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Memory

2012-05-12T08:00:00.000+00:00

Memory consists of electronic components that store instructions waiting to be executed by the processor, data needed by those instructions, and the results of processing the data (information). Memory usually consists of one or more chips on the motherboard or some other circuit board in the computer.

Memory stores three basic categories of items: (1)the operating system and other system software that control or maintain the computer and its devices; (2) application programs that carry out a specific task such as word processing; and (3) the data being processed by the application programs and resulting information. This role of memory to store both data and programs is known as the stored program concept.

Bytes and Addressable Memory

A byte (character) is the basic storage unit in memory. When application program instructions and data are transferred to memory from storage devices, the instructions and data exist as bytes. Each byte resides temporarily in a location in memory that has an address. An address simply is a unique number that identifies the location of a byte in memory. To access data or instructions in memory, the computer references the addresses that contain bytes of data.

Memory Sizes

Manufacturers state the size of memory and storage devices in terms of the number of bytes the chip or device has available for storage. Recall that storage devices hold data, instructions, and formation for future use, while most memory holds these items temporarily. A kilobyte (KB or K) is equal to exactly 1,024 bytes. To simplify memory and storage definitions, computer users often round a kilobyte down to 1,000 bytes. For example, if a memory chip can store 100 KB, it can hold approximately 100,000 bytes (characters). A megabyte (MB) is equal to approximately 1 million bytes. A gigabyte (GB) equals approximately 1 billion bytes. A terabyte (TB) is equal to approximately 1 trillion bytes.

Types of Memory

The system unit contains two types of memory: volatile and nonvolatile. When the computer's power is turned off, volatile memory loses its contents. Nonvolatile memory, by contrast, does not lose its contents when power is removed from the computer. Thus, volatile memory is temporary and nonvolatile memory is permanent. RAM is the most common type of volatile memory. Examples of nonvolatile memory include ROM, flash memory, and CMOS. The following sections discuss these types of memory.

RAM

Users typically are referring to RAM when discussing computer memory. RAM (random access memory), also called main memory, consists of memory chips that can be read from and written to by the processor and other devices. When you turn on power tro a computer, certain operating system files (such as the files that determine how the desktop appears) load into RAM from a storage device such as a hard disk. These files remain ion RAM as long as the computer has continuous power. As additional programs and data are requested, they also load into RAM from storage.

The processor interprets and executes a program's instructions while the program is in RAM. During this time, the contents of RAM may change. RAM can accommodate multiple programs simultaneously.

Most RAM is volatile, which means it loses its contents when the power is removed from the computer. For this reason, you must save any data, instructions, and information you may need in the future. Saving is the process of copying data, instructions, and information from RAM to a storage device such as a hard disk.

Three basic types of Ram chips exist: dynamic RAM, static RAM, and magnetoresistive RAM.

Dynamic RAM (DRAM pronounced DEE-ram) chips must be re-energized constantly or they lose their contents. Many variations of DRAM chips exist, most of which are faster than the basic DRAM. Most personal computers today use some form of SDRAM chips or RDRAM chips.
Static RAM (SRAM pronounced ESS-ram) chips are faster and more reliable than any variation of DRAM chips. These chips do not have to be re-energized as often as DRAM chips, thus the term static. SRAM chips, however, are much more expensive than DRAM chips. Special applications such as cache use SRAM chips. A later section in this chapter discusses cache.
A newer type of RAM, called magnetoresistive RAM (MRAM pronounced EM-ram), stores data using magnetic charges instead of electrical charges. Manufacturers claim that MRAM has greater storage capacity, consumes less power, and has faster access times than electronic RAM. Also, MRAM retains its contents after power is removed from the computer, which could prevent loss of data for users. As the cost of MRAM declines, experts predict MRAM could replace both DRAM and SRAM.

Ram chips usually reside on a memory module, which is a small circuit board. Memory slots on the motherboard hold memory modules. Three types of memory modules are SIMMs, DIMMs, and RIMMs. A SIMM (single inline memory module) has pins on oppositesides of the circuit board that connect together to form a single set of contacts. With a DIMM (dual inline memory module), by contrast, the pins on opposite sides of the circuit board do not connect and thus form two sets of contacts. SIMMs and DIMMs typically hold SDRAM chips. A RIMM (Rambus inline memory module) houses RDRAM chips.

RAM Configurations The amount of RAM necessary in a computer often depends on the types of software you plan to use. A computer executes programs that are in RAM. Think of RAM as the workplace on the top of your desk. Just as the top of your desk needs a certain amount of space to hold papers, a computer needs a certain amount of memory to store programs, data, and information. The more RAM a computer has, the faster the computer will respond.

Retail software typically indicates the minimum amount of RAM it requires. If you want the software to perform optimally, usually you need more than the minimum specifications for the software.

Cache

Most of today's computers improve their processing times with cache (pronounced cash). Two types of cache are memory cache and disk cache.

Memory cache helps speed the processes of the computer because it stores frequently used instructions and data. Most personal computers today have two types of memory cache: L1 cache and L2 cache. Some also have L3 cache.

L1 cache is built directly in the processor chip. L1 cache usually has a very small capacity, ranging from 8 KB to 128 KB. The more common sizes for personal computers are 32 KB or 64 KB.
L2 cache is slightly slower than L1 cache but has a much larger capacity, ranging from 64 KB to 16 MB. When discussing cache, most users are referring to L2 cache. Current processors include advanced transfer cache (ATC), a type of L2 cache built directly on the processor chip.
L3 cache is a cache on the motherboard that is separate from the processor chip. L3 cache exists only on computers that L2 advanced transfer cache. Personal computers often have up to 8 MB of L3 cache; servers and workstations have from 8 MB to 24 MB of L3 cache.

Cache speeds up processing time because it stores frequently used instructions and data. When the processor needs an instruction or data, it searches memory in this order: L1 cache, then L2 cache, then L3 cache (if it exits), then RAM – with a greater delay in processing for each level of memory it must search. If the instruction or data is not found in memory, then it must search a slower speed storage medium such as a hard disk or optical disc.

Windows users can increase the size of cache through Windows Ready Boost, which can allocate available storage space on removable flash memory devices as additional cache. Examples of removable flash memory include USB flash drives, CompactFlash cards, and SD (Secure Digital) cards.

ROM

Read-only memory (ROM) refers to memory chips storing permanent data and instructions. The data on most ROM chips cannot be modified – hence, the name read-only. ROM is nonvolatile, which means its contents are not lost when power is removed from the computer. In addition to computers, many devices contain ROM chips. For example, ROM chips in printers contain data for for fonts.

Manufacturers of ROM chips often record data, instructions, or information on the chips when they manufacture the chips. These ROM chips, called firmware, contain permanently written data, instructions, or information.

A PROM (programmable read-only memory) chip is a blank ROM chip on which a programmer can write permanently. Programmers use microcode instructions to program a PROM chip. Once a programmer writes the microcode on the PROM chip, it functions like a regular ROM chip and cannot be erased or changed.

A variation of the PROM chip, called an EEPROM (electrically erasable programmable read-only memory) chip, allows a programmer to erase the microcode with an electric signal.

Flash Memory

Flash memory is a type of nonvolitale memory that can be erased electronically and rewritten, similar to EEPROM. Most computers use flash memory to hold their startup intructions because it allows the computer easily to update its contents. For example, when the computer changes from standard time to daylight savings time, the contents of a flash memory chip (and the real-time clock chip) change to reflect the new time.

Flash memory chips also store data and programs on many mobile computers and devices, such as smart phones, portable media players, PDAs, printers, digital cameras, automotive devices, digital voice recorders, and pagers.

When you enter names and addresses in a smart phone or PDA, a flash memory chip stores the data. Some portable media players store music on flash memory chips; others store music on tiny hard disks or flash memory cards. Flash memory cards contain flash memory on a removable device instead of a chip.

CMOS

Some RAM chips, flash memory chips, and other memory chips use complementary metal-oxide semiconductor (CMOS pronounced SEE-moss) technology because it provides high speeds and consumes little power. CMOS technology uses battery power to retain information even when the power to the computer is off. Battery-backed CMOS memory chips, for example, can keep the calendar, date, and time current even when the computer is off. The flash memory chips that store a computer's startup information often use CMOS technology.

Memory Access Times

Access time is the amount of time it takes the processor to read data, instructions, and information from memory. A computer's access time directly affects how fast the computer process data. Accessing data in memory can be more than 200,000 times faster than accessing data on a hard disk because of the mechanical motion of the hard disk.

Today's manufacturers use a variety of terminology to state access times. Some use fractions of a second which for memory occurs in nanoseconds. A nanosecond (abbreviated ns) is one billionth of a second. A nanosecond is extremely fast. In fact, electricity travels about one foot in a nanosecond.

Other manufacturers state access time in MHz; for example, 800 MHz DDR2 SDRAM. If a manufacturer states access time in megahertz, you can convert it to nanoseconds by dividing 1 billion ns by the megahertz number. For example, 800 MHz equals approximately 1.25 ns (1,000,000,000/800,000,000).

The access time (speed) of memory contributes to the overall performance of the computer. Standard SDRAM chips can have access times up to 133 MHz (about 7.5 ns), and access times of DDR SDRAM chips reach 266 MHz, DDR2 chips reach 800 MHz, and DDR3 chips reach 1600 MHz. The higher the megahertz, the faster the access time; conversely, the lower the nanoseconds, the faster the access time. The faster RDRAM chips can have access times up to 1600 MHz (about 0.625 ns). ROM access times range from 25 to 250 ns.

While access times of memory greatly affect overall computer performance, manufacturers and retailers usually list a computer's memory in terms of its size, not its access time. Thus, an advertisement might describe a computer as having 2 GB of SDRAM upgraded to 4 GB.

Data Representation

2012-05-05T08:00:00.000+00:00

To understand how a computer process data, you should know how a computer represents data, you should know how a computer represents data. People communicate through speech by combining words into sentences. Human speech is analog because it uses continuous (wave form) signals that vary in strength and quality. Most computers are digital. They recognize only two discrete states: on and off. This is because computers are electronic devices powered by electricity, which also has only two states: on and off.

The two digit, 0 and 1, easily can represent these two states. The digit 0 represents the electronic state of off (absence of an electronic charge). The digit 1 represents the electronic state of on (presence of an electronic charge).

When people count, they use the digits in the decimal system (0 through 9). the computer, by contrast, uses a binary system because it recognizes only two states. The binary system is a number system that has just two unique digits, 0 and 1, called bits. A bit (short for binary digit) is the smallest unit of data the computer can process. By itself, a bit is not very informative.

When 8 bits are grouped together as a unit, they form a byte. A byte provides enough different combinations of 0s and 1s to represent 256 individual characters. These characters include numbers, uppercase and lowercase letters of the alphabet, punctuation marks, and others, such as the letters of the Greek alphabet.

The combinations of 0s and 1s that represent characters are defined by patterns called a coding scheme. In one coding scheme, the number 4 is represented as 00110100, the number 6 as 00110110, and the capital letter E as 01000101. ASCII which stands for American Standard Code for Information Interchange is the most widely used coding scheme to represent data.

The ASCII coding scheme is sufficient for English and Western European languages but is not large enough for Asian and other languages that use different alphabets. Unicode is a 16-bit coding scheme that has the capacity of representing more than 65,000 characters and symbols. The Unicode coding scheme is capable of representing almost all the world's current written languages, as well as classic and historical languages. To allow for expansion, Unicode reserves 30,000 codes for future use and 6,000 codes for private use. Unicode is implemented in several operating systems, including Windows, Mac Os, and Linux. Unicode-enabled programming languages and software include Java, XML, Microsoft Office, and Oracle.

Coding schemes make it possible for humans to interact with a digital computer that processes only bit. When you press a key on a keyboard, a chip in the keyboard converts the key's electronic signal into a special code that is sent to the system unit. Then, the system unit converts the code into a binary form the computer can process and store it in memory. Every character is converted to its corresponding byte. The computer then processes the data as bytes, which actually is a series of on/off electrical states. When processing is finished, software converts the byte into a human-recognizable number, letter of the alphabet, or special character that is displayed on a screen or is printed. All of these conversions take place so quickly that you do not realize they are occurring.

Standards, such as those defined by ASCII and Unicode, also make it possible for components in computers to communicate with each other successfully. By following these and other standards, manufacturers can produce a component and be assured that it will operate correctly in a computer.

Processor

2012-04-28T08:00:00.000+00:00

The processor, also called the central processing unit (CPU), interprets and carries out the basic instructions that operate a computer. The processor significantly impacts overall computing power and manages most of a computer's operations. On larger computers, such as mainframes and supercomputers, the various functions performed by the processor extend over many separate chips and often multiple circuit boards. On a personal computer, all functions of the processor usually are a single chip. Some computer and chip manufacturers use the term microprocessor to refer to a personal computer processor chip.

Most processor chip manufacturers now offer multi-core processors. A processor core, or simply core, contains the circuitry necessary to execute instructions. The operating system views each processor core as a separate processor. A multi-core processor is a single chip with two or more separate processor cores. Two common multi-core processor are dual-core and quad-core. A dual-core processor is a chip that contains two separate processor cores. Similarly, a quad-core processor is a chip with four separate processor cores.

Each processor core on a multi-core processor generally runs at a slower clock speed than a single-core processor, but multi-core processors typically increase overall performance. For example, although a dual-core processor does not double the processing speed of a single-core processor, it can approach those speeds. The performance increase is especially noticeable when users are running multiple programs simultaneously such as antivirus software, spyware remover, e-mail program, instant messaging, media player, disc burning software, and photo editing software. Multi-core processors also are more energy efficient than separate multiple processor, requiring lower levels of power consumption and emitting less heat in the system unit.

Processors contain a control unit and an arithmetic logic unit (ALU). These two components work together to perform processing operations.

The Control Unit

The control unit is the component of the processor that directs and coordinates most of the operations in the computer. The control unit has a role much like a traffic cop: it interprets each instruction issued by a program and then initiates the appropriate action to carry out the instruction. Types of internal components that the control unit directs include the arihtmetic/logic unit, registers, and buses.

The Arithmetic Logic Unit

The arithmetic logic unit (ALU), another component of the processor, performs arithmetic, comparison, and other operations.

Arithmetic operations include basic calculations such as addition, subtraction, multiplication, and division. Comparison operations involve comparing one data item with another to determine wheter the first item is greater than, equal to, or less than the other item. Depending on the result of the comparison, different actions may occur. For example, to determine if an employee should receive overtime pay, software instructs the ALU to compare the number of hours an employee worked during the week with the regular time hours allowed (e.g., 40 hours). If the hours worked exceed 40, for example, software instructs the ALU to perform calculations that compute the overtime wage.

Machine Cycle

For every instruction, a processor repeats a set of four basic operations, which comprise a machine cycle: (1) fetching, (2) decoding, (3) executing, and, if necessary (4) storing. Fetching is the process of obtaining a program instruction or data item from memory. The term decoding refers to the process of translating the instruction into signals the computer can execute. Executing is the process of carrying out the commands. Storing, in this context, mean writing the result to memory (not to a storage medium).

