Saheli Mkherjee - Information-technology [Final]

8/4/2019 Saheli Mkherjee - Information-technology [Final]

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NAME: SAHELI MUKHERJEE

CLASS: IX

SEC: AROLL: 39

SUBJECT: INFORMAL


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Table of ContentsOverview .....................................................................................................................................................................................................3

1.1 Getting Started in IT ....................................................................................................................................................................3

1.1.1 Computer systems and programs ...........................................................................................................................................3

1.1.2 Computer types ......................................................................................................................................................................4

1.1.3 Connecting computer systems ...............................................................................................................................................51.1.4 Birth of the Internet ............................................................................................................................................................. ...6

1.1.5 The cost of technology ...........................................................................................................................................................7

1.2 Windows Desktop Environment ..................................................................................................................................................7

1.2.1 Starting, shutting down, and restarting Microsoft Windows .................................................................................................7

1.2.2 Windows Explorer .................................................................................................................................................................8

1.2.3 The desktop ............................................................................................................................................................................91.2.4 Working with icons ..............................................................................................................................................................10

1.2.5 Recognizing an application window ....................................................................................................................................10

1.2.6 Resizing a desktop window .................................................................................................................................................11

1.2.7 Switching between windows ................................................................................................................................................11

1.3 Basic Features of Windows .......................................................................................................................................................11

1.3.1 Viewing the basic system information of a computer .........................................................................................................11

1.3.2 Setting the clock rate ............................................................................................................................................................121.3.3 Minimizing, maximizing, and exiting ..................................................................................................................................121.3.4 Adjusting the screen display ................................................................................................................................................13

1.3.5 Desktop settings ...................................................................................................................................................................13

1.3.6 Adjusting audio volume .............................................................................................................................................. ...... ...14

1.3.7 Start menu options ...............................................................................................................................................................14

1.3.8 Recycle bin ...........................................................................................................................................................................15

1.4 Overview of Software Applications ...........................................................................................................................................15

1.4.1 Word processors ...................................................................................................................................................................15

1.4.2 Spreadsheets .........................................................................................................................................................................161.4.3 Databases .............................................................................................................................................................................16

1.4.4 Graphics applications ...........................................................................................................................................................17

1.4.5 Presentation applications .....................................................................................................................................................17

1.4.6 Web browser and e-mail ......................................................................................................................................................181.5 Math for a Digital Age ...............................................................................................................................................................18

1.5.1 Measurement-related terminology .......................................................................................................................................18

1.5.2 Analog and digital systems ..................................................................................................................................................19

1.5.3 Boolean logic gates ........................................................................................................................................................... ...19

1.5.4 Decimal and binary number systems ...................................................................................................................................20

1.5.5 Decimal to binary conversions .............................................................................................................................................211.5.6 The hexadecimal number system .........................................................................................................................................22

1.5.7 Binary to hexadecimal conversion .......................................................................................................................................22

1.5.8 Hexadecimal to binary conversion .......................................................................................................................................22

1.5.9 Converting to any base .........................................................................................................................................................23

1.5.10 Introduction to algorithms ..................................................................................................................................................24

1.6 Laboratory Safety and Tools ......................................................................................................................................................26

1.6.1 Basic lab safety principles ...................................................................................................................................................26

1.6.2 Workspace practices that help reduce ESD potential ..........................................................................................................261.6.3 Tools of the trade .................................................................................................................................................................28

1.6.4 Workspace cleaning supplies ...............................................................................................................................................29

1.6.5 Workspace testing equipment ..............................................................................................................................................30

1.6.6 Lab safety agreement ...........................................................................................................................................................30

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Overview

This module will discuss the basics of Information Technology as they relate to the computer technician. It covers differentcomputer types and software applications. A brief overview of the Internet is also included. The student will identify thebasic features of the Windows operating system and the elements of the Windows desktop.

Additionally, the student will learn several vocabulary words that are important to the technician. The student will also

examine the methods used in number conversions, including binary to decimal and decimal to binary. Explanations andintroductions to analog, digital, and algorithms are included.

Safety is the first priority when working with computers. This module will detail safety procedures that pertain to the labsused throughout this course and in the workplace.

1.1 Getting Started in IT

1.1.1 Computer systems andprograms

A computer system is shown in Figure . A computersystem consists of hardware and softwarecomponents. Hardware is the physical equipment such asthe case, floppy disk drives, keyboards, monitors, cables, speakers, and printers. The term software describes theprograms that are used to operate the computer system. Computer software, also called programs, instructs the computeron how to operate. These operations may include identifying, accessing, and processing information. Essentially, aprogram is a sequence of instructions that describe how data will be processed. Programs vary widely depending on thetype of information that will be accessed or generated. For example, instructions for balancing a checkbook are verydifferent from instructions for simulating a virtual reality world on the Internet.

The two types of software are operating systems and applications.

Application software accepts input from the user and then manipulates it to achieve a result. This result is known as theoutput. Applications are programs designed to perform a specific function for the user or for another application program.Examples of applications include word processors, database programs, spreadsheets, Web browsers, Web developmenttools, and graphic design tools. Computer applications are detailed later in this module. Refer to Figures , , and forexamples of common application software.

An operating system (OS) is a program that manages all the other programs in a computer. It also provides the operatingenvironment for applications that are used to access resources on the computer. Operating systems perform basic taskslike recognizing input from the keyboard or mouse, sending output to the video screen or printer, keeping track of files on

the drives, and controlling peripherals such as printers and modems. The Disk Operating System (DOS), Windows 98,Windows 2000, Windows NT, Linux, Mac OS X, DEC VMS, and IBM OS/400 are all examples of operating systems.

Operating systems are platform-specific, meaning they are designed for specific types of computers. For example, theWindows operating system is designed for an IBM-compatible personal computer (PC). The Mac OS will only work withMacintosh computers. PC and Macintosh are called platforms. A platform is the computer system on which differentprograms can be used.

Firmware is a program that is embedded in a silicon chip rather than stored on a floppy disk. Any change to either thehardware or software can cause firmware to become outdated. This can lead to device failure, system failure, or data loss

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When this happens to older firmware, the only solution is to replace it. Current firmware is flashable, meaning that thecontents can be upgraded, or flashed. This subject is covered in more depth in a later module.

1.1.2 Computer types

Two types of computers are detailed in this section. The first is the mainframe, which has provided computing power formajor corporations for more than 40 years. The second is the personal computer, which has had more impact on peopleand business than any other device in history.

Mainframes

Mainframes are powerful machines that allow companies to automate manual tasks,shorten marketing time for new products, use financial models that enhanceprofitability, and so on. The mainframe model consists of centralizedcomputers that are usually housed in secure, climate-controlled computer rooms. Endusers interface with the computers through dumb terminals. These terminals are low

cost devices that usually consist of a monitor, keyboard, and a communication port tocommunicate with the mainframe. Initially, terminals were hard wired directly tocommunication ports on the mainframe and the communications were asynchronous. Anillustration of a mainframe computer is shown in Figure .

NOTE:Asynchronous means without respect to time. In terms of data transmission, asynchronous means that no clock or timingsource is needed to keep both the sender and the receiver synchronized. Without the use of a clock, the sender mustsignal the start and stop of each character so the receiver will know when to expect data.

A mainframe environment consists of a single computer or group of computers that can be centrally managed andmaintained. This configuration has the additional advantage of being more secure for two reasons. First, the computer isstored in a secure room. Second, the ability of the end user to introduce viruses into the system is decreased. Virusprotection and eradication costs companies hundreds of millions of U.S. dollars annually.

At its peak in the late 1970s and early 1980s, the mainframe and minicomputer market was dominated by IBM and DigitalEquipment Corporation. The minicomputer was a smaller and less expensive line of mainframes. However, these high-powered machines came with high price tags. The cost of entry into the mainframe market was typically several hundredthousand to several million U.S. dollars. The minicomputer began to bring similar capabilities at a lower price, but theminicomputer configurations often cost more than ten thousand U.S. dollars.

