastating both to individuals and to businesses and other organizations because their important data is often stolen along with the computer. The data stored in the computer can represent hours and hours of irretrievable work. Because there is a real potential for computer theft, it is important to follow certain security precautions. As described below, the type of computer used (and the way it is used) should help determine the type of security procedures that should be implemented. It is particularly important to bolt down light-weight microcomputers and peripheral devices. A number of different manufacturers have produced security products that can be used to secure hardware. Although, bolting down equipment will not always keep it from being stolen, it does make the equipment less attractive to thieves and may encourage them to look for an easier target. Computer equipment can be protected from theft to some extent by installing it away from high traffic areas in windowless rooms behind locked doors. Although this may not be practical for microcomputers which are generally installed on the desks of individual users, it is possible to secure expensive mainframe computers or minicomputers in this way. Because these large computers are generally controlled and operated by computer professionals, it is possible to limit access to the equipment to those people who are directly responsible for maintenance and operations. Doors can have built-in security systems which require magnetically encoded cards to be used or special codes to be entered before someone can gain access to the room. Closed-circuit television cameras can be used to determine who has gained access. It is also important to set up some kind of system to identify computer equipment in case it is stolen. A number of methods can be used to permanently label computers and peripheral devices with a unique identification number. Most computer equipment has serial numbers which can be used for this purpose, but often these numbers are on plates that can be removed from the computer. A descriptive list of all equipment, including serial numbers, should be kept for insurance purposes. These numbers can also be used to identify a computer if it is stolen and then recovered by police. The list of equipment showing identification numbers should be stored in a safe place. It is also helpful to have photographs of equipment to show to insurance companies in case of theft and to maintain sales receipts or other types of proof of purchase. The theft and illegal use of data is most often associated with large computer systems that are shared by many users. This type of crime may entail the access of data by unauthorized users or the illegal use of data by authorized users. Although many organizations work hard to protect their data from illegal access by someone outside their organization, statistics show that most often the person committing a crime related to data is an employee of the organization, an insider. People who access computers illegally from outside of the organization have been nicknamed hackers, but computer hobbyists who like to explore the lesserknown capabilities of computers are also referred to as hackers. It is probably more appropriate to refer to those who access data illegally simply as computer criminals. What happens once the criminal breaks into a system depends on their motivation. For some it may be enough just to know they were able to get past the security measures and gain access to the system. For others, the intent is to make an illegal copy of the data stored in the system, alter it, or even erase it. The computer criminal's purpose may be to sell the data or use the information illegally. There are also ways to profit from gaining access to banking or credit information. In some cases, the criminal may be trying to damage the organization that stored the data by damaging the data itself. Most organizations protect their important data by requiring each employee to enter a special password each time they use the data system. This password protection not only limits access to the data, but it also identifies each user each time the data system is used. However, someone with a great deal of knowledge about computers might find a way into an organization's data system despite a password protection system. Upon analysis, many organizations have been found to store important information in computers without the use of any data protection system. It is especially common to find unprotected data stored on microcomputers on individual desks. Even when important data is protected on a large computer with a secure password system, legal users of the data may have downloaded the data to a personal computer's storage system, leaving it unprotected.

General Computer Question 13: What is a computer virus? Answer: The computer virus is a new concern for computer users that has appeared in the last decade. Some people have found a way to create computer programs that silently replicate themselves on storage media without the computer user realizing it. These programs are referred to as computer viruses because, in many ways, they act much like a human virus. When human viruses invade the body, they may or may not cause trouble when they reproduce themselves. They begin to cause us trouble when that replication or something inherent to the virus begins to interfere with the body's normal functions. Likewise, when a computer virus begins to replicate, it may or may not be designed to cause trouble (some computer viruses are very dangerous because they are designed to damage data). But, as with human viruses, even if the virus is not designed to damage data, we

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would prefer not to have this kind of undetected replication going on. Even if a virus program was written just to replicate itself and nothing else (some people may write these programs just to see how far they will travel and how many computers they will infect), it may end up causing trouble by interfering with other programs. There are basically two ways to keep computer virus programs out of your computer. The first has to do with an awareness of how the virus gets into your computer. Computer viruses are usually written to "ride along" with another computer program. When a computer user inserts a disk into the computer with an "infected" program on it, the virus is duplicated in the computer and can then be transmitted to other disks. (This can also happen when programs are downloaded from other computer systems.) Some virus programs are written with such sophistication that they can detect whether or not the computer has been previously infected. If the system has not been infected, the virus program is triggered and goes into action. Often, if you are aware of how computer viruses are transmitted, you can avoid them by being careful about which programs you use. Unless a program is a legitimate commercial product from a known supplier, it should be regarded with suspicion. Which leads us to the second way to protect your computer system against virus programs. If you suspect that a program is a carrier of a virus, you can analyze the program (or the entire disk) using a special virus detection program to see if it contains any known viruses. Some newer virus detection programs are capable of analyzing disks or programs to look for "suspicious" elements and may even be able to detect the possibility of a new, unknown type of virus being present. Most virus detection programs can be used to eliminate a found virus from a disk. Many computer users have installed these virus detection programs on their computers and use them to analyze every disk that is inserted into the computer.

General Computer Question 14: Is my data safe on a computer? How can it be protected? Answer: It is often difficult to determine when data has been accessed illegally. Even when data has been altered, it may be difficult to discover it without conducting a full audit of the system. Because these crimes are so hard to detect, it is important that precautions be taken. One of the best ways to protect a large computer system is to establish a special set of procedures that must be followed when using the system. These procedures should be provided in written form to each of the personnel responsible for the operation and maintenance of the computer system. It is important that the procedural manuals be inclusive and that consideration be given to all aspects of computer operation and maintenance, including input, processing, and output procedures. The procedural approach should assure that individual users do not have unlimited access to all of the data in the system. Different data management responsibilities should be assigned to different personnel. Records should be kept of all dataprocessing activities. There should be some kind of system in which data is compared before and after processing. This analysis should take place frequently on a scheduled basis. Carefully maintained records of all data-processing activities (including a record of processing errors and system errors) will often indicate anomalies that can lead to the detection of illegal access. Most importantly, this type of procedural approach establishes the proper way for users to access data. Data-access methods that vary from the set procedures can signal the need for a closer inspection. Because a fair amount of computer crime occurs at night when most of the employees have gone home, it is important to have special controls in place for overtime workers. Remote access can be controlled by having callback devices in place which hang up and return the call to the calling number. A password is a special set of characters that are assigned to users of a computer system to control access to programs and information. Passwords can be used to prevent unauthorized users from accessing data or programs. They can also be used to control the level of interaction a user may have with system files. For example, some users can only view information in files, while others can be authorized to change or modify that information. Passwords are frequently used to protect the individual work of users in a network system and should also be used to provide user security on bulletin boards and e-mail systems. To further protect the data and the programs that are stored in a computer system, data encryption methods can be used. Data encryption scrambles files so that even if someone is able to get hold of a password, they will not be able to use programs or make sense of data. A special decoding program is required to unscramble the encrypted data before it can be used. This security method can be used to protect data on floppy disks, fixed disks, and other types of magnetic media.

General Computer Question 15: What is backing up and why is it so important? Answer: Computer data can be lost or damaged due to theft or intentional "hacking" (breaking into a computer system). But data is most often lost due to reasons other than crime. Natural disasters, or even common events like power outages, can also cause problems if protective measures are not taken. It is very important that computer users of all types keep backup copies of programs and data. Individual computer users can protect their data by frequently backing up files and storing the backup disks in another location. Large databases must also be backed up not only in case of system failure, but to protect data from such things as fire, earthquakes, and flooding. There is now a thriving data-security industry with companies that are in the business of providing data protection and data storage services. Not only do these companies store data in a safe environment, but they can also provide security consulting and some even can provide computers for employees to work on when offices are shut down.

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General Computer Question 16: What is Software Piracy? Answer: A type of computer crime that is engaged in by many people who would not ordinarily consider themselves to be criminals is the theft of computer software. This all-to-common activity is known by the overly colorful name of software piracy. Because it is very easy to make a copy of a computer program, many people do it without really considering that they might be doing something wrong. When you purchase a piece of software, you will generally find a licensing agreement attached to the package. This agreement outlines the terms under which you may use the software. This software licensing agreement lets you know that when you purchase the software, you do not gain ownership of all aspects of program. Rather, you are purchasing a license to use the software. The copyright is held by the company that developed the program. Copyright laws regarding software are very similar to those related to books and other sources of information. Just as you are not supposed to make a copy of a book and sell it to someone else, you can't sell copies of software. Copyright laws regarding what you do with your own copy of a program for your own use are not as clear. In most cases, licensing agreements for off-theshelf software packages allow you to make at least one backup copy of the software. If the software is provided on disk, it is always a good idea to put the original disks away in a safe place and use the backup copy. Then, if something happens to the backup copy, another copy can be made from the original disks. Although there are many restrictions on making multiple copies of commercial programs, in practice making a working copy for your own personal use is generally not restricted. However, making multiple copies of a program for use on different computers in an organization is generally not allowed and can result in legal proceedings being initiated against the person who makes the copies and against the organization that allows it. When a large organization uses the same software on a number of different computers, a separate copy of the program must be purchased for each computer that it is used on. It is up to that organization to maintain records of how many programs were purchased and which computers used which copy. When software can be used with a number of computers that are linked together on a network, software must usually be purchased for each computer attached to the network. However, many software manufacturers now sell a special network version that licenses their program for a set number of computers attached to a network. Alternatively, some software manufacturers sell a site license that licenses their program for use throughout an entire organization. By using the multiple copies license, or site license, approach the software manufacturer can save money because they don't have to provide a large number of separately packaged products. The buyer also saves money by purchasing a number of copies of the software at a discounted price. To avoid illegal copying of programs, some software manufacturers have devised elaborate copy protection schemes that are designed to keep users from making illegal copies of their products. Some of these copy protection methods require the user to keep the original diskette in a drive at all times. Others allow the user to make one copy only. Because these copy protection schemes can, at times, make computing more difficult, users have resisted them. For that reason, many companies have stopped using copy protection methods and have focused on more positive solutions such as offering inexpensive upgrades and special support systems for registered users. However, many programs now require the user to enter a name and the product's unique ID number whenever the program is installed on a new computer. Because businesses and other organizations put themselves at legal risk if they allow illegal copying and use of software, they may be somewhat more reticent to do it than individuals. However, individual users may feel that they can get away with it. Nevertheless, individual users should consider that the money they pay for software goes back into the company where it can be used for development of other programs that may be of value to them. If everyone legally purchased their software, the company would profit from increased sales and the price of software might well be reduced.

General Computer Question 17: What is public domain and shareware? Answer: There is a great deal of software that is available for free or for a nominal copying fee. Users are free to make a copy of public domain software and use it without the restrictions of licenses found on commercial software. Documentation included with this type of software often encourages users to make copies and distribute them to friends. Another category of inexpensive software, called shareware, may be copyrighted, but generally the developer allows users to make copies without an initial charge. However, if you intend to use the software beyond a brief tryout, the developer requests that you pay for the program. The cost of shareware is generally quite a bit less than off-the-shelf software and is frequently sold at computer swap meets, conventions, through the mail, and over the internet.

General Computer Question 18: What is Computer Ethics?

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Answer: Ethics have to do with standards of moral conduct. People who are unethical do not necessarily break the law, but they do engage in activities that are damaging to others and to society at large. Although computers offer us a wide range of exciting and innovative applications that can improve our lives, they also introduce ethical issues that have not been dealt with before. As a society, we have to decide if we will use this new tool for the betterment of mankind or for destructive purposes. If users (individual users as well as businesses and government agencies) do not use computer data in a responsible way, if they use the power of computers or the knowledge inherent in the possession of computer-stored information without regard for individuals, more and more laws will be passed to restrict the use of computers and computer data. Such restrictions can be very detrimental to the free flow of information and to the development of new computer tools that will enrich our lives. As in all issues of ethics, each individual must decide how to act. It is important for our society to educate people at an early age about ethical issues related to the use of computers in order to protect the free flow of information that we currently enjoy.

General Computer Question 19: How can I improve my computer skills? Answer: If you intend to find work in the computer field itself, or if you plan to go into any of the large number of other fields that use computers, it is likely that you will need some kind of specialized computer training. There are a wide variety of resources available for those who do not want to become a computer professional, but who do want to gain some computer skills. They provide skills that will allow you to enter the job market for the first time or improve your chances for promotion in a job that you already have. A number of universities now offer an introductory computer course that must be taken by all students. These courses are designed to introduce students to basic computing concepts, such as those presented in this text. In addition, these courses often provide hands-on tryouts of the most popular computer applications. By providing the student with experience using basic software applications, such as word processing, database management, graphics, communications, and spreadsheet programs, these courses introduce some of the many advantages of getting work done through the use of a computer. Another educational resource for computer training is the variety of workshops and seminars offered by companies that specialize in this type of training. These courses often cover one computing topic intensively for one or two days. Sometimes seminars are offered as part of the program at computer conferences that are put together by a professional group. These seminars are usually related to the main focus of the conference. Attendees can pay a fee to attend the conference and then select from the list of training sessions according to their own needs or interests. Companies are frequently willing to pay for employees to attend these workshops and seminars when the training provides the employee with new computing skills. Alternatively, companies sometimes hire outside consultants to come into the company to conduct computer training with employees. This kind of training is particularly valuable if a company has standardized on a particular application program and wants to bring all of its employees up to speed right away. Also there are now a number of companies who are producing video tapes and computer-based tutorials that cover everything from general computer literacy to very specialized subjects such as how to use one particular application program. Since these training programs include visual components as part of the training process, they can be very helpful for supplementing written training material. Some manufacturers of hardware and software products have produced videos and computer-based tutorials for their own products. Others are produced by companies in the business of selling training materials.

General Computer Question 20: What types of computer jobs are available? Answer: The invention and evolution of the computer has resulted in millions of new types of computer-related jobs. From those who enter the data to those who maintain the largest computer systems, there continues to be a worldwide demand for workers who are trained to play a role in the development and use of computer technology. There are a number of schools and training programs that teach data input skills. This type of program provides training in the kind of skills needed for entry-level jobs in the computer industry. Skills related to the use of the basic types of applications programs will often be sufficient for those who want to be involved in the data input process. Because computers are used to store vast amounts of data, there is a great need for people who can use a keyboard, or other input devices, to get data into the system. As companies have become computerized, much of the training of employees to use computers has taken place on the job. Often this training takes place on the fly: data-entry people learn how to use a word processor while using it to do their job. When they get stuck, they refer to manuals and they ask questions. However, many companies have learned that it is more profitable in the long run to use a more realistic approach that provides in-house training or payment to employees who attend courses offered elsewhere. As the use of computers has become more common, many businesses now are more likely to require potential employees to have computer skills before they are hired.

