Using a ll its parts together, a computer converts data into information by performing various actions on the data. For example, a computer might perform a mathematical operation on two numbers, then display the result. Or the computer might perform a logical operation such as comparing two numbers, then display that result. These operations are part of a process called the information processing cycle, which is a set of steps the computer follows to receive data, process the data according to instructions from a program, display the resulting information to the user, and store the results

The information processing cycle has four parts, and each part involves one or more specific components of the computer:

1.Input

2.Processing

3.Output

4.Storage

» Input. During this part of the cycle, the computer accepts data from some source, such as the user or a program, for processing.

» Processing. During this part of the cycle, the computer’s processing components perform actions on the data, based on instructions from the user or a program.

» Output. Here, the computer may be required to display the results of its processing. For example, the results may appear as text, numbers, or a graphic on the computer’s screen or as sounds from its speaker. The computer also can send output to a printer or transfer the output to another computer

through a network or the Internet. Output is an optional step in the information processing cycle but may be ordered by the user or program.

» Storage. In this step, the computer permanently stores the results of its processing on a disk, tape, or some other kind of storage medium. As with output, storage is optional and may not always be required by the user or program.

As you saw in  previous, computers come in many varieties, from the tiny computers built into household appliances, to the astounding supercomputers that have helped scientists map the human genome. But no matter how big it is or how it is used, every computer is part of a system. A complete computer system consists of four parts :

» Hardware

» Software

» Data

» User

Hardware

The mechanical devices that make up the computer are called hardware. Hardware is any part of the computer you can touch (see Figure 1B.2). A computer’s hardware consists o f interconnected electronic devices that you can use to control the computer’s operation, input, and output. (The generic term device refers to any piece of hardware.)

Software

Software is a set of instructions that makes the computer perform tasks. In other words, software tells the computer what to do. (The term program refers to any piece of software.) Some programs exist primarily for the computer's use to help ir perform tasks and manage its own resources. Other types of programs exist for the user, enabling him or her to perform tasks such as creating documents. Thousands of different software programs arc available for use on personal computers

Data

Data consist of individual facts or pieces of information that by themselves may not make much sense to a person. A computer’s primary job is to process these tiny pieces of data in various ways, converting them into useful information. For example, if you saw the average highway mileages of six different cars, a ll the different pieces o f data might not mean much to you. However; if someone created a chart from the data that visually compared and ranked the vehicles’ mileages, you could probably make sense of it at a glance (see Figure ). This is one example of data being processed into useful information. 

User

A visit to any software store reveals a (toying variety of products. People are the computer operators, also known as users. It can be argued that some computer systems are complete

without a person’s involvement; however, no computer is totally autonomous. Even if a computer can do its job without a person sitting in front of it, people still design, build, program, and repair computer systems. This lack of autonomy is especially true of personal computer systems, which arc the focus of this book and are designed specifically for use by people.

People can list countless reasons for the importance of computers. For someone with a disability, for example, a computer may offer freedom to communicate, learn, or work without leaving home. For a sales professional, a PC may mean the ability to communicate whenever necessary, to track leads, and to manage an ever-changing schedule. For a researcher, a computer may be the workhorse that docs painstaking and time-consuming calculations. But if you took a ll the benefits that people derive from computers, mixed them together, and distilled them down into a single element, what would you have?

The answer is simple: information Computers are important because information is so essential to our lives. And information is more than the stuff you see and hear on television. Facts in a textbook or an encyclopedia are information, but only one kind. Mathematical formulas and their results arc information, too, as arc the plans for a building or the recipe for a cake. Pictures, songs, addresses, games, menus, shopping lists, resumes the list goes on and on. All these things and many others can be thought of as information, and they can all be stored and processed by computers. (Actually,If you work in one place and need to perform various tasks, a desktop computer is the best choice. Choose a desktop computer if you want to:

» Work with Graphics-Intensive or Desktop Publishing Applications. Complex graphics and page-layout programs require a great deal of system resources, and a desktop system’s large monitor reduces eye fatigue.

» Design or Use Multimedia Products. Even though many portable computers have multimedia features, you can get the most for your money with a desktop system.Large screens make multimedia programs easier to see, and stereo-style speakers optimize sound quality.

