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This chapter presents a broad survey of concepts and terminology related to computers. The idea of computer literacy is introduced. You discover what a computer is and what it does. You learn about the components of a computer, the power of computers, computer software, and networks and the Internet. Categories of computers are identified, including personal computers, minicomputers, mainframe computers, and supercomputers.
You discover how people employ computers, from home users to large business users. Finally, you learn how people use computers to provide information. Reading and understanding the material in this chapter should help you better understand these topics as they are presented in more detail in the following chapters.
Explain the importance of computer literacy
Computers have touched every part of our lives: the way we work, the way we learn, the way we live, even the way we play. It almost is impossible to go through a single day without encountering a computer, a device dependent on a computer, information produced by a computer, or a word that was introduced or whose meaning has changed with the advent of computers. Because of the significance of computers in today’s world, it is important to be computer literate. Being computer literate means you have knowledge and understanding of computers and their uses.
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Define the term computer
A computer is an electronic machine, operating under the control of instructions stored in its own memory, that can accept data, manipulate the data according to specified rules, produce results, and store the results for future use. Computers process data to create information. Data is a collection of raw unprocessed facts, figures, and symbols. Information is data that is organized, meaningful, and useful. To process data into information, a computer uses hardware and software. Hardware is the electric, electronic, and mechanical equipment that makes up a computer. Software is the series of instructions that tells the hardware how to perform tasks.
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Identify the components of a computer
Computer hardware components include input devices, output devices, a system unit, storage devices, and communications devices. An input device is any hardware component that allows a user to enter data and instructions into a computer. Six commonly used input devices are the keyboard, mouse, microphone, scanner, digital camera, and PC camera. An output device is any hardware component that can convey information to a user. Three commonly used output devices are a printer, a monitor, and speakers.
The system unit is a box-like case made from metal or plastic that protects the internal electronic components of the computer from damage. The system unit contains the central processing unit and memory. The central processing unit (CPU) is the electronic device that interprets and carries out the basic instructions that operate the computer. Memory is a temporary holding place for data and instructions.
A storage device records and retrieves data to and from a storage medium. Six common storage devices are a floppy disk drive, a Zip® drive, a hard disk drive, a CD-ROM drive, a CD-RW drive, a DVD-ROM drive, and a DVD+RW drive. A communications device enables computer users to communicate and exchange items such as data, instructions, and information with another computer. A modem is a communications device that enables computers to communicate usually via telephone lines or cable.
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Explain why a computer is a powerful tool
A computer is a powerful tool because it is able to perform the information processing cycle operations (input, process, output, and storage) with amazing speed, reliability, and accuracy; store huge amounts of data and information; and communicate with other computers. Computers allow users to generate correct information quickly, hold the information so it is available at any time, and share the information with other computer users.
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Differentiate among the various types of software
There are two categories of computer software: system software and application software. System software consists of the programs that control the operations of a computer and its devices. Two types of system software are the operating system and utility programs. An operating system (OS) coordinates all activities among hardware devices and contains instructions that allow you to run application software. A utility program performs specific tasks, usually related to managing a computer, its devices, or its programs. You interact with software through its user interface.
Application software consists of programs that perform specific tasks for users. Popular application software includes word processing software, spreadsheet software, database software, and presentation graphics software. Application software can be packaged software (copyrighted software that meets the needs of a variety of users), custom software (tailor-made software developed at a user’s request), freeware (copyrighted software provided at no cost), public-domain software (software donated for public use with no copyright restrictions), or shareware (copyrighted software distributed free for a trial period).
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Explain the purpose of a network
A network is a collection of computers and devices connected together via communications devices, such as a modem, and communications media, such as cables, telephone lines, cellular radio, and satellites. Networks allow users to share resources, such as hardware devices, software devices, data, and information. Most business computers are networked, either by a local area network (LAN) in a limited geographic area or by a wide area network (WAN) in a large geographical area.