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Technical support people help in the installation of hardware and systems software. After installation, they are involved in maintenance of the equipment. They also maintain networking hardware and data communications systems. These employees should be familiar with diagnostic procedures and electronics and they should be able to read and understand technical manuals. These jobs require at least two years of college, but often a bachelor's degree is preferred. Customer support technicians are needed by many different types of companies. They hire employees to help customers use technical devices. For example, manufacturers of computer hardware and computer software usually hire technical support personnel to answer user's questions related to the company's products. These people need to know not only about their company's products, but also how the products interface with other systems. Retail stores that sell computer hardware and software may also have positions for technical support people in order to keep their customers satisfied. Technical support personnel usually have a background in computer technology before they are hired; nevertheless, since these positions require knowledge of a great variety of potential hardware and software problems, these employees will usually receive additional specialized training. Technical writers, those who can write instructional manuals describing about how to use computers and related technologies, are always in great demand. All of today's hardware and software products include user manuals, references guides, and often a variety of other technical documents. Technical writers may also work with computer trainers to produce training materials and they may be called upon to produce specification sheets, product information sheets, brochures, and newsletters. The technical writer must be skilled at translating technical jargon into a simplified language that can be readily understood by users of the product. Today, the technical writer is frequently called on to produce camera-ready copy for their employers. This requires special training in the use of desktop publishing and graphics programs, as well as knowledge of page design and a variety of other publishing skills. For large projects, the technical writer may also become a project manager who works with technical editors and documentproduction staff during the production of the manual. As part of the production of technical documents, technical specifications must be deciphered, interviews with engineers and programmers must often be conducted, and arrangements must be made with data-entry people, desktop publishers, artists, photographers, and printers. The more of these skills a technical writer has, the more they can offer to potential employers. Sometimes technical writers are hired as outside consultants. Since technical writers must demonstrate knowledge of computer technology and possess excellent writing skills, they often have extensive experience and considerable education. An applicant for a technical writing position must usually show potential employers copies of manuals they have previously written. With the proliferation of hardware and software products designed to facilitate the creation of high-quality graphics, there is a growing demand for people who have the skills to put them to use. They are known as Computer artists. Ad agencies and design houses are now using microcomputers to create professional marketing documents and other types of advertising. Magazines, newspapers, and book publishers are hiring designers and graphic artists who are able to do their work on computers. Computer artists usually have completed specialized training in art and in the use of computer graphics programs. Many types of organizations are now hiring trainers to develop and implement computer-based training programs for their employees. These training programs may be entirely or partially delivered by computer. The designer of a computer-based training program, the computer-based training specialist, must have a great deal of knowledge about the topics being taught and about the hardware and software that is used in the training. These specialists must have education and experience not only in computer technology, but they must also have skills as a teacher. They must have training in instructional technology, in instructional methods, and they must possess excellent communication skills, both verbal and written. They may also be responsible for developing the training manuals and instructional materials that often accompany computer-based training programs. Customer support staff are often employed by manufacturers of computer hardware and software to provide information and advice to customers. If the customer is purchasing a complex computer system, these employees may have to spend a great deal of time at the customer's office during installation. They are there to assure that no problems arise during and after the installation. These employees must know how to work with programmers and engineers. Usually they have experience and training in systems analysis and programming. They may also be involved in training the customer's employees to use the products. There are a large number of jobs available for sales people in the computer field, people who have the skills to sell computer hardware and software. These people may work for the manufacturers of products or they may work for retail or wholesale houses that sell hardware or software products. The growth of the computer industry has also resulted in technical sales positions with publishers of technical books and magazines and a number of other businesses related to the use of computers. In addition to having skills in sales, these employees must have knowledge of the products they are selling. Database managers (database administrators) are employees responsible for the development of an organization's databasemanagement system. Or they may be responsible for the maintenance of a system already in place. They generally do not have to be hardware specialists, but they must have completed extensive training on using database-management software. In addition, they must have excellent communications skills because they will often be working with users to solve problems

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related to the organization's data. These positions generally require at least two years of specialized training. An applicant with a college degree will have an advantage when applying for these positions. Because data is so important to businesses and other organizations, it is important to have a mechanism for checking the accuracy of data input into the system. Data control employees are responsible for double-checking data that is input by other people. They keep records and conduct periodic checks to be sure procedures are being followed. These employees usually have completed at least two years of training at a college or technical school. In addition, an organization may hire one or more individuals who are responsible for managing and protecting the organization's data storage media. These employees who keep track of active and backup copies of data may also be responsible for the protection of data and programs against theft or damage. Often these employees need at least two years of college or technical school training. Computer operator people keep complex computer systems running. They may be involved in scheduling data analysis, and maintaining program and data files. There are a number of different levels of these positions. The entry-level position usually requires at least a degree from a two-year college or training at a technical school. Experience and on-the-job training can lead to advancement to higher-level positions. A college degree in a technical field is generally required for the highest-level (management) positions in computer operations. The development of new hardware and software and the installation and maintenance of computer systems are areas that are handled by professionals with extensive training in computer science; they are known as computer professionals. Engineers and programmers (software engineers) are responsible for the development of hardware and systems software. They are generally hired both by manufacturers of commercial computer software and by large organizations that develop software in-house. These employees may work with a systems analyst in the design and implementation of data-management systems. Engineers and programmers are generally classified into trainee, junior, or senior (lead) levels. Trainees may have as little as two years of college, but more often a college degree is required. Often trainees have little or no practical experience with the organization's computer system and must therefore work under the supervision of others. With more experience and specialized education, trainees can move to the junior level. Often additional specialized education, such as a graduate degree in a technical field, along with a great deal of experience is required before a junior employee can become a lead engineer or senior programmer. Systems analysts are often responsible for developing and implementing new computer-based, data-management systems. They are also responsible for maintaining and implementing changes to existing computer systems. A systems analyst may be an engineer or a programmer and they often have specialized skills related to the overall design of an organization's computer system. They must also have the organizational and communication skills (written and verbal) to serve as a liaison between all the users of the computer system. This person must have education and experience in computer technology and should have knowledge about computer programming and training in the type of organization where employed. A bachelor's or master's degree in computer science with additional training in business administration or a related technical field may be required. In addition, experienced managers of the departments that are responsible for overseeing an organization's computer operations are always in demand. There are a number of jobs available for people-oriented individuals who want to be involved at the management level. Managers are needed throughout the computer industry as well as in companies and organizations that have installed extensive computer systems. Managers of operations, information systems managers, database managers, managers of systems development, product managers, managers of technical support, and managers of end-user support are all needed in today's computer-using organizations.

General Computer Question 21: Are there health considerations when using computers? Answer: When new devices and new tasks are introduced into the workplace, there is bound to be concern about a person's prolonged exposure to these new conditions. With the growing computerization of businesses, there has been a great deal of concern about exposure to the types of screens that are commonly used in computers, screens based on the cathode-ray tube ( CRT). There has been discussion that prolonged exposure to CRT screens might cause tumors, cataracts, or that they might cause problems for pregnant women. While the evidence related to the use of CRT screens is complicated and produces no clearcut indications, it is a concern that should not be taken lightly. Today, new CRT screens have been designed to limit the emissions they give off and many are now purchasing these types of screens. Other problems related to the use of computers are less mysterious: eyestrain, headaches, backaches, neck pain, and wrist pain can result from extended use of keyboards, monitors, and mice. If an employee is going to use a computer for long periods of time, it is important that employers provide a good ergonomic design for the work environment. Ergonomics involves the study of how humans use devices such as computers. Ergonomic research has yielded many guidelines for the design of safe and comfortable computer workplaces, and these guidelines should be utilized by all businesses that use computers.

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Some ergonomic considerations are summarized in the table below.

Chair

Should be soft and comfortable (but not too soft). Should allow user to adjust seat height, arm rests, angle and height of backrest. Backrest should support curve of user's spine. Arm rests should allow freedom of movement and should be at a height to allow arms to be at a 90 degree angle while typing.

Wrist Rests

Should allow wrist to rest at keyboard height while typing.

Keyboard User's arms should be at 90 degree angle with elbows resting on chair's arm Height rests. The top of the screen should be level with the top of the user's head. Distance from the user's eyes to the computer screen should be between 30 Computer and 48 inches. Light source should not be coming from behind the the Screen computer screen, and it should not reflect in screen. Glare protection may be required for some screens. Foot Rest Should be adjustable to differing angles and heights.

Ergonomic Considerations in the Computer Workplace General Computer Question 22: What is computer-aided engineering (CAE)? Answer: Computer-aided engineering (CAE) programs simulate effects of conditions such as wind, temperature, weight, and stress on product designs and materials. Examples include the use of computers to test stresses on bridges or on airplane wings before the products are built. CAE systems generally require very powerful (and expensive) computer systems. However, the time and money that can be saved during the development and testing stages of a product are significant and usually worth the expense.

General Computer Question 23: What is computer-aided manufacturing (CAM)? Answer: Computer-aided manufacturing ( CAM) involves the use of computers to control production equipment. CAM Software can control such equipment as drilling, lathe, and mailing machines as well as robots. CAM is the total integration of the manufacturing process using computers. Through the use of highly specialized computer programs, individual production processes are linked so that the production flow is balanced and optimized. These systems can control product flow, at an even rate, throughout a production site.

General Computer Question 24: What is computer robotics? Answer: Once a product design has moved to the production stage, robotics can be utilized in the actual manufacturing of the product. Today, many manufacturers use robots for such tasks as spot welding, drilling, lath work, and product assembly. Although the first generation of robots had significant utility in manufacturing, new generations of robots are being developed that are even more impressive, possessing human-like features of vision, tactile senses, and the ability to grip fragile objects.

General Computer Question 25: What is artificial intelligence? Answer: Another trend in computers, the use of artificial intelligence ( AI) programs, gives computers the capability to learn from past events. Some AI programs are already being used to provide expert advice, control robots that learn, or to recognize objects by shape and size. Artificial intelligence programs are expected to give computers new capabilities for understanding the human voice and for interpreting a user's natural language responses to programs.

General Computer Question 26: What is an information system? Answer: Although, all computer information systems are designed for the purpose of storing and accessing information, there are several different potential implementations. They are described below. •

Centralized information system: Generally based on a centrally located mainframe where all processing and storage operations take place at a central location. This type of system is usually designed to computerize a variety of operations within the organization. For example, by using a large, central computer, a business can computerize its order entry, inventory control, billing, and accounting operations. Using a centralized system, computer

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•

communications will undoubtedly be used to transmit data electronically between locations. And although storage and processing take place at the central location on the mainframe, the input and output of data can be performed using terminals and printers at widely dispersed locations. One or more centralized computers may be used to handle an organization's web access system. Decentralized information system: Uses separate computers - usually minicomputers or microcomputers - within individual departments. Sometimes there is a central mini or mainframe computer for applications that are shared between groups, but the basic design gives control of computers to individual departments. A decentralized information system is illustrated below.

A Decentralized System

The advantage of a decentralized system is that users have more immediate access to information and do not have to wait for processing time as they may have to with a centralized system. Also, it may be easier to initiate changes in the system if the changes can be made at the local level rather than being referred to a centralized computer center. However, the decentralized system can make it more difficult to share information because different users may be using different types of hardware and software at the local sites. This can be solved to some degree by establishing an information center that is in charge of establishing hardware, software and procedural standards. The decentralized approach may be cost-effective for individual departments because smaller, lower-cost computers can be used. However, the overall cost to the entire organization may be greater because an entire system must be purchased and maintained at each location.

•

Distributed information system: Very much like a decentralized system except that the computers of each group are networked so that they can communicate. The system may use a local-area network to connect the computers that are in one building or a wide-area network (such as the internet) to connect computers that are located at some distance from one another. A distributed system has the advantages of a decentralized system in that it can provide quick access to data and more control over applications by individual departments. And the communications capability that is designed as an integral part of the system resolves some of the disadvantages of decentralization. Also, because the computers are networked to share data easily, incompatible applications used by individual departments is less of an issue. The use

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of networked computers dictates that data-sharing procedures, at least, are standard at all connected locations. A distributed information system is illustrated below.

A Distributed System

While the use of networked computers solves some of the problems of decentralized systems, the network's communication systems are themselves complex and may require additional software, hardware, and technical support personnel. Many organizations provide one or more trained network managers to oversee network communications and to develop data-sharing programs and procedures. In addition, most organization now must develop specialized programs and staff to support their internet-based information systems.

General Computer Question 27: What is the system development cycle? Answer: Today, the development of a computer system is generally based on a systems development cycle model. In such a model, the systems development process is broken down into a number of manageable phases. By breaking the task down into smaller units, the systems analyst can receive feedback at each stage of development and can thus assure the effectiveness and success of the system. This systems development cycle approach also reduces the cost of systems development because the greatest expenditures are made during the later phases of the cycle (the earlier stages mostly involve planning). Although individual organizations may break the systems development process down differently, the best approach is to break the task down into small, manageable units. For example, we could break the systems development task down into the following five phases: • •

Phase 1: Problem definition (gather information, observe users, prioritize tasks, analyze written documentation, determine cost-effectiveness, prepare a report). Phase 2: Feasibility analysis (put together a study team, determine the impact, interview users, produce data flow diagrams, determine costs, rank the proposed solutions, prepare a report).

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• • •

Phase 3: Solutions analysis (determine the steps that must be undertaken to implement the new system, analyze user reports and compare to system purposes, determine organizational responsibilities, prepare an analytical report of the proposed system). Phase 4: System specification (determine which system - both hardware and software - would meet the needs described in the steps above and determine costs and impact on the organization for that system). Phase 5: Implementation (purchase the system components, develop a continuing data collection system, develop an implementation schedule, specify the steps for a parallel conversion method while continuing to use the existing system or a phased conversion to phase in the new system gradually, or a direct conversion in which the new system immediately replaces the existing system.)

Computer Hardware Questions

Computer Hardware Question 1: What is Computer hardware? Answer: Computer hardware refers to the computer's machinery, its electronic devices and its circuits. What we call a computer is actually a system, a combination of components that work together. The hardware devices are the physical components of that system. The hardware is designed to work hand-in-hand with computer programs, referred to as software. Software programs are usually designed specifically for use with one type of computer hardware.

Computer Hardware Question 2: When was the computer developed? Answer: Saying exactly when the computer came into existence is a little tricky because there were a number of devices and concepts that had to be invented first. The first computers, developed during World War II, were used for mathematical calculations. Although electronic computers have been in existence since then, people have always had a need to manage information and to solve problems. Early thinkers created a number of devices to evaluate information and to solve problems related to that information. One of the earliest known devices, the abacus, was a computational tool that was used to quickly add and subtract numbers. It has been in use in China for thousands of years and is still used in everyday transactions throughout the Far East. Another computational device, known as Napier's Bones, is similar in design to the abacus. Designed by John Napier in the early 1600s, it was comprised of multiplication tables inscribed on ivory rods that looked like bones. It was used for mathematical calculations including multiplication and division and is similar in principle to the modern slide rule. Another notable device on the path to modern computing was invented in 1642 by Blaise Pascal, a French philosopher and mathematician (the Pascal programming language is also named after him). Pascal's adding machine used a hand-powered mechanical system to add and subtract numbers. The system of dealing with numbers in Pascal's device is similar to the system used in today's computers and it is worth noting that, at the time, the device was seen as a threat to the livelihood of those employed to calculate numbers. Pascal's device was not improved upon until 40 years later when a German, Gottfried Wilhelm von Leibniz, developed a device that was not only able to add and subtract, but was also capable of carrying out multiplication and divisions (as a series of repeated additions and subtractions). Another device, the Jacquard loom, may not, on first analysis, seem related to the early computational devices. But the French inventor, Joseph Marie Jacquard, developed a device to automate rug weaving on a loom in 1804. The device used holes punched in cards to determine the settings for the loom, a task that normally required constant attention by the loom operator. By using a set of punched cards, the loom could be "programmed" to weave an entire rug in a complicated pattern. This system of encoding information by punching a series of holes in paper was to provide the basis for the data-handling methods that would eventually be used in the early computers. Despite the great success of Jacquard's loom, many were disturbed by this "high tech" invention when they learned that it could completely eliminate jobs that had been done by humans for centuries. As a result, in England, a group that called themselves Luddities smashed some of the automated looms as a protest against mechanical innovation and the related threat to their jobs. A few years later, in England, Charles Babbage proposed the design for a new calculator that was in many ways the forerunner of today's computers. In 1822, Babbage built a working model of the difference engine and received a grant from the British

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government to develop a full-scale version. Unfortunately, he soon discovered that the parts that he needed could not be manufactured to tolerances that he required. In 1842, Ada Augusta Byron, the daughter of the poet Lord Byron, became interested in Babbage's project. She was a trained mathematician and saw the potential of his device (the Ada programming language that is supported by the U.S. Department of Defense was named after her). She helped provide funds to continue research for the project and she collaborated with Babbage on some of his scientific writings. Today she is credited with coming up with the concept of a programmed loop, a way to carry out the sequence of steps that are part of a mathematical calculation. Based on her published descriptions of the process, many consider her to be the world's first programmer. Forty years later, Dr. Herman Hollerith, an employee of the U.S. Census Bureau, put Jacquard's punched-card concept together with some of the same kind of ideas that had been proposed by Charles Babbage and Ada Byron to solve a real-world problem. The Census Bureau realized that it was taking so long to complete census calculations they wouldn't even be able to complete one census before it was time to undertake the next one. Hollerith proposed a solution based on what he termed a census machine that would count data that was fed in on punched cards. He chose cards that were about the size of dollar bills to be fed into a hand cranked machine. Using Hollerith's machine, the census was tabulated in less than half the time it had previously taken. Based on his Census Bureau success, Hollerith formed the Tabulating Machine Company in 1896 and began designing census tabulation machines. The company eventually evolved into the International Business Machines (IBM) company, the world's largest computer company. Although computational machines continued to evolve, the invention of modern computers could not come about until the supporting technologies of electrical switching devices were in place. By 1937, electricity was in general use in most of the world's cities and the principles of radio were well understood. Using these new tools, several researchers were working on electrically powered versions of the earlier computing devices. Among them was Howard Aiken of Harvard University. Working with the support of the IBM company, in 1944 he completed the basic development of a machine that was dubbed the Mark 1. The machine, which was also known as the Automatic Sequence Controlled Calculator, is now seen as the first full-sized digital computer (smaller-scale electric calculating devices had been created earlier). The Mark 1 filled an entire room and weighed 5 tons, included 500 miles of wiring, and was controlled by punched paper cards and tapes. Despite the many advances in computational technology represented by this new machine, it was very limited by today's standards. It was used only for numeric calculations and took three seconds to carry out one multiplication. However, with the world-wide expansion of industrial technologies that accompanied World War II, others were proceeding along the same path established by the Mark 1. For example, John Mauchly and J. Presper Eckert were developing a large-scale computing device known as the Electronic Numerical Integrator and Calculator ( ENIAC) at the University of Pennsylvania with the support of the U.S. government. Based on mechanical switches and radio vacuum tubes, this device is now seen as the first electronic computer. The huge machine consumed so much power that it often caused the lights in nearby Philadelphia to dim. But it was far more capable than Aiken's Mark 1 computer: it could perform thousands of calculations per second and was used for a variety of purposes including scientific research and weather prediction.

