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CompTIA A+ Exam 220-801 Objective MapObjective chapter
1.0 pc harDWare (40 perceNt) 1.1 ConfigureandapplyBIOSsettings. 21.2 Differentiatebetweenmotherboardcomponents,theirpurposes,andproperties. 1,2,31.3 CompareandcontrastRAMtypesandfeatures. 31.4 Installandconfigureexpansioncards. 5,61.5 Installandconfigurestoragedevicesanduseappropriatemedia. 41.6 DifferentiateamongvariousCPUtypesandfeaturesandselecttheappropriatecoolingmethod. 31.7 Compareandcontrastvariousconnectioninterfacesandexplaintheirpurpose. 4,5,6,9,191.8 Installanappropriatepowersupplybasedonagivenscenario. 11.9 Evaluateandselectappropriatecomponentsforacustomconfiguration,tomeetcustomerspecifi-
cationsorneeds.10
1.10 Givenascenario,evaluatetypesandfeaturesofdisplaydevices. 61.11 Identifyconnectortypesandassociatedcables. 4,5,6,191.12 Installandconfigurevariousperipheraldevices. 5,6,72.0 NetWOrKiNG (27 perceNt)2.1 Identifytypesofnetworkcablesandconnectors. 192.2 Categorizecharacteristicsofconnectorsandcabling. 192.3 ExplainpropertiesandcharacteristicsofTCP/IP. 20,21,242.4 ExplaincommonTCPandUDPports,protocols,andtheirpurpose. 20,212.5 Compareandcontrastwirelessnetworkingstandardsandencryptiontypes. 232.6 Install,configure,anddeployaSOHOwireless/wiredrouterusingappropriatesettings. 22,232.7 CompareandcontrastInternetconnectiontypesandfeatures. 9,182.8 Identifyvarioustypesofnetworks. 18,192.9 Compareandcontrastnetworkdevicesandtheirfunctionsandfeatures. 18,222.10 Givenascenario,useappropriatenetworkingtools. 19,243.0 LaptOpS (11 perceNt) 3.1 Installandconfigurelaptophardwareandcomponents. 83.2 Compareandcontrastthecomponentswithinthedisplayofalaptop. 83.3 Compareandcontrastlaptopfeatures. 84.0 priNterS (11 perceNt)4.1 Explainthedifferencesbetweenthevariousprintertypesandsummarizetheassociatedimaging
process.7
4.2 Givenascenario,install,andconfigureprinters. 74.3 Givenascenario,performprintermaintenance. 75.0 OperatiONaL prOceDUreS (11 perceNt) 5.1 Givenascenario,useappropriatesafetyprocedures. 1,6,195.2 Explainenvironmentalimpactsandthepurposeofenvironmentalcontrols. 1,105.3 Givenascenario,demonstratepropercommunicationandprofessionalism. 105.4 Explainthefundamentalsofdealingwithprohibitedcontent/activity. 10
ExamObjectives Theexamobjectiveslistedherearecurrentasofthisbook‘spublicationdate.ExamobjectivesaresubjecttochangeatanytimewithoutpriornoticeandatCompTIA’ssolediscretion.PleasevisittheCompTIACertificationswebpageforthemostcurrentlistingofexamobjectives:http://certification.comptia.org/getCertified /certifications.aspx.
CompTIA A+ Exam 220-802 Objective MapObjective chapter
1.0 OperatiNG SYSteMS (33 perceNt)1.1 CompareandcontrastthefeaturesandrequirementsofvariousMicrosoftOperatingSystems. 121.2 Givenascenario,install,andconfiguretheoperatingsystemusingthemostappropriatemethod. 11,12,15,16,181.3 Givenascenario,useappropriatecommandlinetools. 14,16,17,241.4 Givenascenario,useappropriateoperatingsystemfeaturesandtools. 7,12,13,14,15,
16,17,22,251.5 Givenascenario,useControlPanelutilities(theitemsareorganizedby“classicview/largeicons”in
Windows).6,8,13,15,22,25
1.6 SetupandconfigureWindowsnetworkingonaclient/desktop. 18,19,21,22,241.7 Performpreventivemaintenanceproceduresusingappropriatetools. 15,16,17,261.8 ExplainthedifferencesamongbasicOSsecuritysettings. 251.9 Explainthebasicsofclient-sidevirtualization. 102.0 SecUritY (22 perceNt)2.1 Applyandusecommonpreventionmethods. 22,25,262.2 Compareandcontrastcommonsecuritythreats. 262.3 Implementsecuritybestpracticestosecureaworkstation. 25,262.4 Givenascenario,usetheappropriatedatadestruction/disposalmethod. 252.5 Givenascenario,secureaSOHOwirelessnetwork. 232.6 Givenascenario,secureaSOHOwirednetwork. 243.0 MObiLe DeviceS (9 perceNt)3.1 Explainthebasicfeaturesofmobileoperatingsystems. 93.2 Establishbasicnetworkconnectivityandconfigureemail. 93.3 Compareandcontrastmethodsforsecuringmobiledevices. 93.4 Compareandcontrasthardwaredifferencesinregardstotabletsandlaptops. 93.5 Executeandconfiguremobiledevicesynchronization. 94.0 trOUbLeShOOtiNG (36 perceNt)4.1 Givenascenario,explainthetroubleshootingtheory. 104.2 Givenascenario,troubleshootcommonproblemsrelatedtomotherboards,RAM,CPUandpower
withappropriatetools.1,2,3,24
4.3 Givenascenario,troubleshootharddrivesandRAIDarrayswithappropriatetools. 4,14,16,174.4 Givenascenario,troubleshootcommonvideoanddisplayissues. 64.5 Givenascenario,troubleshootwiredandwirelessnetworkswithappropriatetools. 19,23,244.6 Givenascenario,troubleshootoperatingsystemproblemswithappropriatetools. 12,15,17,264.7 Givenascenario,troubleshootcommonsecurityissueswithappropriatetoolsandbestpractices. 264.8 Givenascenario,troubleshoot,andrepaircommonlaptopissueswhileadheringtotheappropriate
procedures.8
4.9 Givenascenario,troubleshootprinterswithappropriatetools. 7
ExamObjectives Theexamobjectiveslistedherearecurrentasofthisbook‘spublicationdate.ExamobjectivesaresubjecttochangeatanytimewithoutpriornoticeandatCompTIA’ssolediscretion.PleasevisittheCompTIACertificationswebpageforthemostcurrentlistingofexamobjectives:http://certification.comptia.org/getCertified /certifications.aspx.