In some computers, the processor fetches, decodes, executes, and stores only one instruction at a time. In these computers, the processor waits until an instruction completes all four stages of the machine cycle (fetch, decode, execute, and store) before beginning work on the next instruction.

Most of today's personal computers support a concept called pipelining. With pipelining, the processor begins fetching a second instruction before it completes the machine cycle for the first instruction. Processors that use pipelining are faster because they do not have to wait for one instruction to complete the machine cycle before fetching the next. Think of a pipeline as an assembly line. By the time the first instruction is in the last stage of the machine cycle, three other instructions could have been fetched and started through the machine cycle.

Registers

A processor contains small, high-speed storage locations, called registers, that temporarily hold data and instructions. Registers are part of the processor, not part of memory or a permanent storage device. Processors have many different types of registers, each with a specific storage function. Register functions include storing the location from where an instruction was fetched, storing an instruction while the control unit decodes it, storing data while the ALU computes it, and storing the results of a calculation.

The System Clock

The processor relies on a small quartz crystal circuit called the system clock to control the timing of all computer operations. Just as your heart beats at a regular rate to keep your body functioning, the system clock generates regular electronic pulses, or ticks, that set the operating pace of components of the system unit.

Each tick equates to a clock cycle. In the past, processor used one or more clock cycles to execute each instruction. Processors today often are superscalar, which means they can execute more then one instruction per clock cycle.

The pace of the system clock, called the clock speed, is measured by the number of ticks per second. Current personal computer processors have clock speeds in the gigahertz range. Giga is a prefix that stands for billion, and a hertz ione cycle per second. Thus, one gigahertz (GHz) equals one billion ticks of the system clock per second. A computer that operates at 3 GHz has 3 billion (giga) clock cycles in oen second (hertz).

The faster the clock speed, the more instruction the processor can execute per second. The speed of the system clock has no effect on devices such as a printer or disk drive. The speed of the system clock is just one factor that influences a computer's performance. Other factors, such as the type of processor chip, amount of cache, memory access time, bust width, and bus clock speed, are discussed later.

Comparison of Personal Computer Processor

The leading manufacturers of personal computer chips are Intel and AMD. These manufacturers often identify their processor chips by a model name or model number. High-performance personal computers today may use a processor in the Intel Core family. Less expensive, basic personal computers may use a brand of Intel processor in the Pentium or Celeron family. The Xeon and Itanium families of processors are ideal for workstations and low-end servers.

AMD is the leading manufacturer of Intel-compatible processors, which have an internal design similar to Intel processors, perform the same functions, and can be as powerful, but often are less expensive.

In the past, chip manufacturers listed a processor's clock speed in marketing literature and advertisements. As previously mentioned, though, clock speed is only one factor that impacts processing speed in today's computers. To help consumers evaluate various processors, manufacturers such as Intel and AMD now use a numbering scheme that more accurately reflects the processing speed of their chips.

Processor chips include technologies to improve processing performance, for example, to improve performance of multimedia and 3-D graphics. Most of Intel's processor chips also include vPro technology, which provides the capability to track computers hardware and software, diagnose and resolve computer problems, and secure computers form outside threats.

As mentioned earlier, many personal computer processors are multi-core, with the processor cores working simultaneously on related instructions. These related instructions, called a thread, can be independent or part of a larger task. Software written to support multiple threads, called a multi-threaded program, run much faster than those in no threaded environments.

Processors for traditional notebook computers and Tablet PCs also include technology to optimize and extend battery life, enhance security, and integrate wireless capabilities. For example, Intel's Centrino 2 mobile technology, which may have a Pro designator depending on its capabilities, integrates wireless functionality in notebook computers and Tablet PCs. Netbooks, smart phones, and other smaller mobile devices often use more compact processor that consume less power, yet offer high performance.

Another type of processor, called system-on-a-chip, integrates the functions of a processor, memory, and a video card on a single chip. Lower-priced personal computers, Tablet PCs, networking devices, portable media players, and game consoles sometimes have a system-on-a-chip processor. The goal of system-on-a-chip manufacturers is to create processors that have faster clock speeds, consume less power, are small, and are cost effective.

Buying a Personal Computer

If you are ready to buy a new computer, the processor you select should depend on how you plan to use the computer. To realize greater processing performance, you may want to choose a multi-core processor.

Instead of buying an entirely a new computer, you might be able to upgrade your processor to increase the computer's performance. Be certain the processor you by is compatible with your computer's motherboard; otherwise, you will have to replace the motherboard, too. Replacing a processor is a fairly simple process, whereas replacing a motherboard is much more complicated.

Processor Cooling

Processor chips generate quite a bit of heat, which could cause the chip to burn up.although the computer's main fan generates airflow, many of today's personal computer processors require additional cooling. Heat sinks/pipes and liquid cooling technologies often are used to help dissipate processor heat.

A heat sink is a small ceramic or metal component with fins on its surface that absorbs and disperses heat produced by electrical components such as a processor. Some heat sinks are packaged as part of a processor chip. Others are installed on the top or the side of the chip. Because a heat sink consumes extra space, a smaller device called a heat pipe cools processors in notebooks and Tablet PCs.

Some computers use liquid cooling technology to reduce the temperature of a processor. Liquid cooling technology uses a continuous flow of fluid(s), such as water and glycol, in a process that transfers the heated fluid away from the processor to a radiator-type grill, which cools the liquid, and then returns the cooled fluid to the processor.

Some mobile computers and devices often have Low Voltage or Ultra Low Voltage (ULV) processors, which have such low power demands that they do not require additional cooling.

Parallel Processing

Parallel processing is a method that uses multiple processors simultaneously to execute a single program or task. Parallel processing divides a single problem into portions so that multiple processors work on their assigned portion of the problem at the same time. Parallel processing requires special software that recognizes how to divide the problem and then bring the results back together again.

Some personal computers implement parallel processing with dual-core processors or multi-core processors. Others have two or more separate processor chips, respectively called dual processor or multiprocessor computers.

Massively parallel processing is large scale parallel processing that involves hundreds or thousands of processors. Supercomputers use massively parallel processing for applications such as artificial intelligence and weather forecasting.

The System Unit

2012-04-21T08:00:00.004+00:00

Whether you are a home user or a business user, you most likely will purchase a new computer or upgrade an existing computer at some time in the future. Thus, you should understand the purpose of each component in a computer. A computer includes devices used for input, processing, output, storage, and communications. Many of these components are part of the system unit.

The system unit is a case that contains electronic components of the computer used to process data. System units are available in a variety of shapes and sizes. The case of the system unit, sometimes called the chassis, is made of metal or plastic and protects the internal electronic components from damage. All computers and mobile devices have a system unit.

On desktop personal computers, the electronic components and most storage devices are part of the system unit. Other devices, such as the keyboard, mouse, microphone, monitor, printer, USB flash drive, scanner, Web cam, and speakers, normally occupy space outside the system unit. An all-in-one desktop personal computer is an exception, which houses the monitor and the system unit in the same case. The trend is toward a smaller form factor, or size and shape, of the desktop personal computer system unit.

On most notebook computers, including netbooks, the keyboard and pointing device often occupy the area on the top of the system unit, and the display attaches to the system unit by hinges. The location of the system unit on a Tablet PC varies, depending on the design of the Tablet PC. With the slate Tablet PC, which typically does not include a keyboard, the system unit is behind the display. On a convertible Tablet PC, by contrast, the system unit is positioned below a keyboard, providing functionality similar to a traditional notebook computer or netbook. The difference is the display attaches to the system unit with a swivel-type hinge, which enables a user to rotate the display and fold it down over the keyboard to look like a slate Tablet PC. The system unit on an Ultra-Mobile PC, a smart phone, and a PDA usually consumes the entire device. On these mobile computers and devices, the display often is built into the system unit.

With game consoles, the input and output devices, such as controllers and television, reside outside the system unit. On handheld game consoles, portable media players, and digital cameras, by contrast, the packaging around the system unit houses the input devices and display.

At some point, you might have to open the system unit on a desktop personal computer to replace or install a new electronic component. For this reason, you should be familiar with the electronic components of a system unit. Some of these components include the processor, memory, adapter cards, drive bays, and the power supply.

The processor interprets and carries out the basic instructions that operate a computer. Memory typically holds data waiting to be executed. The electronic components and circuitry of the system unit, such as the processor and memory, usually are part of or are connected to a circuit board called the motherboard. Many current motherboards also integrate sound, video, and networking capabilities.

Adapter cards are circuit boards that provide connections and functions not built into the motherboard or expand on the capability of features integrated into the motherboard. For example, a sound card and a video card are two types of adapter cards found in some desktop personal computers today.

Devices outside the system unit often attach to ports on the system unit by a connector on a cable. These devices may include a keyboard, mouse, microphone, monitor, printer, scanner, USB flash drive, card reader/writer, Web cam, and speakers. A drive bay holds one or more disk drives. The power supply converts electricity from a power cord plugged in a wall outlet into a form that can be used by the computer.

The Motherboard

The motherboard, sometimes called a system board, is the main circuit board of the system unit. Many electronic components attach to the motherboard; others are built into it.

A computer chip is a small piece of semi-conducting material, usually silicon, on which integrated circuits are etched. An integrated circuit contains many microscopic pathways capable of carrying electrical current. Each integrated circuit can contain millions of elements such as resistors, capacitors, and transistors. A transistor, for example, can act as an electronic switch that opens or closes the circuit for electrical charges. Today's computer chips contain millions or billions of transistors. Most chips are in bigger than one-half-inch square. Manufacturers package chips so that the chips can be attached to a circuit board such as a motherboard or an adapter card.

Learning Tools for Application Software

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Learning how to use application software effectively involves time and practice. To assist in the learning process, many programs include an integrated Help feature. Online Help is the electronic equivalent of a user manual. When working with a program, you can use online Help to ask a question or access the Help topics in subject or alphabetical order. Most online Help also links to Web sites that offer Web-based Help, which provides updates and more comprehensive resources to respond to technical issues about software.

If you want to learn more about a particular program from a printed manual, many books are available to help you learn to use the features of personal computer programs. These books typically are available in bookstores and software stores.

Many colleges and schools provide training on several of the programs discussed.

Web-Based Training

Web-based training (WBT) is a type of CBT (computer-based training) that uses Internet technology and consists of application software on the Web. Similar to CBT, WBT typically consists of self-directed, self-paced instruction about a topic. WBT is popular in business, industry, and schools for teaching new skills or enhancing existing skills of employees, teachers, or students. When using a WBT product, students actively become involved in the learning process instead of remaining passive recipients of information.

Many Web sites offer WBT to the general public. Such training covers a wide range of topics, from how to change a flat tire to creating documents in Word. Many of these Web sites are free. Others require registration and payment to take the complete Web-based course.

WBT often is combined with other materials for distance learning and e-learning. Distance learning (DL) is the delivery of education at one location while the learning takes place at other locations. DL courses provide time, distance, and place advantages for students who live far from a college campus or work full time. These courses enable students to attend class from anywhere in the world and at times that fit their schedules. Many national and international companies offer DL training. These training courses eliminate the costs of airfare, hotels, and meals for centralized training sessions.

E-learning, short for electronic learning, is the delivery of education via some electronic method such as the Internet, networks, or optical discs. To enhance communications, e-learning systems also may include video conferencing, e-mail, blogs, wikis, newsgroups, chat rooms, and groupware.

E-learning providers often specialize in presenting instructors with the tools for preparation, distribution, and management of Dl courses. These tools enable instructors to create rich, educational Web-based training sites and allow the students to interact with a powerful Web learning environment. Through the training site, students can check their progress, take practice tests, search for topics, send e-mail messages, and participate in discussions and chats.

Application Software for Communications

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One of the main reasons people use computers is to communicate and share information with others. Some communications software is considered system software because it works with hardware and transmission media. Other communications software makes users more productive and/or assists them with personal tasks, and thus, is considered application software.

Web Applications

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Users can purchase application software from a software vendor, retail store, or Web-based business. Users typically install purchased application software on a computer before they run it. Installed software has two disadvantages: (1) it requires disk space on your computer, and (2) it can be costly to upgrade as vendors release new versions. As an alternative, some users opt to access Web applications.

As previously mentioned, a Web application, or Web app, is a Web site that allows users to access and interact with software from any computer or device that is connected to the Internet. Users often interact with Web applications, directly at the Web site, referred to as the host, through their Web browser. Some Web sites, however, require you download the software to your local computer or device. Web application hosts often store users' data and information on their servers, which sometimes is called cloud storage. Users concerned with data security may shy away from this type of Web application. Thus, some Web applications provide users with an option of storing data locally on their own personal computer or mobile device.

Many of the previously discussed types of application software are available as Web applications. In addition, thousands of games are available as Web applications.

Many Web application hosts provide free access to their software, such as Google Docs. Others, such as Google Earth, offer part of their Web application free and charge for access to a more comprehensive program. Some Web applications, such as online tax preparation programs, allow you to use the Web application free and pay a fee when certain action occurs. For example, you can prepare your tax return free, but if you elect to print it or file it electronically, you pay a minimal fee.

Experts often use the term Web 2.0 to describe Web applications. Recall that Web 2.0 refers to Web sites that provide users with a means to share personal information, allow users to modify Web site content, and/or have application software built into the site for visitors to use.

Software for Home, Personal, and Educational Use

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A large amount of application software is designed specifically for home, personal, and educational use. Most of the programs in this category are relatively inexpensive, often priced less than $ 100 and sometimes free. Let us discuss the features and functions of this application software.

Personal Finance Software

Personal finance software is a simplified accounting program that helps home users and small office/home office users balance their checkbooks, pay bills, track personal income and expenses, set up budgets, manage home inventory, track investments, and evaluate financial plans. Personal finance software helps determine where, and for what purpose, you are spending money so that you can manage your finances. Reports can summarize transactions by category (such as dining), by payee (such as the electric company), or by time (such as the last two months). Financial planning features include analyzing home and personal loans, preparing income taxes, and managing retirement savings.

Most of these personal finance programs also offer a variety of online services, which require access to the Internet. For example, users can track investments online, compare insurance rates from leading insurance companies, and bank online. Online banking offers access to account balances, provides bill payment services, and allows you to download monthly transactions and statements from the Web directly to your computer.

Legal Software

Legal software assists in the preparation of legal documents and provides legal information to individuals, families, and small business. Legal software provides standard contracts and documents associated with buying, selling, and renting property; estate planning; marriage and divorce; and preparing a will or living trust. By answering a series of questions or completing a form, the legal software tailors the legal document to specific needs.

Once the legal document is created, you can fit the paperwork with the appropriate agency, court, or office; or take the document to your attorney for his or her review and signature.