Mainframes continue to be prominent in corporate computing. It is estimated that 24 million dumb terminals are currentlyin use worldwide. In addition, 15 million PCs are currently deployed to function primarily as mainframe terminal emulators.These dumb terminals are American Standard Code for Information Interchange (ASCII) character based devices. Theseare often referred to as green screens because many display green characters.

The term "mainframe" used to refer to the cabinet that housed the CPU. Today it refers to a large computer system.

There are several advantages of mainframes:

Scalability, the ability to add more users as the need arisesCentralized managementCentralized backupLow cost desktop devices (dumb terminals)High level of securityThere are several disadvantages of mainframes:

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Character-based applicationsLack of vendor operating system standards and interoperability in multivendor environmentsExpensive maintenance, initial equipment, and set-up costPotential for a single point of failure in non fault-tolerant configurationsPotential for a bottleneck in timesharing systemsPCs

A personal computer (PC) is a standalone device. This means that it is independent of all other computers as shown inFigure . With the advent of the PC, the graphical user interface (GUI) gained wide introduction to users.

A GUI, pronounced goo-ee, employs a graphics display to represent procedures and programs that can be executed bythe computer. An example is the Windows desktop. These programs routinely use small pictures, called icons, torepresent different programs. The advantage of using a GUI is that the user does not have to remember complicatedcommands to execute a program. The GUIs first appeared in Xerox and Apple computers. Along with GUI, thousands ofWindows based applications were also introduced.

As PC technology has improved, the power of the PC has risen to the point that it can perform enterprise-level functions.

There are several advantages of PC computing:

Standardized hardwareStandardized, highly interoperable operating systems

GUI interfaceLow cost devices and low cost of entry, when compared to mainframesDistributed computingUser flexibilityHigh-productivity applicationsThere are several disadvantages of PC computing:

High cost for desktop computers, which average five times the cost of a dumb terminal accordingto some industry estimatesNo centralized backupNo centralized managementPhysical, data access, and virus security risks can be greaterHigh management and maintenance costs, which are generally cheaper than for mainframes

1.1.3 Connecting computer systems

The PC as a standalone device may be adequate for use as a home computer. However, businesses, government officesand schools need to exchange information and share equipment and resources. Networking was developed as a methodto connect individual computers. The individual computers in a network are referred to as workstations as illustrated inFigure .

A network is a group of computers that are connected to share resources as illustrated in Figure . Computers used bystudents, teachers, and administrators in a school are all connected through networks. This saves the expense of havingto buy peripheral equipment for each computer. For example, the printer in the school computer lab is shared with all ofthe students. A network also allows users to share files. If work is being done on a group project, a file can be saved to acentral computer called a server. This file can then be accessed from any other computer in the school.

Networks are not limited to a building or school campus. Networks can encompass an entire school district or all of theoffices in a company. A school, for example, is connected to a main district office, as are all the other schools in a district.The Internet is the ultimate network because it connects millions of smaller networks.

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Most connections are made by cable. However, wireless connections are becoming more prominent. Cable can carryvoice, data, or both. Homes may have modems that plug into telephone sockets. The telephone line carries voice signalswhen the telephone is plugged into the phone jack, but carries data signals, which are encoded to appear as if they werevoice signals, when the modem is connected. There are other, faster connections to the Internet that are available. Theseconnections include digital subscriber line (DSL), cable, and T1, T3, or E1 lines. In some parts of the world, IntegratedServices Digital Network (ISDN) is used as well. Most of these technologies are used by businesses because of the cost.Some of the high-speed services are only available in a limited area. However, improvements in communication devicesand an ever increasing demand for high-speed links will mean that many home users should have access to theseInternet connections in the next few years.

1.1.4 Birth of the Internet

As the Cold War between the West and the former Soviet Union intensified in the 1960s, the U.S. Department of Defense(DoD) recognized the need to establish communications links between major U.S. military installations. The primarymotivation was to maintain communications if a nuclear war resulted in the mass destruction and breakdown of traditionalcommunications channels. Major universities, such as the University of California and the Massachusetts Institute of

Technology (MIT), were also involved in networking projects.

The DoD funded research sites throughout the United States. In 1968, the Advanced Research Projects Agency (ARPA)contracted with Bolt, Beranek, and Newman, Inc. (BBN) to build a network. This network was based on the packetswitching technology that was developed for better transmission of computer data.

The Growth Begins in the 1970s

When the Advanced Research Projects Agency Network (ARPANET) project began, no one anticipated that the networkwould grow to the extent that it did. Throughout the 1970s, more nodes or access points were added both domesticallyand abroad.

More is Better in the 1980s

In 1983, the ARPANET was split. The Military Network(MILNET), which was integrated with the Defense DataNetwork (DDN), took 68 of the 113 existing nodes. The DDNhad been created in 1982.

The Domain Name System (DNS) was introduced in 1984.This system provided a way to map friendly host names toIP addresses. It was much more efficient and convenientthan previous methods. These methods are discussed inModule 9, Advanced Hardware Fundamentals for Servers.In 1984, more than 1,000 host computers were on thenetwork.

During the last half of the 1980s, networking increasedconsiderably. For example, the National ScienceFoundation (NSF) created supercomputer centers inthe United States at Princeton, the University of California, theUniversity of Illinois, and Cornell University. The InternetEngineering Task Force (IETF) was also created during this time. By 1987, there were 10,000 hosts on the network. By1989, that number increased to over 100,000.

The Net Becomes Big Business in the 1990s

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The phenomenal growth rate of the 1980s was nothing compared to what came in the 1990s. ARPANET evolved into theInternet, while the U.S. government became involved in pushing the development of the so-called informationsuperhighway. The National Science Foundation Network (NSFNET) backbone was upgraded to T3 speed, 44.736 MBps.In 1991, it sent more than 1 trillion bytes per month. In 1992, the Internet Society (ISOC) was formed and more than 1million hosts existed on the Internet.

The 1990s saw the explosion of commerce on the Internet. As more and more college students, faculty, individual homeusers, and companies of all sizes became connected, the business world recognized the opportunity to reach a large andexpanding affluent market. By 1995, online advertising became prominent, online banking had arrived, and even a pizzacould be ordered over the Internet.

The last five years of the century ushered in new major developments on an almost daily basis. Streaming audio andvideo, "push" technologies, and Java and ActiveX scripting took advantage of higher performance connectivity that wasavailable at lower and lower prices. Domain names became big business and particularly desirable names have sold forupwards of one million U.S. dollars. Currently there are millions of sites that exist on the Word Wide Web, and millions ofhost computers participate in this great linking. Figure shows a time line of significant events in PC networking history.The graph in Figure shows the growth of the Internet.

The tremendous growth in the computer industry means exciting job possibilities. According to projections from the U.S.Bureau of Labor Statistics, eight of the ten fastest-growing occupations will be computer-related. This means that thenumber of jobs for IT technicians and computer support personnel will almost double by the year 2010.

1.1.5 The cost of technology

As computer and networking technology have advanced over the past few decades, the cost of the increasinglysophisticated technology has fallen dramatically. Those falling prices are partially responsible for the rising prominence ofconnectivity solutions in the business world and in personal lives.

In the 1970s and 1980s, the PC shown in Figure was considered the best available at the time, and it cost severalthousand U.S. dollars. Online services existed, but they were expensive. Only big businesses and the wealthy couldafford them at the cost of 25 U.S. dollars or more per hour of access. PC veterans can still remember the announcementof the Prodigy bargain rates of only 9.95 U.S. dollars an hour for online access. The available speeds were 1200 or 2400baud, which would be considered unusable by the current user.

Today, a user can buy a computer system in the United States for under 1,000 U.S. dollars that is capable of doing muchmore. Such a machine can also operate better and faster than the mainframe version of 20 years ago, which cost 500,000U.S. dollars. Figure shows an example of a modern PC. Internet access at speeds equivalent to T1 is available throughdigital subscriber line (DSL) or cable modem service for 30 to 40 U.S. dollars per month, and prices are continuallydecreasing. Basic Internet access at 56 kbps can be obtained for much less, even free, if additional advertising on thescreen can be tolerated.