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vii
Contents
introduction xxxv
preparing for the exam xliv
chapter 1 introduction to computers 1ComputingBasics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
NumberingSystems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Binary 6
Hexadecimal 7
Bitsvs.Bytes 8
Kilo,Mega,Giga,andTera 9
CasesandCooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Motherboards 11
CaseFans 12
CleaningCases 14
NotificationSwitchforSecurity 14
PowerSupplies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
ACvs.DC 15
WattagePowerRatings 16
Rails 16
PowerSupplyConnections 17
CableKeying 19
ATXvs.Micro-ATXPowerSupplies 20
ReplacingaPowerSupply 20
ProtectingSystemsfromPowerProblems 21
SafetyIssues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
ElectricalSafety 23
EquipmentandSelf-Grounding 23
ESD 24
MSDS 25
viii Contents
CompliancewithRegulations 26
FireSafety 26
Lifting 27
Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Screwdrivers 27
ExtensionMagnet 27
CompressedAirandCompressors 28
ComputerVacuum 28
Multimeter 28
PowerSupplyTester 30
ChapterSummary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
ChapterReview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
chapter 2 Understanding Motherboards and biOS 39Motherboards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
IdentifyingMotherboardComponents 42
Sizes 44
Busses 46
BusSpeeds 47
ExpansionSlots 48
CPUChipsets 53
Jumpers 56
FrontPanelConnectors 56
ViewinganActualMotherboard 58
BIOS59
BIOSvs.CMOS 60
BIOSVendors 60
AccessingtheBIOSApplication 61
BIOSComponentInformation 62
BIOSConfiguration 63
POSTandOtherDiagnostics 68
POSTCards 69
Monitoring 69
ixContents
FlashingtheBIOS 70
UEFI 71
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
ChapterSummary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
ChapterReview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
chapter 3 Understanding raM and cpUs 79RAM80
DoubleDataRateSDRAM 81
DIMMsandSODIMMs 82
SingleChannel,DualChannel,andTripleChannel 83
SingleSidedvs.DoubleSided 86
RAMCompatibilityandSpeed 87
ParityandECC 90
RambusandRDRAM 91
CPUs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
32-bitvs.64-bit 92
CPUCores 93
Hyper-Threading 94
CPUCache 95
Speeds 97
VirtualizationSupport 98
IntegratedGPU 98
CPUVersions 99
CPUSocketTypes 101
Cooling 105
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
CommonSymptoms 108
Tools 109
ChapterSummary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .113
ChapterReview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
x Contents
chapter 4 comparing Storage Devices 119HardDrives. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
HardDriveCharacteristics 123
HardDriveSpeeds 124
IDE/EIDE/PATADrives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124
PATASpeeds 125
PATAConnectorsandCables 125
MasterandSlaveConfiguration 126
CableSelect 127
PATAPower 127
SATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128
SerialtoParalleltoSerial 128
SATAGenerations 129
SATAandSSD 129
SATADataConnectorsandCables 130
SATAPowerConnectorsandCables 131
Hot-Swappable 132
SCSI132
SCSIInterfaces 133
SCSIIDs 133
Daisy-ChainingandTermination 134
SerialAttachedSCSI 135
ExternalConnectionsTypes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135
USB 136
FireWire 136
eSATA 137
eSATAp 137
Ethernet 138
ExternalEnclosures 139
SolidStateDrives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .139
OpticalDiscsandDrives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
ComboDrivesandBurners 141
Speeds 142
xiContents
InstallingOpticalDrives 142
RemovingDiscsWithoutPower 143
TapeDrives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143
FloppyDrives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144
RecoveringData 145
FloppyConnections 145
RAID . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145
RAID-0 146
RAID-1 147
RAID-5 147
RAID10 149
RAIDandBackups 150
CalculatingUsableStorageSpaceinRAID 150
RAIDSummary 151
CommonSymptoms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
LoudClickingNoise 151
Read/WriteFailure 152
SlowPerformance 152
FailuretoBootorOperatingSystemNotFound 153
RAIDNotFound 153
RAIDStopsWorking 154
BSOD 154
ChapterSummary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155
ChapterReview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .156
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158
chapter 5 exploring peripherals and expansion cards 161PeripheralsandDeviceDrivers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163
DeviceDrivers 163
InstallDeviceDriversbeforeInstallingDevice 163
PlugandPlay 164
USB 165
USB1.1and2.0Connections 166
USB3.0Connections 166
xii Contents
USBController 168
USBCableLengths 169
DirtyBit 169
FireWire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170
FireWireCablesandConnections 170
FireWireS1600andS3200 171
MiscellaneousConnections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172
PS/2 173
Mini-DIN 173
Parallel 173
Serial 173
Sound . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174
CommonSoundSystems 174
ConnectingSoundSystems 175
InputDevices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177
Keyboard 178
Mice 178
Microphone 179
ScannersandDigitizers 180
BarcodeReader 181
KVM 182
BiometricDevices 183
Joysticks 183
GamePads 183
MultimediaDevices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184
DigitalCameras 185
Camcorder 186
Webcam 186
MIDI-EnabledDevices 186
ExpansionCards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .186
ExpansionCardTypes 188
Checklist 189
ChapterSummary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .190
xiiiContents
ChapterReview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193
chapter 6 exploring video and Display Devices 195DisplayDevices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197
CommonTerms 197
CRT 198
LCD 199
LED 199
Plasma 200
Projector 200
OLED 201
UsingMultipleDisplays 201
CommonResolutions 202
ConfiguringtheResolution 203
TouchScreens 204
PrivacyandAnti-GlareFilters 204
Interfaces,Connections,andCables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205
Analogvs.Digital 205
VGA 207
DVI 207
HDMI 208
ComparingVGAandHDMI 209
Adapters 210
OtherConnections 210
VideoInterfaceSummary 213
VideoCardsandDrivers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214
VideoMemory 215
Drivers 215
VideoCardPorts 215
SafetyConcerns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216
WorkingwithCRTs 216
DisposalofCRTs 217
CleaningSupplies 217
xiv Contents
TroubleshootingVideoandDisplayIssues . . . . . . . . . . . . . . . . . . . . . . . . . . 217
Dxdiag 217
VGAMode 218
NoImageonScreen 218
DimImage 220
FlickeringImage 220
Discoloration(Degaussing) 220
OverheatShutdown 221
DeadPixels 221
ArtifactsandDistortedImages 221
ColorPatternsIncorrect 222
BSOD 222
ChapterSummary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .223
ChapterReview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .223
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225
chapter 7 exploring printers 227PrintingBasics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .229
Terminology 230
Paper 231
CommonMaintenanceTools 232
LaserPrinters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233
LaserComponents 233
LaserImagingProcess 234
LaserPrinterMaintenance 241
InkjetPrinters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244
InkjetInkCartridges 245
RefillingInkjetCartridges 246
InkjetPrintingProcess 246
InkjetPrintHeads 248
InkjetCalibration 248
InkjetPrinterMaintenance 248
ImpactPrinters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249
CreatingCharacterswithaDotMatrix 250
xvContents
Near-LetterQuality 251
ImpactPrinterMaintenance 251
ThermalPrinters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251
InstallingandConfiguringPrinters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 252
DeviceDrivers 252
RequiredPermissions 253
WiredConnections 253
WirelessConnections 255
PrinterSharing 255
AddingaNetworkPrinter 256
PrintManagement 257
PrinterWebpages 257
PrintSpooler 258
TroubleshootingPrinters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 259
ChapterSummary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .262
ChapterReview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .263
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .265
chapter 8 Working with Laptops 267CommonLaptopFeatures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269
SpecialFunctionKeys 270
TroubleshootingKeyboardIssues 273
DockingStationvs.PortReplicator 274
HardwareProfiles 275
Locks 276
LaptopDisplays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 277
DisplayTypes 277
Wi-FiAntenna 280
TroubleshootingDisplayIssues 280
InstallingandConfiguringLaptopHardware . . . . . . . . . . . . . . . . . . . . . . . 282
DisassemblingProcesses 282
HardwareandDeviceReplacement 284
ExpansionOptions 292
xvi Contents
ConservingPower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .294
ACPI 294
Sleep/Suspend/Standby(G1S3) 295
Hibernate(G1S4) 295
HybridSleep 296
PowerOptions 296
PowerPlans 296
TroubleshootingPowerIssues 297
TroubleshootingConnectivityIssues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .298
IntermittentWireless 298
NoWirelessConnectivity 299
NoBluetoothConnectivity 299
ChapterSummary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .299
ChapterReview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .300
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .302
chapter 9 Understanding Mobile Devices 305Tabletsvs.Laptops . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .307
AccelerometersandGyroscopes 308
GPS 310
Geotracking 310
ScreenCalibration 310
ComparingOperatingSystems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 311
OpenSourcevs.ClosedSource 311
iOS 312
Android 313
Windows 313
ApplicationSources 314
Connectivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 315
RF(Wireless) 315
Cellular 316
MobileHotspot 317
Bluetooth 317
Infrared 318
xviiContents
EmailConfiguration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 319
ConfiguringSettings 320
EmailPortSettings 321
UsingMobileDevices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .322
SynchronizingData 323
InstallingSynchronizationApplications 323
ConnectionTypesforSynchronization 324
SecuringMobileDevices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 325
PasscodeLocks 325
FailedLogonAttemptsRestrictions 325
RemoteWipe 326
LocatorApplications 326
RemoteBackupApplications 328
AntivirusSoftware 328
Patching/OperatingSystemUpdates 329
ChapterSummary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .329
ChapterReview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .330
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 332
chapter 10 Working with customers 335InteractingwithCustomers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .338
CommunicationandProfessionalism 338
RespondingtoProhibitedContent/Activity 342
TroubleshootingTheory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .345