Tax Preparation Software

Tax preparation software, which is available both as packaged software and as Web applications, can guide individuals, families, or small businesses through the process of filling taxes. These program forecast tax liability and offer money-saving tips, designed to lower your tax bill. After you answer a series of questions and complete basic forms, the software creates and analyzes your tax forms to search for potential errors and deduction opportunities. Once the forms are complete, you can print any necessary paperwork, and then they are ready for filing. Instead of mailing forms through the postal service, the IRS allows taxpayers to file their tax returns online, called e-filing.

Desktop Publishing software (for Personal Use)

Instead of using professional DTP software, many home and small business users work with simpler, easy-to-understand DTP software designed for smaller-scale desktop publishing projects. Personal DTP software helps home and small business user create newsletters, brochures, flyers, advertisements, postcards, greeting cards, letterhead, business cards, banners, calendars, logos, and Web pages.

Although many word processing programs include DTP features, users often prefer to create DTP documents using DTP software because of its enhanced features. For example, personal DTP programs provide hundreds of thousands of graphical images. You also can import (bring in) your own digital photos into the documents. These programs typically guide you through the development of a document by asking a series of questions, offering numerous predefined layouts, and providing standard text you can add to documents. Then, you can print a finished publication on a color printer or post it on the Web in a format that can be viewed by those without DTP software.

Many personal DTP programs also include paint/image editing software and photo editing and photo management software.

Paint/Image Editing Software (for Personal Use)

Personal paint/image editing software provides an easy-to-use interface, usually with more simplified capabilities than its professional counterpart, including functions tailored to meet the needs of the home and small business user.

As with the professional versions, personal paint software includes various simplified tools that allow you to draw pictures, shapes, and other images. Personal image editing software provides the capabilities of paint software and the ability to modify existing graphics and photos. The programs also include many templates to assist you in adding images to documents such as greeting cards, banners, calendars, signs, labels, business cards, and letterhead. Some operating systems include a basic/image editing program.

Photo Editing and Photo Management Software

Instead of professional photo editing software, many home and small business users work with easier-to-use personal photo editing software, which is available both as packaged software and as Web applications. Personal photo editing software allows users to edit digital photos by removing red-eye, erasing blemishes, restoring aged photos, adding special effects, enhancing image quality, or creating electronic photo albums. When you purchase a digital camera, it usually includes photo editing software. Some digital cameras even have basic photo editing software built in so that you can edit the image directly on the camera. You can print edited photos on labels, calendars, business cards, and banners, or you can post them on the Web. Some photo editing software allows users to send digital photos to an online print service, which will deliver high-resolution printed images through the postal service or allow you to pick them up at a local store. Many online print services also have a photo community where users can post photos on the Web for others to view and purchase, if desired.

With photo management software, you can view, organize, sort, catalog, print, and share digital photos. Some photo editing software includes photo management functionality.

Clip Art/Image Gallery

Application software often includes a clip art/image gallery, which is a collection of clip art and photos. Some programs have links to additional clips available on the Web or are available as Web applications. You also can purchase clip art/image gallery software that contains thousands of images.

In addition to clip art, many clip art/image galleries provide fonts, animations, sounds, video clips, and audio clips. You can use the images, fonts, and other items from the clip art/image gallery in all types of documents, including word processing, desktop publishing, spreadsheet, and presentations.

Video and Audio Editing Software (for Personal Use)

Many home users work with easy-to-use video and audio editing software, which is much simpler to use than its professional counterpart, for small-scale movie making projects. With these programs, home users can edit home movies, add music or other sounds to the video, and share their movies on the Web. Some operating systems include video editing and audio editing software.

Home Design/Landscaping Software

Homeowners or potential homeowners can use home design/landscaping software to assist them with the design, remodeling, or improvement of a home, deck, or landscape.

Home design/landscaping software includes hundreds of predrawn plans that you can customize to meet your needs. These programs show changes to home designs and landscapes, allowing homeowners to preview proposed modifications. Once designed, many home design/landscaping programs print a materials list outlining costs and quantities for the entire project.

Travel and Mapping Software

Travel and mapping software enables users to view maps, determine route directions, and locate points of interest. Using travel and mapping software, which is available both as packaged software and as Web applications, you can display maps by searching for an address, postal code, telephone number, or point of interest ( such as airports, lodging and historical sites). This software often provides driving directions when a user enters a starting and destination point. Most programs also allow you to download construction reports and calculate mileage, time, and expenses. Many are compatible with mobile devices such as smart phones and portable media players. Many navigation devices, including those in vehicles, have travel and mapping software.

Reference and Educational Software

Reference software provides valuable and thorough information for all individuals. Popular reference software includes encyclopedias, dictionaries, and health/medical guides.

Educational software is software that teaches a particular skill. Educational software exists for just about any subject, from learning how to type to learning how to cook. Preschool to high-school learners use educational software to assist them with subjects such as reading and math or to prepare them for class or college entrance exams. Educational software often includes games and other content to make the learning experience more fun.

Many educational programs use a computer-based training approach. Computer-based training (CBT), also called computer-aided instruction (CAI), is a type of education in which students learn by using and completing exercises with instructional software. CBT typically consists of self-directed, self-paced instruction about a topic. Beginning athletes, for example, use CBT programs to learn the intricacies of baseball, football, soccer, tennis, and golf. The military and airlines use CBT simulations to train pilots to fly in various conditions and environments.

Entertainment Software

Entertainment software for personal computers, game consoles, and mobile devices includes interactive games, videos, and other programs designed to support a hobby or provide amusement and enjoyment. For example, you might use entertainment software to play games individually or with others online, make a family tree, or fly an aircraft. Many games are available as Web applications, allowing you to play individually or with other online players.

Graphics and Multimedia Software

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In addition to business software, many people work with software designed specifically for their field of work. Power users such as engineers, architects, desktop publishers, and graphic artists often use sophisticated software that allows them to work with graphics and multimedia. This software includes computer-aided design, desktop publishing, paint/image editing, photo editing, video and audio editing, multimedia authoring, and Web page authoring.

Many graphics and multimedia programs incorporate user-friendly interfaces and/or have scaled-down versions, making it possible for the home and small business users to create documents using these programs. The following sections discuss the features and functions of graphics and multimedia software.

Computer-Aided Design

Computer-aided design (CAD) software is a sophisticated type of application software that assists a professional user in creating engineering, architectural, and scientific designs. For example, engineers create design plans for vehicles and security systems. Architects design building structures and floor plans. Scientists design drawings of molecular structures.

CAD software eliminates the laborious manual drafting that design processes can require. Three-dimensional CAD programs allow designers to rotate designs of 3-D objects to view them from any angle. Some CAD software even can generate material lists for building designs.

Desktop Publishing Software (for the Professional)

Desktop publishing (DTP) software enables professional designers to create sophisticated documents that contain text, graphics, and many colors. Professional DTP software is ideal for the production of high-quality color documents such as textbooks, corporate newsletters, marketing literature, product catalogs, and annual reports.

Although many word processing programs have some of the capabilities of DTP software, professional designers and graphic artists use DTP software because it supports page layout. Page layout is the process of arranging text and graphics in a document on a page-by-page basis. DTP software includes color libraries to assist in color selections for text and graphics. A color library is a standard set of colors used by designers and printers to ensure that colors will print exactly as specified. Designers and graphic artists can print finished publications on a color printer, take them to a professional printer, or post them on the Web in a format that can be viewed by those without DTP software.

Paint/Image Editing Software (for the Professional)

Graphic artists, multimedia professionals, technical illustrators, and desktop publishers use paint software and image editing software to create and modify graphical images such as those used in DTP documents and Web pages.

Paint software, also called illustration software, allows users to draw pictures, shapes, and other graphical images with various on-screen tools such as a pen, brush, eyedropper, and paint bucket.

Image editing software provides the capabilities of paint software and also includes the capabilities of paint software and also includes the capability to enhance and modify existing images and pictures. Modifications can include adjusting or enhancing image colors, adding special effects such as shadows and glows, creating animations, and image stitching, which is the process of combining multiple images into a larger image.

Photo Editing Software (for the Professional)

Professional photo editing software is a type of image editing software that allows photographers, videographers, engineers, scientist, and other high-volume digital photo users to edit and customize digital photos. Professional photo editing software allows users to save images in a wide variety of file formats. With professional photo editing software, users can retouch photos, crop images, remove red-eye, change image shapes, color-correct images, straighten images, remove or rearrange objects in a photo, and apply filters.

Video and Audio Editing Software (for the Professional)

Video editing software allows professionals to modify a segment of a video, called a clip. For example, users can reduce the length of a video clip, reorder a series of clips, or add special effects such as words that move horizontally across the screen.

Video editing software typically includes audio editing capabilities. Audio editing software lets users modify audio clips, produce studio-quality soundtracks, and add audio to video clips. Audio editing software usually includes filters, which are designed to enhance audio quality. For example, a filter might remove a distracting background noise from the audio clip. Most television shows and movies are created or enhanced using video and audio editing software.

Multimedia Authoring Software

Multimedia authoring software allows users to combine text, graphics, audio, video, and animation in an interactive application. With this software, users control the placement of text and images and the duration of sounds, video, and animation. Once created, multimedia presentations often take the form of interactive computer-based presentations or Web-based presentations designed to facilitate learning, demonstrate product functionality, and elicit direct-user participation. Training centers, educational institutions, and online magazine publishers all use multimedia authoring software to develop interactive applications. The applications may be available on an optical disc, over a local area network, or via the Internet.

Web Page Authoring Software

Web page authoring software helps users of all skill levels create Web pages that include graphical images, video, audio, animation, and other special effects with interactive content. In addition, many Web page authoring programs allow users to organize, manage, and maintain Web sites.

Application software, such as Word and Excel, often includes Web page authoring features. This allows home and small business users to create basic Web pages using application software they already own. For more sophisticated Web pages, users work with Web page authoring software. Many Web page developers also use multimedia authoring software along with, or instead of, Web page authoring software for Web page development.

Business Software

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Business software is application software that assists people in becoming more effective and efficient while performing their daily business activities. Business software includes programs such as word processing, spreadsheet, database, presentation, note taking, personal information manager, business software for phones, business software suites, project management, accounting, document management, and enterprise computing software.

The following sections discuss the features and functions of business software. Word processing and spreadsheet software have a heavier emphasis because of their predominant use.

Word Processing Software

Word processing software is one of the more widely used types of application software. Word processing software, sometimes called a word processor, allows users to create and manipulate documents containing mostly text and sometimes graphics. Millions of people use word processing software every day to develop documents such as letters, memos, reports, mailing labels, newsletters, and Web pages.

A major advantage of using word processing software is that users easily can change what they have written. For example, you can insert, delete, or rearrange words, sentences, paragraphs, or entire sections. Word processing software also has many features to make documents look professional and visually appealing. For example, you can change the shape, size, and color of characters; apply special effects such as three-dimensional shadows; and organize text in newspaper-style columns. When using colors, however, they print as black or gray unless you have a color printer.

Most word processing software allows users to incorporate graphical images, such as digital photos and clip art, in documents. Clip art is a collection of electronic drawings, photos, and other images. Word processing software usually includes public-domain images. You can find additional public-domain and proprietary images on the Web or purchase them on optical disc. With word processing software, you easily can modify the appearance of an image after inserting it in the document.

With word processing software, you can define the size of the paper on which to print and specify the margins – that is, the portion of the page outside the main body of text, including the top, the bottom, and both sides of the paper. A feature, called wordwrap, allows users to type words in a paragraph continually without pressing the ENTER key at the end of each line. When you modify paper size or margins, the word processing software automatically rewraps text so it fits in the adjusted paper size and margins.

As you type more lines of text than can be displayed on the screen, the top portion of the document moves upward, or scrolls, off the screen. Scrolling is the process of moving different portions of the document on the screen into view.

Word processing software typically includes a spelling checker, which reviews the spelling of individual words, sections of a document, or the entire document. The spelling checker compares the words in the document with an electronic dictionary that is part of the word processing software. You can customize the electronic dictionary by adding words such as personal names. Some word processing programs also check for contextual spelling errors, such as a misuse of homophones (words pronounced the same but have different spellings or meanings, such as one and won).

Word processing software also enables you to insert headers and footers in a document. A header is text that appears at the top of each page, and a footer is text that appears at the bottom of each page. Page numbers, company names, reports titles, and dates are examples of items included in headers and footers.

In addition to these basic capabilities, most current word processing programs provide numerous additional features.

Developing a Document

With application software, such as a word processing program, users create, edit, format, save and print documents. During the process of developing a document, users likely will switch back and forth among all of these activities.

When you create a document, you enter text or numbers, insert images, and perform other tasks using an input device such as a keyboard, mouse, digital pen, or microphone. If you are using Microsoft Word to design a flyer, for example, you are creating a document.

To edit a document means to make changes to its existing content. Common editing tasks include inserting, deleting, cutting, copying, and pasting. Inserting text involves adding text to a document. Deleting text means that you are removing text or other content. Cutting is the process of removing a portion of the document and storing it in a temporary storage location, sometimes called a clipboard. A clipboard also contains items that you copy (duplicate) in a document. Pasting is the process of transferring an item from a clipboard to a specific location in a document.

When users format a document, they change its appearance. Formatting is important because the overall look of a document significantly can affect its ability to communicate clearly. Examples of formatting tasks are changing the font, font size, and font style.

A font is a name assigned to a specific design of characters. Two basics types of fonts are serif and sans serif. A serif font has short decorative lines at the upper and lower ends of some characters. Sans means without. Thus, a sans serif font does not have the short decorative lines at the upper and lower ends of the characters. Cambria is an example of a serif font. Calibri is an example of a sans serif font.

Font size indicates the size of the characters in a particular font. Font size is gauged by a measurement system called points. A single point is about 1/72 of an inch in height. A font style adds emphasis to a font. Bold, italic, underline, and color are examples of font styles.

During the process of creating, editing, and formatting a document, the computer holds it in memory. To keep the document for future use requires that you save it. When you save a document, the computer transfers the document from memory to a storage medium such as a USB flash drive or hard disk. Once saved, a document is stored permanently as a file on the storage medium.

When you print a document, the computer places the contents of the document on a paper or some other medium. You can print the same document many times, with each copy looking just like the first. Instead of printing a document and physically distributing it, some users e-mail the document to others on a network such as the Internet.

Spreadsheet Software

Spreadsheet software is another widely used type of application software. Spreadsheet software allows users to organize data in rows and columns and perform calculations on the data. These rows and columns collectively are called a worksheet. For years, people used paper to organize data and perform calculations by hand. In an electronic worksheet, you organize data in the same manner, and the computer performs the calculations more quickly and accurately. Because of spreadsheet software's logical approach to organizing data, many people use this software to organize and present non-financial data, as well as financial data.

Like word processing software, most spreadsheet software has basic features to help users create, edit, and format worksheets. Spreadsheet software also incorporates many of the features found in word processing software such as macros, checking spelling, changing fonts and font sizes, adding colors, tracking changes, inserting audio and video clips, providing research capabilities, recognizing handwritten text and drawings, and creating Web pages from existing spreadsheet documents.