1.2 Windows Desktop Environment

1.2.1 Starting, shutting down, and restarting Microsoft Windows

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The basic functions of a computer include turning the computer on, restarting the computer, and shutting down thesystem. Because most computers have both the power button and reset button on the front of the machine, it is importantto know how do differentiate between them.

Turning on the PC

To turn on a PC, there is an external switch, or pair of switches, that must be activated. The rear switch, if included,provides the physical connection between the house power from the wall outlet and the computer power supply. Thisswitch has to be on prior to turning on the front switch. Most PCs will have a single switch in the front that is activated toprovide power.

The monitor will also have a power switch in most cases. Usually this is in the front or lower right portion of the displaycase. Switches can be push or rocker switches. They are manufactured to withstand thousands of cycles and will typicallyoutlast the PC itself.

The startup process of a computer is also referred to as booting the system.A cold boot is performed when the PC is turned on using the powerbutton. At the end of this process, the Windows operating systemdesktop will be displayed.

Shutting Down a Computer

To shutdown the computer, click on the Start button on the lower left corner ofthe Windows Taskbar as shown in Figure , and select Shut Down.Alternatively, press Ctrl-Alt-Delete and click Shut Down from the menu thatdisplays.

Do not switch the computer off until a message displays indicating thatit is safe to do so. Important data that is stored in memory while thesystem is operating needs to be written to the hard disk before switchingoff the computer. Newer computers will automatically shut off power whenthe shutdown process is complete.

NOTE:

It is extremely important not to power off the computer with the power switch. Most operating systems like Macintosh andWindows have a specific method for turning the system off. In Windows, choose the Shut Down button from the Startmenu. On a Macintosh, choose the Shut Down button from the Special menu.

Restarting the PC

Restarting a PC that has already been powered up is referred to as a warm boot. This can be achieved by pressing thereset button on the front panel. Alternatively, press Ctrl- Alt-Delete, and click Restart from the menu that displays. Theconcepts of warm boot and cold boot are discussed more thoroughly in Module 2, How Computers Work.

1.2.2 Windows Explorer

The Windows Explorer file manager in Windows provides he ability to create, copy, move, and delete files and folders. Asshown in Figure , Explorer displays the hierarchy of folders stored on the hard disk or other storage device in the leftwindow. When a user clicks on a folder in the left Explorer window, its contents will display in the right window. Two ormore instances of Explorer can be launched in order to drag and drop between them.

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Explorer can be accessed in Windows 95, 98, and Millennium (9x), by choosing Start > Programs > WindowsExplorer,from the Windows desktop as shown in Figure . In Windows 2000, choose Start > Programs > Accessories > WindowsExplorer from the menu as it displays in Figure . Another way to open Windows Explorer in Windows 9x, 2000, and XP isto right-click on Start and then select Explore.

1.2.3 The desktop

The main display screen in Windows is known as the desktop. The Windows desktop has remained consistent for mostversions of Windows including 95, 98, 98 SE, Millennium (ME), NT, 2000, and XP. Figure shows the desktop in Windows98. However, some variations may be seen in older versions of Windows 95 or in a special type of installation, such as on

a laptop or network, when certain features are disabled.

An icon is an image that represents an application or a capability. Typically, an icon is selectable as a shortcut to aprogram or file on the computer desktop. An icon can also be nonselectable as in a company logo on a web page.

Some of the icons on the desktop, such as My Computer, Network Neighborhood, My Network Places, Recycle Bin, or MyDocuments, are shortcuts to those directories. Directories will be discussed in Module 4. Other icons that may be on thedesktop, such as Microsoft Word, Excel, or Adobe Photoshop, are shortcuts to those applications.

The My Computer icon gives access to all the installed drives, which are computer storage components.

My Documents is a shortcut to personal or frequently accessed files. Network Neighborhood allows the users to seeneighboring computers in a networked environment. The Recycle Bin is discussed later in this module under the sectionBasic Features of Windows.

The taskbar is located at the bottom of the desktop. The taskbar contains the Start button, quick launch buttons, and thesystem tray. The Start button displays the Start Menu. This menu allows access to almost every program and function onthe PC. The Start Menus for Windows 98 and Windows 2000 are shown in Figure .

The quick launch buttons are located on the taskbar next to the Start button. These buttons allow immediate access to thedesktop from any application, as well as access to Internet Explorer and Outlook Express. Quick launch buttons aresimilar to desktop icons because they are shortcuts to applications. These buttons are particularly useful when severalapplications or documents are already opened and a quick way to open another application is needed.

TIP:

Test Tip: Know the different ways to open Windows Explorer.

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1.2.4 Working with icons

This section explains how to select and move desktop icons. The student will also learn how to recognize basic desktopicons such as the hard disk, directory tree, directories or folders and files, and the recycle bin or wastebasket. This section

also explains how to create a desktop shortcut icon or a desktop menu alias.

Creating Shortcuts (Icons)

To create a shortcut (icon), navigate to the program or file in Windows Explorer. Right-click the program or file and selectCreate Shortcut. The shortcut icon will appear as the last item. This icon can be moved using cut and paste or drag anddrop. An icon can also be created directly onto the desktop. Right-click on the desktop and select New > New Shortcut orCreate Shortcut. Enter the path for the program or file, and the shortcut will display on the desktop.

Moving Icons

To move the created icon or another desktop icon to another position on the desktop, click on it as shown in Figure andthen drag it to the desired location. The icon becomes semi-transparent while being dragged. To restore the icon to full

intensity, click outside of it. If the icon does not move, disable the Auto Arrange function on the desktop. To do this, right-click on an empty space of the desktop and uncheck the Auto Arrange selection as shown in Figure . Shortcut icons canbe created for frequently used programs such as web browsers, word processors,spreadsheets, and instant messengers.

Selecting Multiple Icons

To simultaneously select and move several icons, hold down the Ctrl key andclick on all the icons that are to be moved. Then drag the group of icons to the newlocation and let go of the mouse button as shown in Figure . De-select the icons byclicking on an empty part of the desktop.

Renaming Icons

There are two ways to rename an icon. The first way is to simply click once on the name under the icon as shown inFigure . Then type in a new name as shown in Figure . Click on an empty part of the desktop to complete the action. Thesecond way is to right-click on the icon and select the Rename option.

Navigating and working with the desktop is easier with the use of icons. Since icons are simply shortcuts that point toprograms and files, they can be copied, moved, and even deleted without affecting the program or file.

1.2.5 Recognizing an application window

Application windows typically have a title bar, tool bar, menu bar, status bar, and scroll bar. WordPad will be used todemonstrate the features common to most Windows applications as shown in Figure . WordPad, or Notepad on someWindows computers, is a simple word processing program located in the Start > Programs > Accessories directory of aWindows environment.

The functions of the toolbar are easy to understand and are each described below:

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Title Bar Displays the name of the document and application. In this example, it is Document - WordPad. Also locatedin the title bar are the Minimize, Maximize, and Exit buttons that will be discussed in this module.Menu Bar Contains menus for manipulating the document, such as creating new documents, copying text, insertingimages, and so on. To see the menu for each item, click on a button. A drop-down menu will display as shown in Figure .Status Bar Shows useful information such as the page number, whether the file is being saved, how to access the Helpfeature, and so on. The Status bar is located at the bottom of the window.Scroll Bar Moves the images or text through the window. Clicking and dragging the scroll bar moves the images or texteven more quickly through a window. Windows may have scroll bars that appear on the right side or the bottom of thewindow, or both. These scroll bars appear when the document is too large to be viewed entirely on one screen.A user may want to move a window to another location on the screen, particularly if there is more than one window openon the screen. Click on the title bar and then drag the window to the desired position as shown in Figure . The window willdynamically follow the cursor around similar to moving a piece of paper on a real desktop.

Most Windows applications have similar-looking menus and functions. Differences depend on the type of application.

1.2.6 Resizing a desktop window

Windows that display applications, such as WordPad, can have sizes ranging from full screen to very small as shown inFigure . To resize a window, move the cursor to any corner or side of the application window. A double-headed arrow will

appear as shown in Figure . Click and drag on the window edge to change the window size.

