COMPUTER FUNDAMENTALS
Learning computer and Internet concepts is partly about learning new terms. So let's start with the most basic term of all—computer.
UNDERSTANDING THE COMPUTER:
Learning computer and Internet concepts is partly about learning new terms. So let's start with the most basic term of all—computer.
UNDERSTANDING THE COMPUTER:
BASIC DEFINITIONS
A computer is a machine that performs four basic operations: input, processing, output, and storage. Together, these four operations are called the information-processing cycle. Input, processing, output, storage—that's what computers do. The processing function relies on input; output depends on the results of processing; and storage is where output may be kept for later use. Because these operations depend on one another, the information-processing cycle is always performed in order.
A computer is a machine that performs four basic operations: input, processing, output, and storage. Together, these four operations are called the information-processing cycle. Input, processing, output, storage—that's what computers do. The processing function relies on input; output depends on the results of processing; and storage is where output may be kept for later use. Because these operations depend on one another, the information-processing cycle is always performed in order.
You'll often hear the term computer system, which is normally shortened to system. This term is more inclusive than computer. A computer system is a collection of related components that have been designed to work together. These components can be broken down into two major categories: hardware and software. A computer system's hardware includes the physical components of the computer, including the system unit itself, as well as keyboards, monitors, speakers, and so on.
In order for a computer system's hard-ware to function, a computer needs a program. A program is a list of instructions that tells the computer how to perform the four operations in the information-processing cycle to accomplish a task. Software includes all of the programs that give the computer its instructions. You can divide software into two categories: system software and application software. System software includes all of the programs that help the computer function properly. The most important type of system software is the computer's operating system (OS), such as Microsoft Windows. Other parts of the system software include system utilities such as Help and antivirus programs. Application software consists of all of the programs you can use to perform a task, including word-processing, spreadsheet, database, presentation, e-mail, and Web browser software.
To better understand how computer system components are interrelated, you might compare a computer system with an aquarium. The computer hardware is like the fish tank, the operating system is like the water, and the software applications are like the fish. You wouldn't put fish in an empty aquarium. Fish can't survive without water, just as software applications can't function without an operating system. And without the water and fish, an aquarium is an empty box, just like computer hardware isn't much use without an operating system and applications.
Now that we have the basic terms under our belt, let's take a closer look at the operations in the information-processing cycle (input, processing, output, and storage) and at the hardware devices involved in each step.
INPUT:
GETTING DATA INTO THE COMPUTER.
In the first operation, called input, the computer accepts data. The term data refers to unorganized raw facts, which can be made up of words, numbers, images, sounds, or a combination of these.
Input devices enable you to enter data into the computer for processing. The most common input devices are the keyboard and mouse, microphones, disk drives, and devices such as scanners and digital cameras offer other ways of getting data into the computer.
PROCESSING:
TRANSFORMING DATA INTO INFORMATION.
In the second operation, called processing, computers transform data into information. Information is data that have been simplified and organized in a way that people can use. During processing, the computer's processing circuitry, called the central processing unit (CPU) or microprocessor (or just processor for short), performs operations on the input data. The processor is located within the computer system's case, also called the system unit. Even though the CPU is often referred to as the "brain" of the computer, computers don't really "think" at all. They are only capable of simple, repetitive processing actions organized into an algorithm—a series of steps that result in the solution to a problem.
Because the CPU needs to juggle multiple input/output requests at the same time, it uses memory chips to store program instructions and data. Memory is essential to the smooth operation of the CPU. A typical computer includes several different types of memory, but the most important of these is random access memory (RAM), which temporarily stores the programs and data with which the CPU interacts.
OUTPUT:
DISPLAYING INFORMATION
In the third operation, called output, the computer provides the results of the processing operation in a way that people can understand. Output devices show the results of processing operations. The most common output devices are monitors and printers, or. if the computer is processing sounds, you may hear the results on the computer's speakers.