IdentifytheProblem 345
EstablishaTheoryofProbableCause 346
TesttheTheorytoDetermineCause 346
EstablishaPlanofActionandImplementIt 347
VerifyFullSystemFunctionality 348
DocumentFindings,Actions,andOutcomes 348
IdentifyingCustomerNeeds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .349
StandardThickClient 350
ThinClient 350
GamingPC 351
xviii Contents
VirtualizationWorkstation 352
HomeTheaterPC 355
HomeServerPC 355
Graphic/CAD/CAMDesignWorkstation 356
Audio/VideoEditingWorkstation 356
EnvironmentalImpacts 357
ChapterSummary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .358
ChapterReview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 359
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 361
chapter 11 introducing Windows Operating Systems 363AnOverviewofWindowsOperatingSystems . . . . . . . . . . . . . . . . . . . . . . .364
Comparing32-Bitand64-BitCapabilities 365
Windows7Editions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .368
Windows7SystemRequirements 369
Windows7SystemLimits 369
WindowsXPEditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 371
WindowsXP64-Bit 372
WindowsXPSystemRequirements 372
WindowsXPSystemLimits 372
WindowsVistaEditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 373
WindowsVistaSystemRequirements 374
WindowsVistaSystemLimits 374
WindowsFeatures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 375
CommonFeatures 375
Windows7Features 377
WindowsVistaFeatures 377
WindowsAero 378
UserAccountControl 379
WindowsXPMode 384
StartBarLayout 385
WindowsSidebarandGadgets 387
CompatibilityMode 389
xixContents
ExaminingDirectoryStructuresinWindows . . . . . . . . . . . . . . . . . . . . . . . .390
WindowsExplorer 390
CommonFileLocations 391
Bootvs.SystemPartition 392
ProfileLocations 393
ChapterSummary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .394
ChapterReview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .395
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .398
chapter 12 installing and Updating Windows Operating Systems 401
InstallingandUpgradingWindows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 402
CleanInstall 403
Dual-BootSystem 403
Upgrade 405
FileSystems 406
MethodsofInstallation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 407
InstallationMedia—CDorDVD 407
RemoteNetworkInstallation 408
ImageDeployment 408
Sysprep 411
UnattendedInstallationwithAnswerFiles 412
RecoveryDiscorFactoryRecoveryPartition 412
UpgradePathstoWindows7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 413
WindowsAnytimeUpgrade 414
RepairInstallation 415
Windows7UpgradeAdvisor 416
CompatibilityTools 417
InstallingWindows7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 417
SelectingTime/Date/Region/LanguageSettings 417
ChoosingtheInstallMethod 418
DriveOptions 419
SystemReservedPartition 422
PerformingaCleanInstall 423
xx Contents
Activation 426
UpgradingWindowsVista . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 427
MigratingUserData . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 427
WindowsEasyTransfer 428
UserStateMigrationTool 430
FileAndSettingsTransferWizard 430
ChapterSummary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 431
ChapterReview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 432
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .434
chapter 13 Using Windows Operating Systems 437WindowsBasics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 439
MouseActions 439
WindowsActions 440
Libraries 441
TaskManager . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 441
StartingTaskManager 441
MicrosoftManagementConsole . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 447
ControlPanel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .448
Views 449
Applets 449
CommonApplets 450
AppletsUniquetoWindowsXP 458
AppletsUniquetoWindowsVista 459
AppletsUniquetoWindows7 459
OtherApplets 460
AdministrativeTools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .461
ComputerManagement 461
TaskScheduler 462
Performance 463
Services 464
ComponentServices 465
DataSources 466
xxiContents
OtherAdministrativeTools 466
ChapterSummary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .467
ChapterReview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .468
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 470
chapter 14 Using the command prompt 473StartingtheCommandPrompt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 475
AccessDeniedErrors 476
StartingwithAdministrativePrivileges 477
CommandPromptvs.Cmd 478
UnderstandingPaths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 478
DefaultPaths 479
Commands,Programs,andBatchFiles 480
UnderstandingExtensions 480
CommandPromptBasics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 481
CaseSensitivity 482
UnderstandingSwitches 482
GettingHelp 482
UsingQuoteswithSpaces 483
BewareofTypos 484
RecallingCommands 484
CopyingandPasting 485
SavingtheOutputinaTextFile 487
UnderstandingVariables 487
UsingWildcards 489
FileCommands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .489
Attrib 490
Dir 491
Md 493
CD 493
ChangingDrives 494
Rd 494
Del 495
Copy 495
xxii Contents
Xcopy 497
Robocopy 497
Sfc 498
UsingNotepadtoCreateaBatchFile 499
OperatingSystemCommands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 500
DiskCommands. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 501
NetworkingCommands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 502
ChapterSummary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .503
ChapterReview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .504
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 507
chapter 15 Configuring Windows Operating Systems 509UsingSystemConfiguration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 510
General 511
Boot 511
Services 512
Startup 513
Tools 514
UsingtheSystemApplet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 515
RemoteSettings 515
SystemProtectionandSystemRestore 517
ShadowCopy(PreviousVersions) 518
AdvancedSystemSettings 519
UnderstandingPaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 520
PagingOverview 520
64-KBPages 521
ExcessivePaging 521
Performance(VirtualMemory)Settings 522
WorkingwithDeviceManager . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 524
StartingtheDeviceManager 524
ViewingDeviceManager 524
UpdatingDrivers 525
DisablingandUninstalling 527
xxiiiContents
RollingBackDrivers 528
SignedDrivers 528
Sigverif 528
WindowsUpdate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .529
ServicePacks 530
AutomaticallyInstallingUpdates 530
PatchManagement 531
BackupCapabilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 532
WindowsXP 532
WindowsVista 532
Windows7 534
ProgramCompatibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 535
ModifyingDocumentsLocation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .536
ReadyBoost . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 537
ChapterSummary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .538
ChapterReview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 539
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 541
chapter 16 Understanding Disks and File Systems 543UnderstandingDisks,PartitionsandVolumes . . . . . . . . . . . . . . . . . . . . . . .544
MBRPartitions 545
GPTPartitions 546
RecoveryPartition 547
BasicDisksvs.DynamicDisks 548
FileSystems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 550
UnderstandingClusters 551
FAT16andFAT32 553
NTFS 554
CDFS 555
DiskManagementTools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 555
DiskManagement 555
Diskpart 564
ChkdskandCheckDisk 565
xxiv Contents
Convert 566
DiskDefragmenterandDefrag 567
DiskCleanup 568
Fdisk 569
Shares . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .569
AdministrativeShares 570
LocalShares 570
OfflineFiles 571
ChapterSummary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 572
ChapterReview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 573
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 575
chapter 17 troubleshooting Windows Operating Systems 577UnderstandingtheBootProcess . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 579
PowerOnSelf-Test(POST) 579
LookForMasterBootRecordandBootSector 579
LoadSystemBootFilesonWindowsXP 580
LoadBootManageronWindowsVistaandWindows7 581
UnderstandingtheRegistry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 581
StartingtheRegistryEditor 581
Hives,Keys,andValues 582
BackUptheRegistry 583
AdvancedBootOptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .583
SafeModes 585
EnableBootLogging 585
EnableLow-ResolutionVideo 586
LastKnownGoodConfiguration 586
DisableDriverSignatureEnforcement 588
DisableAutomaticRestartonSystemFailure 588
OtherAdvancedBootOptions 588
RepairYourComputer 588
RecoveryConsoleandWindowsRECommandPrompt 590
MsconfigandAdvancedBootOptions 592
StartupandRecoveryOptions 593
xxvContents
WindowsTroubleshootingTools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 595
EventViewer 595
RecoveryImages 598
FileRecoverySoftware 598
AutomatedSystemRecovery 598
EmergencyRepairDisk 599
SystemRepairDisc 599
TroubleshootingApplet 600
CommonSymptomsandTheirSolutions . . . . . . . . . . . . . . . . . . . . . . . . . . .600
BSOD 601
FailuretoBoot 601
ImproperShutdown 603
SpontaneousShutdownorRestart 604
DeviceFailstoStart 604
MissingDLLMessage 604
ServiceFailstoStart 606
CompatibilityError 606
SlowSystemPerformance 606
BootstoSafeMode 607
FileFailstoOpen 607
MissingNTLDRandMissingBoot.ini 607
BootSectorandMBRErrors 609
ChapterSummary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 610
ChapterReview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 611
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 613
chapter 18 introducing Networking components 615TypesofNetworks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 617
LocalAreaNetwork 617
WideAreaNetwork 618
PersonalAreaNetwork 619
MetropolitanAreaNetwork 620
VirtualPrivateNetwork 620
xxvi Contents
IdentifyingBasicNetworkHardware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 621
NetworkInterfaceCard 621
Hub 622
Switch 623
Router 624
Bridge 625
Modem 626
NetworkAttachedStorage(NAS) 626
VoIPPhones 627
Link,Activity,andSpeedLights 627
ComparingWorkgroupsandDomains . . . . . . . . . . . . . . . . . . . . . . . . . . . . .629
Workgroup 630
Domain 631
JoiningaWorkgrouporaDomain 632
ConnectingtotheInternet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .633
CableandFiberBroadbandConnections 633
PhoneConnections 635
WiMAX 638
Satellite 639
StandardsOrganizations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .640
ChapterSummary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .641
ChapterReview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .642
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .644
chapter 19 exploring cables and connectivity 647IntroducingEthernet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .649
SafetyandEnvironmentalIssues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .650