There are types of arrows, pointers, cursors, and other items that can be used to navigatearound in Windows as shown in Figure . To modify the mouse pointers, go to MyComputer > Control Panel > Mouse > Pointer.

1.2.7 Switching between windows

When more than one window is open, the user can switch between windows by pressing Alt-Tab. As shown in Figure , awindow appears that indicates which applications are open. While holding down the Alt button, keep pressing Tab to findthe desired window.

Document windows can also be selected by clicking the desired document on the desktop taskbar, which displays at thebottom of the screen.

1.3 Basic Features of Windows

1.3.1 Viewing the basic system information of a computer

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This section will discuss how to find system information in Windows 2000. It will also show how to view information suchas the type of operating system, the processor type, and the type and amount of random-access memory (RAM) that isinstalled. This information is valuable to the PC technician for troubleshooting and for updating the system or applications.

To view information about the system in Windows 2000, go to the Start menu and choose Programs > Accessories >System Tools > System Information as shown in Figure .

A window will open that gives the operating system (OS) name and version, the system manufacturer and model, theprocessor type and manufacturer, the BIOS version, and the memory. Figure shows this window. This information can besaved as a text file by selecting Action from the toolbar and Save As Text File as shown in Figure . The location where thefile is to be saved can be specified as shown in Figure . Figure shows the System Info.txt file in the directory. The usercan open the System Info.txt file in Notepad text editor by double-clicking on it. If the System Info.txt file is too large,Windows will prompt the user to open it in WordPad instead. The contents will be similar to what is shown in Figure . Thetext can then be copied and pasted into a word processing program such as Microsoft Word, or a spreadsheet programlike Microsoft Excel, so that the information is easier to read as shown in Figure .

NOTE:The preceding steps are specific to Windows 2000. These steps are slightly different when using Windows 98 or ME. Toachieve the same result, click Start > Programs > Accessories > System Tools > System information. Then select File >Export from the window that displays and specify a file name and directory where to save the file. The system information

is saved as a text file.

1.3.2 Setting the clock rate

The next few sections will show how to use the Microsoft Windows graphical user interface (GUI) to make changes to thedesktop. These changes include the date and time, the volume settings for the speaker, and other desktop display optionssuch as background options, screen settings, screen saver options, and so on.

To adjust the date and time, double-click on the clock on the taskbar. A popup window similar to Figure will display. Clickon the down arrow next to month to select the current month as shown in Figure . Change the year in the same manner ifneeded. To adjust the date, click on the desired numerical day of the month. Set the clock by entering the new time in thefield and selecting AM or PM.

Click on the tab labeled Time Zone as shown in Figure . Click the down arrow and choose the appropriate time zone asshown in Figure . The clock will automatically adjust itself for daylight savings changes annually.

In Windows 98, the display window to adjust the date and time properties will be different from Windows 2000. The TimeZone drop-down menu is located in the main Date & Time tab. To select the time zone, click on the Time Zone downarrow, which will open a drop-down menu, and select a time zone.

1.3.3 Minimizing, maximizing, and exiting

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Most applications in Windows have three small icons in the upper right corner of the screen that are used to minimize thescreen, maximize the screen, or exit the application. Figure shows these icons.

By clicking on the Minimize button, which is the left button, the application is placed on the taskbar. It is still open and canbe accessed by clicking on it in the taskbar.

The middle button, which is the Maximize or Restore button, changes depending on whether the window being viewed isopened partially or fully as shown in Figure . Click on this button to make the application screen smaller or larger. The farright button, which is marked with an X, closes the application.

Hint: The fastest way to minimize all windows quickly is to click the Show Desktop icon next to the Start button. Clickingthis button again restores all windows.

1.3.4 Adjusting the screen display

The screen resolution setting is dependent upon the requirements of the user, the application being used, and the version

of Windows that is installed. Young children, older adults, and those with vision difficulties may prefer larger text andimages. In addition, older video cards may not support more detailed colors or speed of display as demanded by the mostadvanced computer games, computer graphics, design software, or video editing tools.

To adjust the screen display, first minimize all windows that are open. Right-click on empty space on the desktop andchoose Properties to open the Display Properties window as shown in Figure . Alternatively, choose Settings > ControlPanel > Display from the Start menu. The following list details the tabs found on the Display Properties window:

The Background tab, as shown in Figure , allows users to choose what is displayed as background for the desktop.Windows default background is a blue screen.The Screen Saver tab, as shown in Figure , permits the selection of a screen saver and when it should activate on thedesktop. The screen saver can also be set up to require a password. Energy savings features of the monitor are alsoapplied in this tab.The Appearance tab, as shown in Figure , has settings that allow users to choose the size and color of text andbackgrounds for applications.The Effects tab, as shown in Figure , allows users to choose visual effects such as fade effects, large icons, and the abilityto show contents while dragging windows.The Web tab, as shown in Figure , has a feature that allows users to decide whether or not to show web content on theactive desktop. This tab is not available in Windows 95.The Settings tab, as shown in Figure , allows users to adjust the screen area display and colors.Setting the screen display properties is a matter of preference. Individual users can set the features of the windows for abetter visual appearance to work with.

1.3.5 Desktop settings

To adjust the desktop settings, access the Display Properties window as explained in the previous section. In the Settingstab, adjust the number of colors and the number of pixels that will be displayed as shown in Figure . Pixels are the tinydots that make up the light on the screen and determine the intensity of a screen image. For example, lower values tendto display cartoon-like color images, which are grainy with few details. Higher values display more realistic color images,which approach a "true color" of 16.7 million colors and have superb detail. Once the color or number of pixels has been

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selected, click Apply. The message in Figure will appear. Click on OK. The message in Figure will appear. Choose Yesto reconfigure the desktop. The screen display may become blank, or the desktop screen may jump around. Do not worry.Windows is adjusting the desktop to match the new settings.

NOTE:When first installing a video card, Windows will default to the lowest settings of 640x480 resolution and possibly eveneight colors. When a video card driver is installed with driver software that is supplied by the manufacturer, more colorsand resolutions can be displayed. This topic will be discussed in more detail under "Display Components" in Module 2.

1.3.6 Adjusting audio volume

To access the volume control, click on the speaker icon on the taskbar. Audio properties can also be accessed from theSounds and Multimedia icon in the Control Panel. Slide the bars up and down until the volume level and other audiosettings are adjusted. The volume control screen includes a mute option that can be used to turn off the sound completely

as shown in Figure .

1.3.7 Start menu options

The Start button is located on the Windows taskbar in the lower left hand corner of the Windows desktop. Imbedded in itare several useful Windows features. Click on the Start button as shown in Figure to access these options.

Run

The Run feature is another method of starting a program. This feature can be used instead of clicking the programshortcut icon on the desktop or in the list of programs within the Programs directory. The directory is discussed morethoroughly in Module 4. Access the Run feature by clicking on Start and choosing Run. A command line entry space willappear as shown in Figure . The user may now enter the program name and any necessary parameters as in a DOSprompt window.

NOTE:This feature is used often by the IT Technician to access the command editor and to execute diagnostic routines such asping.

Help

The Help feature provides tips and instructions on how to use Windows. The Help feature includes an index and searchfunction as shown in Figure . The Help feature for Windows is easy to use, and learning to navigate it will allow a user tofind useful information quickly. This example shows how to search for help, and how to format a floppy disk:

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Select Help from the Start menu on the taskbar.Click on the Index tab and type the keyword phrase "formatting disks".Click Display, as shown in Figure .As shown in Figure , the right side of the screen will display instructions on how to format a disk.

Find or Search

In Windows 95, 98, and Windows NT, the Find feature is used to locate files, folders, and network connections to othercomputers and peripherals. In Windows 2000, Find has been renamed Search.

Documents

The Documents menu shows a list of the most recent documents that have been accessed or created. This menu canalso be used as a shortcut method for returning to these documents. These documents are linked to the applications thatcreated them. The application will launch when the document is opened.