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Discuss the uses of the Internet and the World Wide Web
The world’s largest network is the Internet, which is a worldwide collection of networks that links together millions of businesses, government agencies, educational institutions, and individuals. Users connect to the Internet to send messages, access information, shop for goods and services, meet or converse with other users, and access sources of entertainment and leisure. Most users connect to the Internet through an Internet service provider (ISP) or an online service provider (OSP). The World Wide Web is a popular segment of the Internet that contains billions of documents called Web pages. These documents can contain text, graphics, sound, video, and built-in connections, or links, to other Web pages stored on computers throughout the world.
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Describe the categories of computers and their uses
The six major categories of computers are personal computers, handheld computers, Internet appliances, mid-range servers, mainframes, and supercomputers. These categories are based on differences in size, speed, processing capabilities, and price. A personal computer can perform all of its input, processing, output, and storage activities by itself. Personal computers include desktop computers and notebook computers. A desktop computer is designed so the system unit, input devices, output devices, and any other devices fit entirely on or under a desk or table. Variations of desktop computers include tower models (computers with tall and narrow system units that can sit vertically on the floor), all-in-one computers (less expensive computers that combine the monitor and system unit into a single device), and workstations (more expensive and powerful computers designed for work that requires intense calculation and graphics capabilities).
A notebook computer is a portable personal computer small enough fit on your lap. Notebook and desktop computers are used at home or in the office to perform application software-related tasks or to access the Internet. A handheld computer is a small computer that fits in your hand. Handheld computers can perform specific, industry-related functions, or can be general-purpose.
A PDA (personal digital assistant) is a handheld computer that provides personal organizer functions, such as a calendar, appointment book, and notepad. An Internet appliance is a computer with limited functionality whose main purpose is to connect to the Internet from home. A mid-range server is more powerful and larger than a workstation computer. Users typically access a mid-range server through a personal computer or a terminal, which is a device with a monitor and a keyboard that usually has no stand-alone processing power.
A mainframe is a large, expensive, very powerful computer that can handle hundreds or thousands of connected users simultaneously. A supercomputer is the fastest, most powerful, and most expensive category of computer.
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Identify the various types of computer users
Computer users can be divided into five categories: home user, small office/home office users, mobile users, large business users, and power users. A home user spends time on the computer for personal and business communications, budgeting and personal financial management, entertainment, and Web access. A small office/home office (SOHO) user includes any company with fewer than 50 employees, as well as self-employed people that work out of their home. A mobile user travels to and from a main office or school to conduct business, communicate, or do homework. A large business user works for a company that has a large number of employees and computers usually connected to a network. The power user – such as an engineer, architect, or desktop publisher – typically works with multimedia, which combines several media elements into one application, and requires the capabilities of a workstation or other powerful computer.
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Understand how a user can be a Web publisher
In addition to being a recipient of information, Internet users have the ability to provide information to other connected users around the world. Users can create a Web page with word processing software or with Web page authoring software. Publishing a Web page is the process of making it available on the Internet.
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|Expand Your Knowledge|
Here you will find additional information that will expand and enhance your knowledge beyond that contained in your textbook. Compare this information to what may be provided in a traditional classroom by your instructor or peers.
It is difficult to think of a field in which computers are not used. In addition to general-purpose computers, special-purpose computers are used in everything from automobiles to electric razors. Consider how computers have influenced our daily lives, both positively and negatively. (“To err is human, but to really foul things up requires a computer.” – Anonymous, from a BBC Radio broadcast.) List ways in which computers are being used today. What is the most common use? What is the most unusual use? As a result of the expanding use of computers, in 1986 Florida became the first state to demand computer literacy of all students by grade 12.
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Although computers are thought of as a relatively recent innovation, the term computer has a long history. Prior to 1940, “computer” was a job title that referred to anyone performing calculations.