STORAGE:
HOLDING PROGRAMS AND DATA FOR FUTURE USE
In the fourth operation, called storage, the computer saves the results of processing to be used again later. Storage devices hold all of the programs and data that the computer system uses. Most computers are equipped with the following storage devices: a hard disk drive, a floppy disk drive, and a CD-ROM drive and/or DVD-ROM drive. These devices are commonly not removable and are mounted inside the system unit.
Although communications hasn't traditionally been a part of the information-processing cycle, it can be considered an additional step in the process.
COMMUNICATIONS:
MOVING DATA BETWEEN COMPUTERS
Communications, which is often the fifth operation in the information-processing cycle, involves moving data within the computer or between computers. To move data between computers, communications devices are necessary. Communications devices enable computers to connect to a computer network. A network is a group of two or more computer systems connected together, usually for the purpose of sharing input/output devices and other resources.
Most computers are equipped with a modem, a communications device that enables the computer to access other com-puters and the Internet via telephone lines, cable, and even wireless connections. Most modems are housed inside the system unit.
in a typical computer system, let's look at an example of how the computer uses the basic functions of input, processing, output, and storage.
THE INFORMATION-PROCESSING CYCLE IN ACTION
Even if you haven't wondered what goes on "behind the scenes" when using a computer, the following example illustrates your role and the computer's role in each step of the information-processing cycle.
•Input. You've just finished writing a research paper for one of your classes. You think it's probably riddled with misspellings and grammatical errors, so you run your word-processing program's spell checker on it. In this example, your entire word-processed document is the input.
•Processing. A spell checker makes use of the computer's ability to perform very simple processing operations at very high speeds. To check your document's spelling, the program begins by constructing a list of all of the words in your document. Then it compares these words, one by one, with a huge list of correctly spelled words. If you've used a word that isn't in the dictionary, the program puts the word into a list of apparent misspellings.
Note that the computer isn't really "checking spelling" when it performs this operation. The computer can't check your spelling because it doesn't possess the intelligence to do so. All it can do is tell you which of the words you've used aren't in the dictionary. Ultimately, only you can decide whether a given word is misspelled.
•Output. The result of the processing operation is a list of apparent misspellings. The word apparent is important here because the program doesn't actually know whether the word is misspelled. It is able to tell only that these words aren't in its massive, built-in dictionary. But many correctly spelled words, such as proper nouns (the names of people and places), aren't likely to be found in the computer's dictionary. For this reason, the program won't make any changes without asking you to confirm them.
•Storage. Once you've corrected the spelling in your document, you save or store the revised document to disk.
In sum, computers transform data (here, a document full of misspellings) into information (a document that is free of misspellings).
Up to this point, we've been talking about computers in general. We now need to examine the specific types of computers used in a wide variety of tasks and job situations.
TYPES OF COMPUTERS
Computers come in all sizes, from large to small. It's convenient to divide them into two categories: computers for individuals and computers for organizations. Computers for individuals are mainly designed for one user at a time. They process and store smaller amounts of data and programs, such as a research paper or a personal Web page. In contrast, computers for organizations are designed to meet the needs of many people concurrently. They process and store large amounts of data and more complex programs, such as all the research papers for every class on campus or the school's entire Web site. Computers are also categorized by power (their processing speed) and purpose (the tasks they perform).
COMPUTERS FOR INDIVIDUALS
A personal computer (PC), also called a microcomputer, is designed to meet the computing needs of an individual. The two most commonly used types of personal computers are Apple's Macintosh systems and the more numerous IBM-compatible personal computers, which are made by manufacturers such as Dell, Gateway, Sony, HP, and many others. These PCs are called "IBM-compatible" because the first such computer was made by IBM. The price range of personal computers has steadily dropped to between $300 and $3,000, even as they have become more powerful and useful.