Computer Hardware Question 3: What is a first generation computer? Answer: The first generation of computers is represented by the first commercial electronic computers that were based on the vacuum tube. After the conclusion of the Second World War, the first commercially successful computer was produced by Mauchly and Eckert. They formed the Electronic Controls Company, expressly for the purpose of developing and selling electronic computers. One of their first projects, a new and more powerful computer named the UNIVAC 1, was delivered to the U.S. Census Bureau in 1951. Computers of the first generation were all very large, room-sized computers that used thousands of vacuum tubes (the same kind of glowing glass tubes that were used in radios of that era). Their design was functional for the time, but their role in business was limited by three factors - their size, the heat they generated, and their reliability problems. And, during this period, new methods of programming evolved along with the hardware developments. The programs for the first large-scale computers were generally changed via a slow, detailed changing of the computer's circuits. Later John von Neumann joined Maunchley and Eckert and his ideas for designing a programmable computer were incorporated into their design (that method of using stored programs is still used in computers today). To transfer data and programs, a number of devices were invented that were based on punched paper tapes or punched cards.

Computer Hardware Question 4: What is a second generation computer?

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Answer: The second generation of computers began in 1959 with the appearance of the first computers based on the transistor. The transistor was invented at Bell Labs and resulted in the awarding of a Nobel prize to its co-inventors, John Bardeen and Walter Brattain. The transistor was used to replace the thousands of vacuum tubes that were used in the first generation of computers, resulting in smaller and faster computers that could be built at a lower cost. Most importantly, this new generation of computers used less electricity and could be built to operate more reliably. This made them more useful to a variety of business and government organizations.

Computer Hardware Question 5: What is a third generation computer? Answer: By the beginning of the 1960s, scientists were building on what they had learned about transistor technology by designing new computers based on integrated circuits. These integrated circuits, tiny circuits on wafers of silicon, could take the place of hundreds, even thousands, of transistors and their related electronic components. Computers based on this new technology were known as third generation computers. In 1964 IBM changed the way computers were sold by introducing a "family" of computers known as the System 360. The family consisted of six different computers, but programs written for one of them could also be used on the others. IBM planned to sell an entry-level computer to a company and then later sell them an even more powerful computer as their business grew. The company could buy more computing power without rewriting their software. This plan was very successful and was a key to IBM's growth. As the market for computers grew, so did the variety of computing solutions. The Digital Equipment Company developed a smaller, less costly computer, the PDP-8. Whereas all of the first generations of computers were huge, room-sized computers known as mainframes, these new smaller computers became known as minicomputers. The availability of these lower-cost, smaller-scale computers meant smaller businesses could computerize. Eventually, computerization became a key to business success. It also meant that a new group of users began to deal with computers. Prior computer users had been professionals who learned about computer design and computer programming in advanced courses. Now, clerical employees were expected to enter data into the computer. It required a rethinking of how to design the interface between the computer and the end user. That analysis of the human-computer interface is still going on today.

Computer Hardware Question 6: What is a fourth generation computer? Answer: During the 1970s, The downsizing of mainframe and minicomputers continued. By the late 1970s, most businesses were using computers for at least part of their data-management needs. However, the need for smaller and faster computers meant that even the integrated circuits of the third generation of computers had to be made more compact. Fourth generation computers are based on large-scale integration (LSI) of circuits. New chip manufacturing methods meant that tens of thousands and later hundreds of thousands of circuits could be integrated into a single chip (known as VLSI for very large-scale integration). Nevertheless, at that time, computing was still mostly seen as a time-sharing process. One mainframe or minicomputer could service many users, each with a terminal that was connected to the computer by wire. But during this period, a new concept of "personal" computing was being developed. And, surprisingly, this new type of computer was not being developed by the wellestablished computer companies. It was the electronics hobbyists and a few fledgling electronics companies that were beginning to create computing devices that used small, limited processors, known as microprocessors. These microprocessors were being built into small computers known as microcomputers that were designed to be used by only one user at a time. For that reason, most businesses did not at first recognize their value. To users who had grown up with expensive room-sized mainframes that served the needs of the entire organization, the idea of a small computer that could serve the needs of only one user at a time seemed more like a toy. Many believed that these new "personal" computers would continue to be only a hobby for "electronics nuts." But this view was soon to change as new microprocessor designs began to deliver considerable computing power in a very small package. Although several scientists were working with microprocessor technology during this period, the best known team was working for the Intel Corporation. The team of Ted Hoff, Jr., Frederick Faggin, and Stan Mazor were in the process of expanding on the sophisticated electronics that were being used in the very small Japanese calculators. They reduced all the processing power needed for basic computing down to a set of four small circuits, or chips, one of which was to become known as the Intel 4004 microprocessor. Several special-purpose microprocessors followed and in 1974 Intel produced the 8080, their first generalpurpose microprocessor. During this period Steven Jobs and Steven Wozniak began putting together kit computers in Jobs' garage. These personal computers sold very well and their endeavor eventually became the Apple Computer Corporation, the most successful of the early microcomputer companies.

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But it was the world's largest computer company that legitimized the personal computer (PC). In 1981, the International Business Machine (IBM) Corporation introduced their own microcomputer. Its widespread acceptance by the business community instigated a flood of copycat PCs. During the next few years just about every company in the world that had anything to do with electronics produced a microcomputer, most of them very similar to the IBM PC. During the 1980s, with the spread of specialized software, personal computers found a role in almost all organizations. As many businesses purchased an IBM PC (or one of its work-alike "clones"), it gradually became something of a standard for PC design. This much-needed standardization of PC design meant that programs that ran on one brand of microcomputer would also run on other similar types of PCs that used the same microprocessor. Computer programming methods continued to evolve during the fourth generation as new high-level programming languages continued to be developed that were both easier to use and more closely related to specific computer tasks.

Computer Hardware Question 7: What types of computers will we use in the future? Answer: Many believe that we are entering a fifth generation of computing, a period of smaller faster computers that we can talk to, computers that incorporate new software methods known as artificial intelligence (AI). AI methods give computers the capability to make decisions based on the evidence of the past, rather than on a set of programmed procedures. If computers can be taught the rules of decision making used by human experts, expert systems based on AI methods can be developed to take over some human tasks. Others believe that the emergence of the internet and enhanced communications systems (including wireless) will make the concept of computer generations irrelevant. The overriding trends in computer evolution - smaller, faster, more powerful continue today. Today's little microcomputers are far faster and more capable than any of the earlier generation computers; today's PCs are even more powerful than most of the huge mainframe computers of the past. But today's mainframe and minicomputers are also more powerful and they now work in close concert with PCs rather than using the dumb terminals that used to be attached to large computers. Each new generation of computers is faster, includes more memory and storage, and their operating system are constantly being improved. Software development methods are being improved just fast enough to keep up with the new computing capabilities and, despite the new capabilities, new user-computer interface designs are making them easier to use. Perhaps the most important of today's trends is the fact that computers and the internet are both becoming a part of our daily lives. As computers continue to be used in marketing, retailing, and banking, we will grow ever more accepting of their presence. As computers are incorporated into other machines, we may find ourselves operating a computer when we drive, buy a can of soda, or when we want a tank of gas or a bite to eat. And as the computer's presence grows in our society, it will become far easier to use. As this history of computing has demonstrated, it is the needs of humans that continually drives the development of new computers and new computing technologies.

Computer Hardware Question 8: What is a mainframe? Answer: The largest, most expensive computers are known as mainframes (see computer hardware questions 8 through 12 for information about the different types of computers). They generally cost hundreds of thousands or even millions of dollars and they usually are used as central data processing and storage devices by large businesses or government agencies. The computer users can usually access the mainframes from many different offices that can be in different buildings or even in different cities. Many people can be in contact with the mainframe at the same time and, at any one moment, the mainframe can be processing several different programs for several different users. For that reason, mainframes are often referred to as host computers in that they are host to many users in many different locations. Many printers and a variety of storage devices may be attached to the mainframe computer. Businesses that process and store large amounts of data will generally use one or more mainframe computers. For example, banks use mainframes to keep track of checks and transactions at both human and automated tellers (ATMs). Libraries use mainframes to keep track of the books on hand and the ones that have been checked out. Businesses of all sizes use mainframes to maintain inventories, accounts, and payroll. The first computers were mainframes. Although they were very slow - even when compared to today's low-cost personal computers - the early mainframe computers were very large and very expensive. Nevertheless, they were able to process data faster than anything previously available.

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Computer Hardware Question 9: What is a supercomputer? Answer: Supercomputers are often grouped together with the mainframes. But supercomputers are even more powerful (and expensive) than most mainframes. Although they are similar in basic design to the mainframes, they may use many processors at the same time and can process data faster than any other type of computer. Supercomputers are generally used by very large companies and research institutions to process complex mathematical calculations (see computer hardware questions 8 through 12 for information about the types of computers).

Computer Hardware Question 10: What is a minicomputer? Answer: Minicomputers are smaller and less expensive than mainframes. Although they may be accessed by a number of different users just as mainframes are, there are usually fewer access sites and the access sites are usually located in closer proximity to the minicomputer. Because they are designed to serve the needs of many different users, they are also referred to as host computers (see computer hardware questions 8 through 12 for information about the different types of computers). Minicomputers are generally thought of as medium-sized computers: while the mainframe may do the data processing and data storage for the widespread offices of an entire large company, minicomputers are generally limited to data processing and storage in one location (often for one department or for a smaller company). Like the mainframe computers, minicomputers can serve a number of different users at the same time, but because of their somewhat more limited capacity and speed when many users are in contact with the minicomputer, the computer's response time may be noticeably slower. Mincomputers sometimes use operating systems designed specifically for them, but many use either the UNIX or Linux operating system (also see Computer Software Question 2: What is systems software).

Computer Hardware Question 11: What is a microcomputer (PC, desktop computer)? Answer: The world's newest type of computer, the microcomputer, is now by far the most plentiful of the three computer types (see computer hardware questions 8 through 12 for information about the different types of computers). Known as personal computers or PCs, microcomputers come in many different sizes and they offer users a number of different capabilities. When microcomputers first became popular in the early 1980s, they were found mostly on individual desks in homes and in small businesses. But soon, these "desktop" computers began to show up in larger business and in schools and government offices. At first, these "micros" were made by very small companies and were sold in retail shops or through the mail. But eventually they became so popular that just about every company that made any product that had anything to do with electronics began to manufacture a microcomputer. Big companies soon began to order microcomputers to attach to their mainframes and minicomputers. This let their employees run their own programs on a microcomputer and still maintain a data communications link with a large host computer. Today, micros come in all sizes and shapes. Some have grown too large to fit on desks and now reside under the desk. On the other hand, some of the new microcomputers are so small that you can carry them in your pocket (but they are still referred to as microcomputers. Sometimes more powerful microcomputers are tucked away in the back room where they serve the function of a file server for a group of networked microcomputers. Regardless of their size and appearance, all microcomputers are, basically, "personal"; that is, they are designed to be used by one person at a time. This was the revolutionary idea that PCs brought to the computer world. Up to that point, no one could have conceived of the idea that individual users might have access to their very own computer. Previously, it was part of the very concept of computers that they were big, expensive, and that they were to be shared by many people. Unlike mainframes and minicomputers, microcomputers generally are not "host" to several users at the same time.

Computer Hardware Question 12: What is a workstation? Answer: As PCs and the internet have become more popular, their use has expanded beyond their traditional role for word processing and simple data management. Some manufacturers have designed very powerful microcomputers that have taken over some of the more complex data management tasks that were formerly reserved for mainframes and minicomputers. These more powerful microcomputers have come to be called workstations (see computer hardware questions 8 through 12 for information about the different types of computers). Workstations are microcomputers in that they are based on a microprocessor. And, like other microcomputers, they are designed to be used by one person at a time. However, workstations are usually faster than PCs, often have more storage then PCs, and may use more complex and powerful operating systems than PCs. Workstations are often used for scientific tasks or for managing detailed design and graphics tasks. Often they are used as

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multiprocessing machines: that is, because they are fast and use a powerful operating system, they can be used to carry out more than one type of data-processing task at the same time. Workstations can be very expensive so they are usually reserved for applications that would overtax the capabilities of a standard PC. Often they are attached to a minicomputer or a mainframe so that data can be downloaded (transferred by wire) from these larger, host computers.

Computer Hardware Question 13: What is an embedded microprocessor? Answer: These days microprocessors can be found in many places besides microcomputers. Microprocessors are now used as control devices inside appliances like microwave ovens and stereo systems. These embedded microprocessors do not use standard input and output devices because they are not intended to be used directly by humans. Instead, they are used to control the complex switching and regulating tasks used in modern appliances. In more complex devices such as automobiles and copy machines these embedded microprocessors may have a self-diagnostic function that results in the output of information that can be used by humans.

Computer Hardware Question 14: What is computer storage? Answer: Storage devices store data that can be retrieved later. Primary storage refers to the temporary storage of data and computer instructions as they are being processed while secondary storage devices store data not currently being processed.

Computer Hardware Question 15: What is input? Answer: The computer's input devices provide a way for humans to input data into the computer. Input devices include keyboards, digital scanners, touch-screen monitors, and pointing devices (also see Computer Software Question #31: What is a mouse?) such as mice, track balls, and light pens. Data can also be input from a variety of storage devices such as magnetic disks and tape.

Computer Hardware Question 16: What is an output device? Answer: The computer's output devices output data in a form that can be interpreted by humans. Monitors (also known as video display devices) and printers are the most common output devices. The computer can also output data using devices that convert it into other forms such as sound or to storage media.

Computer Hardware Question 17: What is the central processing unit (CPU)? Answer: The central processing unit is the computer's main processing device. It functions through the interaction of three different units: (1) the control unit that interprets instructions and directs the processing, (2) the arithmetic/logic unit that performs arithmetic operations and makes comparisons, and (3) the primary storage unit that temporarily stores data during processing (main memory).The central processing unit is the most complex of the computer's hardware components, directing most of the information processing activities. Each new generation of CPUs adds new processing capabilities and, at the same time gets faster. As new processing methods are invented, new ways of miniaturizing the required circuits are also devised. This miniaturization has resulted in ever smaller, faster computers. Microcomputers that fit comfortably on your desk now have more processing power than mainframe computers that used to fill an entire room. Today's CPUs are incredibly complex devices. To understand them, it is best to view them in terms of their function. Functionally, the CPU is composed of two main parts, the control unit and the arithmetic logic unit. The CPU and processing system is illustrated below.