Consider how data is different from information. Data is processed into information. Clifford Stoll – lecturer, computer security expert, and author of Silicon Snake Oil: Second Thoughts on the Information Superhighway – notes a wide gap between data and information. Stoll insists that information has a pedigree, or lineage. Its source is known, whether by a respected professor or a seventh grader. “The Internet has great gobs of data,” Stoll maintains, “and little, little information.”
The first three operations in the information processing cycle — input, process, and output — are performed to process data into information, while the fourth operation — storage — refers to a computer’s electronic reservoir capability. Think about how we perform each phase in the information processing cycle in the “human computer” (i.e., the human brain) while completing a common task, such as learning a telephone number.
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Different types of input devices are designed to transmit different types of data or to transmit data in different ways. Think of other input devices (joysticks, scanners, digital cameras, and so on) and the different types of data they transmit or the different ways they transmit data.
Because it is more lasting than output from a monitor or speaker, the printer’s output often is called hard copy. Think of other output devices with which you are familiar (data projectors, computer output microfilm, and so on).
Some computer components are considered internal, while others are considered external. External components are called peripherals. Input, output, and communications devices often are peripheral devices.
The difference between the temporary character of memory and permanent nature of storage will be made painfully clear the first time you experience a power failure while working on a computer. Think of other examples of storage devices (magnetic tape, PC Cards, and so on).
The capability to communicate may be one of the most significant factors influencing how computers are used now and in the future.
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In one billionth of a second, an electronic signal travels almost 12 inches. This means that today’s supercomputer (the fastest, most powerful, and most expensive category of computers) can perform 1.8 trillion operations per second. If a person did one arithmetic operation a second without stopping, it would take more than 31,000 years to perform the number of operations a supercomputer can do in one second. Researchers predict that one day computer speed will be measured in exaflops, or one quintillion (1 x 1018) calculations per second.
The reliability of computer components often is measured in MTBF (mean time between failure, in hours). A typical component might be rated 10,000 MTBF.
Although the term “computer error” is widespread, most computer errors can be traced to human mistakes. Consider instances of computer error with which you are familiar. How might human blunders have resulted in the computer error? Why are people apt to blame computers?
Supercomputers have more than 600 gigabytes of memory, meaning that they can store more than 600 billion letters, numbers, and special characters, and have 2 terabytes (2 trillion bytes) of disk space. Equally important is the speed at which data can be retrieved, processed, and stored again.
Connected computers can share each operation in the information processing cycle. To recognize the value of communication, imagine trying to solve a problem individually, and then trying to solve the same problem with the assistance of several classmates.
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The difference between computer hardware and computer software is important. A 3˝-inch floppy disk is hardware; however the programs stored on it are software. Programs or software, like data, are input into the computer.
Because you interact with it directly, you may be more consciously aware of application software than system software. Remember that system software determines how you interact with application software. Popular operating systems include DOS (Disk Operating System), Windows 3.x (technically, not an operating system but an operating environment that makes DOS easier to use), Windows 95, Windows 98, Windows 2000, Windows XP, Mac OS, OS/2, UNIX, Linux (rhymes with cynics), and NetWare. DOS was developed by Microsoft for IBM personal computers. DOS started Microsoft’s climb to the top of the software world -- at one time, versions of DOS were used worldwide by more than 100 million people. DOS has a command-line interface, meaning that people have to memorize and type instructions.
Today, operating systems with a graphical user interface, such as Microsoft’s Windows, are far more popular.
Most application software packages are designed to be used with specific operating systems. Much of the software with which you are familiar is packaged software. Because of their complexity, most software programs are written by teams of programmers working together. Just as people understand a variety of spoken languages (English, French, Chinese, and so on), computers recognize a number of programming languages.
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A network with which you might be familiar is the school computer lab. Consider resources that can be shared on a network. For example, the school computer lab may share a single printer. Think of advantages of sharing resources. Why are most business computers part of a network?