TYPES OF COMPUTERS
Computers come in all sizes, from large to small. It's convenient to divide them into two categories: computers for individuals and computers for organizations. Computers for individuals are mainly designed for one user at a time. They process and store smaller amounts of data and programs, such as a research paper or a personal Web page. In contrast, computers for organizations are designed to meet the needs of many people concurrently. They process and store large amounts of data and more complex programs, such as all the research papers for every class on campus or the school's entire Web site. Computers are also categorized by power (their processing speed) and purpose (the tasks they perform).
COMPUTERS FOR INDIVIDUALS
A personal computer (PC), also called a microcomputer, is designed to meet the computing needs of an individual. The two most commonly used types of personal computers are Apple's Macintosh systems and the more numerous IBM-compatible personal computers, which are made by manufacturers such as Dell, Gateway, Sony, HP, and many others. These PCs are called "IBM-compatible" because the first such computer was made by IBM. The price range of personal computers has steadily dropped to between $300 and $3,000, even as they have become more powerful and useful.
Designed for use at a desk or in an office environment, a desktop computer is a personal computer that runs programs to help individuals accomplish their work more productively or to gain access to the Internet. Dell is the leading producer of desktop computers.
A notebook computer is small enough to fit into a briefcase and is portable, because many people need a computer to travel with them. Many notebook computers are as powerful as desktop computers and include nearly all of a desktop computer's components, such as speakers, a CD-ROM drive, and a modem. Notebook computers are generally manufactured by the same companies as desktop computers. Some of the most popular notebook computers are Dell's Inspiron series, Toshiba's Satellite and Tecra series, IBM's Thinkpad, HP's Pavillion, and, for Mac lovers, the Apple iBook. They range in price from $900 to over $3,000.
Laptop computers are like notebook computers except that they are a bit too large to fit into a briefcase. The most popular maker of laptop computers is IBM with models that range in price from $700 to as much as $3,000. Fewer laptops are being sold now that the smaller notebooks have become so powerful.
Subnotebooks are notebook computers that omit some components (such as a CD-ROM drive) so as to cut down on weight and size. A significant advantage of subnotebooks is that some of them weigh less than three pounds. For example, the newest Sony Vaio subnotebook weighs only 1.7 pounds and is less than 1 inch thick. One disadvantage of subnotebooks is that users must often carry along external disk drives and their attendant wiring. A sub-notebook might be used by a UPS driver or by salespeople whose specific computing needs do not require all of the peripherals and accessories that are available with desktops, notebooks, and laptops. The top manufacturers of subnotebooks are Sony and Panasonic. Subnotebooks range in price from $1,300 to $2,500.
A tablet PC is a type of notebook computer that has an LCD screen that the user can write on using a special-purpose pen or stylus. The user's handwriting is converted to standard text through handwriting-recognition software or it can remain as handwritten text. Tablet PCs also typically have a keyboard and/or a mouse for input. HP's Compaq brand is the most popular, with prices ranging from $1,000 to over $3,900. Toshiba and Acer are two other brands in the top 10 manufacturers. Tablet PC prices will come down as they become more accepted in the marketplace and their production numbers increase.
Personal digital assistants (PDAs), sometimes called handheld computers, pack much of a notebook's power into a much lighter package and lower price (between $350 and $700). Most PDAs include built-in software for scheduling appointments and sending and receiving e-mail. Pen computers accept handwritten input. The Palm series, Sony's CLIE series, HP's iPAQ series, and BlackBerry are the most popular PDAs.
All-in-one computers, such as the Apple iMac, are essentially a monitor with everything else built in. The only external devices are a keyboard and a mouse. The microprocessor, memory, storage, and speakers are all contained within the monitor case. This design may be the wave of the future. The Gateway Profile, the Sony Vaio W, and a relatively new player—the Pelham Sloane PS 1500—are all major players in the all-in-one market. All-in-one computers cost about the same as other desktop PCs, ranging from $1,400 to $2,300.
Network computers (NCs) and Internet appliances provide much of a personal computer's functionality but at a lower price. These computers are designed to connect to a network, such as the Internet. In the consumer market, NCs such as MSN TV enable consumers to use their televisions to connect to the Internet. Because they have limited memory, disk storage, and processing power, NCs rely on computer networks for their power and software. Popular in the mid to late 1990s, they haven't been able to achieve much of a hold in the marketplace.