Programs

The Programs menu lists all of the programs that are installed on the computer. To start a program, click Start >Programs, locate the program to be started, and click on it. Shortcut icons can be made on the desktop for programs thatare used regularly.

1.3.8 Recycle bin

The Recycle Bin stores files, folders, graphics, and web pages from the hard disk that have been deleted. These itemscan be undeleted or restored back to their original location. Items remain in the Recycle Bin until they are permanentlydeleted from the computer. When the Recycle Bin fills up, Windows 2000 automatically cleans out enough space toaccommodate the most recently deleted files and folders. Figure shows the recycle bin in Windows 98 and Windows2000 with deleted files and folders.Getting to Know Windows

Upon completion of this lab, the student will have been introduced to the proper way of shutting down Windows andnavigating the Windows interface, as well as using Windows Help features.

1.4 Overview of Software Applications

1.4.1 Word processors

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As discussed earlier in this module, software applications are the programs that allow the completion of tasks. Thesetasks include writing a report, keeping track of clients, drawing a company logo, displaying web pages, and writing e-mail.

A word processor is an application that creates, edits, stores, and prints documents. Figure shows Microsoft Word 2000as an example of a word processor. All word processors can insert or delete text, define margins, copy, cut, and paste.These features, called text editors, are only supported by word processors. Most word processors support additionalfeatures that enable the manipulation and formation of documents in very sophisticated ways. Examples include filemanagement, macros, spell checkers, headers and footers, merge capabilities, advanced layout features, multiplewindows, and preview modes. The most prominent word processors are Corel WordPerfect, Microsoft Word, and Lotus.

1.4.2 Spreadsheets

In a spreadsheet, numerical data is stored in cells that are arranged on a grid. A cell is identified by its position in the grid

according to the column and row that it occupies, such as A3. The data in a cell could be a number, text, or calculation.Consider that A3 contains the value 10, and the adjacent cell, B3, contains the calculation =A3*2.54, or the value in A3multiplied by 2.54. The cell, B3, would display the value 25.4. In other words, a value in inches in A3 is converted tocentimeters in B3, since 2.54 is the conversion factor.

Spreadsheets can be used to calculate a range of numerical values and to carry out large and complex calculations. Manyspreadsheets have the ability to plot data in the form of graphs, bar charts, and pie charts. Microsoft Excel, as shown inFigure , and Lotus 1-2-3 are both examples of spreadsheet applications.

1.4.3 Databases

A database is an organized collection of data that can be easily accessed, managed, and updated. Microsoft Access,Oracle Database, and FileMaker are all examples of database applications. Microsoft Access is shown in Figure . PCdatabases are divided into two distinct categories, flat-file and relational.

Flat-File Database

A flat-file database stores information in a single table. Each column, called a field, contains a particular piece ofinformation such as first name, last name, address, or telephone number. Each row, called a record, contains information

for a particular database item. An ordinary telephone directory might be stored in this format.

Relational Database

Relational databases are a collection of flat-file databases, or tables, linked through some particular relationship. Forexample, a bank would use a relational database to store information about its clients. Individual tables would be used tocontain the names and addresses of clients, detailed information about each bank account, the amount in each account,passwords, and so on. A unique identifier, called a key, forms the relationship between records in different tables andlinks the information in these tables. For example, when money is withdrawn from a cash machine, the details of thebankcard and the password number are verified in a security table. Next, the account balance table is accessed to ensurethat sufficient funds are available. Finally, the transaction is stored in an account transaction table.

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Relational databases are the best way to store large amounts of interrelated data. These databases can manage multiplerelationships with a minimum duplication of data, which is advantageous over flat-file databases. For example, each bankaccount will have many transactions stored in conjunction with it, known as a one-to-many relationship. A single flat-filedatabase would be too overwhelmingly large and inefficient for the task. Flat-file databases are two dimensional, whilerelational databases have three or more dimensions.

1.4.4 Graphics applications

Graphics applications are used to create or modify graphical images. The two types of graphical images include object- orvector-based images, and bitmaps or raster images. To understand the difference, imagine creating a letter T as shown inFigure . A bitmap would represent the T as if it was drawn on graph paper with the corresponding squares shaded in. Avector-based graphic would describe the T with geometrical elements such as two rectangular shapes of the same size,one standing up, the other resting on top at its middle. The vector-based graphic can be enlarged or shrunk to any size.However, the bitmap will show the individual squares if the image is enlarged. Bitmaps often require much more file space

than vector graphics.

There are several types of graphic programs, which can be broken down into four main categories:

Image editing The process of creating bitmaps or raster images. The industry standard image editing software is AdobePhotoshop as shown in Figure . Its vast tool set makes it possible to manipulate and create raster or bitmap images.Illustration The process of creating object- or vector-based images. The most prominent illustration software is AdobeIllustrator. It has a tool set similar to Photoshop that creates vector-based images as opposed to raster images. Figureshows an example of this program.Animation The process of creating sequential images that give the impression of continuous movement when played ina series. There are many ways to accomplish this process. The most prominent types of animation are frame-by-frameanimation and keyframe animation. Frame-by-frame animation involves the creation of each frame. Keyframe animationallows the animator to define two key points, and uses the computer to calculate the "in between" frames. This process iscommonly known as tweening.3D graphics editing The process of using a simulated, three-dimensional environment to create geometric objects,which can be textured, painted, and animated. The geometry of 3D graphics can have real world scale and depth to assistin the creation of floor plans, model cars, or even movie special effects.Other graphics applications are used in multimedia, audio, and games.

Computer-Aided Design (CAD)

Another type of graphics application is computer-aided design (CAD). CAD software requires high-speed workstations ordesktop computers. CAD is available for generic design or specialized uses such as architectural, electrical, andmechanical.

More complex forms of CAD are solid modeling and parametric modeling, which allow objects to be created with real-world characteristics. For example, objects created in solid modeling can be sectioned, or sliced down the middle, to

reveal their internal structure.

1.4.5 Presentation applications

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Presentation applications, also known as business graphics, permit the organization, design, and delivery of presentationsin the form of slide shows and reports. Bar charts, pie charts, graphics, and other types of images can be created basedon data that is imported from spreadsheet applications. Figure shows Microsoft PowerPoint, which is a prominentpresentation application.

1.4.6 Web browser and e-mail

A web browser is an application that is used to locate and display pages from the World Wide Web (WWW). The two mostcommon browsers are Netscape Navigator shown in Figure , and Microsoft Internet Explorer shown in Figure . These aregraphical browsers, which means that they can display graphics as well as text. In addition, most modern browsers canpresent multimedia information, including sound and video, though they require plug-ins for some formats.

NOTE:

A plug-in is an auxiliary program that works with a major software package to enhance its capability. An example of aplug-in is a filter that adds special effects in an imaging program such as Photoshop. Plug-ins are added to web browsersto enable them to support new types of content including audio, video, and so on. Although the term is widely used forsoftware, it can also be used to refer to a plug-in module for hardware.

E-Mail Electronic mail (e-mail) is the exchange of computer-stored messages by network communication. Both Netscapeand Microsoft include an e-mail utility with their web browsers. Figure shows the Netscape e-mail utility.

1.5 Math for a Digital Age

1.5.1 Measurement-related terminology

When working in the computer industry, it is important to understand the terms that are used. Whether reading thespecifications about a computer system, or talking with another computer technician, there is a rather large dictionary ofterms that should be known. The technician needs to know the following terminology:

bit The smallest unit of data in a computer. A bit can take the value of either one or zero. A bit is the binary format inwhich data is processed by computers.byte A unit of measure that is used to describe the size of a data file, the amount of space on a disk or other storagemedium, or the amount of data being sent over a network. One byte consists of eight bits of data.nibble Half a byte or four bits.kilobyte (KB) 1024, or approximately 1000, bytes.kilobytes per second (kBps) A measurement of the amount of data that is transferred over a connection such as anetwork connection. kBps is a data transfer rate of approximately 1,000 bytes per second.kilobit (Kb) 1024, or approximately 1000, bits.kilobits per second (kbps) A measurement of the amount of data transferred over a connection such as a networkconnection. kbps is a data transfer rate of approximately 1,000 bits per second.megabyte (MB) 1,048,576 bytes, or approximately 1,000,000 bytes.megabytes per second (MBps) A common measurement of the amount of data transferred over a connection such as a

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network connection. MBps is a data transfer rate of approximately 1,000,000 bytes or 106 kilobytes per second.megabits per second (Mbps) A common measurement of the amount of data transferred over a connection such as anetwork connection. Mbps is a data transfer rate of approximately 1,000,000 bits or 106 kilobits per second.