CableManagementandTripHazards 650
PVCvs.Plenum-SafeJackets 651
UnderstandingInterferenceandCrosstalk 651
ComparingHalf-DuplexandFull-Duplex . . . . . . . . . . . . . . . . . . . . . . . . . . .654
CommonNetworkCablesandConnectors. . . . . . . . . . . . . . . . . . . . . . . . . 657
EthernetTwisted-Pair 657
xxviiContents
FiberOpticCable 664
CoaxialCable 665
SpeedsandSpecifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .666
EthernetSpeeds 667
FastEthernet 667
GigabitEthernet 668
10-GigabitEthernet 668
Topologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .669
Star 669
Bus 670
Ring 670
Mesh 671
Hybrid 672
ChapterSummary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .673
ChapterReview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 674
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 676
chapter 20 Understanding protocols 679IntroducingNetworkProtocols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .680
TCP/IP 680
ConnectivityProtocols 681
IntroducingPorts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .683
PortRanges 684
PortsandFirewalls 685
ExploringNetworkProtocols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .685
EncryptionProtocols 685
EmailProtocols 686
WebBrowserProtocols 687
FileTransferProtocols 688
NameResolutionProtocols 690
RemoteConnectivityProtocols 693
SNMP 696
LDAP 696
xxviii Contents
SummarizingWell-KnownPorts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .696
SendinganHTTPQueryUsingPorts 697
AWebServerResponseUsingPorts 698
ChapterSummary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .699
ChapterReview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 700
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 702
chapter 21 comparing ipv4 and ipv6 705ExaminingIPv4Addresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .706
DottedDecimalFormat 707
TwoPartsofanIPAddress 707
NetworkIDChallenge 709
NetworkIDsinaNetwork 710
ClassfulIPAddresses 711
LoopbackAddresses 712
CIDRNotation 713
Unicast,Broadcast,andMulticastAddressing 713
TCP/IPAddressinginaNetwork . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 714
DefaultGateway 714
Publicvs.PrivateIPs 715
NAT 716
Staticvs.DynamicIPAddresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 717
UsingDHCPforDynamicIPAddresses 717
ManuallyAssigningStaticIPAddresses 719
ExaminingIPv6Addresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 723
OmittingIPv6LeadingZeros 724
IPv6ZeroCompression 725
IPv6Prefixes 726
PeacefulCoexistencewithIPv4 726
IPv6LoopbackAddress 726
ChapterSummary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 727
xxixContents
ChapterReview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 728
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .730
chapter 22 Network Security Devices 733SecuringaNetwork . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .734
ThreatsandAttacks 734
UnderstandingFirewalls 735
UnderstandingDMZs 737
PortForwarding 738
PortTriggering 741
UsingProxyServers 742
BasicQoS 746
WindowsFirewall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 747
Homevs.Workvs.PublicNetworkSettings 747
ConfiguringWindowsFirewallonWindowsXP 749
ConfiguringWindowsFirewallonWindowsVistaandWindows7 750
WindowsFirewallwithAdvancedSecurity 753
OtherSecurityTools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 754
SecurityCenter 754
ActionCenter 755
Netsh 756
Appliances 756
ChapterSummary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 759
ChapterReview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 760
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 762
chapter 23 exploring Wireless Networking 765WirelessComponents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 766
WirelessAccessPoint 767
WirelessRouter 767
WirelessDevice 769
InfrastructureModevs.Ad-HocMode 769
Wi-FiandWi-FiAlliance 770
xxx Contents
WirelessStandards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 770
AntennaandAccessPointPlacement 772
Channels 772
RadioPowerLevels 774
WirelessSecurity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 775
EncryptionTypes 775
PersonalMode 776
EnterpriseMode 777
MACFiltering 777
Wi-FiProtectedSetup 778
SSID779
UnderstandingSSIDBroadcast 780
EnablingorDisablingSSIDBroadcast 780
RenamingtheSSID 781
ConfiguringWirelessNetwork . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 782
ChangingDefaultUserNamesandPasswords 782
ConfiguringWirelessSettingsonWindows7 784
ConfiguringDHCP 786
TroubleshootingWirelessConnections 787
ChapterSummary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .789
ChapterReview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 791
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 793
chapter 24 connecting and troubleshooting a Network 795InstallandConfigureaSOHONetwork . . . . . . . . . . . . . . . . . . . . . . . . . . . . 797
Devices 798
Cables 799
Protocols 800
VoIP 800
SecuringaSOHOWiredNetwork 800
EstablishNetworkingConnections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 801
Wired 801
Wireless 802
Dial-UpConnections 802
xxxiContents
WWAN(Cellular) 803
VPN 804
HomegroupsandNetworkPlaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .806
AccessingMyNetworkPlacesandNetwork 806
UnderstandingHomegroups 807
CommandPromptTools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 811
Ping 812
Ipconfig 815
Client-SideDNSandIpconfig 816
Tracert 817
Nslookup 818
Netstat 819
Nbtstat 820
Arp 821
Net 822
HardwareTools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 824
CableTester 824
LoopBackPlugs 824
TonerProbe 824
TroubleshootingNetworkProblems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 825
CannotCommunicateontheNetwork 825
CannotGetoutofNetwork 826
RemembertheLights 827
UseWindowsNetworkDiagnostics 827
CommonSymptoms 828
ChapterSummary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .829
ChapterReview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .830
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .832
chapter 25 Understanding it Security 835Prevention . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .837
UserEducation 837
PrincipleofLeastPrivilege 837
Authentication 838
xxxii Contents
SomethingYouKnow 838
SomethingYouHave 840
SomethingYouAre 842
SingleSign-On 843
RequiringPasswordwiththeScreenSaver 844
LocalSecurityPolicy 845
UsersandGroups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 847
UserAccounts 848
UnderstandingGroups 851
UnderstandingPermissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 854
NTFSPermissions 855
SharePermissions 859
CombiningNTFSandSharePermissions 860
UnderstandingEncryption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .861
EncryptingFileswithEFS 861
OfflineFilesEncryption 863
BitLockerDriveEncryption 863
DestructionandDisposalofDataandMedia . . . . . . . . . . . . . . . . . . . . . . .864
HardDriveSanitization 865
PhysicalDestruction 867
ChapterSummary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .868
ChapterReview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .869
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 871
chapter 26 recognizing Malware and Other threats 873ExploringMalware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 875
Botnets 876
Virus 877
Worm 878
TrojanHorse 878
Rogueware 879
Rootkits 880
xxxiiiContents
Spyware 880
SpamandMalware 880
Phishing 881
DigitalSecurity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 882
AntivirusSoftware 882
Antispyware 887
KeepingSystemsUptoDate 888
DisablingAutorun 888
SymptomsofanInfection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 891
RemovingMalware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .893
DeleteTemporaryFiles 893
UsingSafeMode 894
UsingPreinstallationEnvironments 895
UsingRecoveryConsoleandWindowsRE 896
SystemRestore 896
BestPracticesforMalwareRemoval 896
RecognizingOtherSecurityThreats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .897
SocialEngineering 898
PhysicalSecurity 898
ChapterSummary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .900
ChapterReview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .901
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .903
Glossary 905
Index 933
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xxxv
Introduction
Thistrainingkitisdesignedforinformationtechnology(IT)professionalswhowanttoearntheCompTIAA+certification.Itisassumedthatyouhaveabasicunderstandingof
computersandWindowsoperatingsystems.However,theA+certificationisanentry-levelcertification,soyouarenotexpectedtohaveanyin-depthknowledgetousethistrainingkit.
TobecomeanA+certifiedtechnician,youmusttakeandpassthe220-801and220-802exams.TheprimarygoalofthistrainingkitistohelpyoubuildasolidfoundationofITknowl-edgesothatyoucansuccessfullypassthesetwoexamsthefirsttimeyoutakethem.
Thematerialscoveredinthistrainingkitandonexams220-801and220-802relatetothetechnologiesasuccessfulpersonalcomputer(PC)technicianisexpectedtounderstand.ThisincludesPChardwareconcepts,Windowsoperatingsystemtechnologies,networkingbasics,andITsecurity.Youcandownloadtheobjectivesforthe220-801and220-802examsfromtheCompTIAwebsite:http://certification.comptia.org/Training/testingcenters/examobjectives.aspx.
Byusingthistrainingkit,youwilllearnhowtodothefollowing:
■■ Recognizehardwarecomponentsusedwithinacomputer.
■■ Assembleacomputer’shardwarecomponents.
■■ Install,configure,andmaintaindevices.
■■ Troubleshootandrepairhardwareproblems.
■■ Install,configure,andtroubleshootlaptopcomputers.
■■ Describe,install,configure,andtroubleshootprinters.
■■ Describethefeaturesusedinmobileoperatingsystems.
■■ Configureandsecuremobiledevices.
■■ Describethedifferencesbetweencommonoperatingsystems.
■■ Installandconfigureoperatingsystems.
■■ Usevariouscommandlineandoperatingsystemtools.
■■ Troubleshootandrepairoperatingsystemissues.
■■ Recognizecommoncomponentsusedinanetwork.
■■ Connectacomputerandconfigureitonanetwork.
■■ Troubleshootbasicnetworkingissues.
■■ Recognizecommonpreventionmethodsusedtoenhancesecurity.
Refertotheobjectivemappingpageinthefrontofthisbooktoseewhereinthebookeachexamobjectiveiscovered.
xxxvi introduction
About the ExamsThe220-801examisfocusedonskillsrequiredtoinstallandmaintainhardware.Itincludesobjectivesinthefollowingfiveareas:
■■ PCHardware(40percentofexam)
■■ Networking(27percentofexam)
■■ Laptops(11percentofexam)
■■ Printers(11percentofexam)
■■ OperationalProcedures(11percentofexam)
The220-802examisfocusedonoperatingsystemsandtroubleshooting.Thisincludestroubleshootingoperatingsystems,securityissues,andhardware.Itincludesobjectivesinthefollowingfourareas:
■■ OperatingSystems(33percentofexam)
■■ Security(22percentofexam)
■■ MobileDevices(9percentofexam)
■■ Troubleshooting(36percentofexam)
Theseexamsbecameavailableinlate2012andarethefifthversionofA+exams.Previ-ousversionscameoutin1993,2003,2006,and2009,andovertheyears,morethan900,000peoplearoundtheworldhaveearnedtheA+certification.ITprofessionalscommonlystartwiththeA+certificationtolayasolidfoundationofITknowledgeandlatermoveontohigher-levelcertificationsandbetter-payingjobs.