The following sections describe the features of most spreadsheet programs.

Spreadsheet Organization A spreadsheet file is similar to notebook that can contain more than 1,000 related individual worksheets. Data is organized vertically in columns and horizontally in rows on each worksheet. Each worksheet usually can have more than 16,000 columns and 1 million rows. One or more letters identify each column, and a number identifies each row. Only a small fraction of the columns and rows are visible on the screen at one time. Scrolling through the worksheet displays different parts of it on the screen.

A cell is the intersection of a column and row. Each worksheet has more than 17 billion cells in which you can enter data. The spreadsheet software identifies cells by the column and row in which they are located. For example, the intersection of column B and row 4 is referred to as cell B4.

Cell can contain three types of data: labels, values, and formulas. The text, or label, entered in a cell identifies the worksheet data and helps organize the worksheet. Using descriptive labels, such as Gross Margin and Total Expenses, helps make a worksheet more meaningful.

Calculations Many of the worksheet cells can contain a number, called a value, that can be used in a calculation. Other cells, however, contain formulas that generate values. A formula performs calculations on the data in the worksheet and displays the resulting value in a cell, usually the cell containing the formula. When creating a worksheet, you can enter your own formulas.

A function is a predefined formula that performs common calculations such as adding the values in a group of cells or generating a value such as the time or date. For example, the function = SUM (B9:B13) instructs the spreadsheet program to add all of the number in cells B9 through B13.

Recalculation One of the more powerful features of spreadsheet software is its capability of recalculating the rest of the worksheet when data in a worksheet changes.

Spreadsheet software's capability of recalculating data also makes it a valuable budgeting, forecasting, and decision making tool. Most spreadsheet software includes what-if analysis tools, where you change certain values in a spreadsheet to reveal the effects of those changes.

Charting Another standard feature of spreadsheet software is charting, which depicts the data in graphical form. A visual representation of data through charts often makes it easier for users to see at a glance the relationship among the numbers.

Three popular chart types are line charts, column charts, and pie charts. A line chart shows a trend during a period of time, as indicated by a rising or falling line. A column chart, also called a bar chart, displays bars of various lengths to show the relationship of data. The bars can be horizontal, vertical, or stacked on top of one another. A pie chart, which has the shape of a round pie cut into slices, shows the relationship of parts to a whole.

When you modify data in a worksheet, any associated charts automatically update to reflect the worksheet changes. Charts, as well as any other part of a worksheet, can be linked to or embedded in a word processing document.

Database Software

A database is a collection of data organized in a manner that allows access, retrieval, and use of that data. In a manual database, you might record data on paper and store it in a filing cabinet. With a computerized database, the computer stores the data in an electronic format on a storage medium such as a hard disk.

Database software is application software that allows users to create, access, and manage a database. Using database software, you can add, change, and delete data in a database; sort and retrieve data from the database; sort and retrieve data from the database; and create forms and reports using the data in the database.

With most personal computer database programs, a database consists of a collection of tables, organized in rows and columns. Each row, called a record, contains data about a given person, product, object, or event. Each column, called a field, contains a specific category of data within a record.

Users run queries to retrieve data. A query is a request for specific data from the database. For example, a query might request clients whose balance is greater than $ 45. Database software can take the results of a query and present it in a window on the screen or send it to the printer.

Presentation Software

Presentation software is application software that allows users to create visual aids for presentations to communicate ideas, messages, and other information to a group. The presentations can be viewed as slides, sometimes called a slide show, that are displayed on a large monitor or on a projection screen.

Presentation software typically provides a variety of predefined presentation formats that define complementary colors for backgrounds, text, and graphical accents on the slides. This software also provides a variety of layout for each individual slide with clip art, a picture, a chart, a table, or a diagram. In addition, you can enhance any text, charts, and graphical images on a slide with 3-D, animation, and other special effects such as shading, shadows, and textures.

When building a presentation, users can set the slide timing so that the presentation automatically displays the next slide after a preset delay. Presentation software allows you to apply special effects to the transition between slides. One slide, for example, might fade away as the next slide appears.

To help organize the presentation, you can view thumbnail versions of all the slides similarly to how 35 mm slides look on a photographer's light table.

Presentation software typically includes a clip gallery that provides images, photos, video clips, and audio clips to enhance multimedia presentations. Users with an artistic ability can create their own graphics using paint/image editing software and then import (bring in) the graphics into a slide. Some audio and video editing programs work with presentation software, providing users with an easy means to record and insert video, music, and audio commentary in a presentation.

You can view or print a finished presentation in a variety of formats, including an outline of text from each slide, audience handouts that show completed slides, and speaker notes for each slide. Current presentation software enables users to work with multiple monitors, for example, displaying the presentation on one monitor and the speaker notes on another.

Presentation software incorporates some of the features found in word processing software such as checking spelling, formatting, providing research capabilities, recognizing handwritten text and drawings, and creating Web pages from existing slide shows.

Note Taking Software

Note taking software is application software that enables users to enter typed text, handwritten comments, drawings, or sketches anywhere on a page and then save the page as part of a notebook. The software can convert handwritten from. Users also can include audio recordings as part of their notes.

Users find note taking software convenient during meetings, class lectures, conferences, in libraries, and other settings that previously required a pencil and tablet of paper for recording thoughts and discussions.

Business Software Suite

A software suite is a collection of individual programs available together as a unit. Business software suites typically include, at a minimum, the following programs: word processing, spreadsheet, presentation, and e-mail. Popular business software suites include Microsoft Office, Apple iWork, Corel WordPerfect Office, and Google Docs.

Software suites offer two major advantages: lower cost and ease of use. When you purchase a collection of programs as a software suite, the suite usually costs significantly less than purchasing the programs individually. Software suites provide ease of use because the programs in the suite normally use a similar interface and share features such as clip art and spelling checker. For example, once you learn how to print using the software suite's word processing program, you can apply the same skill to the spreadsheet and presentation programs in the suite.

Personal Information Manager Software

A personal information manager (PIM) is application software that includes an appointment calendar, address book, notepad, and other features to help users organize personal information. With a PIM, you can take information previously tracked in a weekly or daily calendar, and organize and store it on your computer.

Mobile devices such as smart phones and PDAs include, among many other features, PIM functionality. You can synchronize, or coordinate, information so that both the mobile device and your personal computer and/or organization's server have the latest version of any updated information. Some mobile devices synchronize with the computer wirelessly. With others, you connect the mobile device to the computer with a cable, or you insert the device in a cradle, which has a cable that plugs in the computer.

Business Software for Phones

In addition to PIM software, a huge variety of business and other software is available for phones. Some software is preloaded on the phone, while other programs can be downloaded or accessed on memory cards that you insert in a slot on the device.

Business software available for phones enables users to create documents and worksheets, manage databases and lists, create slide shows, take notes, manage budgets and finances, view and edit photos, read electronic books, plan travel routes, compose and read e-mail messages, send instant messages, send text and picture messages, view maps and directions, read the latest news articles, and browse the Web. Many of the programs discussed have scaled-down versions that work with smart phones and other mobile devices.

Project Management Software

Project management software allows a user to plan, schedule, track, and analyze the events, resources, and costs of a project. Project management software helps users manage project variables, allowing them to complete a project on time and within budget. An engineer, for example, might use project management software to manage new product development to schedule timing of market analysis, product design, marketing, and public relations activities. A customer service manager might use this software to schedule the process of administering customer surveys, evaluating responses, and presenting recommendations.

Accounting Software

Accounting software helps companies record and report their financial transactions. With accounting software, business users perform accounting activities related to the general ledger, accounts receivable, account payable, purchasing, invoicing, and payroll functions. Accounting software also enables business users to write and print checks, track checking account activity, and update and reconcile balances on demand.

Most accounting software supports online credit checks, invoicing, bill payment, direct deposit, and payroll services. Some accounting software offers more complex features such as job costing and estimating, time tracking, multiple company reporting, foreign currency reporting, and forecasting the amount of raw materials needed for products. The cost of accounting software for small businesses ranges from less than one hundred to several thousand dollars. Accounting software for large businesses can cost several thousand dollars.

Document Management Software

Document management software provides a means for sharing, distributing, and searching through documents by converting them into a format that can be viewed by any user. The converted document, which mirrors the original document's appearance, can be viewed and printed without the software that created the original document. Some document management software allows users to edit and add comments to the converted document.

A popular file format that document management software uses to save converted documents is PDF (Portable Document Format), developed by Adobe Systems. Because of the widespread use of PDF files, some current business programs such as Microsoft Office include a feature that allows users to save their documents as PDF files. To view and print a PDF file, you need Acrobat Reader software which can be downloaded free from Adobe's Web site.

Many businesses use document management software to share and distribute company brochures, literature, and other documents electronically to the public. Home users distribute flyers, announcements, and graphics electronically.

Larger enterprises use more sophisticated document management software that enables users to check in and out documents or sections of documents from a central library, which stores all documents. Depending on their needs, users are granted access to certain parts of documents in the library.

Enterprise Computing Software

A large organization, commonly referred to as an enterprise, requires special computing solutions because of its size and large geographic distribution. A typical enterprise consists of a wide variety of departments, centers, and divisions – collectively known as functional units. Nearly every enterprise has the following functional units: human resources, accounting and finance, engineering or product development, manufacturing, marketing, sales, distribution, customer service, and information technology. Software used in functional units is not mutually exclusive; however, each functional unit uses specific software, as outlined below.

Human resources software manages employee information such as benefits, personal information such as benefits, personal information, performance evaluations, training, and vacation time.
Accounting software manages everyday transactions, such as sales and payments to suppliers. Financial software helps managers budget, forecast, and analyze.
Engineering or product development software allows engineers to develop plans for new products and test their product designs.
Manufacturing software assists in the assembly process, as well as in scheduling and managing the inventory of parts and products.
Marketing software allows marketing personnel to create marketing campaigns and track their effectiveness.
Sales software enables the sales force to manage contacts, schedule meetings, log customer interactions, manage product information, and take customer orders.
Distribution software analyzes and tracks inventory and manages product shipping status.
Customer service software manages the day-to-day interactions with customers, such as phone calls, e-mail messages, Web interactions, and instant messaging sessions.
Information technology staff use a variety of software to maintain and secure the hardware and software in an enterprise.

Application Software

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With the proper software, a computer is a valuable tool. Software allows users to create letters, memos, reports, and other documents; develop multimedia presentations; design Web pages and diagrams; draw and alter images; record and enhance audio and video clips; prepare and file taxes; play single player or multiplayer games; compose e-mail messages and instant messages; and much more. To accomplish these and many other tasks, users work with application software.

Application software consists of programs designed to make users more productive and/or assist them with personal tasks. Application software has a variety of uses:

To make business activities more efficient
To assist with graphics and multimedia projects
To support home, personal, and educational tasks
To facilitate communications

Application software is available in a variety of forms: packaged, custom, Web application, open source, shareware, freeware, and public domain.

Packaged software is mass-produced, copyrighted retail software that meets the needs of a wide variety of users, not just a single user or company. Packaged software is available in retail stores or on the Web.
Custom software performs functions specific to a business or industry. Sometimes a company cannot find packaged software that meets its unique requirements. In this case, the company may use programmers to develop tailor-made custom software, which usually costs more than packaged software.
A Web application is a Web site that allows users to access and interact with software from any computer or device that is connected to the Internet. Many Web sites provide free access to their programs; some charge a fee. Types of Web applications include e-mail, word processing, tax preparation, and game programs.
Open source software is software provided for use, modification, and redistribution. This software has no restrictions from the copyright holder regarding modification of the software's internal instructions and its redistribution. Open source software usually can be downloaded from the Internet, often at no cost.
Shareware is copyrighted software that is distributed at no cost for a trial period. To use a shareware program beyond that period, you send payment to the program developer. Shareware developers trust users to send payment if software use extends beyond the stated trial period. In some cases, a scaled-down version of the software is distributed free, and payment entitles the user to the fully functional product.
Freeware is copyrighted software provided at no cost by an individual or a company that retains all rights to the software. Thus, programmers typically cannot incorporate freeware in applications they intend to sell. The word, free, in freeware indicates the software has no charge.
Public-domain software has been donated for public use and has no copyright restrictions. Anyone can copy or distribute public-domain software to others at no cost.

Thousands of shareware, freeware, and public-domain programs are available on the Internet for users to download. Examples include communications, graphics, and game programs. These programs usually have fewer capabilities than packaged programs. Some packaged programs have trial versions, which you can use at no charge for a limited time, to see if the software meets your needs.

After you purchase or download software, you install it. During installation, the program may ask you to register and/or activate the software. Registering the software is optional and usually involves submitting your name and other personal information to the software manufacturer or developer. Registering the software often entitles you to product support. Product activation is a technique that some software manufacturers use to ensure the software is not installed on more computers than legally licensed. Usually, the software does not function or has limited functionality until you activate it via the Internet or telephone. Thus, activation is a required process for programs requesting it. You can activate some software more than once, for example, to run a program on both a desktop and notebook computer. Registering and/or activating the software also usually entitles you to free program updates for a specified time period, such as a year.

The Role of System Software

System software serves as the interface between the user, the application software, and the computer's hardware. To use application software, such as a word processing program, your computer must be running system software – specifically, an operating system. Three popular personal computer operating system are Windows, MacOS, and Linux.

Each time you start a computer, the operating system is loaded (copied) from the computer's hard disk into memory. Once the operating system is loaded, it coordinates all the activities of the computer. This includes starting application software and transferring data among input and output devices and memory. While the computer is running, the operating system remains in memory.

Utility Programs A utility program is a type of system software that assists users with controlling or maintaining the operation of a computer, its devices, or its software. Utility programs tipycally offer features that provide an environment conducive to successful use of application software. For example, utility programs protect a computer against malicious software and unauthorized intrusions, manage files and disks, compress files, play media files, and burn optical discs.

One of the more important utility programs protects a computer against malicious software, or malware, which is a program that acts without a user's knowledge and deliberately alters the computer's operations. A computer virus is a type of malicious software.

Working with Application Software

To use application software, you must instruct the operating system to start the program.

Personal computer operating systems often use the concept of a desktop to make the computer easier to use. The desktop is an on-screen work area that has a graphical user interface. An icon is a small image displayed on the screen that represents a program, a document, or some other object. A button is a graphical element that you activate to cause a specific action to occur. One way to activate a button is to click it. To click a button on the screen requires moving the pointer to the button and then pressing and releasing a button on the mouse (usually the left mouse button). The pointer is a small symbol displayed on the screen that moves as you interact with the mouse or other pointing device.

The Windows desktop contains a Start button on the lower-left corner of the taskbar. When you click the Start button, the Start menu is displayed on the desktop. A menu contains a list of commands from which you make selections. A command is an instruction that causes a program to perform a specific action.

To start a program, you can click its program name on a menu or in a list. This action instructs the operating system to start the program, which means the program's instructions load from a storage medium (such as a hard disk) into memory.