Professional workstations are powerful tools for engineers, architects, circuit designers, financial analysts, and other professionals who need exceptionally powerful processing and output capabilities. HP dominates the workstation market. It produces workstations that range in price from $1,000 to over $7,000, making workstations the most expensive type of computer made for individuals.
COMPUTERS FOR ORGANIZATIONS
Servers are computers that make programs and data available to people who are connected to a computer network. They are not designed for individual use and are typically centralized or operated from one location. Users connect to the network on clients, which can be desktops, laptops, workstations, or any other computer for individuals, to contact the server and obtain the needed information. This use of remote or off-site clients and centralized servers is called client/server computing. It plays an important role in today's businesses. Servers can be as small as a microcomputer or as large as a mainframe. The top three server manufacturers are IBM, Sun Microsystems, and Dell. Servers typically cost between $1,000 and upwards of $30,000, but HP UNIX servers run from $100,000 to over $1 million!
Minicomputers, also referred to as midrange servers, are midsize computers that handle the computing needs of a smaller corporation or organization. They enable dozens, hundreds, or even thousands of users to connect to them simultaneously through PCs or terminals.
Terminals are basically computers that lack processing capabilities. They simply receive input via a remote keyboard and display output on a monitor. Minicomputers can be slightly larger than microcomputers or as big as a washing machine. In recent years, the minicomputer market has waned.
Mainframes are designed to handle huge processing jobs in large corporations or government agencies. For example, an airline may use a mainframe to handle airline reservations. Some mainframes are designed to be used by hundreds of thousands of people at the same time. People connect to mainframes using terminals or PCs. Mainframes are usually stored in special, secure rooms that have a controlled climate. They are manufactured by firms such as IBM, Honeywell, and HP/Agilent, cost hundreds of thousands to millions of dollars, and are very powerful.
Supercomputers are ultrafast computers that process large amounts of scientific data and then display the underlying patterns that have been discovered in the data. In 2000, IBM announced that it had built a supercomputer capable of executing 12 trillion calculations per second. Known as the ASCI White, the supercomputer covers an area the size of two basketball courts and is used by the Department of Energy. In March of 2002, Japan's NEC Corporation announced it had created an even faster supercomputer. The system, known as "the Earth Simulator," takes up the space of four tennis courts and is said to be five times faster than the ASCI White. A supercomputer's price tag is also large—from $1 million to $20 million.
Now that you know the variety of computers available, let's look at how their use has an impact on you as an individual and on society in general.
LISTA DE COGNADOS
REAL | CLOSE | FALSE |
Internet | Computer | Performs |
Hardware | Concept | Use |
Software | Basic | Inclusive |
Antivirus | Definition | Divide |
Digital | Operation | Properly |
Central | Information | Closer |
Multiple | Function | Large |
Monitor | Depend | Individuals |
Modem | Order | Numerous |
Cable | System | . |
Simple | Collection | . |
General | Components | . |
Divide | Categories | . |
Personal | Problem | . |
Web | List | . |
Macintosh | Instructions | . |
Compatible | Application | . |
Popular | Important | . |
... | Consists | . |
. | Presentation | . |
. | Aquarium | . |
. | Data | . |
. | Images | . |
. | Combination | . |
. | Microphones | . |
. | Scanners | . |
. | Cameras | . |
. | Solution | . |
. | Result | . |
. | Communication | . |
. | Traditional | . |
. | Telephone | . |
. | Cycle | . |
. | Classes | . |
. | Document | . |
. | Dictionary | . |
. | Intelligence | . |
. | Organization | . |
. | Microcomputer | . |
. | Special | . |
. | Production | . |
. | Professional | . |
. | Client | . |
. | Corporation | . |
. | Terminals | . |
. | Minicomputers | . |
. | Supercomputers | . |
. | Japan | . |