AsIwritethis,CompTIAhasnotpublishedhowmanyquestionswillbeoneachexam,howlongyou’llhavetocompleteeachexam,orwhatthepassingscoresare.Youcanlookhereforuptodateinformation:http://certification.comptia.org/aplus.aspx.
Inpreviousversions,eachexamincluded100questionsandyouhad90minutestocom-pletetheexam.Thisgaveyoualittlelessthanaminutetoanswereachquestion.Becauseofthis,thequestionswerestraightforward.Forexample,what’s10+10?Eitheryouknowitoryoudon’t,andyouwon’tneedtospendalotoftimeanalyzingthequestion.
Morethanlikely,you’llhavethesamenumberofquestions,butyou’llprobablyhavelongertocompletethemduetotheadditionofperformance-basedquestions.Mostofthequestionswillbesimple,butsomewillrequireyoutoperformatask.
PrerequisitesCompTIArecommendsthattesttakershaveaminimumof12monthsoflaborfieldworkexperiencepriortotakingtheexams.Thatis,theyexpectthatyouhavebeenstudyingcom-puters(labwork)workinginanITjob(fieldwork)oracombinationofbothforatleast12months.
xxxviiintroduction
ThisisdifferentfromwhatCompTIAhaspreviouslyrecommended.The220-701and220-702objectivesrecommendedtesttakershave500hoursoflaborfieldwork,whichequalsaboutthreemonthsof40-hourweeks.
Notethatthisisnotarequirementtotaketheexams.Anyonecantaketheexamsafterpayingforthem,andiftheypass,theyearnthecertification.However,you’llhavethebestchanceofsuccessifyouhavebeenstudyingandworkingwithcomputersforatleast12months.
Performance Based TestingAsignificantdifferenceinthe220-801and220-802examsoverpreviousversionsistheintroductionofperformance-basedtesting.Insteadofjustusingmultiplechoicequestions,CompTIAisintroducingquestionsthatwillrequireyoutoperformatask.
Imaginethatyouwantedtoknowifapersoncouldrideabike.Youcouldasksomemul-tiplechoicequestions,butyou’llfindthatthesequestionsaren’talwaysreliable.Apersonmightanswerquestionscorrectlybutnotbeabletoactuallyridethebike.Putthepersoninfrontofabike,askthepersontorideit,andyou’llquicklyknowwhetherthepersoncanornot.Performance-basedtestingusesthisphilosophytoseeifsomeonehasaskill.
Considerthefollowingmultiplechoicequestion:
1. Whichofthefollowingcommandswillchangeafiletoread-only?
A. assoc-Rstudy.txt
B. attrib+Rstudy.txt
C. readonly-truestudy.txt
D. ren-readonlystudy.txt
Theanswerisattrib,andthe+Rswitchsetstheread-onlyattributetotrue,makingitread-only.
Thissameknowledgemightbetestedinaperformance-basedtestingquestionasfollows:
1. “NavigatetotheC:\Datafolderandchangethestudy.txtfiletoread-only.”Whenyouclickabutton,you’llbeinasimulatedWindowsenvironmentwithaCommandPrompt.Youwouldthenneedtoenterthefollowingtwocommands:
cd \data attrib +R studynotes.txt
Whenit’samultiplechoicequestion,youhavea25-percentchanceofgettingitcorrect.Evenifyoudidn’tremembertheexactsyntaxoftheattribcommandbutknewthepurposeofit,youwouldprobablygetthepreviousquestioncorrect.Theperformance-basedtestingmethodrequiresyoutoknowthematerialandbeabletoenterthecorrectcommands.
xxxviii introduction
Throughoutthebook,withperformance-basedtestinginmind,I’veincludedstepsandinstructionsforhowtodomanytasks.Ifyoudothesetasksasyouworkthroughthebook,you’llbebetterpreparedtosucceedwiththeseperformance-basedtests.I’llalsobepostingA+notesandtipsonBlogs.GetCertifiedGetAhead.com.Checkitout.
Objective ChangesCompTIAincludesanoteintheobjectivesthatstatesthat,“Objectivesaresubjecttochangewithoutnotice.”Idon’tknowofanytimethey’vechangedtheobjectiveswithoutnotice,buttheyhavechangedobjectives.
Forexample,whenthe220-701and220-702objectiveswerepublishedin2009,Windows7wasn’tavailableandtheobjectivesdidn’tincludeanyWindows7topics.However,thepopularityofWindows7increased,andCompTIAdecidedtoaddWindows7topics.InSeptember2010,CompTIAannouncedobjectivemodificationstoincludeWindows7.ThechangesbecameeffectiveforanyonewhotooktheexamafterJanuary1,2011.
Thesametimingisoccurringwiththe220-801/220-802objectivesandWindows8.Whentheobjectiveswerefirstpublished,Windows8wasnotavailable,soyouwon’tseeanyWindows8topicsontheexams.
IsitpossiblethatWindows8willbecomepopularandthatCompTIAwillannouncechangestotheobjectivesin2013?Absolutely.Ifthathappens,Iplanonstayingontopofthechangesandwillpostupdatesonmyblogathttp://blogs.getcertifiedgetahead.com.I’llalsoincludeinformationonthefollowingpage:http://getcertifiedgetahead.com/aplus.aspx.
Study TipsThere’snosinglestudymethodthatworksforeveryone,buttherearesomecommontech-niquesthatmanypeopleusetopasstheseexams,includingthefollowing:
■■ Set a goal. Pickadatewhenyouexpecttotakethefirstexam,andsetyourgoaltotakeitthen.Thedateisdependentonhowlongit’lltakeyoutoreadthechaptersandyourcurrentknowledgelevel.Youmightsetadatetwomonthsfromnow,fourmonthsfromnow,oranothertime.However,pickadateandsetagoal.
■■ take notes.Ifconceptsaren’tfamiliartoyou,takethetimetowritethemdown.Theprocessoftransferringthewordsfromthebook,throughyourhead,anddowntoyourhandreallyhelpstoburntheknowledgeintoyourbrain.
■■ read your notes.Gobackoveryournotesperiodicallytoseewhatyourememberandwhatyouneedtoreviewfurther.Youcan’tbringnoteswithyouintothetestingarea,butyoucanusethemtoreviewkeymaterialbeforetheexam.
xxxixintroduction
■■ Use flash cards.Somepeoplegetalotoutofflashcardsthatprovideaquicktestofyourknowledge.Thesehelpyourealizewhatyoudon’tknowandwhatyouneedtobrushupon.Manypracticetestprogramsincludeflashcards,soyoudon’tnecessarilyhavetocreatethemyourself.
■■ review the objectives.ThisiswhatCompTIAsaysitwilltestyouon.Sometimesjustunderstandingtheobjectivewillhelpyoupredictatestquestionandansweritcorrectly.
■■ record your notes.ManypeoplerecordtheirnotesonanMP3playerandplaythembackregularly.Youcanlistenwhiledriving,whileexercising,orjustaboutanytime.Somepeoplehavetheirhusband/wifeorboyfriend/girlfriendreadthenotes,whichcangiveaninterestingtwisttostudying.
■■ take the practice test questions on the cD.ThepracticetestquestionsontheCDaredesignedtotesttheobjectivesfortheexambutatadeeperlevelthanyou’llhaveontheliveexam.Eachquestionincludesdetailedexplanationsaboutwhythecorrectanswer(s)is/arecorrectandwhytheincorrectanswersareincorrect.Ideally,youshouldbeabletolookattheanswerstoanyquestionandknownotonlythecorrectanswerbutalsowhytheincorrectanswersareincorrect.
System requirements
Theactualsystemrequirementstousethisbookareminimal.Theonlyrequirementisacom-puterthatyoucanusetoinstallthepracticetestsontheCompanionCD.
Ideally,you’llhaveanoldcomputerthatyoucantakeapartandputbacktogether.Itisn’trequired,butactuallyremovingandreinstallingapowersupply,casefan,orharddriveismuchmoremeaningfulthanjustreadingaboutdoingit.
StartingwithChapter11,“IntroducingWindowsOperatingSystems,”theobjectiveshaveastrongfocusonWindowsXP,WindowsVista,andWindows7.AsaPCtechnician,youshouldbefamiliarwiththeseoperatingsystems.
YouwillfindthatmostofthetestedmaterialisthesameinWindowsVistaandWindows7.Therefore,ifyouhaveWindowsXPandWindows7,itisn’timportantthatyouhaveWindowsVista.