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The CPU and Processing System

Computer Hardware Question 18: What is a control unit? Answer: The control unit controls and coordinates all of the CPUs activities. Acting on instructions that it retrieves one by one from main memory (sometimes known as primary storage), the control unit interprets each instruction and carries it out. In addition, it controls input and output devices and transfers data between the arithmetic/logic unit and main memory.

Computer Hardware Question 19: What is an arithmetic/logic unit (ALU)? Answer: The arithmetic/logic unit ( ALU) performs arithmetic computations and logical operations. The arithmetic operations include addition, subtraction, multiplication, and division. The logical operations involve comparisons such as less than, greater than, or equal to. Although these may seem like simple operations, the ALU can carry out extremely complex tasks by combining these functions. To a great degree, the speed of the ALU determines the speed of the computer. Both the control unit and the ALU contain registers. They are temporary storage locations for managing instructions and data as they are being processed. For example, the ALU might temporarily store the result of one arithmetic calculation in a register while it performs a second calculation using that result.

Computer Hardware Question 20: What is the instruction cycle (I-Cycle) and the execution cycle (E-Cycle)? Answer: When the CPU receives an instruction from main memory to perform a specified operation, the period of time it takes to retrieve the instruction and initiate the task is referred to as the instruction cycle. It may also be referred to as the I-cycle or I-time. The execution cycle refers to the period of time in which the instruction is executed and the result is stored in a register. It may also be referred to as the E-cycle or E-time. A machine cycle consists of the instruction cycle and one or more execution cycles. A machine cycle used to be measured in milliseconds (thousandths of a second). But with the advent of ever faster CPUs, we now are more likely to measure machine cycles in microseconds (millionths of a second) or even in nanoseconds (billionths of a second) and picoseconds (trillionths of a second) in the largest and fastest computers.

Computer Hardware Question 21: What is the CPU clock? Answer: The CPU has an internal clock that synchronizes all of the operations in the cycle and the clock speed helps to determine the speed at which operations are carried out.

Computer Hardware Question 22: What is main memory? Answer: Computers act on instructions provided by computer programs. These instructions are temporarily stored in a special data storage area referred to as main memory. Before the CPU can act, it must retrieve instructions from main memory (also known as temporary or internal storage). The CPU may also store data in main memory temporarily as it carries out processing tasks. By far the most common type of temporary storage system in use today is based on sets of silicon chips. Each chip contains millions of miniature circuits and each of those circuits can be in one of two states. This system is known as a binary

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system, the word binary referring to two distinct states, on or off, present or absent. Data is stored in these chips in grouped, coded patterns using this binary method. By setting some circuits to on and others to off, the computer can store many different kinds of data. In fact, all the different types of data that can be used on computers can be stored using complex combinations of this simple on/off binary coding system. Data stored on these chips remains in storage until the computer changes it by changing the pattern or until the computer is turned off. Without power, the circuits in the chips change back to their normal off-state and all the data is lost. For that reason, this type of memory is known as volatile and it is contrasted to more permanent types of storage systems that are known as nonvolatile. This type of primary storage is also known as random-access memory ( RAM) and the chips are referred to as random-access memory chips. However, the term "random" may not be the best way to refer to this type of memory. While almost all of today's computers use some random-access method of storing data (that is, the computer can retrieve data from wherever it is stored, randomly), the term RAM is reserved for the computer's primary, chip-based memory system.

Computer Hardware Question 23: What is a secondary storage system? Answer: Storage devices store data that can be retrieved later. Secondary storage devices store data not currently being processed. Unlike the computer's main memory, or primary storage, which is based on sets of silicon chips, the more permanent secondary storage systems are usually based on magnetic disks or magnetic tape. While computers may need only enough main memory capacity to carry out the computer's processing tasks, secondary storage is usually much larger because it is used to store many different types of data and program files for long periods of time. A computer program will usually be stored in secondary storage. When that program is started, key instructions related to that program's functions are transferred from permanent storage to main memory. The program will usually provide a way for the user to load data from secondary storage to be used while the program is in operation and a way to save data back to secondary storage after processing. Since both data and processing instructions can be temporarily stored in the chip-based primary memory system, it is not necessary for secondary storage systems to be as fast as main memory. The constant data transfers between the CPU and main memory take place in a few billionths of a second (nanoseconds). Data transfers to and from secondary storage are more likely to be measured in thousandths of a second (milliseconds), a considerably slower rate of transfer.

Computer Hardware Question 24: What is disk storage? Answer: Although many types of secondary storage have been invented, the most common type of secondary storage system in use today is based on disks that are coated with a magnetizable surface. On the magnetic medium that coats these disks, tiny areas can be magnetically aligned in one of two different ways. Using this bipolar system of magnetism, data can be stored on the disk using binary code. Each area that can be magnetized is known as a bit and the bits are grouped to form bytes. Typically, each byte stores one character, using the same binary coding method used in primary memory. In these systems, a disk drive is used to rotate the disk. Although, a disk drive may appear to be a fairly simple device, it is actually a complex system with several devices that must work in concert. Based on a system of precise timing, a read head hovers above the spinning diskette surface to "read" magnetically encoded data from the disk. The data is encoded on the diskette by a separate device, the write head, that also floats just above the surface of the spinning diskette. Before the computer can write data to a disk, the disk must be formatted. The formatting process organizes the disk's magnetic medium into tracks. Some disks have as few as 40 tracks, but other special disks have as many as 500.

Computer Hardware Question 25: What is a hard disk (fixed disk) ? Answer: Hard disks, sometimes referred to as fixed disks, use the same magnetic media as diskettes. But while diskettes can be used to carry data from computer to computer, hard disks are internal devices used to store much larger amounts of data inside the computer. Hard disks often use several magnetically coated disks stacked one on top of the other. All of these disk platters, inside the sealed case, spin at the same rate, but each disk has its own set of read/write heads. While the diskette drive's mechanism clamps onto the diskette and starts it spinning after it is placed in the drive, hard disks start spinning as soon as the computer is turned on. And, since hard disks spin very fast inside a tightly sealed case, they can provide faster rates of data transfer to the processor.

Computer Hardware Question 26: What is a diskette (floppy disk?

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Answer: Diskettes (commonly referred to as floppy disks) are a form of portable storage that can be inserted into a computer's diskette drive. The early personal computers used a 5 1/4-inch diskette housed inside a flexible plastic jacket. Today most computers use 3 1/2-inch diskettes that have a stiffer jacket. Both types have the same thin, flexible magnetic disk inside. It is only the jacket and the size that differs. Today's diskettes for personal computers vary considerably in their storage capacities. These diskettes may have 40 tracks, 80 tracks, or more. More tracks mean more storage capacity, but it also means that the data on diskettes with differing numbers of tracks cannot be read by disk drives that do not have the capability to read or write that many tracks. This can cause problems when you are using diskettes to transport data from one computer to another.

Computer Hardware Question 27: What is tape storage? Answer: Many of today's large computers store data using magnetic tape. Magnetic tape drives use tapes that are made of plastic, coated with the same type of magnetizable iron oxide that is used on disks. The tape is usually 1/2-inch wide and may be purchased in lengths of 200 to 4,000 feet. The magnetic tape is delivered on a reel or in a cartridge and is relatively inexpensive. Because the very long tapes provide far more magnetic surface area than disks, they can hold far more data. The tape moves through the tape drive at speeds up to 17 feet per second. The fastest tape drives can read over a million characters per second. While magnetic tape is an effective tool for the storage of data that is not likely to change very often, it is not very useful when data is constantly being altered. The reason is that data must be sent to and retrieved from the tape sequentially as the tape runs through the drive. Finding data on one small section of the tape can be a time-consuming process, especially when using very long tapes. Nevertheless, tape storage is still widely used with large computer systems and it is useful for long-term storage of data that is not often changed.

Computer Hardware Question 28: What is an optical disk? Answer: Although magnetizable surfaces have long represented the primary method used in computer storage, a number of new methods are now emerging. For example, some newer storage devices use a nonmagnetic technology that is based on optical disks. Optical disk storage is growing in popularity because the disks are less subject to damage from dirt or heat and because they can be used to store large amounts of information. A typical optical disk system for microcomputers can store 500 megabytes or more on each disk. Some, using larger diameter disks, can store many thousands of megabytes. Like magnetic disks, optical disks use a spinning platter; but information is stored on the disk by a laser that burns tiny pits into the surface of the disk. Then, to retrieve data from the disk, a laser-based mechanism can detect information coded in the pattern of pits in the disk surface. This method of storing and retrieving information on a spinning disk is very much like the method used with magnetic disks, but, since the data is encoded by physically burning patterns into the surface of the disk, it can't be accidentally erased. The drawback is that these disks can't be re-recorded. Therefore, they are more appropriate for the storage of large amounts of data that is not likely to change often. Today, CD-ROM ( compact disk - read-only memory) and DVD systems are very popular, especially for use with microcomputers. These systems use a disk that is less than 5 inches in diameter and yet can hold very large amounts of data. Although these disks look just like the well-known music CDs, they are used to store the kind of digital information used in computers. The large color graphic and video image files that are used with multimedia are often stored on optical disks and, in addition, these disks can store two channels of sound just like the popular music CDs. In fact, a computer-controlled optical drive can be used to play the two music channels on a standard music CD, and optical disks are now available with both the music and computerized information about the music. Some users want the high capacity and reliability of optical disks but also want to periodically re-record data on the disks; as a result, some optical systems provide a way to store new data on the disks. One version, known as write once, read many, or WORM drives, are optical disk systems that can be written to, but only once. New data cannot overwrite old data. Another newer type of optical storage can be written to as often as necessary. This type, known as magneto-optical storage actually uses a combination of laser and magnetic technologies.

Computer Hardware Question 29: What is read-only memory (ROM)?

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Answer: In addition to RAM (also see Computer Hardware Question #22: What is main memory?), there is another storage system that also uses silicon chips, but with this type of storage, known as read-only memory ( ROM), the data is NOT lost when the computer's power is turned off. This type of memory is known as "read-only" memory because the computer cannot store data to ROM but data can be read from ROM as often as needed. Computer makers use this type of chip-based storage system to permanently store data that is needed for the computer's operation. ROM is not considered to be part of main memory.

Computer Hardware Question 30: What is a pointing devce? Answer: Pointing devices such as mice, graphics tablets, light pens, and trackballs are becoming more varied as more computers adopt graphically oriented interfaces. Although they use differing methods, each of these devices provide a way to interact with images on the display monitor. Pointing devices are required with modern computer graphics applications that let you "paint" using a number of painting "tools." These tools are used to draw lines or shapes with differing thicknesses or patterns.

Computer Hardware Question 31: What is an image scanner? Answer: Digitizers provide a way to input nondigital information into the computer. An example of this type of device is the image scanner (sometimes referred to as a graphics scanner). These devices are used to convert pictures into a form that can be stored by the computer as digital data. The digitizing process is illustrated below.

How an Image Scanner Works

The scanner is connected to the computer and special software is used to control the digitizing process. Once the scanning process is complete, and the smooth tones of the picture have been converted into a digital map the image can be displayed on the computer's display monitor. And, once it has been digitized and stored as a computer file, the picture can be modified using a graphics management program.

Computer Hardware Question 32: How does a display monitor work?

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Answer: Display monitors (sometimes called video display terminals or VDTs) have long been the computer's main output device. Most computers in use today (except portable computers) display information using a monitor that is based on a cathode-ray tube ( CRT), similar to the one used in television sets. The CRT's electron beam creates a visible pattern on the display screen by activating (lighting up) the phosphor dots on the screen: these dots are known as picture elements or pixels. Today's display screens do not all use the same number of pixels on the screen to display characters and graphics: the higher the number of pixels used, the better the clarity of the image formed. The display screen's resolution refers to the clarity of the image and it is directly related to the number of pixels used to create the image: the higher the number of pixels used, the higher the resolution. The original display monitors were monochrome, designed only to produce individual characters in one color (usually green) on a black background. But, with the advent of personal computers, more and more manufacturers began to provide monitors that could display images in color. In these monitors, three electron beams are used to activate the screen's phosphors with a combination of three basic colors, red, green, and blue. For that reason, these monitors are often known as RGB monitors (illustrated below).

The RGB Color Monitor

The early monochrome monitors showed characters on the screen by displaying pre-set patterns of dots in the character's shape. Such monitors are known as a character-mapped displays. These alphanumeric monitors were limited to the display of a standard set of letters, numbers, and special characters like the period (.), the equal sign (=), and the dollar sign ($). Most were capable of displaying up to 80 characters on each line with up to 24 lines on the screen at the same time. When this type of monitor is used, the characters that appear on the screen all match a standard format that is built into the computer (usually in a special video read-only memory known as the video ROM). When, in response to software requests, a character is to appear on the screen, the pattern for that character is looked up in a table that is stored in the video ROM. The CRT's electron beam then uses that character's pattern to activate a matching pattern in the phosphor dots (pixels) that appear on the screen. Monitors that can display a variety of images, including characters, designs and patterns, are known as graphics monitors. These monitors are known as dot-addressable monitors because all of the pixels on the screen can be addressed by software. That means that any pattern of pixels can be illuminated to produce any type of text, character or picture. Both character-based alphanumeric monitors and bit-mapped graphics monitors can display characters, but bit-mapped monitors can display characters in different shapes and styles, as dictated by the software program that is running. This gives these monitors the capacity to display the same character in a different font (a font represents a type style) and in a different size. These monitors are also known as bit-mapped monitors because a representation, or map, of the image on the screen is maintained in the memory of the computer. Today's monitor types are known by the names of their image-producing technology. A PC could be configured to use a color graphics adapter ( CGA) monitor that displays four colors at a resolution of 320 by 200 pixels or monochrome images at 640 by 200 pixels. Or, it could use an extended graphics adapter ( EGA) monitor that produces images in up to 16 different colors at a higher resolution, 640 by 350 pixels. A video graphics array ( VGA) monitor can produce up to 256 color shades simultaneously at resolutions up to 720 by 400 pixels. Not only do these monitors represent a great variety of different display standards, but new ones continue to emerge. For example, S-VGA monitors ( super VGA) can display up to 256 color shades in resolutions up to 800 by 600 and XGA monitors can display up to 256 colors with resolutions up to 1024 by 768. New display monitors are still being designed today with even higher resolution capabilities.

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Computer Hardware Question 33: What is an impact printer? Answer: We can categorize printers generally into two types, impact and nonimpact based on the method they use to create the image on paper. Impact printers use varying technologies to place ink on paper by striking through an inked ribbon.

Computer Hardware Question 34: What is a nonimpact printer? Answer: Most of the new developments in printers are in nonimpact technology. These printers use a number of different technologies to produce an image on paper without striking through an inked ribbon. In the past few years, laser printers have become the most popular nonimpact type of printer. Laser printers output an entire page at a time using the same sort of technology that was pioneered in dry-toner copiers (also see Computer Hardware Question #38: What is a laser printer?). Another nonimpact printer that is often used with both desktop and portable PCs is the ink-jet printer. This type is like the dotmatrix printer in that characters are developed one dot at a time (also see Computer Hardware Question #39: What is an inkjet printer?). A number of other new nonimpact printer technologies are currently being developed. New printing technologies are yielding attractive color output through ink-jet and thermal technologies and printing technologies based on ion-deposition, light-emitting diodes (LED), and liquid crystal shutters are showing promise. These evolving technologies may provide the basis for the printers of the future.