NOTE:A common error is confusing KB with Kb and MB with Mb. A capital B indicates bytes while a lower case b indicates bits.Similarly, multipliers greater than one are capitalized and multipliers less than one are lower case. For example,M=1,000,000 and m=0.001. Remember to do the proper calculations when comparing transmission speeds that aremeasured in KB with those measured in Kb. For example, modem software usually shows the connection speed in kilobitsper second, such as 45 kbps. However, prominent browsers display file-download speeds in kilobytes per second.Therefore, the download speed with a 45-kbps connection would be a maximum of 5.76-kBps.

In actual practice, the download speed of a dialup connection cannot reach 45 kbps because of other factors thatconsume bandwidth at the same time as the download. The technician needs to know the following terminology:

hertz (Hz) A unit of frequency measurement. It is the rate of change in the state, or cycle, in a sound wave, alternatingcurrent, or other cyclical waveform. Hertz is synonymous with cycles per second, and it is used to describe the speed of acomputer microprocessor.megahertz (MHz) One million cycles per second. This is a common measurement of the speed of a processing chip.gigahertz (GHz) One billion cycles per second. This is a common measurement of the speed of a processing chip.

NOTE:PC processors are becoming faster all the time. The microprocessors used on PCs in the 1980s typically ran under 10

MHz, and the original IBM PC was 4.77 MHz. In the start of the year 2000, PC processors approached the speed of 1GHz, and approached 3.0 GHz as of the year 2002.

1.5.2 Analog and digital systems

The variables that characterize an analog system may have an infinite number of values. For example, the hands on ananalog clock face may show an infinite number of times of the day. Figure shows a diagram of an analog signal. Thevariables that characterize digital systems only occupy a fixed number of discrete values. In binary arithmetic, as used incomputers, only two values are allowed. These values are 0 and 1. Computers and cable modems are examples of digitaldevices. Figure shows a diagram of a digital signal.

1.5.3 Boolean logic gates

Computers are built from various types of electronic circuits. These circuits depend on what are called AND, OR, NOT,and NOR logic gates. These gates are characterized by how they respond to input signals. Figures , , and show logicgates with two inputs. The "x" and "y" represent inputs, and the "f" represents output. Think of 0 (zero) as representing"off" and 1 as representing "on".

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There are only three primary logic functions. They are AND, OR, and NOT:

AND gate If either input is off, the output is off.OR gate If either input is on, the output is on.NOT gate If the input is on, the output is off. The same is true of the opposite.The NOR gate is a combination of the OR and NOT gates and should not be presented as a primary gate. A NOR gateacts if either input is on, the output is off.

The "truth tables" in Figure represent these statements in a compact form. Other logic gate combinations or extensionssuch as XOR, NAND, and so on, are beyond the scope of this course.

Boolean Operations

Upon completion of this lab, the student will have been introduced to the AND, OR, NOR, and NOT Boolean operations.The student will also be able to calculate the output of different combinations of Boolean operations based on input.

1.5.4 Decimal and binary number systems

The decimal, or Base 10, number system is used every day for doing math such as counting change, measuring, tellingtime, and so on. The decimal number system uses ten digits including 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9.

The binary, or Base 2, number system uses two digits to express all numerical quantities. The only digits used in thebinary number system are 0 and 1. An example of a binary number is 1001110101000110100101.

It is important to remember the role of the digit 0. Every number system uses the digit 0. However, note that whenever thedigit 0 appears on the left side of a string of digits, it can be removed without changing the string value. For example, inBase 10, 02947 is equal to 2947. In Base 2, 0001001101 is equal to 1001101. Sometimes people include 0s on the leftside of a number to emphasize "places" that would otherwise not be represented.

Another important concept when working with binary numbers is the powers of numbers. The numbers 20 and 23 areexamples of numbers represented by powers. These examples are spoken as "two to the zero" and "two to the third". Thepower is the number of times that a value must be multiplied by itself. For example, 20 = 1, 21 = 2, 22 = 2 x 2 = 4, 23= 2 x2 x 2 = 8. Taking powers is commonly confused with simple multiplication For example, 24 is not equal to 2 x 4 = 8.However, 24 is equal to 2 x 2 x 2 x 2 = 16.

In Base 10, powers of ten are used. For example, 23605 in Base 10 means 2 x 10,000 + 3 x 1000 + 6 x 100 + 0 x 10 + 5 x1.

Note that 100 = 1, 101= 10, 102= 100, 103= 1000, and 104 = 10,000.

CAUTION:

Although 0 x 10 = 0, do not leave it out of the above equation. If it is left out, the base 10 places all shift to the right andresult in the number 2,365 = 2 x 1,000 + 3 x 100 + 6 x 10 + 5 x 1 instead of 23,605. A 0 within a number should never beignored. However, the value of a number is not affected by adding zeros onto the beginning, or by ignoring zeros that areon the beginning of the number. For example, 23,605 can be expressed as 0023605.

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A decimal number can be expressed in terms of powers of 10 such as 100, 101, 102, and so on. However, the actualvalue of a decimal number should be expressed in the expanded form of the powers such as 1, 10, 100, and so on. Usetables to help keep organized. Figure shows the Base 10 number 23,605 as it relates to the powers of 10.

Binary

Binary numbers are converted by using the same method as with powers of 2. Consider the binary number 10010001.Use the table in Figure to convert the binary number 10010001 into decimal.

10010001 = 1 x 128 + 0 x 64 + 0 x 32 + 1 x 16 + 0 x 8 + 0 x 4 + 0 x 2 + 1 x 1 = 128 + 16 + 1 = 145

Although the table method is an efficient way to convert binary numbers to decimal, there are other, faster methods thatcan be used.

1.5.5 Decimal to binary conversions

More than one method exists to convert binary numbers. One method is explored here. However, the student should feelfree to use another method if it is easier.

To convert a decimal number to binary, first find the largest power of 2 that will "fit" into the decimal number. Use the tablein Figure to convert the decimal number 35 into binary:

26, or 64, is larger than 35. Place a 0 in that column.25, or 32, is smaller than 35. Place a 1 in that column. Calculate how much is left over by subtracting 32 from 35. Theresult is 3.24, or 16, is larger than 3. Place a 0 in that column.23, or 8, is larger than 3. Place a 0 in that column.22, or 4, is larger than 3. Place a 0 in that column.21, or 2, is smaller than 3. Place a 1 in that column. Subtract 2 from 3. The result is 1.20, or 1, is equal to 1. Place a 1 in that column.The binary equivalent of the decimal number 35 is 0100011. By ignoring the first 0, the binary number can be written as100011.

This method works for any decimal number. Consider the decimal number 1 million. The largest power of 2 that fits in thedecimal number 1,000,000 is 219, or 524288, because 220, or 1048576, is larger than 1,000,000. According to theprocedure that was used for the previous conversion, the decimal number 1 million is converted to the binary number11110100001001000000.

This technique can rapidly become clumsy when dealing with very large numbers. A simpler technique is shown in the

section, "Converting to Any Base".

Figure includes some binary to decimal conversion exercises.

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1.5.6 The hexadecimal number system

The Base 16, or hexadecimal, number system is used frequently when working with computers because it can be used torepresent binary numbers in a more readable form. The computer performs computations in binary. However, there areseveral instances when a computer binary output is expressed in hexadecimal to make it easier to read. One way forcomputers and software to express hexadecimal output is using "0x" in front of the hexadecimal number. Whenever "0x"

is used, the number that follows is a hexadecimal number. For example, 0x1234 means 1234 in Base 16. This wouldtypically be found in a router configuration register.