Insteadofhavingtwoorthreeseparatecomputers,youcanuseasinglePCwithvirtualiza-tionsoftwarehostingtheseoperatingsystems.Chapter2,“UnderstandingMotherboardsandBIOS,”introducesvirtualization,andChapter10,“WorkingwithCustomers,”discussesvirtual-izationworkstations.Thefollowingsectionsdescribehardwareandsoftwarerequirementstosetupavirtualizationworkstation.
xl introduction
Hardware Requirements for VirtualizationIfyouplanonusingvirtualization,yourcomputershouldmeetthefollowingrequirements:
■■ Aprocessorthatincludeshardware-assistedvirtualization(AMD-VorIntelVT),whichisenabledintheBIOS.(Note:youcanrunWindowsVirtualPCwithoutIntel-VTorAMD-V.)Ideally,theprocessorwillbea64-bitprocessorsothatyoucanhavemoreRAM.
■■ Atleast2.0GBofRAM,butmoreisrecommended.
■■ 80GBofavailableharddiskspace.
■■ Internetconnectivity.
Software Requirements YoushouldhaveacomputerrunningWindows7.TheobjectivesheavilycoverWindows7,andifyouhaveit,youcaneasilyrunWindowsXPinavirtualenvironment.
Additionalrequirementsincludethefollowing:
■■ Windows virtual pc and Windows Xp Mode.WindowsVirtualPCallowsyoutorunmultiplevirtualWindowsenvironments.ThefollowingpageintroducestheWindowsVirtualPCandWindowsXPMode:http://www.microsoft.com/windows/virtual-pc/. Thefollowingpageincludesthedownloadlinkafteryouidentifyyouroperatingsystemandthedesiredlanguage:http://www.microsoft.com/windows/virtual-pc /download.aspx.
■■ Windows 7 (32-bit).Youcandownloada90-daytrialcopyofWindows7Enterprisehere:http://technet.microsoft.com/en-us/evalcenter/cc442495.aspx.
AfterfollowingtheinstructionstodownloadandinstallWindowsVirtualPCandWindowsXPMode,youwillhaveVirtualPCinstalledonyoursystem.YouwillalsohaveafullyfunctioningcopyofWindowsXPthatyoucanuseforWindowsXPModeandtoexplorethefunctionalityofWindowsXPwhileyouarestudying.
Next,downloadthe90-daytrialofWindows7andinstallitasaVMwithinWindowsVirtualPC.Ifyouhaven’tcompletedtheexamsbythetimethe90-daytrialexpires,createanewVMandinstallitagain.Theexperienceisworthit.
AsanalternativetoWindowsVirtualPC,youcanuseeitherVirtualBoxorVMware.OracleprovidesVirtualBoxasafreedownloadhere:https://www.virtualbox.org/wiki /Downloads;andyoucandownloadafreeversionofVMwareplayerhere:http://www .vmware.com/products/player/overview.html.BothVirtualBoxandVMwareplayersupport64-bithostmachines,butyoucanonlyrun32-bithostswithinWindowsVirtualPC.
xliintroduction
Using the companion cD
AcompanionCDisincludedwiththistrainingkit.ThecompanionCDcontainsthefollowing:
■■ practice tests Youcanreinforceyourunderstandingofthetopicscoveredinthistrainingkitbyusingelectronicpracticeteststhatyoucancustomizetomeetyourneeds.Youcanpracticeforthe220-801and220-802 certificationexamsbyusingtestscreatedfromapoolof400realisticexamquestions,whichgiveyoumanypracticeexamstoensurethatyouareprepared.
■■ an ebook Anelectronicversion(eBook)ofthisbookisincludedforwhenyoudonotwanttocarrytheprintedbookwithyou.
■■ a list of video links Throughoutthebook,videosarepointedouttosupplementlearning.TheCDincludesalistofallthevideolinksmentionedinthechaptersandafewmore.Therearealsolinkstoafewmoreresourcesthatyoumightfindvaluableduringyourstudies.
■■ the cpU-Z freeware utility Chapter3discusseshowthisutilitycanbeusedtopro-videinformationontheCPU,themotherboard,memory,andmore.
Note Companion content for digital book readers
If you bought a digital-only edition of this book, you can enjoy select content from the print edition’s companion CD. Visit http://go.microsoft.com/FWLink/?Linkid=265182 to get your downloadable content.
How to Install the Practice TestsToinstallthepracticetestsoftwarefromthecompanionCDtoyourharddisk,performthefollowingsteps:
1. InsertthecompanionCDintoyourCDdriveandacceptthelicenseagreement.ACDmenuappears.
Note If the CD meNu Does Not appear
If the CD menu or the license agreement does not appear, AutoRun might be disabled on your computer. Refer to the Readme.txt file on the CD for alternate installation instructions.
2. ClickPracticeTestsandfollowtheinstructionsonthescreen.
xlii introduction
How to Use the Practice TestsTostartthepracticetestsoftware,followthesesteps:
1. ClickStart,AllPrograms,andthenselectMicrosoftPressTrainingKitExamPrep.
AwindowappearsthatshowsalltheMicrosoftPresstrainingkitexamprepsuitesinstalledonyourcomputer.
2. Double-clickthepracticetestyouwanttouse.
Whenyoustartapracticetest,youcanchoosewhethertotakethetestinCertificationMode,StudyMode,orCustomMode:
■■ Certification Mode Closelyresemblestheexperienceoftakingacertificationexam.Thetesthasasetnumberofquestions.Itistimed,andyoucannotpauseandrestartthetimer.
■■ Study Mode Createsanuntimedtestduringwhichyoucanreviewthecorrectanswersandtheexplanationsafteryouanswereachquestion.
■■ custom Mode Givesyoufullcontroloverthetestoptionssothatyoucancustomizethemasyoulike.
Inallmodes,theuserinterfacewhenyouaretakingthetestisbasicallythesamebutwithdifferentoptionsenabledordisableddependingonthemode.
Whenyoureviewyouranswertoanindividualpracticetestquestion,a“References”sec-tionisprovidedthatlistswhereinthetrainingkityoucanfindtheinformationthatrelatestothatquestionandprovideslinkstoothersourcesofinformation.AfteryouclickTestResultstoscoreyourentirepracticetest,youcanclicktheLearningPlantabtoseealistofreferencesforeveryobjective.
How to Uninstall the Practice TestsTouninstallthepracticetestsoftwareforatrainingkit,usetheProgramAndFeaturesoptioninWindowsControlPanel.
acknowledgments
Theauthor’snameappearsonthecoverofabook,butIamonlyonememberofamuchlargerteam.Firstofall,thankstoSteveWeissfororiginallyreachingouttomeandinvitingmetowritethisA+TrainingKit.Severaleditorshelpedthroughoutthisprocess,andIamgratefulforalltheirwork.IespeciallyappreciatethecopyeditingbyRichardCareyandthetechnicaleditingbyBillTalbott.IextendahugethankstoJoséVargas,whohelpedoutwithsomewritingontwoofthehardwarechapters.Iespeciallyappreciatemywifeputtingupwith
xliiiintroduction
mylongdaysandnightsworkingonwhatshehasnicknamed“theforeverbook”becauseitseemslikeI‘vebeenworkingonthisbookclosetoforever.Last,aspecialthankstoreaderswhohaveprovidedfeedbacktomeovertheyears,lettingmeknowwhathelpsthemlearnandwhatthingsIcanimprove.
Support & Feedback
Thefollowingsectionsprovideinformationabouterrata,booksupport,feedback,andcon-tactinformation.
errata & book Support
We’vemadeeveryefforttoensuretheaccuracyofthisbookanditscompanioncontent.AnyerrorsthathavebeenreportedsincethisbookwaspublishedarelistedonourMicrosoftPresssiteatoreilly.com:
http://go.microsoft.com/FWLink/?Linkid=265181
Ifyoufindanerrorthatisnotalreadylisted,youcanreportittousthroughthesamepage.
Ifyouneedadditionalsupport,emailMicrosoftPressBookSupportat:
mspinput@microsoft.com
PleasenotethatproductsupportforMicrosoftsoftwareisnotofferedthroughtheaddressesabove.
We Want to hear from You
AtMicrosoftPress,yoursatisfactionisourtoppriority,andyourfeedbackisourmostvalu-ableasset.Pleasetelluswhatyouthinkofthisbookat:
http://www.microsoft.com/learning/booksurvey
Thesurveyisshort,andwereadeveryoneofyourcommentsandideas.Thanksinadvanceforyourinput!
Stay in touch
Letuskeeptheconversationgoing!WeareonTwitter:http://twitter.com/MicrosoftPress.
xliv preparing for the exam
Preparing for the Exam
Microsoftcertificationexamsareagreatwaytobuildyourrésuméandlettheworldknowaboutyourlevelofexpertise.Certificationexamsvalidateyouron-the-jobexperience
andproductknowledge.Whilethereisnosubstitutionforon-the-jobexperience,preparationthroughstudyandhands-onpracticecanhelpyoupreparefortheexam.Werecommendthatyouroundoutyourexampreparationplanbyusingacombinationofavailablestudymaterialsandcourses.Forexample,youmightusethetrainingkitandanotherstudyguideforyour“athome”preparationandtakeaMicrosoftOfficialCurriculumcoursefortheclass-roomexperience.Choosethecombinationthatyouthinkworksbestforyou.