Once loaded into memory, the program appears in a window on the desktop. A window is a rectangular area of the screen that displays data and information. The top of a window has a title bar, which is a horizontal space that contains the window's name.

With the program loaded, you can create a new file or open an existing one. A file is a named collection of stored data, instructions, or information. A file can contain text, images, audio, and video. To distinguish among various files, each file has a file name. A file name is a unique combination of letters of the alphabet, numbers, and other characters that identifies a file. The title bar of the document window usually displays a document's file name.

In some cases, when you instruct a program to perform an activity such as print, the programs displays a dialog box. A dialog box is a window that provides information, presents available options, or requests a response.

Netiquette

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Netiquette, which is short for Internet etiquette, is the code of acceptable behaviors users should fellow while on the Internet; that is, it is the conduct expected of individuals while online. Netiquette includes rules for all aspects of the Internet, including the World Wide Web, e-mail, instant messaging, chat rooms, FTP, and newsgroups and message boards.

Other Internet Services

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The Web is only one of the many services on the Internet. The Web and other Internet services have changed the way we communicate. We use computers and mobile devices to send e-mail messages to the president, have a discussion with experts about the stock market, chat with someone in another country about genealogy, and talk about homework assignments with classmates via instant messages. Many times, these communications take place completely in writing – without the parties ever meeting each other.

We shall discuss these Internet services: e-mail, mailing lists, instant messaging, chat rooms, VoIP (Voice over IP), newsgroups and message boards, and FTP (File Transfer Protocol).

E-mail

E-mail (short for electronic mail) is the transmission of messages and files via a computer network. E-mail was one of the original services on the Internet, enabling scientists and researchers working on government-sponred projects to communicate with colleagues at other locations. Today, e-mail is a primary communications method for both personal and business use.

You use an e-mail program to create, send, receive, forward, store, print, and delete e-mail messages. Outlook and Windows Live Mail are two popular desktop e-mail programs; Gmail and Windows Live Hotmail are two popular free e-mail Web applications.

The message can be simple text or can include an attachment such as a word processing document, a graphic, an audio clip, or a video clip.

Just as you address a letter when using the postal system, you address an e-mail message with the e-mail address of your intended recipient. Likewise, when someone sends you a message, he or she must have your e-mail address. An e-mail address is a combination of a user name and a domain name that identifies a user name and a domain name that identifies a user so that he or she can receive Internet e-mail.

A user name is a unique combination of characters, such as letters of alphabet and/or numbers, that identifies a specific user. You user name must be different from the other user names in the same domain.

Sometimes, organizations decide user names for new users. In many cases, however, users select their own user names, often selecting a nickname or any other combination of characters for their user name. Many users select a combination of their first and last names so that others can remember it easily.

In a Internet e-mail address, an @ (pronounced at) symbol separates the user name from the domain name. Your service provider supplies the domain name. Most e-mail programs allow you to create an address book, or contacts folder, which contains a list of names and e-mail addresses. When you send an e-mail message, an outgoing mail server that is operated by your Internet access provider determines how to route the message through the Internet and then sends the message. STMP (simple mail transfer protocol) is a communications protocol used by some outgoing mail servers.

As you receive e-mail messages, an incoming mail server – also operated by your Internet access provider – holds the messages in your mailbox until you use your e-mail programs have a mail notification alert that informs you via a message and/or sound when you receive new mail.

Mailing Lists

A mailing list, also an e-mail list or distribution list, is a group of e-mail names and addresses given a single name. When a message is sent to a mailing list, every person on the list receives a copy of the message in his or her mailbox. For example, your credit card company may add you to its mailing list in order to send you special offers. To add your e-mail name and address to a mailing list, you subscribe to it. To remove your name, you unsubscribe from the mailing list.

Thousand of mailing lists exist about a variety of topics in areas of entertainment, business, computers, society, culture, health, recreation, and education. Many vendors use mailing lists to communicate with their customer base.

Instant messaging

Instant messaging (IM) is a real-time Internet communications service that notifies you when one or more people are online and then allows you to exchange messages or files or join a private chat room with them. Real time means that you and the people with whom you are conversing are online at the same time. Some IM services support voice and video conversations. Many IM services also can alert you to information such as calendar appointments, stock quotes, weather, or sports scores. They also allow you to send photos or other documents to a recipient, listen to streaming music, and play games with another online party. For IM to work, both parties must be online at the same time. Also, the receiver of a message must be willing to accept messages.

To use IM, you may have to install instant messenger software on the computer or mobile device, such as a smart phone, you plan to use. Some operating systems, such as Windows, include an instant messenger. Popular IM software includes AIM (AOL Instant Messenger, Google Talk, MySpace IM, Windows Live Messenger, and Yahoo! Messenger.

Few IM programs follow IM standards. To ensure successful communications, all individuals on the contact list need to use the same or a compatible instant messenger.

Chat Rooms

A chat is a real-time typed conversation that takes place on a computer. A chat room is a locatrion on an Internet server that permits user to chat with each other. Anyone in the chat room can participate in the conversation, which usually is specific to a particular topic.

As you type on your keyboard, a line of characters and symbols is displayed on the computer screen. Others connected to the same chat room server see what you have typed. Some chat rooms support voice chats and video chats, in which people hear or see each other as they chat.

To start a chat session, you connect to a chat server through a program called a chat client. Today's browsers usually include a chat client. If yours does not, you can download a chat client from the Web. Some Web sites allow users to conduct chats without a chat client.

Once you have installed a chat client, you can create or join a conversation on the chat server to which you are connected. The chat room should indicate the discussion topic. The person who creates a chat room acts as the operator and has responsibility for monitoring the conversation and disconnecting anyone who becomes disruptive. Operator status can be shared or transferred to someone else.

VoIP

VoIP, (Voice over IP, or Internet Protocol) also called Internet telephony, enables users to speak to other users over the Internet. That is, VoIP uses the Internet (instead of the public switched telephone network) to connect a calling party to one or more local or long-distance called parties.

To place an Internet telephone call, you need a high-speed Internet connection (such as a DSL or cable modem); Internet telephone service; a microphone or telephone, depending on the Internet telephone service; and Internet telephone software or VoIP router, or a telephone adapter, depending on the Internet telephone service. VoIP services also are available on some mobile devices that have wireless Internet service. Calls to other parties with the same Internet telephone service often are free.

As you speak in a microphone connected to your computer or a telephone connected to the VoIP router or telephone adapter, the Internet telephone software and the computer's sound card or the VoIP router or telephone adapter convert your spoken words (analog signals) to digital signals and then transmit the digitized audio over the Internet to the called parties. Software and equipment at the receiving parties can hear what you have said.

Newsgroups and Message Boards

A newsgroup is an online area in which users have written discussions about a particular subject. To participate in a discussion, a user posts a message, called an article, to the newsgroup, and other users in the newsgroup read and reply to the message. A thread or threaded discussion consists of the original article and all subsequent related replies.

A computer that stores and distributes newsgroup messages is called a news server. Some newsgroups require you to enter a user name and password to participate in the discussion. For example, a newsgroup for students taking a college course may require a user name and password to access the newsgroup. This ensures that only students in the course participate in the discussion.

To participate in a newsgroup, typically you use a program called a newsreader. Windows Live Mail includes a newsreader. Some Web sites, such as Google Groups, that sponsor newsgroups have a built-in newsreader.

A popular Web-based type of discussion group that does not require a newsreader is a message board. Many Web sites use message boards instead of newsgroups because they are easier to use.

FTP

FTP (File Transfer Protocol) is an Internet standard that permits file uploading and downloading with other computers on the Internet. Uploading is the opposite of downloading; that is, uploading is the process of transferring documents, graphics, and other objects from your computer to a server on the Internet. Web page authors, for example, often use FTP to upload their Web pages to a Web server.

Many operating systems include FTP capabilities. If yours does not, you can download FTP programs from the Web, usually for a small fee.

An FTP server is a computer that allows users to upload and/or download files using FTP. An FTP site is a collection of files including text, graphics, audio clips, video clips, and program files that reside on an FTP server. Many FTP sites have anonymous FTP, whereby anyone can transfer some, if not all, available files. Some FTP sites restrict file transfers to those who have authorized accounts (user names and passwords) on the FTP server.

Large files on FTP sites often are compressed to reduce storage space and download time. Before you can use a compressed (zipped) file, you must uncompress (unzip) it.

E-Commerce

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E-commerce, short for electronic commerce, is a business transaction that occurs over an electronic network such as the Internet. Anyone with access to a computer or mobile device, an Internet connection, and a means to pay for purchased goods or services can participate in e-commerce. Some people use the term m-commerce that takes place using mobile devices.

Popular uses of e-commerce by consumers include retail, finance, travel, entertainment, and health. Users can purchase just about any product or service on the Web, including groceries, flowers, books, computers, music, movies, cars, airline tickets, and concert tickets. They also can pay bills, invest in stocks, make airline reservations, reserve a hotel or car, and fill prescriptions.

Three types of e-commerce are business-to-consumer, consumer-to-consumer, and business-to-business. Business-to-consumer (B2C) e-commerce consists of the sale of goods and services to the general public. For example, Apple has a B2C Web site. Instead of visiting a retail store to purchase an iPod, customers can order one directly from Apple's Web site.

A customer (consumer) visits an online business through an electronic storefront, which contains product description, images, and a shopping cart. The shopping cart allows the customer to collect purchases. When ready to complete the sale, the customer enters personal data and the method of payment, which should be through a secure Internet connection. E-retail, short for electronic retail, occurs when businesses use the Web to sell products.

Consumer-to-consumer (C2C) e-commerce occurs when one consumer sells directly to another, such as in an online auction. With an online auction, users bid on an item. eBay is one of the more popular online auction Web sites.

As an alternative to entering credit card, bank account, or other financial information online, some shopping and auction Web sites allow consumers to use an online payment service such as PayPal or Google Checkout. To use an online payment service, you create an account that is linked to your credit card or funds at a financial institution. When you make a purchase, you use your online payment service account, which transfers money for you without revealing your financial information.

Most e-commerce, though, actually takes place between businesses, which is called business-to-business (B2B) e-commerce. Businesses often provide goods and services to other businesses, such as online advertising, recruiting, credit, sales, market research, technical support, and training. For example, some MasterCard and Visa credit card companies provide corporations with Web-based purchasing, tracking, and transaction downloading capabilities.

The World Wide Web

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Although many people use the terms World Wide Web and Internet interchangeably, the World Wide Web actually is a service of the Internet. While the Internet was developed in the late 1960s, the World Wide Web emerged in the early 1990s. Since then, it has grown phenomenally to become one of the more widely used Internet services.

The World Wide Web emerged in the early 1990s. Since then, it has grown phenomenally to become one of the more widely used Internet services.

The World Wide Web (WWW), or Web, consist of a worldwide collection of electronic documents. Each electronic document on the Web is called a Web page, which can contain text, graphics, animation, audio, and video. Additionally, Web pages usually have built-in connections to other documents. Some Web pages are static (fixed); others are dynamic (changing). Visitors to a static Web page all see the same content. With a dynamic Web page, by contrast, visitors can customize some or all of the viewed content such as desired stock quotes, weather for a region, or ticket availability for flights.

A Web site is a collection of related Web pages and associated items, such as documents and pictures, stored on a Web server. A Web server is a computer that delivers requested Web pages to your computer. The same Web server can store multiple Web sites. Some industry experts use term Web 2.0 to refer to web sites that provide a means for users to share personal information (such as social networking Web sites), allow users to modify Web site content (such as wikis, which are discussed later in this chapter), and have application software built into the site for visitors to use (such e-mail and word processing programs).

Browsing the Web

A Web browser, or browser, is application software that allows users to access and view Web pages access and view Web pages or access Web 2.0 programs. To browse the Web, you need a computer or mobile device that is connected to the Internet and has a Web browser. The more widely used Web browsers for personal computers are Internet Explorer, Firefox, Opera, Safari, and Google Chrome.

With an Internet connection established, you start a Web browser. The browser retrieves and displays a starting Web page, sometimes called the browser's home page. The initial home page that is displayed is one selected by your Web browser. You can change your browser's home page at anytime.

Another use of the term, home page, refers to the first page that a Web site displays. Similar to a book cover or table of contents for Web site, the home page provides information about the Web site's purpose and content. Many Web sites such as iGoogle, allow you to personalize the home page so that it contains areas of interest to you. The home page usually contains links to other documents, Web pages, or Web sites. A link, short for hyperlink, is a built-in connection to another related Web page or part of a Web page.

Internet-enabled mobile devices such as smart phones use a special type of browser, called a phones use a special type of browser, called a microbrowser, which is designed for their small screens and limited computing power. Many web sites design Web pages specifically for display on a microbrowser.

For a computer or mobile device to display a Web page, the page must be downloaded. Downloading is the process of a computer or device receiving information, such as a Web page, from a server on the Internet. While a browser downloads a Web page, it typically displays an animated logo or icon in the browser window. The animation stops when the download a Web page varies depending on the speed of your Internet connection and the amount of graphics involved.

Web Addresses

A web page has a unique address, called a URL (Uniform Resource Locator) or Web address. For example, the home page for the United States National Park Service Web site has http://www.nps.gov/grsm/planyourvisit/wildlifeviewing.htm in the Address bar and then press the ENTER key, the browser downloads and displays the Web page.

A Web address consists of a protocol, domain name, and sometimes the path to a specific Web page or location on a Web page. Many Web page addresses begin with http://. The http, which stands for Hypertext Transfer Protocol, is a set of rules that defines how pages transfer on the Internet.

To help minimize errors, many browsers and Web sites do not require you enter the http:// and www portions of the Web address in the Address bar. If you enter an incorrect Web address, the browser may display a list of similar address or related Web sites from which you can select.

When you enter the Web address, http://www.nps.gov/grsm/planyourvisit/wildlifeview.htm in the web browser, it sends a request to the Web server that contains the nps.gov Web site. The server then retrieves the Web page named wildlifeviewing.htm that is located in the grsm/planyourvisit path and delivers it to your browser, which then displays the Web page on the screen.

To save time, many users create bookmarks for their frequently visited Web pages. A bookmark, or favorite, is a saved Web address that you access by clicking its name in a list. That is, instead of entering a Web address to display a Web page, you can click a previously saved bookmark.

When you enter a Web address in a browser, you request, or pull, information from a Web server. Some Web servers also can push content to your computer at regular intervals or whenever updates are made to the site. For example, some Web servers provide the capability of displaying current sporting event scores or weather reports on your computer screen.

Navigating Web Pages

Most Web pages contain hypertext or hypermedia links. Hypertext refers to links in text-based documents, whereas hypermedia combines text-based links with graphic, audio, and video links. Links allow you to obtain information in a nonlinear way. That is, instead of accessing topics in a specified order, you move directly to a topic of interest. Branching from one related topic to another in a nonlinear fashion is what makes links so powerful. Some people use the phrase, surfing the Web, to refer to the activity of using links to explore the web, to refer to the activity of using links to explore the Web.