Computer Hardware Question 35: What is a line printer (also known as a chain, band, or drum printer)? Answer: They are all types of the impact printers known as line printers. A number of different types of high-speed printers have been developed to satisfy the high-volume needs of large computer systems. These wide-carriage printers are known as line printers because they print characters an entire line at once. The most common types of line printers in use today are band printers, chain printers, and drum printers. Each uses a slightly different technology to produce characters, but all are very fast because each character on the line has its own print hammer which allows for 132 printing positions. The output of these high-speed printers is too fast to be measured in characters per second (as other printers are). Instead, they are measured in lines per minute. Some of these printers can produce over 3000 lines of type per minute (almost 80,000 words per minute).

Computer Hardware Question 36: What is a dot-matrix printer? Answer: The old workhorse of impact desktop printers is the dot-matrix printer (illustrated below). It places a dot on paper when one of a group of pins in the printhead strikes an inked ribbon that is held just above the paper. The early dot-matrix printers used only a few pins and printed characters made up of only a few dots each. This resulted in printouts of limited quality (known as draft quality). Today, although they are not used as much as in the past, dot-matrix printers are much more capable. While early dot-matrix printers produced only a 5 by 7 matrix of dots, some can now produce a matrix as large as 36 by 24 dots. In addition, some dot-matrix printers can improve print quality by printing each character twice and some of them can even shift the position of the dot on the second printing to produce an even better image.

Dot Matrix Output

Computer Hardware Question 37: What is a letter-quality printer?

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Answer: A letter-quality printer in a type of impact printer. These printers are not so common now that ink-jet printers have become more capable of producing higher-quality output. Like dot-matrix printers, letter-quality printers also place ink on paper by striking through an inked ribbon, but instead of tapping out the shape of the character with pins in the printhead, the characters are already formed. They are embossed on a striking device that is very much like the striker used in a typewriter. The daisywheel printer is of this type. It uses a replaceable wheel (that looks something like a daisy) with characters that are of one type and size.

Computer Hardware Question 38: What is a laser printer? Answer: Laser printers have become popular because they are fast and quiet, and because they produce high-quality, highresolution output, even when pages include graphics. The image that is transferred to paper using a laser printer is made up of dots, just as it is on a dot-matrix printer. However, laser printers create an image using far more dots per inch. A laser printer will typically use 300 to 600 dots per inch (dpi) to print both characters and graphics. That means that a one-inch solid black square produced by a 300-dpi laser printer will be composed of 90,000 dots. More expensive, higher-resolution laser printers can create up to 1200 dots per inch (1,440,000 dots per square inch).

Computer Hardware Question 39: What is an ink-jet printer? Answer: The ink-jet printer is a nonimpact printer that is often used with both desktop and portable PCs. This type is like the dot-matrix printer in that characters are developed one dot at a time. However, instead of producing a dot by striking through an inked ribbon, the ink-jet printer creates each dot using a tiny ink jet to place a droplet of ink on the paper. These printers are quiet and fast. They can output both characters and graphics in resolutions that equal those of the laser printers. They can also be used to output color at a relatively low cost.

Computer Hardware Question 40: What is a point-of-sale system? Answer: Today, we are all familiar with the special computers that are used in point-of-sale stations. In the past few years, these computer-based systems have been installed in every kind of business from the neighborhood grocery store to the auto parts chain. These systems utilize a bar code that is printed on the packaging of the product. This is the universal product code ( UPC) and it uses a set of printed lines of varying width to store information about the product. When a scanner beam is passed across the coded lines, a signal is sent to the computer with coded information. The computer returns a price and, at the same time, stores information for inventory control. Point-of-sale computers are used in other innovative ways. Some companies have begun using point-of-sale computers in place of sales personnel. For example, some fast-food restaurant chains now take orders directly from the customer and then relay the order to the food preparer. In other businesses the computer can be used to provide the customer with information about products and sales locations.

Computer Hardware Question 41: What is a plotter? Answer: Plotters are designed to produce graphics output, in black and white or color, on paper of varying sizes. Most plotters produce images on paper using colored pens. A flatbed, or x-y plotter, uses drawing arms to draw the image on paper rolled out onto a flat surface. In a drum plotter, the paper is rotated on a drum as the drawing arm is lowered to the paper's surface and moved left and right to produce the image. Electrostatic plotters do not use drawing pens. These plotters produce graphics by applying an electrostatic charge to rolls of special paper. Although they are generally more expensive, electrostatic plotters are faster than plotters that use drawing pens and they produce higher-quality output.

Computer Software Questions

Computer Software Question 1: What is software? Answer: Software refers to computer programs. A computer program is a set of instructions written by a computer programmer to control the computer's activity. The computer program not only coordinates and controls the internal operations and resources of the computer system, but also provides the interface through which the user instructs the computer to perform

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specific tasks. Without computer programs a computer system is of little value to the user. Software is required to accomplish all the activities performed by a computer, including the input, processing, output, and storage of data. If we analyze the history of computer development, we see that while the basic design of the computer itself has not changed much in the last few decades, the way we interact with computer programs is undergoing rapid changes. Software that emerged after the punched-card era provided ways to more directly access the computer by using a keyboard to input data and a monitor based on a television-type cathode-ray tube (CRT) to get information about what the computer was doing. However, results of data processing were still generally output on a printer. This system of keyboard-based, one-character-at-a-time, input via a keyboard and output on display monitors and printers continued until the beginning of the personal computer era (also see Computer Software Question #11: What is the human-computer interface?).

Computer Software Question 2: What is systems software? Answer: The group of programs that control and coordinate the resources and operations of a computer system are known collectively as the systems software. The systems software controls basic computer operations and coordinates the activity of the other two software types. The systems software has many tasks related to the operation and control of the computer's resources, but its primary role for computer users is related to file management and the control of the devices attached to the computer. For example, users will use one or more systems-control programs to copy or delete files, to check the status and contents of storage devices, and to regulate input and output speeds and protocols. Despite their size, the earliest large computers were designed to be used for only one task, by only one user at a time. As a result, the systems programs that were used with these computers were relatively simple and their capabilities were directly related to the needs of that single user. Today's large computers operate in a multiuser environment; that is, the systems software must keep track of many users who are all in contact with the computer at the same time. This is known as time-sharing and it requires more sophisticated systems software. To avoid the necessity for specialized training and to make it easier to hire skilled computer operators, some large computers are now being designed to use the same standardized operating systems that are used on other computer models. For example, some manufacturers of large computers have adopted a version of the UNIX operating system that is also used on desktop and midrange computers. Unix was first developed for minicomputers by Bell Laboratories in the early 1970s. Over the years, it has undergone many revisions and today it is available for many different types of computers, large and small. As described above, on host computers, the system software must manage computer resources for the many users that may be in contact with the computer at any time. It must handle all the user processing and it must keep track of requests from the user terminals, prioritizing them and determining when to allow input from or output to the many users that may be in contact with the computer simultaneously. On personal computers, the system software only has to deal with one user; for that reason, system software is usually provided as a set of specialized utility programs that are used to manage the computer and its storage devices and input and output devices. Collectively, these programs are known as the personal computer's operating system. It is important to understand that software must be designed specifically for the operating system it is to be used with. For example, many of today's personal computers are designed to be used with a collection of programs that comprise the MS-DOS operating system (developed by the Microsoft Corporation). Computers made by IBM, Compaq, Dell, Gateway, Tandy, and many, many others use the same basic processing components designed to work with the MS-DOS operating system. Thousands of different computer programs have been designed to run "under" this operating system on these types of computers. On the other hand, some computers, such as the Macintosh line of personal computers made by the Apple Corporation include a built-in operating system that is not shared with most of the other computer types. Software developed for Macintosh computers must be specifically designed for use with the Macintosh operating system.

Computer Software Question 3: What is applications software? Answer: Applications software includes most of the types of programs we use every day to get our computerized work done. Applications programs are widely used in our society for entering and editing text (word processing and desktop publishing programs), for entering and manipulating numeric data (spreadsheets and many other business programs), and for record keeping (database management programs). These types of programs are sometimes referred to as general-purpose applications. Today, PC users expect that no matter what their need might be, someone will soon create a program to meet it. PC applications programs were created for farmers and mechanics, for dog breeders and beauty shop owners, for scientists and teachers. Today, there are so many software packages available that it is impossible to calculate exactly how many there are.

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Generally PC applications software comes in a package that includes not only the disks with the program files, but a set of user's manuals, known as documentation, that provide instructions on using the program. The package will also usually include registration cards, license agreements, and promotional information on upgrades (improved versions of the program) and other products manufactured by the same company.

Computer Software Question 4: What is programming software? Answer: Programming software is used to carry out a specialized task that is crucial to the use of computers - the creation of computer programs. Software packages in this category are development systems that are used by computer programmers to create all the computer programs we use. Programming software is used to formulate and store the complex sets of instructions that are used to dictate computer tasks. Every program, including all of the systems and applications programs, and even the programming languages themselves, begin as a set of specific instructions to the computer. These software-development systems provide a way for the computer programmer to set down rules of computer activity and store them so that they can be triggered later when the computer user starts the program.

Computer Software Question 5: What is an operating system? Answer: All computers require special software, known as operating software to run. The most popular operating software, the MS-DOS/Windows operating software, is designed to work with the Intel (or compatible) microprocessors. Many software manufacturers design their software to run on any computer that uses the Intel microprocessor and the MS-DOS and/or Windows operating system. Although the computers themselves may be made by different manufacturers and may look very different, if they are based on this hardware/operating system combination, they should all be capable of running the software designed for it. Even though these computers are made by many different manufacturers, they are often referred to collectively as MS-DOS or Windows based computers. Sometimes they are referred to as IBM-compatible or IBM clones since the IBM Corporation was the first to use the Intel microprocessor in combination with the MS-DOS operating system. These first IBM PCs were very successful and many other manufacturers were quick to create (or clone) their own versions of it. A somewhat different system is employed by other hardware manufacturers. For example, although computers made by the Apple Corporation are based on a microprocessor made by a third party company (they use microprocessors made by Motorolla and IBM), Apple has designed their own operating system. This graphically oriented operating system is used on Apple computers, such as the Macintosh. Software developers who want to design programs for Apple's Macintosh computers must create their programs to run specifically on the Macintosh. Because Apple Corporation controls the operating system, they also control the way programs present information to the user. This results in much greater consistency from one program to the next. The advantage to the user is that when programs look and act more alike, it is much easier to learn each new program. In the past few years, several new graphically-oriented operating environments have been created to bring this kind of consistency to the MS-DOS based group of microcomputers. Although microcomputers and larger computers can now use other operating systems (such as the Linux operating system), the vast majority still use the hardware/software systems described above.

Computer Software Question 6: What is the binary number systemand how does it compare to the decimal number system? Answer: A great deal of the activity managed by the computer's processing hardware deals with the manipulation of numbers. And numbers can be represented using many different number systems. The number system we usually use is the decimal system, a method of representing all numbers using ten symbols, the digits 0 through 9. For numbers higher than 9, the position (or place value) of the digit determines the value. In the decimal system, each position represents a certain power of ten. The digit that is farthest to the right represents a value and each digit to the left of that value represents that value times an incremental power of ten. Since the system is based on the value of 10, it is known as the base-ten number system. In the figure below, the number 4,082 is represented in the decimal notation system we are used to seeing. As indicated, the farthest number to the right is the unit position (the value of 2). The next digit to the left is the tens position (the value of 80). As we keep moving to the left, each position represents an increment of ten.

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The Binary and Decimal Number Systems

In contrast to the base ten decimal system, the binary number system uses only two symbols, 0 and 1. These two symbols are used to represent all numbers: it is therefore a base two number system. The principle of representing numbers is the same though, except that each position represents a power of 2 instead of 10. If you look at the diagram, you will see that to represent the number 29, five digit positions are required. Again, each digit to the left represents an incremental value of the base number, in this case the number 2. Although the base two number system does not seem natural to us, it works well in a computer system that represents data in one of two states, on or off.

Computer Software Question 7: What is hexadecimal representation? Answer: If the binary number system has a disadvantage, it is that it requires a large number of bits to represent a number. In the example above, it required five digit positions to represent the relatively small number, 29. For that reason, many computers represent data using the hexadecimal number system, (hexadecimal indicates a base of 16). Using hexadecimal numbers, a large number that would be represented as a long string of ones and zeros using the binary number system, can be represented using fewer digit positions. The hexadecimal number system uses 16 symbols. The first nine digits are represented as 0 through 9, just as they are in the decimal system, but the remaining six are represented using the capital letters A through F. Using the decimal system, the number 10 is represented using two digits (10). Using the binary system, the number 10 is represented as 1010, but it requires four digit positions (and therefore four bits to represent an on or off state). In the hexadecimal system, the number 10 is represented using the letter A. In each case, the higher the base number, the fewer digits that are required to represent large numbers. Although the binary system is useful to the computer, very large numbers require far more digits, making the data difficult to read when printed out. The hexadecimal system makes it easier for computer professionals to read a printout of data stored in main memory (known as a memory dump) and that is one of the primary uses of this number system.

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Comparison of Numbering Systems

Computer Software Question 8: What is ASCII? Answer: The acronym ASCII (pronounced as-kee) stands for American Standard Code for Information Interchange. Today, it is the most widely used computer code. It is used by nearly every type of microcomputer and by many larger computers as well. ASCII was originally developed as a seven-bit code, meaning that it uses seven bits (binary digits) to represent each character. Later, eight-bit versions of ASCII were developed and they are more common today. In an eight-bit ASCII character representation, the capital letter A is represented in binary form as 00110000. B is 00110001.

Computer Software Question 9: What is EBCDIC? Answer: The acronym EBCDIC (pronounced eb-si-dik) stands for Extended Binary Coded Decimal Interchange Code. It is used on IBM mainframes and on other large computers. It is also an eight-bit code and can therefore provide 256 different characters (there are 256 possible combinations of the eight on/off binary designators).

Computer Software Question 10: What do the terms bit, byte, and word refer to? Answer: The smallest unit of data that a computer can deal with is based on the on/off state of a circuit and can be represented as a binary digit (0 or 1). A single binary digit is known as a bit. However, computers generally do not deal with data as single bits. Instead, computers usually deal with bits in groups of eight. Each group is referred to as a byte. As a result, the size of computer data capacity, including storage, is measured in bytes. The symbol K (commonly used to symbolize thousands) is often used to represent the number of bytes of storage capacity. One K is actually 1,024 units; therefore, if a computer's main memory is described as providing the capability to store 500 K bytes, it would be able to store 500 X 1,024 bytes (512,000 bytes). The symbol M (commonly used to symbolize millions) is used to represent 1,048,576 units. These days, a computer's main memory is likely to have a capacity of many M bytes, rather than K bytes. An even larger measure of storage capacity is represented as G bytes, for gigabytes (over a billion bytes). Most personal computers today have storage capacities that are measured in G bytes. A word refers to the size of a group of binary digits that can be stored in each of the computer's memory locations. The wordsize or word length is, therefore, the number of bits of data that can be manipulated by the CPU in one block. A computer with a word length of 32 bits should be able to transfer data between the CPU's memory and its internal registers considerably faster than a computer with a word length of 16 bits. However, in many microcomputers, the circuits that are used to transfer data between CPU components (referred to as the data path or the data bus) limit the transfer of data to 16-bit groups, resulting in a somewhat slower overall rate of data processing.