Notethatthistrainingkitisbasedonpublicallyavailableinformationabouttheexamandtheauthor'sexperience.Tosafeguardtheintegrityoftheexam,authorsdonothaveaccesstotheliveexam.
1
C H A P T E R 1
Introduction to Computers
Inthischapter,you’lllearnaboutsomebasiccomputer-relatedconceptsthatareimportantforanytechniciantounderstand.Forexample,differentnumberingsystemsareoftenunfamiliartomanypeople,butdon’tunderestimatetheirimportanceinunderstandinghowacomputerworks.TheNumberingSystemssectionlaysthefoundationfortopicsinmanyfuturechapters.Thischapteralsoincludesinformationaboutcases,fans,andpowersupplies—corehardwarecomputercomponentsthatoftenrequireperiodicmaintenancebytechnicians.Last,you’lllearnaboutsomebasicsafetyissuesandtoolsyoucanusewhenmaintainingcomputers.
Exam 220-801 objectives in this chapter:■■ 1.2Differentiatebetweenmotherboardcomponents,theirpurposes,andproperties.
■■ Powerconnectionsandtypes
■■ Fanconnectors
■■ 1.8Installanappropriatepowersupplybasedonagivenscenario.
■■ Connectortypesandtheirvoltages
■■ SATA
■■ Molex
■■ 4/8-pin12v
■■ PCIe6/8-pin
■■ 20-pin
■■ 24-pin
■■ Floppy
■■ Specifications
■■ Wattage
■■ Size
■■ Numberofconnectors
i m p o r t a n t
Have you read page xliv?It contains valuable information regarding the skills you need to pass the exams.
2 CHAPTER 1 IntroductiontoComputers
■■ ATX
■■ Micro-ATX
■■ Dualvoltageoptions
■■ 5.1Givenascenario,useappropriatesafetyprocedures.
■■ ESDstraps
■■ ESDmats
■■ Self-grounding
■■ Equipmentgrounding
■■ Personalsafety
■■ DisconnectpowerbeforerepairingPC
■■ Removejewelry
■■ Liftingtechniques
■■ Weightlimitations
■■ Electricalfiresafety
■■ Compliancewithlocalgovernmentregulations
■■ 5.2Explainenvironmentalimpactsandthepurposeofenvironmentalcontrols.
■■ MSDSdocumentationforhandlinganddisposal
■■ Temperature,humiditylevelawarenessandproperventilation
■■ Powersurges,brownouts,blackouts
■■ Batterybackup
■■ Surgesuppressor
■■ Protectionfromairborneparticles
■■ Enclosures
■■ Airfilters
■■ Dustanddebris
■■ Compressedair
■■ Vacuums
■■ Componenthandlingandprotection
■■ Antistaticbags
■■ Compliancetolocalgovernmentregulations
chapter 1 3
Exam 220-802 objectives in this chapter:■■ 4.2Givenascenario,troubleshootcommonproblemsrelatedtomotherboards,RAM,CPUandpowerwithappropriatetools.
■■ Commonsymptoms
■■ Nopower
■■ Overheating
■■ Loudnoise
■■ Intermittentdevicefailure
■■ Smoke
■■ Burningsmell
■■ Tools
■■ Multimeter
■■ Powersupplytester
Real WoRld Dirty fans might sounD like jet engines
Not too long ago, a friend was complaining to me about a computer she had. She said she was going to have to replace it because it was just too loud and slow. I took a look, or per-haps I should say a listen, and sure enough it reminded me of being next to a jet engine. However, I knew how to solve this problem.
I bought a can of compressed air, took the computer outside, and removed the case. There was dust gunked up in just about every vent and throughout the inside of the computer. I methodically blew out all the dust and put the computer back together. Sure enough, without the extra dust, the computer was quieter and quicker.
The extra dust in the vents was making the fans work harder, and louder. The extra dust on the central processing unit (CPU) and its fan was causing the CPU to quickly overheat, and it was running slower as a result. However, with all the dust gone, the computer was hum-ming along quietly and returned to its previous speed.
It made me wonder how many people toss out perfectly good computers when all they need to do is clean them. I certainly understand how intimidating it can be for some users to open up a computer case and look inside. However, the A+ technician (you) with just a little bit of knowledge can be the hero for these people. You can help them restore their computer to its previous glory.
4 CHAPTER 1 IntroductiontoComputers
computing basics
Atthemostbasiclevel,acomputerhasthreefunctions:input,processing,andoutput.Itacceptsinput,performssomeprocessing,andprovidesanoutput,asshowninFigure1-1.Thisisoftenshortenedtojustinput/output (I/O).
Input Processing
CPURAM
Output
FiGUre 1-1 Input,processing,andoutput.
■■ input.User-providedinputcomesfromakeyboard,amouse,orevenatouchscreen.Sometimesinputisprovidedbyothersources,suchasadiskdrivewhenopeningfilesoranetworkinterfacecard(NIC)whenreceivingdata.
■■ processing.Thecomputerrespondstotheinputbycompletinganaction.Thecentralprocessingunit(CPU)isthebrainofthecomputer.Itdoestheprocessing,anditusesrandomaccessmemory(RAM)tostoreandmanipulatedata.
■■ Output.Outputiscommonlyprovidedtoascreenoraprinter.However,computersalsoprovideoutputtootherdestinations.Thesecanincludeoutputtospeakersorheadphonestoplaysound,todiskdriveswhensavingfiles,andtoaNICwhentrans-mittingdata.
Note Long-term and short-term storage
Computers are unable to work with data or programs until the information is in memory. Disk drives provide long-term storage, but information must be moved to the memory before the CPU can work with it. This is often transparent to the user.
Forexample,imagineyouwantedtoopenupaMicrosoftWorddocumentthathasyourA+studynotes.Youwouldstartbydouble-clickingthedocument,usingthemouseasyourinput.
Thecomputerprocessesyourdouble-clickwithseveralactions:
1. ItidentifiestheextensionoftheMicrosoftWordfile(.docor.docx).ItrecognizesthatthisextensionisassociatedwithMicrosoftWord.
2. ItlocatesandretrievestheMicrosoftWordprogramfromthediskdriveandbeginsmovingtheprogramfromthediskdrivetomemory.
Key Terms
NumberingSystems chapter 1 5
3. Whentheprogramisinmemory,thecomputercanactuallyrunit.
4. Thecomputerbeginssendingresultstothegraphicscard,showingtheprocessofMicrosoftWordstarting.
5. WhenMicrosoftWordisinmemoryandstarted,thecomputerlocatestheWordStudyNotesfileandmovesitfromtheharddrivetomemory.
6. Whenthefileisinmemory,thecomputerbeginssendingresultstothegraphicscard.
Note IPO
Computer troubleshooting can often be reduced to identifying what is not working: input, processing, or output (IPO). When you identify this, it’s much easier to troubleshoot and resolve the problem.
TheprecedingIPOprocessisconstantlyrepeated.ConsidertypingyourA+notesaboutfansorpowersuppliesintoyourstudyfile.Eachkeypressisanotherinputthatisprocessedandgeneratesanoutput.Thecomputeridentifieswhatkeyyoupressed,storesitsvalueinmemory,anddisplaysitonthescreen.Whenyousavethefile,itwriteseverythinginitsmemorytothefileonthedrive.
Despitebeingabletodosomuch,it’sworthpointingoutthatcomputersareprettydumb.Theycanworkonlywithnumbers.Specifically,theycanworkonlywithonesandzeros.Everythingthatiswrittentoadiskdriveortomemoryisaseriesofonesandzeros.
Admittedly,computerscanworkwiththeseonesandzerosveryquickly.Askittomultiplytwofive-digitnumbers,andacomputerwilldosoinaflash.However,itmustfirsttranslateanyinputyougiveittoastringofonesandzeros,processthesestrings,andthentranslatetheresultofonesandzerosintoausabledisplay.
Withthisinmind,it’simportantforanyA+techniciantohavearudimentaryunderstand-ingofsomebasicnumberingsystems.
Numbering Systems
YouandIcountbyusingdecimalnumbers.Weunderstandthemeaningofthenumbers0through9.Afteryougetupto9,thenextnumberis10.Thisisalsoknownasanumberingsystemwithabaseoften,becausetherearetendigitsinthenumberingsystem.
Ifyouseeanumberlike2,357,youknowthatitsdecimalpartsaretwothousand,threehundred,fifty,andseven.Table1-1showstheunderlyingmath,whichshouldmakealotofsensetoyouifyou’refamiliarwithdecimalnumbers.