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Estimates claim that more than 50 percent of U.S. homes are connected to the Internet, and more than 13 million do so through an online service provider. Although the growth rate of the Internet and online services has slowed from a peak of more than 140 percent in 1994-95, the growth rate still is around 20 percent annually. Surveys show the number of Web site visitors continues to expand rapidly, practically doubling every year. Interestingly, surveys show that teenage boys and girls are accessing the Internet for different reasons. While boys seem to focus on entertainment, girls use the Internet more for schoolwork and chat.
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In addition to differences in size, speed, processing capabilities, and price, other factors, such as the size of main memory and number of peripheral devices, also can be considered when categorizing computers. Rapid changes in technology make it difficult to define categories precisely. As a rule of thumb, today’s PCs have about as much memory and processing power as the mainframes of a decade ago.
Think of personal computers with which you are familiar. How is the computer used? What factors influence the choice of a personal computer? In addition to such obvious considerations as processing speed and amount of memory, less apparent factors, such as available software or even the computer’s “footprint” (the amount of space it occupies on the work surface) also may be important. A desktop computer monitor often is placed on top of the system unit case. This sometimes can be an ergonomic problem, forcing users to look up. Server computers often are used in academic environments. What features of server computers would make them particularly attractive to schools? In today’s mobile society, notebook computers have become indispensable tools. Since 1993, sales of notebook, and smaller computers have rivaled sales of larger systems, partly because of their enhanced capabilities and increased use by field sales forces. The capabilities of handheld computers also continue to expand. Visor, a new handheld computer from Handspring, is an electronic organizer but also offers video games, a cell phone, a modem, an MP3 player, and a two-way pager. Called the “Swiss Army knife of handheld computers,” Visor uses the Palm operating system, which is the same operating system used by the Palm Pilot, a popular handheld computer from 3Com, and is available for about $200.
The growing movement toward decentralization in business, coupled with the increasing power of mid-range servers, has led to a recent trend away from mainframe computers and toward mid-range servers. What advantages might mid-range servers have over mainframe computers for a business?
Organizations that deal with huge, constantly changing collections of data accessed simultaneously by many users, such as banks, insurance companies, universities, and government agencies, often use mainframe computers. Despite this, mainframe sales are declining approximately 10 percent per year.
One of the most important features of supercomputers is their capability to create complex, three-dimensional images almost instantaneously. Television networks often use supercomputers to generate complicated images and then give viewers the sense of “going through” the image. Due to their size and expense, only large businesses and government agencies use supercomputers. IBM’s Option Blue supercomputer was used by the Department of Energy to simulate nuclear explosions, allowing the effects of aging and adverse conditions on nuclear weapons to be explored without underground detonations.
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Types of Computer Users
A major concern related to the home user is the digital divide, which is the idea that the people of the world can be separated into two distinct groups: those that have access to technology with the ability to use it and those that do not have access to technology or are without the ability to use it. Recent reports suggest that the digital divide exists on several levels:
Individuals in higher income levels have greater access to the Internet than people in lower levels, and the gap may be growing.
African-Americans earning less than $40,000 are less than half as likely to own a computer as whites in the same income group.
Women are under-represented in today’s computer classes and technology jobs.
A number of efforts are being made to narrow the digital divide.
Networks have changed the face of both small and large business. In the 1970s, executives usually worked with monthly reports; in the 1980s, they used weekly reports; today, daily or even hourly reports are available. How have computers affected the efficiency of businesses? What impact have computers had on the “interpersonal” side of business (i.e., employee and customer relationships)? How have computers changed people’s jobs? Have computers cost any people their jobs?
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With today’s Web page authoring software, children as young as 10 years old, and sometimes younger, can create and publish their own Web pages. If you created a Web page, what type of information would you provide? Why? Would you be interested in seeing someone else’s Web page? Why or why not? If you have created a Web page, what type of software did you use? What was the most difficult part of creating your Web page?
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