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Computer Software Question 11: What is the human-computer interface (also known as the computer-user interface? Answer: Traditionally, computers were used to deal with data that was input and output as letters and numbers. But, as computers began to be used to deal with other types of data such as pictures and sound, new types of devices have been invented to better respond to the computer user's needs. The methods and devices we use to interact with the computer can be collectively thought of as the human-computer interface. The term relates not only to the input and output devices we use, but also to how we think about computer-based information. An important part of the human-computer interface is how information is presented to the computer user. In the past, computers dealt with data that was in the form of discrete units, usually in the form of characters that could be input using a keyboard and output using a printer. The human-computer interface was designed around those functions. For example, if a computer user was required to choose from one of several options, those options would be presented as a numbered list. To choose an option, the computer user would enter its number from the list by pressing the appropriate number key on the keyboard. The input device was the keyboard, an effective tool for entering a number. The display monitor was the most common output device, quite effective at displaying the numbered options using single characters. These types of humancomputer interfaces were known as character-based interfaces because all input at the keyboard and all output on the screen was in the form of discrete characters. As more and more people began to use computers to deal with data that was in the form of images, the human-computer interface began to change. Since computers were being used to present pictures, some computer makers began to redesign the human-computer interface to make it more graphical also. In the 1970s, as part of a research program on how humans use computers, the Xerox Corporation designed a computer with this type of interface. It was a powerful personal computer known as the Star and it used a special type of pointing device that was designed to rest on the desktop next to the computer. It was about the right size to fit nicely under the human hand and when the computer user moved it about on a desktop, a pointer would mimic those movements on the screen. When the user moved the pointing device to the right, the pointer on the screen moved to the right. When the device moved to the left, the pointer moved to the left. When the user moved the device forward, the pointer on the screen moved up toward the top of the screen. Downward movements were translated by the computer as pointer movement toward the bottom of the screen. This type of pointing device became known as a mouse and it led to other changes in the human-computer interface. For example, in the character-based example described above, the computer user chose an option from a numbered list by entering the number of the desired option. Using the pointing method, the user can move the mouse on the desktop until the mouse pointer on the screen rests over the name of the desired option. Then the user can select that option by pressing a button on the mouse. The computer determines the location of the mouse pointer on the screen and, if it is positioned over a valid option, takes action just as if the user had entered the number of an option in the character-based example. The pointing method has steadily grown more popular because, as shown in this example, the process of interacting with the computer can be much more direct and intuitive: instead of typing in a character to represent an option, the user can simply "point" to the option and click. These types of human-computer interfaces are known as graphical user interfaces ( GUIs) because pointing devices are used to interact with output on the screen that is often in the form of pictures. Today, most manufacturers of personal computers and computer programs are adopting these GUI methods. Now that pointing devices have become a common component of the computer system, new interfaces are being developed to take advantage of them. In the past, when the computer user choose one option from a list of options, the program had to be interrupted to present the options list. With that method, the entire screen changed to show the list of options (often known as a menu of choices). This method worked alright, but it required a series of special keystrokes just to display the list, to make a choice, and then to hide the list again. Today, such menus of choices are more likely to be hidden away with only a keyword displayed to indicate the existence of a menu. An example from Microsoft's Windows program is reproduced in the figure below.

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Windows File Menu

In the figure above, the keywords shown across the top of the first screen represent available menus. The user of this type of system can use the pointing device to select any one of the keywords which, in turn, "opens" the selected menu. The second example shows the File menu after it has been opened. Once the menu is open, the pointing device can then be used to select one of the listed options.

Computer Software Question 12: What is optical character recognition (OCR)? Answer: With special software, image scanners can also be used to capture text from printed material and store it in a form that can be edited using a computer program such as a word processing program. This is known as optical character recognition ( OCR). First, a page of text is scanned and stored as a digital map (as if it was a picture). Then the optical character recognition software analyzes the digital map, attempting to recognize the shapes of letters, numbers, and punctuation symbols. Any character shapes that are recognized are stored as those characters, which means that they can be edited using word processing software, database management software, or other types of programs that deal with letters and numbers.

Computer Software Question 13: What is a programming language? Answer: A programming language is, in many ways, much like the languages we use to communicate with each other. But, while natural languages like English are used to convey information between individual humans that understand that particular language, a programming language provides a special set of rules and a vocabulary that have to do with a computer's operation. In this country, the English language is widely used, but it can be used as a communications tool only by those who understand the language's rules and vocabulary. Likewise, before communication with a computer can be established, the rules and specialized vocabulary of the programming language must be known to both the computer programmer and the computer itself. A programming language has words, symbols, and rules of grammar (known as the syntax of the language). A computer programmer, operating within the structure of these rules, develops instructions to guide the computer's operation. The resulting set of instructions is the computer program. Often these instructions tell the computer what to do when the user of the program initiates some kind of action (when, for example, the user types in characters from the computer's keyboard).

Computer Software Question 14: What is machine language? Answer: Machine languages are designed for a specific type of computer processor and are referred to as low-level languages. Each instruction in the machine language set is represented in binary form and is designed to trigger one specific capability of a particular processor. A binary instruction (for example, 01011010) is not easy to understand and once it has joined hundreds of such sets of ones and zeros in a computer program it is very hard for others to read it. Because these types of instructions are very detailed and vary from one computer to the next, they are difficult to modify for use on another type of computer. On the other hand, they do give the programmer very precise control over all of the computer's activities.

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Machine languages were developed in the early days of computing. For that reason, they are now often referred to as firstgeneration languages. Many other types of languages are used today, but, since all computer programs must in the end interact with the computer's processing hardware, all programs, no matter what computer language was used to create them, must eventually be converted into machine language. The figure below shows an example of programming instructions written in machine language.

A Machine Language Example

Computer Software Question 15: What is assembly language? Answer: Assembly languages are similar to machine languages in function. However, instead of representing a binary operation instruction to the computer as a set of ones and zeros (for example, 01011010), the programmer could use the more English-like instruction "ADD." Each assembly language instruction is eventually translated into one machine language instruction. The computerized translation program is referred to as an assembler. The figure below shows what the same program that was written in machine language would look like when it is rewritten in an assembly language.

An Assembly Language Example

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Because computer instructions written in an assembly language use a meaningful code word to symbolize a machine instruction, they are somewhat easier to use. Like machine languages, programs written in assembly language are for use on computers that use only one type of processing hardware. As with machine language, the resulting program is not easily transportable to other types of computers. Assembly languages are now referred to as second-generation languages.

Computer Software Question 16: What is a high-level language? Answer: The first high-level languages were developed in the 1950s. High-level languages use English-like vocabularies that are considerably easier to use than either machine language or assembly language, and programs written using a high-level language can often be used on different types of computers with few modifications. While each instruction in assembly language is equivalent to one machine-language instruction, each instruction in a high-level language may be equivalent to many machine-language instructions. The figure below illustrates an example of instructions written in BASIC, one of the high-level programming languages.

A High-Level Language Example

High-level languages are now referred to as third-generation languages. Since the 1950s, many different high-level programming languages have been created. They vary in design based on their purpose. Some examples include APL, BASIC, C, C++, COBOL, FORTH, FORTRAN, FORTH, LISP, Modula-2, Pascal, Perl, and PROLOG. And with the advent of the internet, new programming tools like Java are working hand-in-hand with internet browsers to enhance the online experience. Some languages are better suited for one task than another. For example, FORTRAN, one of the first high-level languages, was designed for scientific uses. COBOL is often used in business and C is well known for its portability across different kinds of computers. The table below provides a brief description of some common high-level languages.

Ada

Developed specifically for the U.S. Department of Defense to replace both FORTRAN and COBOL. The language was named for Ada Byron who many consider to be the first programmer.

APL

(A Programming Language) Designed for mathematical applications, APL uses a symbolic notation system that is useful for scientific and engineering programming.

BASIC

(Beginner's All-Purpose Symbolic Instruction Code) Designed as a

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straightforward approach to line-by-line programming. Often used to train beginning programmers. Simple versions of BASIC were commonly provided as the only programming software packaged with the early PCs. C

Originally developed as part of the UNIX operating system. C was designed to provide a structured, machine-independent approach to programming. C includes features that provide programming approaches similar to assembly languages. C is very popular today for application development.

C++

Versions of C that include object-oriented methods are often referred to as C++. These new versions of the C language are especially useful for applications development when the application is being designed for modern graphical user interfaces.

COBOL

(COmmon Business Oriented Language) Designed as an easier-to-use business oriented language. It includes many English-like statements for automating business tasks.

Fortran

(FORmula TRANslation) One of the early high-level languages, FORTRAN was designed to solve mathematical problems in science and mathematics. However, it became a programming standard in many different fields, the most widely used language with the earlier generations of computers.

Pascal

Designed to be a powerful, structured approach to applications development. Pascal is still widely used and is one of the most popular languages used in college programming courses. The language was named for Blaise Pascal, the pioneering mathematician and philosopher.

Perl

Another structured language, Perl has become very popular since the advent of the internet. It is often used to create communications-related programs on computers that host web pages.

PL/1

(Programming Language 1) Designed as a general purpose, easy-to-use language, PL/1 combines many of the features pioneered in earlier languages. It is used in business, science, engineering, and education.

The latest in programming tools that are supposed to be platform independent, Java programs work with your internet browser. Java can be used to create programs to enhance the user interface at web sites. It is often Java and used to create complete programs that reside on computers that host web Javascript pages, programs that are used in conjunction with an internet browser. Javascripts are small programs that reside within HTML-based web pages; these small programs supplement the user interface provided by web browsers.

High-Level Languages

As with assembly language, programs written in any of the high-level languages must be translated into machine language. There are different ways to do this. Programs may be compiled using a special translator program called a compiler. As with assembly language, a programmer creates a source program by creating a series of instructions using the programming language. Then the compiler program translates the source program into the compiled version that is ready for use (referred to as the object program). Programming languages that use this compiling system are known as compiled languages. Programming languages such as FORTRAN, C, and Pascal usually use this type of translation system. A few languages, especially those used to teach programming, use a system in which the source code is interpreted; that is, a translator program (known as an interpreter) translates each instruction of the source program to machine language and then the instruction is executed before the next instruction is translated. This can slow down the execution of the program, but this instruction-by-instruction method of execution makes it easy to find errors in the program and makes it easy to fix them immediately. The BASIC programming language is often interpreted, though compiled versions also exist.

Computer Software Question 17: What is a fourth-generation language? Answer: All of the third-generation, high-level programming languages have one thing in common - the programmer is required to list each computer instruction in sequence and to indicate the order in which each procedure is to be carried out. For that reason, the high-level languages have become known as procedural languages. Some newer languages don't require such

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specificity. They are known as fourth-generation languages (4GLs) and they are referred to as nonprocedural languages because the user can tell the computer what to do without being so specific about how to do it. Fourth-generation languages are often used to retrieve information from a database - in fact, they are sometimes provided with database-management programs. They are used to organize the data and print out reports based on the stored information. A database query language is an example of this type of programming method. These systems provide report-generation routines that give users a way to ask questions about the stored data. While there is a specified format for these questions, the requests can be phrased as normal human-language statements. An example of an instruction in a database query language is illustrated below.

A Fourth-Generation Language Example A computer program based on these 4GL methods will usually require far fewer statements. Because they are even easier to use than high-level languages, they are sometimes referred to as very high-level languages. Today, you'll find not only trained computer programmers using these fourth-generation programming languages, but many other types of computer users. These high-level languages can be used by almost anyone who needs to develop reports based on information stored in the computer.

Computer Software Question 18: What is a fifth-generation language? Answer: Many people believe that the next generation of programming languages will use query-based methods that are even easier to use. Some refer to them as fifth-generation languages. These new programming methods generally do not have the special syntax requirements of the fourth-generation languages. Using these newer programming systems, a computer user can write statements that are very much like normal human language. This natural language approach is similar to that used in query languages but since the programmer does not have to learn special rules of statement entry, they are even easier to use. A programming statement can be written in many different ways; in some cases, words can even be misspelled. With these languages, the computer interprets the request based on key words in the statement. If needed, the user may be prompted to enter more information to clarify the request. A brief program written in a fifth-generation language might look something like the example below.

A Fifth-Generation Language Example

Computer Software Question 19: What is object-oriented programming (OOP)?

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Answer: object-oriented programming ( OOP) methods represent a new direction in programming. These programming languages are based on a concept of "objects" that combine data and programming instructions. Traditional programming methods are used procedurally, that is, when the programmer creates instructions that act on data, the program's procedures are stored as a file on disk and the data is stored as a separate component of that file -- it may even be stored as a separate file. This can result in programs that require different programming instructions for each new set of data. A programming language using OOP methods can be used to combine the programming instructions and the data into objects that are used any time that same programming task is required. The objects contain instructions and data that dictate how the object acts when it is used in a program. Examples of object-oriented languages that use these methods are Smalltalk and C++ (an object-oriented version of C). The methods used in object-oriented programming can be represented schematically. The figure below illustrates how a few programming instructions can be used to initiate computer activity by sending messages to objects.

An Object-Oriented Programming Example

Computer Software Question 20: What is object-oriented authoring (OOA)? Answer: A new type of "authoring" tool has emerged to take advantage of some of these object-oriented techniques used in OOP. These object-oriented authoring (OOA) programs do not provide all the capabilities of object-oriented programming, but they include a number of object-like methods. These authoring systems provide graphics tools and a set of standard "objects" that can have a number of different on-screen characteristics (they can also be made invisible). These on-screen objects can be used to create screen displays that respond to user input, giving nonprogrammers an easy way to prototype applications programs. OOA systems are especially useful for creating applications that give the user a way to interact with graphics-oriented conventions like those used with the Microsoft Windows operating environment and the Apple Macintosh operating system. The first OOA program, HyperCard, was created in 1987 and was introduced to Macintosh users when it was given away free with every Macintosh sold. A similar OOA program, ToolBook, made by the Asymetrix Company, can be used to create applications that run with the Windows operating environment.

Computer Software Question 21: What is structured programming? Answer: Today's computer programs are larger and more complex than those of the past. As a result, modern programming techniques are much more structured; that is, they structure the programming task into segments that relate to the design and development task. Although it may be a little difficult to precisely define it, structured programming could be described as a process that results in well-structured programs; that is, programs that are well planned and systematically laid out so they are easy to understand by any skilled programmer. A straightforward design that is clear and understandable is an especially important attribute for modern, complex programs because they may have to be periodically modified by other programmers. The structured programming process consists of a definition stage (programmer defines the problem), a program logic stage (begins the formal design process), a program coding stage (the actual writing of the program code), a testing and debugging Stage (finding and fixing a program's errors), and a program documentation stage (programmer develops written information about how each aspect of the program works).

Computer Software Question 22: What is an algorithm?

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Answer: When writing a new computer program, in the first stage of program planning the sequence of steps that will form a programmed solution to the problem is known as an algorithm. There are a number of different ways to express the algorithm. For example, the programmer may create a flowchart (see next question), an outline of the program using a set of geometric symbols. Each of the symbols in the flowchart indicates a step in the logical sequence of the program and each indicates a program statement that must be created.

Computer Software Question 23: What is a flowchart? Answer: As part of the process of designing a new computer program, a programmer uses the knowledge of the problem gained in the design stage to begin planning the sequence of steps that will form a programmed solution to the problem. There are a number of different ways to express the design, but one popular method is to create a flowchart, an outline of the program using a set of geometric symbols. Each of the symbols in the flowchart indicates a step in the logical sequence of the program and each indicates a program statement that must be created. As an example, the flowchart illustrated below describes a simple program that reads a record from a database and takes action based on the contents of that record.

A Flowchart

Computer Software Question 24: What is pseudocode? Answer: When writing a new computer program, in the planning stages a programmer may express the program's logic in pseudocode, a set of statements in English that map out the program plan just as the flowchart does. Instead of using a set of predefined graphic symbols, the pseudocode statements look something like the statements of the final program. Although individual programmers usually create their own pseudocoding style, a typical example might look something like the one illustrated below.

A Pseudocode Example

As shown in this example, the English-like statements in pseudocode are very much like the kinds of comments a programmer may include in a program. In fact, with the cut-and-paste capabilities of many of today's programming editors, the pseudocode statements may be pasted into the final program as comments. Many of today's structured programs use indention as a way for the programmer to clarify the structure of the program. Pseudocode statements are often indented for the same reason.

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Many programmers prefer the use of pseudocode over a flowchart because the pseudocoding process is more like the actual programming process. To use a flowchart, the programmer must thoroughly understand the meaning of the flowchart's symbols. Pseudocode, on the other hand, conveys program steps via the meaning of the words used and therefore requires less mental translation. However, many believe that the logic of a complex program is more easily understood when it is indicated by the structure of a flowchart.

Computer Software Question 25: What is debugging? Answer: When writing a new computer program, there comes a time when the program is run and tested. No matter how well planned the program is, no matter how much care is taken during the program coding process, errors will be found in every complex program. Errors in programs are often referred to as bugs and finding and fixing a program's errors is referred to as debugging. Some errors may be due to simple mistakes in entering the program. For example, if the programmer misspells a key word in the program, it will usually be indicated by an error message that is displayed during the programming process before the program is executed. These simple syntax errors are usually the first to be discovered.