» Set Up Complex Hardware Configurations. A desktop computer can support multiple peripherals including printers, sound and video sources, and various external devices at the same time. If you want to swap components, or perform other configuration tasks, a desktop system with provide many options. computers store these things as data, not as information, but you’ll learn the difference between the two later in the book.) So, when you consider the importance of computers in our society, think instead about the importance o f information. As tools for working with information, and for creating new information, computers may be one of humanity's most important creations.

Home

In many American homes, the family computer is nearly as important as the refrigerator

or the washing machine. People cannot imagine living without it. In fact, a growing number of families have multiple PCs in their homes; in most cases, at least one of those computers has an Internet connection. Why do home users need

their computers?

» Communications. Electronic mail (e-mail) continues to be the most popular use for home computers, because it allows family members to communicate with one another and to stay in contact with friends and coworkers.

» Business Work Done at Home. Thanks to computers and Internet connections, more people arc working from home than ever before. It is possible for many users to connect to their employer’s network from home and do work that could not be done during regular business hours. Computers also are making it easier for people to start their own home-based businesses.

» School work: Today’s students are increasingly reliant on computers, and not just as a replacement for typewriters. The Internet is replacing printed books as a reference tool, and easy-to-use software makes it possible for even young users to create polished documents.

» Entertainment. If you haw ever played a computer game, you know how enjoyable they can be. For this reason, the computer has replaced the television as the entertainment medium of choice for many people. As computer; audio, video, and broadcast technologies converge, the computer w ill someday be an essential component o f any home entertainment center.

» Finances.'Computers and personal finance software can make balancing your checkbook an enjoyable.experience. Well, almost. At any rate, they certainly make it easier, and home users rely on their PCs for bill paying, shopping, investing, and other financial chores .

Education

More and more schools are adding computer technology to their curricula, not only teaching pure computer skills, but incorporating those skills into other  classes. Students may be required to use a drawing program, for example, to draw a plan of the Alamo for a history class, or use spreadsheet software to analyze voter turnouts during the last century’s presidential elections. Educators see computer technology as an essential learning requirement for all students, starting as early as preschool. Even now, basic computing skills such as keyboarding are being taught in elementary school dasscs . In the near future, high school graduates w ill enter college not only with a general

diploma, but with a certification that proves their skills in some area of computing, such as networking or programming.

Small Business

Many of today’s successful small companies simply could not exist without computer  technology. Each year, hundreds o f thousands of individuals launch businesses based from their homes or in small-office locations. They rely on inexpensive computers and software not only to perform basic work functions, but to manage and grow their companies.These tools enable business owners to handle tasks such as daily accounting chores, inventory management, marketing, payroll, and many others that once required the hiring of outside specialists .

As a result, small businesses bccome more self-sufficient and reduce their operating expenses.

Industry

Today, enterprises use different kinds of computers in many combinations. A corporate headquarters may have a standard PC-based network, for example, but its production facilities may use computer controlled robotics to manufacture products. Here arc just a few ways computers are applied to industry:

» Design. Nearly any company that designs and makes products can use a computer-aided design or computer-aided manufacturing system in their creation.

» Shipping. Freight companies need computers to manage the thousands of ships, planes, trains, and trucks that are moving goods at any given moment. In addition to tracking vehicle locations and contents, computers can manage maintenance, driver schedules, invoices and billing, and many other activities.

» Process Control. Modem assembly lines can be massive, complex systems, and a breakdown at one point can cause chaos throughout a company. So phisricatcd process-control systems can oversee output, check the speed at which a machine runs, manage conveyance systems, and look at parts inventories, with very little human interaction.

Government

Not only are governments big consumers of technology, but they help to develop it as well.

“ Presenting the Internet," the U.S. government played a key role in developing the Internet.Similarly, NASA has been involved in the development of computer technologies of all sorts. Today, computers play a crucial part in nearly every government agency:

» Population. The U.S. Census Bureau was one o f the first organizations to use computer technology, recruiting me chanical computers known as “ difference engines" to assist in tallying the American population in the early 20th century.

»Taxes. Can you imagine trying to calculate Americans’ tax bills without the help of computers? Neither could the Internal Revenue Service. In fact, the IR S now encourages taxpayers to file their tax returns online, via the Internet. Military. Some of the world's most sophisticated computer technology has been developed primarily for use by the military. In fact, some of the earliest digital computers were created for such purposes as calculating the trajectory of missiles. Today, from payroll management to weapons control, the armed forces use the widest array of computer hardware and software imaginable.