Base 16 uses 16 characters to express numerical quantities. These characters are 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E,and F. An "A" represents the decimal number 10, "B" represents 11, "C" represents 12, "D" represents 13, "E" represents14, and "F" represents 15. Examples of hexadecimal numbers are 2A5F, 99901, FFFFFFFF, and EBACD3. Thehexidecimal number B23CF is equal to 730,063 in decimal format as shown in Figure .

The traditional conversion between decimal and hexadecimal is outside the scope of this course. However, someshortcuts for conversion to any base, including decimal and hexadecimal, will be discussed in this module.

1.5.7 Binary to hexadecimal conversion

Binary to hexadecimal conversion is uncomplicated for the most part. First observe that 1111 in binary is F in hexadecimaas shown in Figure . Also, 11111111 in binary is FF in hexadecimal. One useful fact when working with these two numbersystems is that one hexadecimal character requires 4 bits, or 4 binary digits, to be represented in binary.

To convert a binary number to hexadecimal, first divide the number into groups of four bits at a time, starting from theright. Then convert each group of four bits into hexadecimal. This method will produce a hexadecimal equivalent to the

original binary number, as shown in Figure .

For example, consider the binary number 11110111001100010000. Breaking it down into groups of four bits to produce1111 0111 0011 0001 0000. This binary number is equivalent to F7310 in hexadecimal, which is a much easier number toread.

As another example, the binary number 111101 is grouped as 11 1101. Because the first group does not contain 4 bits, itmust be "padded" with 0s to produce 0011 1101. Therefore, the hexadecimal equivalent is 3D.

1.5.8 Hexadecimal to binary conversion

Use the reverse method of the previous section to convert numbers from hexadecimal to binary. Convert each individualhexadecimal digit to binary, and then string together the solution. However, be careful to pad each binary representation

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with zeros to fill up four binary places for each hexadecimal digit. For example, consider the hexadecimal number FE27. Fis 1111, E is 1110, 2 is 10 or 0010, and 7 is 0111. Therefore, the answer in binary is 1111 1110 0010 0111, or1111111000100111.

1.5.9 Converting to any base

Most people already know how to do many number conversions. For example, convert inches to yards. First divide thenumber of inches by 12 to determine the number of feet. The remainder is the number of inches left. Next divide thenumber of feet by 3 to determine the number of yards. The remainder is the number of feet left. These same techniquesare used for converting numbers to other bases.

Consider that decimal is the normal base and octal, Base 8, is the foreign base. To convert from decimal to octal, divideby 8 successively and record the remainders starting from the least significant remainder.

Convert the number 1234 in decimal and to octal.

1234 / 8 = 154 R 2 154 / 8 = 19 R 2 19 / 8 = 2 R 3 2 / 8 = 0 R 2

The remainders in the order of least to most significant provide the result of 2322 in octal.

To convert back again, multiply a running total by 8 and add each digit successively beginning with the most significantnumber.

2 x 8 = 16 16 + 3 = 19 19 x 8 = 152 152 + 2 = 154 154 x 8 = 1232 1232 + 2 = 1234

The same results in the reverse conversions can be achieved by using numerical powers.

2 x 83 + 3 x 82 + 2 x 81 + 2 x 80 = 1024 + 192 + 16 + 2 = 1234.

NOTE:Any number raised to the power of zero is one.

Using Numerical Powers to Convert

Similar techniques can be used to convert to and from any base, simply by dividing or multiplying by the foreign base.

However, binary is unique because odd and even can be used to determine ones and zeros without recording theremainders. Determine the binary equivalent of 1234 in decimal simply by dividing it by 2 successively. If the result iseven, the bit associated with it is 0. If the result is odd, the binary digit associated with it is 1.

1234 is even. Record a 0 in the least significant position, 0. 1234/2 = 617 is odd. Record a 1 in the next most significantposition, 10. 617/2 = 308 is even, 010 308/2 = 154 is even, 0010 154/2 = 77 is odd, 10010 77/2 = 38 is even, 010010 38/2

= 19 is odd, 1010010 19/2 = 9 is odd, 11010010 9/2 = 4 is even, 011010010 4/2 = 2 is even, 0011010010 2/2 = 1 is odd,10011010010

With practice, the running dividend can be mastered and the binary can be written quickly.

Note that just as a hexadecimal digit is a group of four bits, octal is a group of three digits. Group the above number intogroups of three, starting at the right.

010 011 010 010 = 2322 octal

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For hexadecimal, group the binary number by four bits starting from the right.

0100 1101 0010 = 4D2 hexadecimal or 0x4D2

This is a quick and easy method to convert to any base.

Converting Numbers Overview

Upon completion of this lab, the student will be able to identify the places in binary and decimal numbers and know thevalue of each. Also, the student will work with powers of ten and relate them to decimal places, as well as work withpowers of two and relate them to binary places. Finally, the student will manually convert between simple binary numbersand decimal numbers and describe the differences between binary and decimal number systems.

1.5.10 Introduction to algorithms

An algorithm is a systematic description or method of exactly how to carry out a series of steps to complete a certain task.Computers use algorithms in practically every function they perform. Essentially, a software program is many algorithmspieced together into a huge set of "code". Learning computer programming means learning how to create and implementalgorithms. Many algorithms are prepackaged for use in programs. This keeps programmers from having to start fromnothing every time a program is written. The concept, especially with "object-oriented" programming, is to use existingcode to build more sophisticated programs or code. Three particular examples of algorithms are described in the followingsections.

Euclidean Algorithm

The Euclidean algorithm is used to do long division when dividing two numbers.

Dijkstra Algorithm

The Dijkstra algorithm is used by networking device on the Internet. This algorithm is used to find the shortest pathbetween a specific networking device and all other devices in its "routing domain". This algorithm uses bandwidth tomeasure the shortest path.

Encryption Algorithm

Encryption algorithms are used to prevent hackers from viewing data as it passes through the Internet. For example, anencryption algorithm is used by 3DES, pronounced "triple dez". 3DES is an encryption standard used to secureconnections between networking devices and hosts. Further details about 3DES are outside the scope of this course.

Algorithms are step-by-step procedures that perform a specific task. Computers use algorithms to accelerate and simplifyprocedures. Most algorithms used by computers are fairly complex and require some background in computer science tounderstand.

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1.6 Laboratory Safety and Tools

1.6.1 Basic lab safety principles

In the following modules, the student will assemble a computer. Observe this list of guidelines to help create a safe,efficient work environment, as shown in Figure :

The workspace should be large enough to accommodate the system unit, the technicians tools, the testing equipment,and the electrostatic discharge (ESD) prevention equipment. Near the workbench, power outlets should be available toaccommodate the system unit power and the power needs of other electrical devices.The optimal level of humidity in the workspace should be between 20 percent and 50 percent to reduce the likelihood ofESD. The temperature of the workspace should also be controlled to avoid too much heat.The workbench should be a nonconductive surface, which is flat and cleanable.The workspace should be distant from areas of heavy electrical equipment or concentrations of electronics. For example,a workspace should not be near a buildings heating, venting and air-conditioning (HVAC) or phone system controls.The workspace should be cleaned of dust. Dust can contaminate the workspace, causing premature damage to computercomponents. The work area should have a filtered air system to reduce dust and contaminants.Lighting should be adequate to see small details. Two different illumination forms are preferred, such as an adjustablelamp with a shade and fluorescent lighting.Temperatures should be maintained so they are consistent with the specifications of the components. Extreme variationsof temperature can affect computer components.AC electrical current should be properly grounded. Figure shows the components of an outlet. Power outlets should betested with an outlet tester for proper grounding.

1.6.2 Workspace practices that help reduce ESD potential

The workspace should be situated away from carpeted areas because carpets can cause the build up of electrostaticcharges. If distance from carpeting is not possible, the carpeted surface could be covered with a plastic anti-static matsuch as those commonly used under desk chairs. The use of ESD protection tools such as a wrist strap and a mat, whichare commonly sold in kits, can largely eliminate this type of danger.