A link can be text or an image. Text links may be underlined and/or displayed in a color different from other text on the Web page. Pointing to, or positioning the pointer on, a link on the screen typically changes the shape of the pointer to a small hand with a pointing index finger. Pointing to a link also sometimes causes the link to change in appearance or play a sound. For example, an underline may disappear, the text may change color, the image may change, etc.

Each link on a Web page corresponds to a Web address or a document. To activate a link, you click it, that is, point to the link and then press the left mouse button. Clicking a link causes the Web page or document associated with the linked object might be on the same Web page, a different Web page at the same Web site, or a separate Web page at a different Web site in another city or country. To remind you visually that you have clicked a link, a text link often changes color after you click it.

Most current Web browsers support tabbed browsing, where the top of the browser displays a tab (similar to a file folder tab) for each Web page you open. To move from one open Web to another, you click the tab in the Web browser. Tabbed browsing allows users to have multiple home pages that automatically open when the browser starts. You also can organize tabs in group, called a tab group, and save the group as a favorite, so that at any time you can display all tabs at once.
Because some Web sites attempt to track your browsing habits or gather personal information, some current Web browsers include a feature that allows you to disable and/or more tightly control the dissemination of your browsing habits and personal information.

Searching the Web

The Web is a worldwide resource of information. A primary reason that people use the Web is to search for specific information, including text, pictures, music, and video.

The first step in successful searching is to identify the main idea or concept in the topic about which you are seeking information. Determine any synonyms, alternate spellings, or variant word forms for the topic. Then, use a search tool to locate the information.

Two types of search tools are search engines and subject directories. A search engine is a program that finds Web sites, Web pages, images, videos, news, maps, and other information related to a specific topic. A subject directory classifies Web pages in an organized set of categories, such as sports or shopping, and related subcategories.

Some Web sites offer the functionality of both a search engine and a subject directory.

Search Engines A search engine is helpful in locating information for which you do not know an exact Web address or are not seeking a particular Web site. Thousands of search engines are available. Some search through Web pages for all types of information. Other search engines can restrict their searches to a specific type of information, such as the following items:

Images – pictures, diagrams, and drawings.
Video – home videos, music videos, television programs, and movie clips.
Audio – music, song, recordings, and sounds.
Publications – news articles, journals, and books.
Maps – maps of a business or address, or driving directions to a destination.
People or Businesses – addresses and telephone numbers.
Blogs – specific opinions and ideas for others.

Search engines require that you enter a word or phrase, called search text or search query, that describes the item you want to find. Each word in the search text can be broad, such as spring break destinations, or more specific, such as Walt Disney World. Search engines often respond with thousands of results, whose content varies depending on the type of information you are seeking. Some results are links to Web pages or articles; other results are media, such as images and videos. You may find that many items that appear in the search results have little or nor bearing on the item you are seeking. You can eliminate the superfluous items in your search results by carefully crafting search text that limits the search.

If you misspell search text, many search engines identify alternative search text. Some also provide suggested keywords, links, and/or images as you begin typing your search text. The results of a search text, called hits, include many links to Web pages that reference the search. Each hit in the list has a link that, when clicked, displays an associated Web site or Web page. Most search engines sequence the hits based on how close the words in the search text are to one another in the titles and descriptions of the hits. Thus, the first few links probably contain more relevant information.

Some Web browsers contain an Instant Search box that, when filled in, uses a predefined or default search engine to perform searches. Using the Instant Search box eliminates the steps of displaying the search engine's Web page prior to entering the search text.

If you enter a phrase with spaces between the words in the search text, most search engines display results (hits) that include all of the words, except for common words (e.g., to, the, and). You can include some operators (e.g., +, -, *, OR, “”) in your search text to refine your search. Instead of using operators to refine your search text, many search engines have an Advanced Search feature that displays a form that assists with refining your search.

Other techniques you can use to improve your search include the following:

Use specific nouns.
Put the most important terms first in the search text.
List all possible spellings, for example, email, e-mail.
Before using a search engine, read its Help information.
If the search is unsuccessful with one search engine, try another.

Some search engines that work with navigation devices are location based, meaning they display results related to the device's current geographical position. For example, your mobile device can display all gas stations within a certain distance of your current location.

Many search engines use a program called a spider to build and maintain a lists of words found on Web sites. When you enter search text, the search engine scans this prebuilt list for hits. The more sophisticated the search engine combined with precise search criteria, the more rapid the response and effective the search.

Subject Directories A subject directory provides categorized lists of links arranged by subject. Using the search tool, you locate a particular topic by clicking links through different levels, moving from the general to the specific. Each time you click a category link, the subject directory displays a list of subcategory links, from which you again choose. You continue in this fashion until the search tool displays a list of Web pages about the desired topic.

The major disadvantage with the subject directory is that users have difficulty deciding which categories to choose as they work through the menus of links presented.

Types of Web Sites

Thirteen types of Web sites are portal, news, informational, business/marketing, blog, wiki, online social network, educational, entertainment, advocacy, Web application, content aggregator, and personal. Many Web sites fall in more than one of these categories.

Portal A portal is a Web site that, offers a variety of Internet services from a single, convenient location. Most portals offer these free services: search engine; news; sports and weather; Web publishing; reference tools such as yellow pages, stock quotes, and maps; shopping; and e-mail and other communications services.

Many portals have online communities. An online community is a Web site that joins a specific group of people with similar interests or relationships. These communities may offer online photo albums, chat rooms, and other services to facilitate communications among members.

Popular portals include AltaVista, AOL, Excite, GO.com, iGoogle, Lycos, MSN, and Yahoo!. A wireless portal is a portal designed for Internet-enabled mobile devices.

News A news Web site contains newsworthy material including stories and articles relating to current events, life, money, sports, and the weather. Many magazines and newspapers sponsor Web sites that provide summaries of printed articles, as well as articles not included in the printed versions. Newspapers and television and radio stations are some of the media that maintain news Web sites.

Informational An informational Web site contains factual information. Many United States government agencies have informational Web sites providing information such as census data, tax codes, and the congressional budget. Other organizations provide information such as public transportation schedules and published research findings.

Business/Marketing A business/marketing Web site contains content that promotes or sells products or services. Nearly every enterprise has a business/marketing Web site. Allstate Insurance Company, Dell Inc., General Motors Corporation, Kraft Foods Inc., and Walt Disney Company all have business/marketing Web sites. Many of these enterprises also allow you to purchase their products or services online.

Blog A blog, short for Weblog, is an informal Web site consisting of time-stamped articles, or posts, in a diary or journal format, usually listed in reverse chronological order. A blog that contains video clips is called a video blog, or vlog. A microblog allows users to publish short messages, usually between 100 and 200 characters, for others to read. Twitter is a popular microblog. The term blogosphere refers to the world wide collection of blogs, and the vlogosphere refers to all vlogs worldwide.

Blogs reflects the interests, opinions, and personalities of the author, called the blogger or vlogger (for vlog author), and sometimes site visitors.

Blog have become an important means of worldwide communications. Businesses create blogs to communicate with employees, customers, and vendors. Teachers create blogs to collaborate with other teachers and students. Home users create blogs to share aspects of their personal life with family, friends, and others.

Wiki A wiki is a collaborative Web site that allows users to create, add to, modify, or delete the Web site content via their Web browser. Many wikis are open to modification by general public. Wikis usually collect recent edits on a Web page so that someone can review them for accuracy. The difference between a wiki and a blog is that users cannot modify original posts made by the blogger. A popular wiki is Wikipedia, a free Web encyclopedia.

Online Social Network An online social network, also called a social network Web site, is a Web site that encourages members in its online community to share their interest, ideas, stories, photos, musics, and videos with others registered users. Most include chat rooms, newsgroups, and other communications services. Popular social networking Web sites include MySpace and Facebook, with Facebook alone boasting more than 300 million active users. In some social networking Web sites, such as Second Life, users assume in a role-playing type of environment.

A media sharing Web site is a specific type of online social network that enables members to share media such as photos, musics, and videos. Flickr, Fotki, and Webshots are popular photo sharing communities; PixelFish and YouTube are popular video sharing communities.

Educational An educational Web site offers exciting, challenging avenues for formal and informal teaching and learning. On the Web, you can learn how airplanes fly or how to cook a meal. For a more structured learning experience, companies provide online training to employees; and colleges offer online classes and degrees. Instructors often use the Web to enhance classroom teaching by publishing course materials, grades, and other pertinent class information.

Entertainment An entertainment Web site offers an interactive and engaging environment. Popular entertainment Web sites offer music, videos, sports, games, ongoing Web episodes, sweepstakes, chat rooms, and more.

Sophisticated entertainment Web sites often partner with other technologies. For example, you can cast your vote about a topic on a television show.

Advocacy An advocacy Web site contains content that describes a cause, opinion, or idea. These Web sites usually present views of a particular group or association. Sponsors of advocacy Web sites include the Democratic National Committee, the Republican National Committee, the Society fro the Prevention of Cruelty to Animals, and the Society to Protect Human Rights.

Web Application A Web application, or Web app, is a Web site that allows users to access and interact with software through a Web browser on any computer or device that is connected to the Internet. Some Web applications provide free access to their software. Others offer part of their software free and charge for access to more comprehensive features or when a particular action is requested. Example of Web application include Google Doc (word processing, spreadsheet, presentations), TurboTax Online (tax preparation), and Windows Live Hotmail (e-mail).

Content Aggregator A content aggregator is a business that gathers and organizes Web content and then distributes, or feeds, the content to subscribers for free or a fee. Examples of distributed content include news, music, video, and pictures. Subscribers select content in which they are interested. Whenever the selected content changes, it is downloaded automatically (pushed) to the subscriber's computer or mobile device.

RSS 2.0, which stands for Really Simple Syndication, is a specification that some content aggregators use to distribute content to subscribers. Atom is another specification sometimes used by content aggregators to distribute. Some current browsers include a feature, such as Internet Explorer's WebSlices, that enables content aggregators to mark sections of their Web pages as feeds to which users can subscribe.

Personal A private individual or family not usually associated with any organization may maintain a personal Web site or just a single Web page. People publish personal Web pages for a variety of reasons. Some are job hunting. Others simply want to share life experiences with the world.

Multimedia on the Web

Most Web pages include more than just formatted text and links. The more exciting Web pages multimedia. Multimedia refers to any application that combines text with graphics, animation, audio, video, and/or virtual reality. Multimedia brings a Web page to life, increases the types of information available on the Web, expands the Web's potential uses, and makes the Internet a more entertaining place to explore. Multimedia Web pages often require specific hardware and software and take more time to download because they contain large graphics files and video or audio clips. Many Web sites have an option that allows visitors to disable multimedia, for example, if they have a slower-speed Internet connection.

The sections that follow discuss how the Web uses graphics, animation, audio, video, and virtual reality.

Graphics A graphic, or graphical image, is a digital representation of nontext information such as a drawing, chart, or photo. Today, many Web pages use colorful graphical designs and images to convey messages.

The Web contains countless images about a variety of subjects. You can download many images of these images at not cost and use them for noncommercial purposes. Recall that downloading is the process of transferring an object from the Web to your computer. For example, you can insert images into greeting cards, announcements, and other documents.

Of the graphics formats that exit on the Web, the two more common are JPEG and GIF formats. JPEG is a format that compresses graphics to reduce their file size, which means the file takes up less storage space. Smaller file sizes result in faster downloading of Web pages because small files transmit faster than large files. The more compressed the file, the smaller the image and the lower the quality. The goal with JPEG graphic is to reach a balance between image quality and file size. Digital photos often use the JPEG format.

GIF graphics also use compression techniques to reduce file sizes. The GIF format works best for images that have only a few distinct colors, such as company logos. The newer PNG graphics format improves upon the GIF format, and thus may eventually replace the GIF format.

The BMP and TIFF formats may require special viewer software, and they have larger file sizes. Thus, these formats are not used on the Web as frequently as JPEG, GIF and PNG formats.

Some Web sites use thumbnails on their pages because graphics can be time-consuming to display. A thumbnail is a small version of a larger graphic. You usually can click a thumbnail to display a larger image.

Animation Many Web pages use animation which is the appearance of motion created by displaying a series of still images in sequence. Animation can make Web pages more visually interesting or draw attention to important information or links. For example, text that animates by scrolling across the screen can serve as a ticker to display stock updates, news, sports scores, weather, or other information. Web-based games often use animation.

Web page developers add animation to Web pages using a variety of techniques. Web page authoring programs, such as Adobe Flash and Microsoft Expression Web, enable Web site developers to combine animation and interactivity in Web pages. Developers unfamiliar with Web page authoring programs can create an animated GIF, which combines several GIF images in a single GIF file.

Audio On the Web, you can listen to radio clips and live audio. Audio includes music, speech, or any other sound. Simple applications consist of individual audio files available for download to a computer or device. Once downloaded, you can play (listen to) the contents of these files. Some common Web audio file formats are: AAC, AIFF, ASF, MP3, Ogg, WAV, WMA, RA, QT. Audio files are compressed to reduce their file sizes. For example, the MP3 format reduces an audio file to about one-tenth its original size, while preserving much of the original quality of the sound.

Some music publishers have Web sites that allow users to download sample tracks free to persuade them to buy all the songs contained on the CD. Others allow a user to purchase and download an entire CD. It is legal to download copyrighted music only if the song's copyright holder has granted permission for users to download and play the song.

To listen to an audio file on your computer, you need special software called a player. Most current operating systems contain a player, for example, Windows Media Player. Some audio files, however, might require you to download a player. Players available for download include iTunes and RealPlayer. You can download the players free from the Web; some are plug-ins, which are discussed later.

Some applications on the Web use streaming audio. Streaming is the process of transferring data in a continuous and even flow. Streaming allows users to access and use a file while it is transmitting. For example, streaming audio enables you to listen to music as it downloads to your computer. Many radio and television stations use streaming audio to broadcast music, interviews, talks shows, sporting events, music, video, news, live concerts, and other segments.

Podcasting is another popular method of distributing audio. A podcast is recorded audio, usually an MP3 file, stored on a Web site that can be downloaded to a computer or a portable media player such as an iPod. Examples of podcasts include music, radio shows, news stories, classroom lectures, political messages, and television commentaries. Podcasters register their podcasts with content aggregators. Subscribers select podcast feeds they want to be downloaded automatically whenever they connect. Most smart phone users who subscribe to a wireless Internet service provider can listen to streaming audio and podcasts.

Video On the Web, you can view video clips or watch live video. Video consists of images displayed in motion. Most video also has accompanying audio. You can use the Internet to watch live and/or prerecorded coverage of your favorite television programs or enjoy a live performance of your favorite vocalist. You can upload, share, or view video clips at a video sharing Web site such as YouTube. Educators, politicians, and businesses are using video blogs and video podcasts to engage students, voters, and consumers.