Police. When it comes to stocking their crime-fighting arsenals, many police forces consider computers to be just as important as guns and ammunition. Today’s police cruisers are equipped with laptop computers and wireless Internet connections that enable officers to search for information on criminals, crime scenes, procedures, and other kinds of

Health Care

Pay a visit to your family doctor or the local hospital, and you'll find yourself surrounded by computerized equipment of all kinds. Computers, in fact, arc making health care more efficient and accurate while helping providers bring down costs. Many different health care procedures now involve computers, from ultrasound and magnetic resonance imaging, to laser eye surgery and fetal monitoring .

Surgeons now can use robotic surgical devices to perform delicate operations, and even to conduct surgeries remotely. New virtual-reality technologies are being used to train new surgeons in cutting-edge techniques, without cutting an actual patient.

But not all medical computers arc so hightech. Clinics and hospitals use standard computers to manage schedules, maintain patient records, and perform billings. Many transactions between physicians, insurance companies, and pharmacies are conducted by computers, saving health care workers time to devote to more important tasks generation of PC possibilities. PCs by then had evolved sophisticated graphical user interfaces and detailed displays.

Combining the CD's digital sound with these visual technologies went a long way toward making computer experiences interactive something that previously only people and unpopular toys had been. The PC world increasingly became a place where many other worlds met particularly the varied worlds of information and entertainment an interactive, multimedia world.

This is today's world. It's a world in which we expect our to toot, whistle, plunk, and boom; to speak to us an to listen when we dictate; to remember what we forget us so we will forget. Having spent much of actually getting that a technology company must  produce something useful in order to realize a profit the computing world turned back to substance with a renewed focus on the PC as the center of media. As I write this, a new generation of media PCs is appearing on the market. These systems can blend virtually every media technology in existence into a seamless, single experience. The traditional capabilities of PCs, CD and DVD players, DVD recorders, televisions, VCRs, surround-sound music systems can all be provided by one device—or two, if you add the possibilities of printing and film. What's really new about these systems is their power—practical video editing has been the private world of a wealthy few until the latest advances in processor, memoiy, and massive storage all came together in affordable systems that put these capabilities into homes and small offices.

This means that you can produce your own DVD movies with just a consumer video camera and a media PC (fast talking agents are now entirely optional). In a band? Record and distribute albums of your music directly or through a Web site that software almost automatically designs for you.

Paint? Create your own online gallery. Write? Self-publish on demand while promoting your creations through an existing on the bookseller. Watt Disney said, “If you can dream it you can do it. Technology has helped prove him right Today the "you" who can “do it” means more people from more cultures and backgrounds than ever before.

How important are computers to our society? This is a big question for us. People often talk in fantastic terms about computers and their impact on our lives. You probably have heard or read expressions such as “ computers have changed our world" or “computers have changed the way we do everythings” many times. Such statements may strike you as exaggerations, and sometimes they are. But if you stop and really think about the effect computers have had on our daily lives, you still may be astonished.

One way to gauge the impact of computers is to consider the impact of other inventions. Can you imagine, for instance, the many ways in which American life changed after the introduction of the automobile .

Consider a few examples:

» Because of the cat: people were able to travel farther and cheaper than ever before, and this created huge opportunities for businesses to meet the needs of the traveling public.

» Because vehicles could be mass-produced, the nature of manufacturing and industry changed and throngs of people began working on assembly lines.

» Because of road development, suburbs became a feasible way for people to live dose to a duty without actually living in one.

» Because of car travel, motels, restaurants, and shopping centers sprang up in piaccs where there had previously been nothing could envision how the alterable world change. 

» Today, the same  true (computers and other  technology).Buying a computer is a lot like buying a car because there are so many models and options from which to choose! Before deciding which model is best for you, identify the type of work for which you want to use the computer. Depending on your job, you may need to use a computer on a limited basis. A handheld system is great if you want to Manage Your Schedule on a Daily or Hourly Basis.

» Handheld computers are popular for their calendar and schedule management capabilities, which enable you to set appointments, track projects, and record special events.

» Manage a List of Contacts. If you need to stay in touch with many people and travel frequently, personal digital assistants provide contact management features.

» Make Notes on the Fly. Some PDAs feature small keyboards, which are handy for tapping out quick notes. Others feature pens, which enable the user to 'w rite" directly on the display screen. Many newer handheld systems also provide a built-in microphone, so you can record notes digitally.