Computer Software Question 26: What is beta testing? Answer: When writing a new computer program, after the program has been thoroughly tested, it is often sent out to be tested by others. If the program is not coded correctly to carry out a process such as mathematical calculations, it is known as an error in logic. Errors in program logic are usually discovered by actually using the program. It is very important to have other testers in addition to the programmer. These days, most complex programs go through a period of beta testing during which knowledgeable users try out the program before it is released for general use. Because programmers know how the program is supposed to work, they may never use the program in ways real users will. The beta testing period often reveals errors not only in program logic, but in problems within the human-computer interface (how users deal with the program's options). These kinds of problems have to do with ease-of-use issues; that is, during beta testing, users may find that methods of using the program employed by the programmer are too difficult or too confusing for those less knowledgeable about computers. It is as important to fix these types of problems in computer programs as it is to fix errors in the program's logic: both kinds of errors can mean that the program will not meet the user's needs.

Computer Software Question 27: What is end-user documentation? Answer: End-user documentation provides written information about how to use a computer program or device. Information about how to use the program must be written using language that can be clearly understood by untrained users. This type of documentation is often created by professional technical writers who have been trained to present technical information in clear, understandable steps. To create documentation for end users, the programmer usually works closely with the technical writer. It is the technical writer's job to understand the technical information presented by the programmer and translate that information into documentation that makes it easy for the end user to understand and use the program.

Computer Software Question 28: What is an internet (web) browser? Answer: The internet is stimulating a variety of new software tools that make online activity easier and more interesting. A new type of computer program known as an internet browser was created to access specially coded text files and pictures using the internet. It made it possible to move out of the text-only era of online access and into the realm of fonts, tables, color, and pictures. When you use an internet browser to access information from a remote computer, the browser quickly downloads the file to your computer. That frees the remote computer to respond to the next user. This method also gave third-party software developers a way to interact with that kind of data and they are developing new programs that enhance the internet experience. As a result, we are continually seeing improved sound, video, and 3-D interfaces with browser-displayed data from the internet.

Computer Software Question 29: What is word processing? Answer: Word processing programs are designed to make it easy to get ideas down on paper in an attractive, easy-to-read form. Word processing programs provide (1) a way to see the pages of a document on the computer screen before it is printed, (2) a way to edit text and prepare it for printing, (3) a way to save a document as a file on disk, and (4) a way to retrieve the file later.

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The term word processing also refers to the use of a computer program to prepare and print documents. A word processing program can be used to create letters, memos, and a variety of other types of documents. Word processing programs include features that are used to create, edit, format, save, and print documents. We can define a word-processed document as a text file that was created using a computerized word processing program. Such a file can be revised and reformatted as often as necessary. If the computer has a printer attached, the document can be printed as often as necessary. Today, if you are using a modern, full-featured word processing program, your documents can even include graphics. In addition to text, a modern word-processed document can contain special page-design elements such as lines and boxes and tables designed to make pages easier to read.

Computer Software Question 30: What is the cursor? Answer: Modern computer programs display either an on-screen cursor or an insertion point indicator. The cursor indicates the position at which the next character entered will be placed. The cursor may be a horizontal bar that is displayed beneath text characters or a rectangle that overlays each character. Most modern word processing programs use an insertion point indicator that is a vertical bar that is narrow enough to be displayed between characters. Both types are referred to as a "cursor."

Computer Software Question 31: What is a mouse? Answer: Modern computer programs support the use of a mouse, a computer device that can be easily rolled around on a flat surface to display an accompanying moving representation on the computer screen. Although the mouse itself is considered part of a computer system's hardware, it also requires a software component to control the position of the mouse pointer on the computer screen. Using a mouse, the cursor (refer to Computer Software Question #30 above: What is a cursor?) can be moved to a new position by repositioning the mouse pointer and clicking the mouse button (the left button on a multiple button mouse).

Computer Software Question 32: What is dragging? Answer: Modern computer programs support the use of a mouse as a pointing device. You can use the mouse to "drag" onscreen images to a new location or you can highlight text with the mouse pointer by holding down a button on the mouse as you "drag" it across the text.

Computer Software Question 33: What is the scroll bar and the scroll box? Answer: Using a mouse, you can move through an onscreen document by repeatedly clicking the mouse button while the pointer is positioned over the scroll bar that is displayed at the right side of the screen. An example of a word processing screen with a scroll bar is shown in the figure below.

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The Scroll Bar

You can also move to a new position in the document by dragging the scroll box (also illustrated above) up or down. "Dragging" means to position the mouse pointer over the scroll box, hold down one of the buttons on the mouse, and move the scroll box up or down. When you release the mouse button, a new section of text will be displayed that is associated with the area of the scroll bar where you placed the scroll box. You can also move the area of text displayed by positioning the mouse pointer over the scroll arrows at the top or bottom of the scroll bar (they are also illustrated above) and then clicking the mouse button. Each click on the scroll arrow moves the display one line. It may take some experimenting with the scroll bar, the scroll box, and the scroll arrows to learn how much each action changes the displayed position in the document.

Computer Software Question 34: What is a ruler line? Answer: Word processing programs provide a visual representation of the current margins, indents, and tab settings by displaying a ruler line. A ruler line is a horizontal line across the top of the screen which shows the margins, indents, and tab settings for the document. An example of a ruler line is illustrated below.

A Ruler Line

Notice that there are small pictures, known as icons, displayed along this type of ruler line. After highlighting areas of text (by holding down the mouse button and dragging the mouse pointer across the text area), you can reset the indents, tabs, and other formatting features by clicking on the ruler's icons with the mouse. For example, you could use the mouse to drag the left-indent marker to the right until it is positioned under the ruler's one-inch mark. As a result, the text that was highlighted would be indented one inch.

Computer Software Question 35: What is background printing? Answer: Background printing refers to using a computer program to print in the "background" while you continue to use the program.

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Computer Software Question 36: What is a macro? Answer: A macro is the software capability that provides a way to carry out a series of steps to replicate functions that are repeated often. You can usually start the stored keystroke sequence by pressing one special key or a combination of two keys.

Computer Software Question 37: What is desktop publishing? Answer: Desktop publishing programs are more than glorified word processing programs. Word processing programs were originally designed to produce simple documents like letters or memos. Today, even the most capable of our modern fullfeatured word processing programs are line oriented: that is, they make it easy to create and print documents that are composed of lines of print. But as personal computers and printers become more capable, users want to put more than simple lines of text into their documents. With today's computer systems, you can work with graphics as well as text, and while some of the newer word processing programs can import graphics files, they are not designed to work with lines of text that flow around or interact with graphics. That specialty area is the domain of desktop publishing programs. Desktop publishing programs are designed to help you work on page details and they attempt to show you as close a representation of what your printed pages will look like as possible. This is known as WYSIWYG (what-you-see-is-what-you-get). The term is pronounced as "wizzy-wig."

Computer Software Question 38: What is a spreadsheet? Answer: One of the most popular types of software in use today is the electronic spreadsheet. Electronic spreadsheets provide a way to analyze numerical data and display the results. Electronic spreadsheets are based on the traditional large paper worksheets that have long been used by accountants and financial analysts. These paper worksheets provided rows and columns that were used to organize data that was written in by hand. The electronic spreadsheet has many advantages over its paper counterpart. Data can be entered in columns and rows just as it can with the paper worksheet, but using the electronic spreadsheet, formulas can be added to the spreadsheet to perform arithmetic calculations on the data. You can deal with almost unlimited amounts of data using an electronic spreadsheet: many of today's modern spreadsheet programs will let you enter more than a billion or more separate data entries on one electronic worksheet. Today, spreadsheet programs are used in just about every type of organization. They are used for financial analysis by business managers, by small business owners to determine monthly profits, and by teachers to calculate student's grades. They are even used by individuals to keep track of the family checking account. The design of electronic spreadsheets makes it easy to analyze numerical data. Spreadsheet programs are frequently used in decision-making situations for studying data that represents a history of events or outcomes. They are also useful for analyzing "what if?" situations when you want to predict an outcome based on hypothetical data. An electronic spreadsheet program lets you enter data into rows and columns. The columns are usually identified by a letter and the rows by a number. The intersection of a column and a row is referred to as a cell. The cell address is the combination of the letter to indicate the column it is under and a number to indicate the row it is in. As indicated in the figure below, the cell that is at the intersection of column A and row 1 is referred to as cell A1. Cell A2 is at the intersection of column A and row 2. Cell B1 is at the intersection of column B and row 1. There are as many cells as there are intersections of rows and columns.

Spreadsheet Cells

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Spreadsheet programs provide for three different types of cell entries - labels, values, and formulas. A label is often entered on a spreadsheet to describe the data you are working with. A label can be any combination of letters and numbers. Labels can occupy any cell on the electronic worksheet. Most worksheets include many labels such as "costs" or "total." A value is a number. You can enter any value, positive or negative, with or without a decimal, in any spreadsheet cell. The cellbased design of the electronic spreadsheet makes it easy to enter data and then to make calculations based on the data. The real power of electronic spreadsheets is in the use of formulas. Formulas use cell identifiers, numbers, and arithmetic symbols to indicate the calculations that are to be carried out. Some spreadsheet programs require that you designate a formula by starting it with a special symbol such as an at sign (@) or an equal sign (=). A formula is used to carry out a mathematical function. Often formulas are used to carry out calculations on numbers that are stored in different cells. For example, a formula could be used to subtract the value in one cell from the value in another cell. Formulas can be simple or complex. They can be used to add or subtract, to multiply or divide, or you can create more complex formulas to calculate percentages and averages.

Computer Software Question 39: What is a computer graphic? Answer: Despite the well-known saying that a picture is worth a thousand words, the early computers had very little capability to create or display graphics; they were seen primarily as devices for storing and displaying information in the form of numbers and text. And they were designed to present each character on the computer's screen in a standard size; each number or letter occupied a standard space on the screen. Computers of that era generally displayed 80 characters across the screen in 25 rows. Although some special "graphics" characters were provided so that simple patterns could be drawn, the limitation of having only 2,000 spaces on the screen (80 across and 25 down), meant that when these types of graphics characters were used, they looked very rough, very squared off and "blocky." The ability to display graphics was greatly enhanced when computer screens were redesigned to display information not as preformed characters that took up an exact amount of space on the screen, but as a series of dots that could be turned on or off to create characters or patterns. The quality and smoothness of the image that can be created is directly related to the number of dots or picture elements (pixels) available. The more dots, the better the image. It didn't take long before new computer programs were designed to take advantage of this capability to present much more attractive on-screen graphics. There are five basic types of graphics software. • • • • •

Analysis graphics (also called business graphics): used to transform numerical data into a variety of charts, graphs, and diagrams. Presentation graphics: used to make computer-based presentations to others, such as to business groups. Computer-aided Design (CAD): used by engineers, architects, draftsmen, and other specialists to design and test a variety of products from clothes to aircraft. Creative paint, draw, and animation programs: used to create free-form drawings (bit-mapped, paint, vector or, draw, programs). Multimedia: used to bring together computerized information that is stored on other media in the form of graphics, sound, and video.

Computer Software Question 40: What is a database? Answer: Information stored by computer is known as data. A database is a collection of such data that is managed by computer methods. When data is stored using a computer, it must be organized into files using some type of data-management software. The type of management system used determines how the data is stored by the computer. For example, one type of computer program can be used to store data in a single file. Another type manages data that is saved in a group of related files. However the data is stored, data management software has two primary tasks, data storage and data retrieval. First, the computer and the data-management software must maintain the data securely in an understandable form. Second, the computerized system must provide an easy way to access the stored data. Most commonly, data is stored and retrieved based on one of the following three types of file organization: • • •

Sequential: files are retrieved in sequential order, one at a time; the order in which records are accessed can't be changed. Direct (also known as random or relative): accessed by their storage location or by their relative position in the file. Indexed: uses special indexes to locate stored data; each file includes an index to the data stored in it.

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Computer Software Question 41: What are the types of databases? Answer: Databases can be as many and as varied as there are people who use a computer to store information. However, they can be generally categorized according to their purpose. The most common types of databases are listed below: • • • •

Operational (also called a subject-area or transactional database): composed of information required for the overall operation of an organization (e.g. databases that include information on customers or personnel). Management (also called an informational database): a special compilation of strategic information from the organization's operational database (or from outside databases) that is used to support management decision making (e.g. trends, seasonal patterns, profitability patterns by product, geographical area, or market share). Distributed: In addition to an organization's main operational and management databases, individuals and departments within the organization may maintain their own databases (may be composed of specialized information downloaded from the organization's operational databases). Other: In addition to an organization's main databases, individuals and departments within the organization may maintain other databases such as specialized information about customers (credit ratings, buying patterns, preferences), text databases with specialized bibliographic data banks, or specialized databases with information such as graphics, sound, or video.

Computer Communications Questions Computer Communications Question 1: What is data communications? Answer: As more and more organizations rely on data that is stored electronically by computers, the need to transmit that data from one location to another also increases. The electronic transmission of data between locations is known as data communications. Data can be transmitted over phone lines, over a dedicated wire that connects two or more computers, or by wireless broadcast. Any type of data that can be stored using computers can also be transmitted between computers and computing devices. The communication can be between two microcomputers or between a microcomputer and a host computer such as a mainframe computer or a minicomputer. Today, computer communications serve a variety of needs, but most often we use communications to access data that is stored on another computer or to send data to another computer. That is what is happening when you access data using the largest network of them all, the internet: you are using your personal computer to communicate with another computer somewhere else on that network. The figure below illustrates how computers communicate.

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Computer Communications Systems

Computer Communications Question 2: What does upload and download refer to? Answer: The two main processes involved in computer communications are related to the transfer of data over a network. When you establish communications with another computer, you can download data (transfer data from a remote computer to your computer) or you can upload data (transfer data from your computer to a remote computer).

Computer Communications Question 3: What are the data communications options? Answer: When computer data is transmitted, the information is sent as a coded sequence that is decoded by the receiving device. The way this data is sent can vary. Therefore both of the communicating devices must be capable of encoding and decoding specific types of transmitted information. Most systems include special software that gives users a way to set up their data-receiving system to match the data-sending capabilities of another computer. The communications options that can be selected before transmissions can take place include signal type, data rate, data flow, and transmission method. These options are illustrated below.

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Data Flow

Coded information can be transmitted as either digital signals or analog signals. A system that uses digital signals sends information coded as a set of bits that can have one of two values. For example, a high pulse can carry the value of 1 and a low pulse can carry the value of 0. Before transmission, patterns of these 1 bits and 0 bits are grouped into bytes and encoded using standard computer coding methods. Systems that use analog signals are somewhat different. They send data as a wave pattern that varies continuously. Computers manage data in digital form. The telephone system, however, uses an analog signal type. Therefore, data that is sent over telephone lines must first be converted from the digital-type signal that is used within the computer system to the analog type that is used in the phone system. Since the rate at which information is transmitted over a channel varies, communicating computer devices must be capable of transmitting and receiving data at differing rates. Data rates are measured in bits per second or bps. Each type of channel has a maximum rate at which data can be transmitted, based on the type of media used in the channel and its design. Generally, channels with data rates less than 300 bps are referred to as narrowband. Rates of 300 to 9,600 bps are known as voiceband or voice-grade. The fastest channels are referred to as wideband or broadband. They are considered to be high-speed channels and can carry data at rates in the hundreds of thousands or even millions of bits-per-second. These high-speed channels require the use of special coaxial or fiber-optic cables. Data flow can be managed in one of three modes - simplex, half-duplex, or full-duplex. These three modes refer to the direction of the data flow. If you are using a communications system in the simplex mode, data can only travel through the channel in one direction. Since this mode restricts communication to a one-way transmission, either sending or receiving, it is not used very often for communications between two computers. Using the half-duplex mode, on the other hand, data can be sent in both directions, but not at the same time. Using the full-duplex mode, data can be transmitted in both directions at the same time. Systems with special types of wiring may be able to transmit data at higher speeds using the full-duplex mode. However, the half-duplex mode is more commonly used when transmitting data between two computers. Two methods are used to transmit characters over a channel. The asynchronous transmission method is used to send one character at a time. Since the transmission is synchronized by sending a start bit and a stop bit, data can be sent at any time. The synchronous transmission method is used to send blocks (groups) of characters in a timed sequence. Although this method requires more sophisticated communications equipment it can be used to send data at higher transmission rates. Two computer devices may be connected with no other devices on the line. This configuration is known as a point-to-point connection. This type of connection may be switched line, as used by the phone system. The phone company directs the call and establishes the connection. When the transmission is completed, the line is disconnected. Alternatively, the transmission may use a dedicated line which is never disconnected. Such lines can be private (owned by an organization) or they may be leased from another organization such as a phone company. However, often several computer devices will share the same channel. This is known as a multipoint or multidrop configuration. These systems are designed to establish communications between a number of devices and involve the use of some type of controller to manage the traffic of transmitted data on the shared line.