Simple video applications on the Web consist of individual video files, such as movie or television clips, that you must download completely before you can play them on the computer. Video files often are compressed because they are quite large in size. These clips also are short in length, usually less than 10 minutes, because they can take a long time to download. The Moving pictures Experts Group (MPEG) defines a popular video compression standard, a widely used one called MPEG-4 or MP4. Another popular video format is Adobe Flash.

As with streaming audio, streaming video allows you to view longer or live video images as they download to your computer. Widely used standards supported by most Web browsers for transmitting streaming video data on the Internet are AVI (Audio Video Interleaved), QuickTime, Widows Media Format, and RealVideo. Like RealAudio, RealVideo is supported by RealPlayer.

Virtual Reality Virtual reality (VR) is the use of computers to simulate a real or imagined environment that appears as a three-dimensional (3D) space. VR involves the display of 3-D images that users explore and manipulate interactively.

Using special VR software, a Web developer creates an entire 3-D environment that contains infinite space and depth, called a VR world. A VR world, for example, might show a house for sale. Potential buyers walk through rooms in VR house by moving an input device forward, backward, or to the side.

Games and simulations on optical disc or on the Web often use VR. Many practical applications of VR also exist. Science educators create VR modes of molecules, organisms, and other structures for students to examine. Companies use VR to showcase products or create advertisements. Architects create VR models of buildings and rooms so that clients can see how a completed construction project will look before it is built.

Plug-ins Most Web browsers have the capability of displaying basic multimedia elements on a Web page. Sometimes, a browser might need an additional program, called a plug-in. A plug-in, or add-on, is a program that extends the capability of a browser. You can download many plug-in at no cost from various Web sites. Some plug-ins run on all sizes of personal computers and mobile devices. Others have special versions for mobile devices.

Web Publishing

Before the World Wide Web, the means to share opinions and ideas with others easily and inexpensively was limited to the media, classroom, work, or social environments. Generating an advertisement or publication that could reach a massive audience required much expense; today, businesses and individuals convey information to millions of people by creating their own Web pages. The content of the Web pages ranges from news stories to product information to blogs.

Web publishing is the development and maintenance of Web pages. To develop a Web page, you do not have to be a computer programmer. For the small business or home user, Web publishing is fairly easy as long as you have the proper tools.

The five major steps in Web publishing are as follows:

Plan a Web site.

Think about issues that could affect the design of the Web site. Identify the purpose of the Web site and the characteristics of the people whom you want to visit the Web site. Determine ways to differentiate your Web site from other similar ones.

Analyze and design a Web site.

Design the layout of elements of the Web site such as links, text, graphics, animation, audio, video, and virtual reality. Required hardware may include a digital camera, Web cam, scanner, sound card, and microphone.

Create a Web site.

Use word processing program to create basic Web pages that contain text and graphics. Use Web page authoring software to create more sophisticated Web sites that include text, graphics, animation, audio, video, and special effects. For advanced features such as managing users, passwords, chat rooms, and e-mail, you may need to purchase specialized Web site management software.

Deploy a Web site.

Transfer the Web pages from your computer to a Web server. Many Internet access providers offer their customers storage space on a Web server. Another option is a Web hosting service, which provides storage space on a Web server for a reasonable monthly fee. To help others locate your Web page, register your Web address with various search engines to ensure your site will appear in the hit lists for searches for certain keywords.

Maintain a Web site.

Visit the Web site regularly to ensure the Web site contents are current and all links work properly.

Evolution of Internet

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The Internet has its roots in a networking project started by the Pentagon's Advanced Research Projects Agency (ARPA), an agency of the U.S Department of Defense. ARPA's goal was to build a network that (1) allowed scientists at different physical locations to share information and work together on military and scientific projects and (2) could function even if part of the network were disabled or destroyed by a disaster such as a nuclear attack. That network, called ARPANET, became functional in September 1969, linking scientific and academic researchers across the United States.

The original ARPANET consisted of four main computers, one each located at the University of California at Los Angeles, the University of California at Santa Barbara, the Stanford Research Institute, and the University of Utah. Each of these computers served as a host on the network. A host, more commonly known today as a server, is any computer that provides services and connections to other computers on the network. Hosts often use high-speed communications to transfer data and messages over a network.

As researchers and others realized the great benefit of using ARPANET to share data and information, ARPANET underwent phenomenal growth. By 1984, ARPANET had more than 1,000 individual computers linked as hosts. Today, more than 550 million hosts connect to the Internet.

Some organizations connected entire networks to ARPANET to take advantage of its high-speed communications. In 1986, the National Science Foundation (NSF) connected its huge network of five supercomputer centers, called NSFnet, to ARPANET. This configuration of complex networks and hosts became known as the Internet.

Until 1995, NSFnet handled the bulk of the communications activity, or traffic, on the Internet. In 1995, NFSnet terminated its network on the Internet and resumed its status as a research network.

Today, the Internet consists of many local, regional, national, and international networks. Numerous corporations, commercial firms, and other companies such as IBM provide networks to handle Internet traffic. Both public and private organizations own networks on the Internet. These networks, along with telephone companies such as Verizon and AT&T, cable and satellite companies, and the government, all contribute toward the internal structure of the Internet.

Each organization on the Internet is responsible only for maintaining its own network. No single person, company, institution, or government agency controls or owns the Internet. The World Wide Web Consortium (W3C), however, oversees research and sets standards and guidelines for many areas of the Internet. The mission of the W3C is to contribute to the growth of the Web. More than 350 organizations from around the world are members of the W3C, advising, defining standards, and addressing other issues.

Internet2

Internet2 is a not-for-profit research and development project that connects more than 200 universities and 115 companies via a high-speed private network. Founded in 1996, the goal of Internet2 is to develop and test advanced network technologies that will benefit Internet users in the short-term future. These technologies require an extremely high-speed network that exceeds the capabilities of today's Internet and networks. Examples of previous Internet2 projects that are now mainstream include telemedicine, digital libraries (online books, magazines, music, movies, speeches, etc.), and faster Internet services. Current Internet2 projects include interactive high-definition video and enhanced detection and resolution of network problems.

Connecting to the Internet

Many home and small business users connect to the Internet via high-speed broadband Internet service. With broadband Internet service, your computer or mobile device usually is connected to the Internet the entire time it is powered on. Examples of broadband Internet service include cable, DSL, fiber, radio signals, and satellite.

Cable Internet service provides high-speed Internet access through the cable television network via a cable modem.
DSL (digital subscriber line) provides high-speed Internet connections using regular copper telephone lines.
Fiber to the Premises (FTTP) uses fiber-optic cable to provide high-(speed Internet access to home and business users.
Fixed wireless provides high-speed Internet connections using a dish-shaped antenna on your house or business to communicate with a tower location via radio signals.
A cellular radio network offers high-speed Internet connections to devices with built-in compatible technology or computers with wireless modems.
A Wi-Fi (wireless fidelity) network uses radio signals to provide high-speed Internet connections to compatible or properly equipped wireless computers and devices.
Satellite Internet service provides high-speed Internet connections via a satellite dish that communicates with a satellite modem.

Employees and students typically connect their computers to the Internet through a business or school network. The business or school network connects to a high-speed broadband Internet service.

Many home users set up a Wi-Fi network, which sends signals to a communications device that is connected to a high-speed Internet service such as cable or DSL. Instead of using broadband Internet service, however, some home users connect to the Internet via dial-up access, which is a slower-speed technology. Dial-up access takes place when the modem in your computer connects to the Internet via a standard telephone line that transmits data and information using an analog (continuous wave pattern) signal. Users may opt for dial-up access because of its lower price or because broadband access is not available in their area.

Mobile users access the Internet using a variety of Internet services. Most hotels and airports provide wired or wireless Internet services, such as Wi-Fi networks, allow mobile users to connect easily to the Internet with notebook computers, smart phones, and other mobile devices while away from a telephone, cable, or other wired connection. Many public locations, such as airports, hotels, schools, shopping malls, and coffee shops, are hot spots that provide Wi-Fi Internet connections to users with mobile computers or devices. At public locations, you may be required to agree to terms of service, obtain a password (for example, from the hotel's front desk), or perform some other action in order to connect to the Internet. Some cities provide free Wi-Fi Internet connections to all residents.

Access Providers

An access provider is a business that provides individuals and organizations access to the Internet free or for a fee. For example, some Wi-Fi network provide free access while others charge a per use fee. Other access providers often charge a fixed amount for an Internet connection, offering faster speeds or more services for higher rates. Many Internet access providers offer services such as news, weather, financial data, games, travel guides, e-mail, photo communities, and online storage to hold digital photos and other files.

Access providers are categorized as regional or national ISPs, online service providers, and wireless Internet service providers.

An ISP (Internet service provider) is a regional or national access provider. A regional ISP usually provides Internet access to a specific geographic area. A national ISP is a business that provides Internet access in cities and towns nationwide. For dial-up access, some national ISPs provide both local and tool-free telephone numbers. Due to their larger size, national ISPs usually offer more services and have a larger technical support staff than regional ISPs. Examples of national ISPs are AT&T and EarthLink.

In addition to providing Internet access, an online service provider (OSP) also has many members-only features such as instant messaging or their own customized version of a Web browser. The more popular OSPs are AOL (America Online) and MSN (Microsoft Network). AOL differs from many OSPs in that it provides gateway functionality to the Internet services to which members have access. AOL also provides free access to its services to any user with a broadband Internet connection.

When selecting an ISP or OSP for dial-up access, ensure it provides at least one local telephone number. Otherwise, long-distance telephone charges will apply for the time you connect to the Internet.

A wireless Internet service provider, sometimes called a wireless data provider, is a company that provides wireless Internet access to desktop and notebook computers and mobile devices, such as smart phones and portable media players, with built-in wireless capability (such as Wi-Fi) or to computers using wireless modems or wireless access devices. Wireless modem, which usually are in the form of a USB flash drive or a card that inserts in a slot in a computer or mobile device, generally dial a telephone number to establish a connection with the wireless Internet service provider. An antenna on or built into the computer or device, wireless modem, or wireless access device typically sends signals through the airwaves to communicate with a wireless Internet service provider. Some examples of wireless Internet service providers include AT&T, Boingo Wireless, Sprint Broadband Direct, T-Mobile, and Verizon Wireless.

How Data and Information Travel the Internet

Computers connected to the Internet work together to transfer data and information around the world using servers and clients and various wired and wireless transmission media. On the Internet, your computer is a client that can access data, information, and services on a variety of servers.

The inner structure of the Internet works much like a transportation system. Just as interstate highways connect major cities and carry the bulk of the automotive traffic across the country, several main transmission media carry the heaviest amount of traffic on the Internet. These major carriers of network traffic are known collectively as the Internet backbone.

In the United States, the transmission media that make up the Internet backbone exchange data and information at several different major cities across the country. That is, they transfer data and data and information from one network to another until reaching the final destination.

Internet Address

The Internet relies on an addressing system much like the postal service o send data and information to a computer at a specific destination. An IP Address, short for Internet Protocol address, is number that uniquely identifies each computer or device connected to the Internet.
The IP address usually consists of four groups of numbers, each separated by a period. The number in each group is between 0 and 255. For example, the numbers 72.14.207.99 are an IP address. In general, the first portion of each IP address identifies the network and the last portion identifies the specific computer.

These all-numeric IP addresses are difficult to remember and use. Thus, the Internet supports the use of a text name that represents one or more IP addresses. A domain name is the text version of an IP address. As with an IP address, the components of a domain name are separated by periods.

The text in the domain name up to the first period identifies the type of Internet server.

Every domain name contains a top-level domain (TLD), which is the last section of the domain name. A generic TLD (gTLD), such as the com, identifies the type of organization associated with the domain. The Internet server and gTLD portions of a domain name often are not required.

The organization that assigns and controls top-level domains is the Internet Corporation for Assigned Names and Numbers (ICANN). For TLDs such as biz, com, info, name, net, and org, you register for a domain name from a registrar, which is an organization that sells and manages domain names.

For international Web sites outside the United States, the domain name also includes a country cod TLD (ccTLD), which is a two-letter country code, such as au for Australia. For example, www.philips.com.au is the domain name for Philips Autralia. Some smaller countries have granted use of their ccTLDs for commercial purposes such as tv (Tuvalu) for the television/entertainment industry.

The domain name system (DNS) is the method that the Internet uses to store domain names and their corresponding IP addresses. When you specify a domain name, a DNS server translates the domain name to its associated IP address so that data and information can be routed to the correct computer. A DNS server is an Internet server that usually is associated with an Internet access provider.

The growth of the Internet has led to a shortage of IP addresses. Thus, a new IP addressing scheme, called IPv6, may increase the number of available IP addresses.

The Internet

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One of the major reasons business, home, and other users purchase computers is for Internet access. The Internet is a widely used research tool, providing society with access to global information and instant communications.

Further, access to the Internet can occur anytime from a computer anywhere: at home, at work, at school, in a restaurant, on an airplane, and at a park.

The Internet, also called the Net, is a world-wide collection of networks that links millions of businesses, government agencies, educational institutions, and individuals. Each of the networks on the Internet provides resources that add to the abundance of goods, services, and information accessible via the Internet.

Today, more than one billion home and business users around the world access a variety of services on the Internet. The World Wide Web, or simply the Web, and e-mail are two of the more widely used Internet services. Other services include chat rooms, instant messaging, and VoIP (Voice over Internet Protocol).

Computer Applications in Society

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The computer has changed society today as much as the industrial revolution changed society in the eighteenth and nineteenth centuries.

People interact directly with computers in fields such as education, finance, government, health care, science, publishing, travel, and manufacturing. In addition, they can reap the benefits from breakthroughs and advances in these fields. The following lines describe how computers have made a difference in people's interactions with these disciplines.

Education

Education is the process of acquiring knowledge. In the traditional model, people learn from other people such as parents, teachers, and employers. Many forms of printed material such as books and manuals are used as learning tools. Today, educators also are turning to computers to assist with education.

Many schools and companies equip labs and classrooms with computers. Some schools require students to have a mobile computer or mobile device to access the school's network or Internet wirelessly. To promote education by computer, many vendors offer substantial student discounts on software.

Sometimes, the delivery of education occurs at one place while the learning occurs at other locations. For example, students can take a class on the Web. Some classes are blended; that is, part of the learning occurs in a classroom and the other part occurs on the Web. More than 70 percent of colleges offer distance learning classes. A few even offer entire degrees online.

Finance

Many people and companies use computers to help manage their finances. Some use finance software to balance checkbooks, pays bills, track personal income and expenses, manage investments, and evaluate financial plan. This software usually includes a variety of online services. For example, computer users can track investments and do online banking. With online banking, users access account balances, pay bills, and copy monthly transactions from the bank's computer right into their personal computers.

Many financial institutions' Web sites also offer online banking. When using a Web site instead of finance software on your computer, all your account information is stored on the bank's computer. The advantage is you can access your financial records from anywhere in the world.

Investor often use online investing to buy and sell stocks and bonds – without using a broker. With online investing, the transaction fee for each trade usually is much less than when trading through a broker.