» Send Faxes and E-Mall. Most popular handheld PCs have fax and e-mail capabilities and a port that lets them exchange data with a PC. If your job requires you to travel but you still need a fullfeatured computer, you may consider using a laptop or notebook computer. This option is the best choice if you want to carry Your Data with You. 

» If you need to make presentations on the road or keep up with daily work while traveling, portable PCs are ideal laptop systems offer as much RAM and storage capacity as desktop models. Many portables have built-in CD-ROM or DVD drives; others accept plug-in CD-ROM, DVD, and hard drives, which can greatly increase their capacity.

»Be Able to Work Anywhere. Portable PCs run on either rechargeable batteries or standard current communicate and Share Data from Any Location. Most portable computers have built-in modems or slots for plugging in a modem.

These systems can process huge amounts of data, and the fastest super-computers can perform more than one trillion calculations per second. Some supercomputers can house thousands of processors. Supercomputers are ideal for handling large and highly

Today we will know about electronic voting system or Computer Voting system and its good or bad side.
The dispute over electronic voting is as heated as a debate between presidential candidates. The risks versus the benefits are discussed, investigated, and argued. But what are the facts that lie beneath the fuss? The key function of an electronic voting system is to obtain voter preferences and report them reliably and accurately. Some assert that electronic systems are safer than other methods of voting because they implement security checks and audit trails, and are tougher to tamper with than paper ballots.

One of the most widely used electronic voting systems. Diebold Election Systems boasts some 33,000 voting stations in locations across the United States. Dieboltfs AccuVote-TS system is a voter-activated interactive touchscreen system using an intelligent Voter Card as the voter interface. The interface allows voters to view and cast their votes by touching target areas on an electronically generated ballot pad.

Each unit provides a direct-entry computerized voting station that automatically records and stores ballot information and results. While classified as a direct record entry (ORE) device, the AccuVote-TS system has additional capabilities. The tabulator is a multi functional interface that counts and tabulates the ballots at precincts on election day and communicates with the host computer at Election Central for accurate and timely jurisdiction wide results. However, electronic voting systems have generated concern because their work is not readily accessible for inspection; what goes on behind the screen is a mystery to the general public and therefore causes uneasiness. With computer voting, voter records are intangibly stored on a hard drive, with voting results recorded in electronic memory.

Indeed, a July 2003 analysis of the Diebold touch screen by computer researchers from Johns Hopkins and Rice universities (found at http://www.newscientist.coin) showed that the software was riddled with errors and open to fraud. However, even with the possibility of fraud, electronic. When setting up your computing work-space, make it a priority to choose a comfortable, ergonomically designed chair . Your office chair should

» Allow you to adjust its height.

» Provide good lower-back support.

» Have adjustable armrests.

Your desk also should be well-suited to computer use, like the one shown in Figure. The desk should hold your keyboard and mouse at the proper height, so that your hands are at the same height as your elbows (or a few inches lower) when you hold them over the keyboard. Here arc some other tips that can help you avoid RSI's while working with your keyboard and mouse:

» Use an Ergonomic Keyboard:

Traditional, flat keyboards arc not well-suited to the shape of human hands. An ergonomic keyboard allows you to hold your hands in a more natural position (with wrists straight, rather than angled outward) while typing.

» Use a Padded Wrist Support: 

If you type a lot, a wrist support can be helpful by allowing you to rest your hands comfortably when you are not actually typing. Remember; however, that systems may still be safer than prior methods of voting because they implement redundant security checks and audits and may be more difficult to tamper with because of the size and nature of their tabulating components. 

Another argument in favor of paper ballots, or at least paper receipts, is that in order to verify an election, all you need to do is gather up the ballots and tabulate them a second (or third, as the case may be) time. However, auditing paper ballot systems is not always as easy as it sounds. Ballots, particularly punch-cards, sometimes provide ambiguous results, as seen in a recent presidential election. They are easily forged and they must be physically handled and transported, which provides the opportunity for substitution or loss. Whether computerized or traditional, no election system is infallible, and in truth, perhaps it doesn't need to be. As some have said, every safe has the capability to be cracked.

The same is true for voting systems. The issue is not whether they are 100 percent secure, but whether they present adequate safeguards to give us faith in the integrity of our elections. you should never rest your wrists on anything—even a comfortable wrist support—while you type. Use the support only when your fingers are not moving over the keyboard.