TIP:

Test Tip: Know when and how damage from ESD occurs.

When working with components, lay the mat on the workspace next to or under the system case. Clip the mat to the caseto provide a grounded surface on which parts can be placed as they are removed from the system. Always handle allcomponents by their edges. Avoid touching pins, chips, or anything else made of metal. This practice will reduce thechance of producing a damaging electrostatic discharge. Reducing the potential for electrostatic discharge reduces thelikelihood of damage to delicate circuits or components.

Avoid touching the computer screen for any reason while it is turned on. Even brief touches to an active screen can put anelectrostatic charge in the hand, which can discharge through the keyboard.

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Using a Wrist Strap

A wrist strap, as shown in Figure , is a device that is attached to the technicians wrist. This device is then clipped to themeta l system chassis, on which work is being performed on. The wrist strap prevents ESD damage by channeling staticelectricity from the person to the ground.

After the wrist strap is attatched, wait 15 seconds before touching any sensitive electronic components with bare hands.This pause allows the wrist strap to neutralize the static electricity that already exists on the technicians body. ESDpotential can also be reduced by not wearing clothing made of silk, polyester, or wool. These fabrics tend to build staticcharges. Figure shows a typical workbench setup that is used to protect against ESD.

A wrist strap, as shown in Figure , can only offer protection from ESD voltages carried on the body. ESD charges onclothing can still cause damage. Therefore, avoid making contact between electronic components and clothing. If staticshocks are still being experienced in the workspace while working near a computer, try using a fabric softener or an anti-static spray on clothing. Be certain to spray clothing and not the computer. A wrist-grounding strap does not dischargeelectrostatic charges that have built up on hair. Take precautions to ensure that hair does not rub across any of thecomponents.

When should a wrist strap not be used for grounding?

There are some exceptions to wearing a wrist strap in order to provide a safe ground. A wrist strap is never worn whenworking on a monitor or a computer power supply. Monitors and power supplies are considered replaceable components.

Only highly skilled professionals will attempt to open and repair them.

WARNING:

Monitors and power supplies should not be opened. Doing so could expose a person to danger.

Components inside a monitor can hold a charge for a long time, even after the monitor has been unplugged from itsexternal power source. The amount of voltage that a monitor can contain, even when turned off and unplugged, is enoughto kill. The risk of contacting the dangerous electric charge in the monitor is heightened when a wrist strap is worn. Thecathode ray tube (CRT) in the monitor is charged to 20,000 volts or more. This charge can remain for weeks after the

monitor is turned off.

Storage of Equipment

Electronic components or circuit boards should be stored in shielded antistatic bags, which are easily recognized by ashielding characteristic. These bags usually have a silver color and a shiny, transparent appearance. Shielded antistaticbags are important because they protect components from static electricity. Shielded antistatic bags need to be in goodcondition, without crinkles or holes. Even tiny openings from crinkles will limit the ability of the bag to provide protectionfrom electrostatic discharges. When original packaging is not available, circuit boards and peripherals should betransported in a shielded antistatic bag. However, never put a shielded anti-static bag inside a PC. In addition, never plugin a motherboard while it is sitting on top of an anti-static bag. Remember that anti-static bags are partially conductive. Amotherboard could easily be shorted out while starting up if several hundred pins from its components were touching theconductive bag.

If computer components are stored in plastic bins, the bins should be made of a conductive plastic. A non-conductiveplastic bin will tend to build up an electrostatic charge. Make a habit of touching the bins to equalize the bin charge to thebody before reaching for the components in the bin. Also remember to touch the skin of the hands of another individualbefore passing the component to that individual.

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1.6.3 Tools of the trade

Most tools used in the computer assembly process are small hand tools. They are available individually, or included aspart of PC toolkits that can be purchased at computer stores. If a technician is working on laptops, then a small Torxscrewdriver will be necessary. This tool does not come in all PC toolkits. The figure shows a typical tool set used by atechnician.

The correct tools can save time and help the technician avoid causing damage to the equipment. Tool kits range widely insize, quality, and price. PC Technicians typically have these tools:

An ESD wrist strapStraight head screwdriver, large and smallPhillips head screwdriver, large and smallTweezers or part retrieverLong-nosed pliersWire cuttersChip extractorHex wrench setTorx screwdriver

Nut driver, large and smallThree-claw component holderDigital multimeterWrap plugsSmall mirrorSmall dust brushSoft, lint-free clothCable tiesScissorsSmall flashlightElectric tapeNotebook-size pencil or penThese materials should also be readily available:

Additional screwsExpansion card insertsDrive faceplatesMounting kitsExtra cablesOrganizational Aids

These items are workspace organizational aids:

A parts organizer for small parts, such as screws and connectorsAdhesive or masking tape to make labels that identify partsA small notebook to keep track of assembly or troubleshooting stepsA place to keep quick references and detailed troubleshooting guides

A clipboard for paperworkDiagnostic Software for System Repair and Maintenance

Once a computer system has been assembled, it is necessary to load the software that allows it to boot. If there are anyproblems in booting up a new system, testing software is available on floppy disk.

These software tools are commonly used in PC computing:

Partition Magic Advanced drive partitioning softwareCheckIt Fault isolation software

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Spinrite Hard drive scanning toolAmiDiag Hardware fault isolation softwareDiskSuite Hard drive defrag softwareSecureCRT Feature filled terminal softwareVNC Remote access softwareNorton Antivirus Prominent virus protection software

Information on each of these software tools can be downloaded from the respective manufacturer sites. Always find outwhat a particular software tool can do before purchasing it to ensure that it meets the job requirements.

1.6.4 Workspace cleaning supplies

Although a new system will not need to be cleaned during the assembly process, computer systems can gather dust andother residues over time. Dust particles themselves may contain chemical residues that can degrade or short-circuit chipscontact surfaces, and wire contacts. Oil from human fingers can contaminate or corrode a sensitive electrical connection.Even perspiration from skin contains chemical salts that can corrode electrical connections. A technician will hold all

electronic boards by their edges, and not where the metal contacts are located.

The component surfaces of a computer need periodic cleaning. A cleaning constitutes more than blowing off orvacuuming out the dust and lint. Commonly used cleaning products include spray contact cleaner, canned air, solvents,swabs, and cleaning pads. Most vendors provide guidelines for the cleaning supplies that should be used with theequipment they produce. Be familiar with these guidelines and obtain the recommended supplies. Figure shows an imageof the canned air.

Spray contact cleaner is a mixture of solvent and lubricant. It is used to penetrate into a very small area such as a contactpoint. The can usually has a long, thin plastic nozzle inserted into the head, which enables it to discharge the solution in aprecise manner.

Spray contact cleaner is useful when removing corroded electrical contacts or loosening adapter boards that haveadhesive residues on the connection points.

Solvents are used with swabs to remove residues that adhere to circuit boards or contacts, especially when boards orcontacts cannot be easily reached with regular cleaning pads. Isopropyl alcohol is a reliable and frequently used solvent,and is commonly sold in drugstores.

CAUTION:

Do not confuse isopropyl alcohol with rubbing alcohol. Rubbing alcohol is relatively impure and can contaminate electricalconnections. Swabs that resemble typical cotton swabs, but have a foam or chamois cloth on the end, should be usedwith isopropyl alcohol. Cotton swabs should not be used because they shred and leave strands on the components.

Prepackaged cleaning pads are used for open, flat, easily accessible surfaces. These types of swabs and cleaning padscan be obtained at any electronics supply store.

Be especially careful when using cleaning chemicals. Take measures to protect the eyes against volatile solutions. Thetechnician must also be careful when storing volatile cleaning chemicals because they can escape from the storagecontainer.

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1.6.5 Workspace testing equipment

When assembling a computer system, the technician may need to test electrical signals on a motherboard or itscomponents. The technician may also need to test the external power environment. A troublesome power source cancause difficulties for the computer systems that are plugged in. Figure shows a Fluke 110 Multimeter, which is used totest high-voltage devices. In addition to the outlet tester and digital multimeter, wrap plugs should be part of the standard

equipment kept in the workspace. These plugs are also referred to as