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These connection options are illustrated below.

Connection Options

Computer Communications Question 4: What is a modem? Answer: While computers manage data using digital methods that are expressed in binary form (either on or off), most communications devices use analog methods that deal with continuous patterns of sound frequencies. When computers transmit data using standard communications systems (such as the phone system), binary data must be converted to the analog signals used by that system. This is known as modulation. When such data is received by computers, it must be converted back again to its digital form. This is known as demodulation. A communications device that carries out both tasks is referred to as a modem (a contraction of the terms modulation and demodulation). A variety of modems are available. Direct-connect modems that connect the computer directly to the phone line are the most common. The types of modems that are used with microcomputers and ordinary phone lines transmit and receive data at speeds from 300 bps to 56,000 bps or more. Faster specialized modems are available that use special telephone hookups - such as Digital Subscriber Line (DSL) - or cable TV.

Computer Communications Question 5: What type of equipment do I need for computer communications? Answer: Simple communications between a computer and an attached device such as a printer can be accomplished without special communications hardware. However, when data is transmitted between incompatible devices or over longer distances, special devices are required. A multiplexer is a communications device that allows a number of computing devices to share the same communications line. Such devices are often used to take signals from several computing devices and combine them for transmission via a modem over high-speed channels. Another multiplexing device at the other end of the connection is used to split the signals back into their original components. Today, multiplexers are also playing another role in communications systems. Because data is often transmitted in a variety of different formats (known as protocols), many organizations use multiplexers that include a protocol converter. They provide a way for different types of computers using different types of transmission methods to communicate with each other. Such systems are often used to allow communications between microcomputers and mainframes. Multiplexing can also be done by a concentrator. This device, which may be a computer with special multiplexing capabilities, divides the data channel into separate channels. It allocates channel space as the need arises by providing internal storage of the transmitted data when traffic on the channel is high and then forwarding the data later when the channel is available. A concentrator can also have additional data-management capabilities making it more flexible than other multiplexers. These devices are illustrated in the figure below.

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Long Distance Communications Devices

Computer Communications Question 6: What are the communications network types? Answer: A communications network links computers and computing devices so they can share information but continue to operate independently. Such networks can link microcomputers, terminals, minicomputers, mainframe computers, and computing devices such as printers and storage devices. Networks have grown rapidly in popularity because they give users access to computers and devices beyond the computer they are currently using. There are two basic network types:

1. Local-Area Networks (LANs) are used to connect computers and computing devices that are located in the same general area - in one office, in one building, or in one group of buildings in the same organization. Examples include microcomputers connected together in a college lab, microcomputers in a sales office that are connected to a minicomputer that is on another floor of the same building, or a complex array of microcomputers, terminals, and printers in several different buildings that are connected to the organization's mainframe computer that is located in the basement of one of the buildings.

2. Wide-area networks ( WANs) are used to connect computers and computing devices that are separated by greater distances. This would include the internet: you might call it a very wide area network. But WANs do not have to be worldwide, like the internet; it could simply be an inventory-management network that ties together groups of microcomputers in local sales offices in many different cities. The local networks may in turn be interconnected with a set of company mainframes and minicomputers that are located at the company's headquarters in a yet another city. Additionally, networks are often categorized as either baseband or broadband. The difference lies in the speed of communications between stations on the network. Baseband networks are the slower of the two, usually using twisted-pair wire connections. Broadband networks use higher-speed, multiple channel cable connections that are capable of carrying a variety of signals including data, voice, and video.

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Networks can be established in a variety of configurations. Three typical configurations are: •

Star network: Typically used to connect a group of computers or terminals to a host computer that manages communications between computers and other devices on the network. One advantage to this configuration is that devices attached to the host computer are independent, that is, a malfunctioning network device does not affect other devices on the network. On the other hand, the entire network is dependent on the host computer that is at the center of the star configuration. If it fails ("goes down"), the network will be rendered inoperable.

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Bus network: Interconnects a group of computers and computing devices using one master cable. All communications share this one cable, known as the bus. There is no one host computer and these networks do not use a dedicated server. Instead, data is directed from one device to another when the sending device specifies the address of another device on the network. Bus networks are often used in organizations that store data in a variety of locations instead of one central location.

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Ring Network: A ring network is similar in function to a bus network. What is different is the fact that devices are connected in a circular configuration. Each computer is connected directly to two adjoining devices on the network. Since this configuration operates much like a bus network, it does not require a central host computer or server. On this type of network, before a device sends data, it first checks to be sure the network is inactive. Data is not transmitted until it receives information that no other device on the network is sending. This leads to some delays in data transmission. A special version of this network type, known as a token ring network, is designed to speed up data transmissions. With this type, a special code (known as a "token") is constantly sent between devices on the network. When a device on the network receives the token, it is free to transmit a message. This system is used to notify each device of an opportunity to transmit data and prevents two devices from transmitting at the same time.

The network configurations are illustrated below.

Network Configurations

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Computer Communications Question 7: What is a bridge? Is it the same as a gateway? Answer: A bridge is used to establish communications between two different networks. To enable such a bridge, a cabling connection is provided between two networks. When the two networks are of different types, special bridge software is used to facilitate communications between them. A gateway establishes communications between local-area networks and host computers. Often such gateways link microcomputers, minicomputers, and mainframes. In addition to the physical links between these systems, special software is required to manage the differences in data-transmissions methods. For example, microcomputers can use special terminal emulation software which can mimic the function of terminals that are generally used to communicate with mainframe computers.

Computer Communications Question 8: What exactly is the internet? Is it the same as the world wide web? Answer: The internet is the fulfillment of a dream that has been around for a long time. It has long been the hope of computer users that we could use our individual computers to communicate with others anywhere in the world. It has only been one short decade since the internet was established, but it is now estimated that more than 200 million people worldwide use the internet. And about half of all internet users go online daily, many of them to use email (electronic mail) (see the description of email in the next question below). The very wide area network that is the internet has been around since the late 1980s. Originally designed by the U.S. military to be a communications tool, it was soon adopted by other government organizations and then by many universities. In other words, it was originally a link between a group of local area networks that already existed in universities and in military establishments. The communication rates were limited by the slow modems of the time and the design of the system limited viewable data to text only. Despite the slow speed, the early users used it often to access information about government or university programs. You may ask: why was the original internet so slow, and why was it limited to text? To answer that question, you have to understand that the world wide web we use today was quite different from the internet we used back then. Today's new version of the internet is known as the world wide web or simply the web because its many varied connections resemble a spider's web. And it is based on a couple of key design differences that change the way we access data. First off, in the old internet, all of the information we read (remember, it was text only) was stored on remote computers. The text was stored on the distant host computer you were in contact with. Your computer monitor was like a window into that computer. As more and more remote users tried to read that text at the same time, the computer had to try to send out the information to each user before responding to the requests of the next user. The more people trying to download the information, the slower the response. But, because of today's new internet browser programs, today's internet is different (the two most popular browser programs in use today are Internet Explorer made by Microsoft and the browsers developed by Netscape). Today, when you read information (or look at pictures) that are coming from another computer somewhere out there on the internet, not only is the transfer of data much faster, but you are actually in contact with that remote computer for only a few brief moments. The information you are looking at on your computer screen has actually been retrieved from that remote computer and stored on your own computer; in other words, the information is quickly downloaded from that remote computer to the hard disk of the computer you are using. The text and pictures are still stored in files on the other computer, but using the new internet's system, you will also have a copy of those files on your computer. Using your internet browser, you can look at the information to your heart's content, leaving the original computer free to respond to the download requests of the next user. The files you download using this system are stored in special cache files somewhere on your hard disk. The downloaded files are regular text files, but they are coded in a special way to be understood by the internet browser program you are using. The coding, known as HTML (HyperText Markup Language) is used to "mark up" the text file that contains the information. For example, the word bold in this sentence should appear in bold when it is interpreted by your internet browser. That is because the word is preceded by a code to turn on the bold highlight and followed by another code to turn it off. The markup codes are interpreted by your browser as they are displayed on your computer. The HTML codes are also used to indicate pictures that will displayed (the pictures are also stored as files on the remote computer and they too are quickly downloaded to your computer. A special aspect of the HTML-based files used on the world wide web is that they can be coded to provide links to other files (pages) on the internet. Each file on the web has an address (known as its URL, or Uniform Resource Locator). It consists of an IP (internet protocol) number (or its associated domain name) which designates the specific computer where the file is stored. A URL can also include the name of folders and/or files. Take, for example, the following URL: http://www.easywindows.com/techbooks.html If you are connected to the internet and you click on the above internet address, it will take you to a page with technical book reviews. In the above URL, computerseasy.com is a domain name. Domain names have at least two parts: the part on the left

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which names the subdomain, the organization's name (in this case, computerseasy), and the part on the right, after the dot, which identifies the domain (in this case, com). New domains are periodically approved, but the initial domains in the US were com for commercial, edu for an educational institution, orgfor an organization, gov for a government location, mil for a military installation, and net for a network provider. The domain can also identify the country of origin (for example, ca for Canada or fr for France). The last part of the URL (in this case, techbooks.html) is the name of a file stored at that location. The file has been coded using the HTML coding system to tell your internet browser how to format the page as you view it. Computer communications require the use of two computers that are connected to the same network. The internet has expanded that concept to take advantage of the worldwide interconnection that is the backbone of the entire system. These large capacity wide area networks are accessed by individuals by registering with a company that will serve as the internet service provider (ISP). If you are accessing the internet from an office or a university computer lab, the computer you are using may already be connected. But it you are connecting from home, you may have to use a modem to "dial in" to your ISP's computers to establish the connection. Either way, as soon as you are connected, your computer becomes a part of the world's largest computer communications network, the world wide web.

Computer Communications Question 9: What is email? Answer: Email became a very popular way to communicate when many internet sites began to provide free email addresses. These free email addresses provide you with a unique email name and a way to store your messages at a fixed address that can be accessed from anywhere on the internet. Your friends can send you a message using your email name, followed by the at sign (@), followed by the name of the provider. For example: [email protected]. Messages sent to that location will be stored there under your email name until you use your special password to go in and retrieve them. Electronic mail ( e-mail) messages are transmitted by computer in the form of text. Instead of sending voice messages, you can type a message that will be stored in the receiver's name for later retrieval. An electronic mail system is a combination of computer hardware and software especially designed for message storage and retrieval. Each user makes contact with the e-mail system by using their own computer system. If the e-mail system is an "inhouse" system (operated by an organization for the exclusive use of the personnel in that organization), each user will be provided with software for use on microcomputers that are interconnected. The software will provide a way to establish contact with the e-mail management system. Today, users are often encouraged to use free email systems that can be accessed using their internet browsers. These e-mail systems are not maintained in-house; instead, business users contact the e-mail system via the internet. Whether you are using an in-house system or an internet-based e-mail system, you must have an identifying "logon" name (often called a user name). This user name is used when you connect to or "log onto" the system. The user name is also referred to whenever someone wants to leave you a message. When a message is sent, it is sent to a user's identifying name (or to a group of user names). When the user with that name logs onto the system, a list of messages that have been received is displayed. The user can then read the messages, save them as a file, or print them out on paper. Some systems can also send and receive files that have been "attached" to the email message.

Computer Communications Question 10: What is a fax? Answer: A FAX machine can receive a copy of any type of document at any time of the day or night. Using standard phone lines, the fax machine - which is based on modern computer telecommunications technology - can send a copy of a document to another fax machine anywhere in the world. When a document is fed into a fax machine, it is scanned, digitized, and sent to another fax machine. The receiving fax machine must be attached to a phone line that can be accessed by dialing the number of that line. When the phone number of that line is dialed and an appropriate audio signal is recognized, a connection is established between the two fax machines. The receiving fax machine receives a digitized version of the patterns that are on the document in the sending fax machine and, as the digitized pattern is received, the receiving machine prints out the copy. Today, a microcomputer can also be used to send computer files to fax machines. Special software is used to send the dialing tones and the proper signals that will be recognized by a fax machine. Once the connection is established, the user can specify a computer file to send. The file will be received and printed out by a fax machine just as if it were a copy of a document sent

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from another fax machine. Usually the document that is printed by the fax machine will be of higher quality than a normal fax because the document didn't have to be scanned and digitized before sending. A computer can also be used to receive a faxed document by mimicking the kinds of signals sent out by a fax machine. The received document is stored by the computer as a file which can be modified and printed out later. In addition, a number of internet sites now provide fax receiving and forwarding services. Using these services, businesses can manage their fax traffic virtually, that is, without the need to purchase and maintain actual fax machines.

Computer Communications Question 11: What is Voice Mail? Answer: Many organizations are now using special computerized voice mail telephone systems that allow callers to leave messages. The voice message is saved digitally and can be retrieved from any phone by the owner of the voice "mailbox." Some sophisticated systems provide a way to record a response, to forward messages, and to send messages to groups, or even to cell phones and wireless handheld devices.

Computer Communications Question 12: What is a computer bulletin board? Answer: Computer bulletin boards were popular before the emergence of the internet, but they are still used by many businesses. They are special hardware/software systems used to store computer files for remote access. Organizations often establish computer bulletin boards to store files regarding products. These computer files may provide information to customers about using or repairing products or they may provide ordering information. Computer bulletin boards are also used to store computer files that provide technical information or sales information to employees of the corporation. Users of the bulletin board access it by dialing into the bulletin board's phone line using their own computer system and modem. Once communications have been established between the two computers, a file can be sent to the bulletin board (uploaded), or retrieved from the bulletin board (downloaded) so it can be saved to a storage device attached to the user's computer.

Computer Communications Question 13: What is computer teleconferencing? Answer: Sophisticated telephone systems have long been able to connect several callers to one line. This method is often used in business when not everyone can be physically present for a meeting. But today's computer technologies are expanding the capabilities of this sort of teleconferencing. For example, a business group might meet in a location that has video cameras to record the meeting for broadcast to others who cannot attend. Those who cannot attend can watch the broadcast and call in on the telephone with comments. Some businesses are expanding on this basic capability by establishing video cameras and broadcast capabilities in several locations. That way, business meetings can be held simultaneously in these locations, with the proceedings broadcast to television sets at each site. Today video signals can be digitized and stored as computer files. This means that these video files can be quickly sent to other computer systems using standard phone lines (images can be sent even faster if dedicated fiber-optic lines are installed between sites). Using these methods, teleconferencing can be conducted by recording and sending digitized video images between computers at different meeting sites using the same type of interlinked phone lines that are used for telephone conference calls. As this technology improves, internet-based system are likely to make teleconferencing even more popular. The ability to see other people who are participating in the teleconference may become one of the internet's most important capabilities for business users. This capability becomes especially important at meetings when participants have charts or physical objects to show to the participants at other sites. These methods of storing video images as computer files also make it possible to send and receive video e-mail using a computerized system similar to that described in the electronic mail section above.

Computer Communications Question 14: What is file transfer protocol (FTP)? Answer: File Transfer Protocol ( FTP) provides a way to upload files to remote computers (FTP sites) or to download files from them. Today, FTP programs are commonly used to send information to remote web servers or to retrieve information from them.

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