» Keep Your Wrists Straight: When typing, your hands should be in a straight line with your forearms, when viewed either from above or from the side (see Figure 2A.32). Keeping the wrists bent in either direction can cause must be fatigue.

» Sit Up Straight: Avoid slouching as you type, and keep your feet flat on the floor in front of you. Avoid crossing your legs in front of you or under your chair for long periods.

» Learn to Type: You will use the keyboard more efficiently and naturally if you know how to type. If you Mhunt and peek," you are more likely to slouch and keep your head down while looking at rite keyboard. This technique not only slows you down, but it leads to fatigue and stiffness.

» Take Frequent Breaks: Get up and move around for a few minutes each hour, and stretch occasionally throughout the day.

Now a days computer is an important parts of our everyday life. But most of all user of a computer doesn't how many types. Today we will discuss about it.

Most computers are meant to be used by only one person at a time. Such computers are often shared by several people (such as those in your school’s computer lab), but only one user can work with the machine at any given moment .

Personal computers are also called microcomputer, because they are among the smallest computers created for people to use. Note, however, that the term personal computer or PC is most often used to describe desktop computers, which you will learn about in the following section. Although personal computers are used by individuals, they also can be connected together to create networks (see Figure) . 

In fact, networking has become one of the most important jobs of personal computers, and even tiny handheld computers can now be connected to networks. You will learn about computer networks in , “ Networks."

Desktop Computers:

The most common type of personal computer is the desktop computer a PC that is designed to sit on (or under) a desk or table. These are the systems you sec all around you, in schools, homes, and offices, and they are the main focus of this articles.

Today's desktop computers are far more powerful than those of just a few years ago, and are used for an amazing array of tasks. Not only do these machines enable people to do their jobs with greater ease and efficiency, but they can be used to communicate, produce music, edit photographs and videos, play sophisticated games, and much more. Used by everyone from preschoolers to nuclear physicists, desktop computers arc indispensable for learning, work, and play (see Figure).

Workstations:

A workstation is a specialized, single-user computer that typically has more power and features than a standard desktop PC (see Figure). These machines are popular among scientists, engineers, and animators who need a system with greater-than-average speed and the power to perform sophisticated tasks. Workstations often have large, high-resolution monitors and accelerated graphics handling capabilities, making them suitable for advanced architectural or engineering design, modeling, animation, and video editing.

Notebook Computers:

Notebook computers, as their name implies, approximate the shape of an 8.5-by-ll-inch notebook and easily fit inside a briefcase. Because people frequently set these devices on their lap, they are also called laptop computers. Notebook computers can operate on

alternating current or special batteries. These amazing devices generally weigh less than eight pounds, and some even weigh less than three pounds! During use, the computer’s lid is raised to reveal a thin monitor and a keyboard.

Tablet PCs:

The tablet PC is the newest development in portable, full-featured computers (see Figure). Tablet PCs offer a ll the functionality of a notebook PC, but they are lighter and can accept input from a

special pen called a stylus or a digital pen that is used to tap or write directly on the screen. Many tablet PCs also have a built-in microphone and special software that accepts input from the user's voice. A few models even have a fold-out keyboard, so they can be transformed into a standard notebook PC. Tablet PCs run specialized versions of standard programs and can be connected to a network. Some models also can be connected to a keyboard and a full-size monitor.
Handheld PCs:
Handheld personal computers are computing devices small enough to fit in your hand (see Figure). A popular type of handheld computer is the personal digital assistant (PDA). A PDA is no larger than a small appointment book and is normally used for special applications, such as taking notes, displaying telephone numbers and addresses, and keeping track of dates or agendas. Many PDAs can be connected to larger computers to exchange data.
Most PDAs come with a pen that lets the user write on the screen. Some handheld computers feature tiny built-in keyboards or microphones that allow voice input.
Many PDAs let the user access the Internet through a wireless connection, and several models offer features such as cellular telephones, cameras, music players, and global positioning systems.

Smart Phones:
Some cellular phones double as miniature PCs (see Figure). Because these phones offer advanced features not typically found in cellular phones, they are sometimes called smart phones. These features can include Web and c-mail access, special software such as personal organizers, or special hardware such as digital cameras or music players. Some models even break in half to reveal a
miniature keyboard.