Government

A government provides society with direction by making and administering policies. To provide citizens with up-to-date information, most government offices have Web sites. People in the United States access government Web sites to file taxes, apply for permits and licenses, pay parking tickets, buy stamps, report crimes, apply for financial aid, and renew vehicle registrations and driver's licenses. To provide these services, some Web sites require users provide personal information.

Employees of government agencies use computers as part of their daily routine. North American 911 call centers use computers to dispatch call for fire, police, and medical assistance. Military and other agency officials use the U.S. Department of Homeland Security's network of information about domestic security threats to help protect against terrorist attacks. Law enforcement officers have online access to the FBI's National Crime Information Center (NCIC) through in-vehicle notebook computers, fingerprint readers and mobile devices. The NCIC contains more than 52 million missing persons and criminal records, including names, fingerprint, parole/probation records, mug shots, and other information.

Health Care

Nearly every area of health care today uses computers. Whether you are visiting a family doctor for a regular checkup, having lab work or an outpatient test, or being rushed in for emergency surgery, the medical staff around you will be using computers for various purposes:

Hospitals and doctors use computers and mobile devices to maintain and access patients records.
Computers monitor patients' vital signs in hospital rooms and at home.
Robots deliver medication to nurse stations in hospitals.
Computers and computerized devices assist doctors, nurses, and technicians with medical tests.
Doctors use the Web and medical software to assist with researching and diagnosing health conditions.
Doctors use e-mail to correspond with patients.
Pharmacists use computers to file insurance claims.
Surgeons implant computerized devices, such as pacemakers, that allow patients to live longer.
Surgeons use computer-controlled devices to provide them with greater precision during operations, such as for laser eye surgery and robot-assisted heart surgery.

Many Web sites provide up-to-date medical, fitness, nutrition, or exercise information. These Web sites also maintain lists of doctors and dentist to help you find the one that suits your needs. They have chat rooms, so that you can talk to others diagnosed with similar conditions. Some Web sites even allow you to order prescriptions online.

Two forms of long-distance health care are telemedicine and telesurgery. Through telemedicine, health-care professionals in separate locations conduct live conferences on the computer. For example, a doctor at one location can have a conference with a doctor at another location to discuss a bone X-ray. Live images of each doctor, along with the X-ray, are displayed on each doctor's computer.

With telesurgery, also called remote surgery, a surgeon performs an operation on a patient who is not located in the same physical room as the surgeon. Telesurgery enables surgeons to direct robots to perform an operation via computers connected to a high-speed network.

Science

All branches of science, from biology to astronomy to meteorology, use computers to assist them with collecting, analyzing, and modeling data. Scientists also use the Internet to communicate with colleagues around the world.

Breakthroughs in surgery, medicine, and treatments often result from scientists' use of computers. Tiny computers now imitate functions of the central nervous system, retina of the eye, and cochlea of the ear. A cochlear implant allows a deaf person to listen. Electrodes implanted in the brain stop tremors associated with Parkinson's disease. Cameras small enough to swallow – sometimes called a camera pill – take pictures inside your body to detect polyps, cancer, and other abnormalities.

A neural network is a system that attempts to imitate the behavior of the human brain. Scientists create neural networks by connecting thousands of processors together much like the neurons in the brain are connected. The capability of a personal computer to recognize spoken words is a direct result of scientific experimentation with neural networks.

Publishing

Publishing is the process of making works available to the public. These works include books, magazines, newspapers, music, film, and video. Special software assists graphic designers in developing pages that include text, graphics, and photos; artists in composing and enhancing songs; filmmakers in creating and editing film; and journalists and mobile users in capturing and modifying video clips.

Many publishers make their works available online. Some Web sites allow you to copy the work, such as a book or music, to your desktop computer, mobile computer, smart phone, or other mobile device.

Travel

Whether traveling by car or airplane, your goal is to arrive safely at your destination. As you make the journey, you may interact with some of the latest technology.

Vehicles manufactured today often include some type of onboard navigation system, such as Onstar. Many mobile devices such as smart phones have built-in navigation systems. Some mobile users prefer to carry specialized handheld navigation devices.

In preparing for a trip, you may need to reserve a car, hotel, or flight. Many Web sites offer these services to the public. For example, you can order airline tickets on the Web. If you plan to drive somewhere and are unsure of the road to take to your destination, you can print direction s and a map from the Web.

Manufacturing

Computer-aided manufacturing (CAM) refers to the use of computers to assist with manufacturing processes such as fabrication and assembly. Industries use CAM to reduce product development costs, shorten a product's time to market, and stay ahead of the competition.

Often, robots carry out processes in a CAM environment. CAM is used by variety of industries, including oil drilling, power generation, food production, and automobile manufacturing. Automobile plants, for example, have an entire line of industrial robots that assemble a car.

Special computers on the shop floor record actual labor, material, machine, and computer time used to manufacture a particular product. The computers process this data and automatically update inventory, production, payroll, and accounting records on the company's network.

Examples of Computer Usage

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Every day, people around the world rely on different types of computers for a variety of applications. To illustrate the range of uses for computers, this section takes you on narrative tour of five categories of users:

Home user
Small office/home office (SOHO) user
Mobile user
Power user
Enterprise user

Home User

In an increasing number of homes, the computer no longer is a convenience. Instead, it is a basic necessity. Each family member, or home user, spends time on the computer for different reasons that include personal financial management, Web access, communications, and entertainment.

On the Internet, home users access a huge amount of information, conduct research, take college classes, pay bills, manage investments, shop, listen to the radio, watch movies, read books, file taxes, book airline reservations, make telephone calls, and play games. They also communicate with others around the world through e-mail, blogs, instant messages, and chat rooms using personal computers, smart phones, and other mobile devices. Home users share ideas, interests, photos, music, and videos on social networking Web sites. With a digital camera, home users take photos and then send the electronic images to others. Using a Web cam, home users easily have live video calls with friends, family members, and others.

Many home users have a portable media player, so that they can download music or podcast, and listen to the music and/or audio at a later time through earbuds attached to the player. They also usually have one or more game consoles to play video games individually or with friends and family members.

Today's homes also typically have one or more desktop computers. Many home users network multiple desktop computers throughout the house, often wirelessly. These small networks allow family members to share an Internet connection and a printer.

Home users have a variety of software. They type letters, homework assignments, and other documents with word processing software.

Personal finance software helps the home user with personal finances, investments, and family budgets. Other software assists with preparing taxes, keeping a household inventory, setting up maintenance schedules, and protecting home computers against threats and unauthorized intrusions.

Reference software, such as encyclopedias, medical dictionaries, or a road atlas, provides valuable information for everyone in the family. With entertainment software, the home user can play games, compose music, research genealogy, or create greeting cards. Educational software helps adults learn to speak a foreign language and youngsters to read, write, count, and spell.

Small Office/Home Office User

Computers assist small business and home office users in managing their resources effectively. A small office/home office (SOHO) includes any company with fewer than 50 employees, as well as the self-employed who work from home. Small offices include local law practices, accounting firms, travel agencies, and florists. SOHO users typically have a desktop computer to perform some or all of their duties. Many also have smart phones or other mobile devices to manage appointments and contact information.

SOHO users access the Internet – often wirelessly – to look up information such as addresses, directions, postal codes, flights and package shipping rates or to send and receive e-mail messages or make telephone calls.

Many have entered the e-commerce arena and conduct business on the Web. Their Web sites advertise products and services and may provide a means for taking orders. Small business Web sites sometimes use a Web cam to show the world a live view of some aspect of their business.

To save money on hardware and software, small offices often network their computers. For example, the small office connects one printer to a network for all employees to share.

SOHO users often work with basic business software such as word processing and spreadsheet programs that assist with document preparation and finances. They are likely to use other industry-specific types of software. An auto parts store, for example, will have software that allows for looking up parts, taking orders and payments, and updating inventory.

Mobile User

Today, business and schools are expanding to serve people across the country and around the world. Thus, increasingly more employees and students are mobile users, who work on a computer or mobile device while away from a main office, home office, or school. Examples of mobile users are sales representatives, real estate agents, insurance agents, meter readers, package delivery people, journalists, consultants, and students.

Mobile users often have mobile computers and/or mobile devices. With these computers and devices, the mobile user connects to other computers on a network or the Internet, often wirelessly accessing services such as e-mail and the Web. Mobile users can transfer information between their mobile device and another computer, such as one at the main office or school. For entertainment, the mobile user plays video games on a handled game console and listens to music or watches movies on a portable media player.

The mobile user works with basic business software such as word processing. With presentation software, the mobile user can create and deliver preparations to a large audience by connecting a mobile computer or device to a video projector that displays the preparation on a full screen. Many scaled-down programs are available for mobile devices such as smart phones.

Power User

Another category of user, called a power user, requires the capabilities of a workstation or other type of powerful computer. Examples of power users include engineers, scientists, architects, desktop publisher, and graphic artists.

Power users often work with multimedia, combining text, graphics, audio and video into one application. These users need computers with extremely fast processors because of the nature of their work.

The power user's workstation often contains industry-specific software; for example, engineers and architects use software to draft and design floor plans, mechanical assemblies, or vehicles. A desktop publisher uses software to prepare marketing literature. A graphic artist uses software to create sophisticated drawings. This software usually is expensive because of its specialized design.

Power user exist in all types of businesses.

Some work at home. Their computers typically have network connections and Internet access.

Enterprise User

An enterprise has hundreds or thousands of employees or customers that work in or do business with offices across a region, the country, or the world. Each employee or customer who uses a computer in the enterprise is an enterprise user.

Many large companies use the words, enterprise computing, to refer to the huge network of computers that meets their diverse computing needs. The network facilitates communications among employees at all locations. Users access the network of servers or mainframes through desktop computers, mobile computers, and mobile devices.

Enterprises use computers and the computer network to process high volumes of transactions in a single day. Although they may differ in size and in the products or services offered, all generally use computers for basic business activities. For example, they bill millions of customers, prepare payroll for thousands of employees, and manage thousands of items in inventory. Some enterprises use blogs to open communications among employees, customers and /or vendors.

Enterprises typically have e-commerce Web sites, allowing customers and vendors to conduct business online. The Web site also showcases products, services, and other company information.

The marketing department in an enterprise uses desktop publishing software to prepare marketing literature. The accounting department uses software fro accounts receivable, accounts payable, billing, general ledger, and payroll activities.

The employees in the information technology (IT) department keep the computers and the network running. They determine when the company requires new hardware or software.

Enterprise users work with word processing, spreadsheet, database, and presentation software. They also may use calendar programs to post their schedules on the network. And, they might use smart phones or mobile devices to maintain contact information. E-mail programs and Web browsers enable communications among employees, vendors, and customers.

Many employees of enterprises telecommute. Telecommuting is a work arrangement in which employees work away from a company's standard workplace and often communicate with the office through the computer. Employees who telecommute have flexible work schedules so that they can combine work and personal responsibilities, such as child care.

Elements of an Information System

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To be valuable, information must be accurate, organized, timely, accessible, useful, and cost-effective to produce. Generating information from a computer requires the following five elements:

Hardware
Software
Data
People
Procedures

Together, these elements (hardware, software, data, people, and procedures) comprise an information system.

The hardware must be reliable and capable of handling the expected workload. The software must be developed carefully and tested thoroughly. The data entered into the computer must be accurate.

Most companies with mid-sized and large computers have an IT (information technology) department. Staff in the IT department should be skilled and up-to-date on the latest technology. IT staff also should train users so that they understand how to use the computer properly. Today's users also work closely with IT staff in the development of computer applications that relate to their areas of work.

Finally, all the IT applications should have readily available documented procedures that address operating the computer and using its programs.

Embedded Computers

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An embedded computer is a special-purpose computer that functions as a component in a larger product. Embedded computers are everywhere – at home, in your car, and at work. The following list identifies a variety of everyday products that contain embedded computers.

Consumer Electronics: mobile and digital telephones, digital televisions, cameras, video recorders, DVD players and recorders, answering machines
Home Automation Devices: thermostats, sprinkling systems, security monitoring systems, appliances, lights
Automobiles: antilock brakes, engine control modules, airbag controller, cruise control
Process Controllers and Robotics: remote monitoring systems, power monitors, machine controllers, medical devices
Computer Devices and Office Machines: keyboards, printers, fax, and copy machines

Because embedded computers are components in larger products, they usually are small and have limited hardware. These computers perform various functions depending on the requirements of the product in which they reside. Embedded computers in printers, for example, monitor the amount of paper in the tray, check the ink or toner level, signal if a paper jam has occurred, and so on.

Supercomputers

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A supercomputer is the fastest, most powerful computer – and the most expensive. The fastest supercomputers are capable of processing more than one quadrillion instructions in a single second. With weights that exceeds 100 tons, these computers can store more than 20,000 times the data and information of an average desktop computer.

Applications requiring complex, sophisticated mathematical calculations use supercomputers. Large-scale simulations and applications in medicine, aerospace, automotive design, online banking, weather forecasting, nuclear energy research, and petroleum exploration use a supercomputer.

Mainframes

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A mainframe is a large, expensive, powerful computer that can handle hundreds or thousands of connected users simultaneously. Mainframes store tremendous amounts of data, instructions, and information. Most major corporations use mainframes for business activities. With mainframes, enterprises are able to bill millions of customers, prepare payroll for thousands of employees, and manage thousands of items in inventory. On study reported that mainframes process more than 83 percent of transactions around the world.

Mainframes also can act as servers in a network environment. Servers and other mainframes can access data and information from a mainframe. People also can access programs on the mainframe using terminals or personal computers.

Servers

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A server controls access to the hardware, software, and other resources on a network and provides a centralized storage area for programs, data, and information. Servers can support from two to several thousand connected computer at the same time.

In many cases, one server accesses data, information, and programs on another server. In other cases, people use personal computers or terminals to access data, information, and programs on a server. A terminal is a device with a monitor, keyboard, and memory.

Game Consoles

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A game console is a mobile computing device designed for single-player or multiplayer video games. Standard game consoles use a handheld controller(s) as an Input device(s); a television screen as an output device; and hard disks, optical discs, and/or memory cards for storage. Weighing on average between two and nine pounds, the compact size of game consoles makes them easy to use at home, in the car, in a hotel, or any location that has an electrical outlet. Three popular models are Microsoft's Xbox 360, Nintendo's Wii and Sony's PlayStation 3.

A handheld game console is small enough to fit in one hand, making it more portable than the standard game console. With the handheld game console, the controls, screen, and speakers are built into the device. Because of their reduced size, the screens are small – three to four inches. Some models use cartridges to store games; others use a memory card or a miniature optical disc. Many handheld game consoles can communicate wirelessly with other similar consoles for multiplayer gaming. Two popular models are Nintendo DS Lite and Sony's PlayStation Portable (PSP).

In addition to gaming, many game console models allow users to listen to music, watch movies, keep fit, and connect to the Internet. Game consoles can cost from a couple hundred dollars to more than $ 500.