6 CHAPTER 1 IntroductiontoComputers
tabLe 1-1 DecimalValues
103 102 101 100
Decimalvalue 1000 100 10 1
Number 2 3 5 7
Calculatedvalue 2,000 300 50 7
■■ Thecolumnonthefarleftis103,or10cubed.Thevalueof10x10x10is1,000.Thenumber2,357has2inthiscolumn,soitrepresents2,000.
■■ Thenextcolumnis102,or10squared.Thevalueof10x10is100,andthenumber2,357has3inthiscolumn,soitsvalueis300.
■■ Anynumberraisedtotheonepowerisitself,so101is10.Thenumber2,357has5inthiscolumn,soitsvalueis50.
■■ Last,anynumberraisedtothezeropoweris1,so100is1.Thenumber2,357has7inthiscolumn,soitsvalueis7.
Ifyouadd2,000+300+50+7,youget2,357.Whenyouseethenumber2,357,youprobablydon’tthinkofitthisway,butyoudorecognizethevalue.Forexample,ifIsaidIwasgoingtogiveyouyourchoiceof$2,357or$7,532,you’deasilyrecognizethatthefirstchoiceisalittleover$2thousandandthatthesecondchoiceisover$7thousand.Byreviewingwhatyouknow,it’seasiertobridgethatknowledgetosomethingthatmightbenewtoyou.
Basetennumbersaren’tveryefficientforcomputers.Theyresultinalotofwastedspace.Becauseofthis,computersusedifferentnumberingsystems,suchasbinaryandhexadecimal.
BinaryBinarynumbershaveabaseoftwo.Insteadofusingnumbers0through9,theyonlyusethenumbers0and1.
Note Binary Bit
In binary, a single digit is referred to as a bit. A bit can have a value of 1 or 0. When it is a 1, it is considered to be on, or true. When the bit is a 0, it’s considered to be off, or false.
Considerthebinarynumber1001.Table1-2showshowyoucanconvertthisnumbertoadecimalvaluethathasmoremeaningtoyouandme.
NumberingSystems chapter 1 7
tabLe 1-2 BinaryValues
23 22 21 20
Decimalvalue 8 4 2 1
Binarynumber 1 0 0 1
Calculatedvalue 8 0 0 1
■■ Thecolumnonthefarleftis23,or2cubed.Thevalueof2x2x2is8.Thenumber1001has1inthiscolumn,soitrepresentsacalculateddecimalvalueof8.
■■ Thesecondcolumnis2squared.Thevalueof2x2is4,andthenumber1001has0inthiscolumn,soitsvalueis0.
■■ Anynumberraisedtotheonepowerisitself,so21is2.Thenumber1001has0inthiscolumn,soitsvalueis0.
■■ Last,anynumberraisedtothezeropoweris1,so20is1.Thenumber1001has1inthiscolumn,soitsvalueis1.
Ifyouadd8+0+0+1,youget9.Therefore,thebinarynumber1001hasadecimalvalueof9.
HexadecimalAlthoughbinaryandbitsworkwellwithcomputers,theyaren’tsoeasyforpeopletodigest.Ifyouneedtotellsomeonetousethenumber201,that’srathereasy.Butifyouneedtotellsomeonetousethebinaryequivalent,it’s11001001.Thatstringofonesandzerosisalittledifficulttocommunicate.However,youcouldalsoexpressthesamenumberasC9byusinghexadecimal.
Hexadecimalusesthecharacters0–9andA–F,addingsixextradigitstothebasetennumbersof0–9.Hexadecimalusesabaseof16.Itiseasiertoexpressthanbinaryandmoreefficientforcomputersthanbase10becauseiteasilytranslatestobinary.
Note Binary grouping
When grouping several binary numbers, it’s common to separate groups of four with a space. This is similar to adding commas to decimal numbers. For example, 135792468 is often expressed as 135,792,468 because the commas make it easier to see that it starts with 135 million. Similarly, 11001001 isn’t as easy for most people to process as 1100 1001, although both numbers mean the same thing.
Thebinarynumber11001001canalsobeexpressedasC9,because1100isCinhexa-decimaland1001is9inhexadecimal.Table1-3showsthedecimal,binary,andhexadecimalequivalentforthenumbersuptohexadecimalF.
8 CHAPTER 1 IntroductiontoComputers
tabLe 1-3 Decimal,Binary,andHexadecimalValues
Decimal binary hexadecimal Decimal binary hexadecimal
0 0000 0 8 1000 8
1 0001 1 9 1001 9
2 0010 2 10 1010 A
3 0011 3 11 1011 B
4 0100 4 12 1100 C
5 0101 5 13 1101 D
6 0110 6 14 1110 E
7 0111 7 15 1111 F
Note Hexadecimal case
Hexadecimal numbers are not case sensitive. An uppercase C is the same as a lowercase c, and both equate to 1100 in binary. They are expressed both ways by different applications. Additionally, hexadecimal numbers are often preceded with 0x that to indicate that they are hexadecimal numbers. For example, if Windows 7 stops responding, the screen will display an error code such as STOP Error 0x0000002E, or hexadecimal code 2E. (This error code indicates a problem with memory.)
Acommonexampleofhowhexadecimalnumbersareusediswithmediaaccesscontrol(MAC)addresses.Networkinterfacecardsareassigned48-bitMACaddresses,andthesearecommonlylistedinsixpairsofhexadecimalnumberslikethis:6C-62-6D-BA-73-6C.Withouthexadecimal,theMACwouldbelistedasastringof48bits.
Bits vs. BytesAsinglebinarynumberisabit,andeightbitsmakesupabyte.Youcanextendbinaryasfarasyouneedto,butmostcomputertechniciansdealwithnumbersthatdonotgobeyondabyte.Thisisnottosaythatcomputerscan’tworkwithmorethaneightbits.Theycertainlycan.However,techniciansandotherInformationTechnology(IT)professionalsstillexpressthenumbersasbytes.
Table1-4showsthevalueofeachofthebitsinabyte.Thecolumnonthefarleftis27,or2x2x2x2x2x2x2.Ifyouconvertthistodecimal,itis128.
tabLe 1-4 BitsinaByte
27 26 25 24 23 22 21 20
128 64 32 16 8 4 2 1
Key Terms
NumberingSystems chapter 1 9
Note IPv4 Is 32 bIts
In networking, IPv4 addresses are 32 bits long. These addresses are commonly divided into four groups of eight bits, or four bytes. Additionally, the groups are usually expressed in decimal format. For example, an IPv4 address of 192.168.1.5 could also be expressed in binary as 1100 0000 . 1010 1000 . 0000 0001 . 0000 0101.
Kilo, Mega, Giga, and TeraComputershandlehugenumbersofbytes,whichareoftenexpressedaskilobytes (KB),megabytes (MB),gigabytes (GB),andterabytes (TB).AKBis1,024bytes,butmosttechniciansshortenthisto“aboutathousand”bytes.
Note One thOusand Or 1024
You may be wondering why a KB is 1,024 bytes instead of one thousand bytes. Kilo literally means thousand, so you’d think that one KB would be one thousand bytes. However, the bytes are calculated by using binary with the formula of 210 (or 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2). If you plug these numbers into a calculator, you’ll see that it works out to 1,024.
Here’sacomparisonofthesevalues:
■■ KB=aboutonethousandbytes(210)
■■ MB=aboutonethousandKBoraboutamillionbytes(220)
■■ GB=aboutonethousandMBoraboutabillionbytes(230)
■■ TB=aboutonethousandGBorabouttrillionbytes(240)
Quick Check1. What is the decimal value of the hexadecimal character C?
2. How many bits are in a byte?
Quick Check Answers1. 12
2. 8
Key Terms
10 CHAPTER 1 IntroductiontoComputers
cases and cooling
Computercaseshousemanyofthecomponentsinthecomputer,andtherearemanydiffer-enttypes,sizes,andshapesofcases.Standardpersonal computers (PCs)usedesktopcases.Somecasesaretowersthatstandupbesideadesk,andothersfitontopofadesk.Thecom-monpurposeofacomputercaseistohousethecomponentsneededwithinacomputer.
Figure1-2showsanopenedcomputercasewithseveralcomponentshighlighted.
23
15
6
3
4
FiGUre 1-2 Computercase.
1. power supply. Thewirescomingoutoftherightsideofthepowersupplyarecon-nectedtodifferentcomputercomponents.
2. cpU fan.ThisisadedicatedfantokeeptheCPUcool.TheCPUisdirectlybeneaththisfanandcan’tbeseen.
Key Terms
CasesandCooling chapter 1 11
3. case fans.Thiscasehastwofans,asmalleroneontheleftandalargeroneonthebottomright.Thesefanspullairintothecase.Ventsonthecasearepositionedsothatairconstantlyflowsoverkeycomponentstokeepthemcool.
4. Motherboard.Thelargewhitesquareoutlinesthemotherboard.Multiplecompo-nentsarelocatedonthemotherboard,includingtheCPU,RAM,andthegraphicscard.Chapter2,“UnderstandingMotherboardsandBIOS,”providesmoredetailsonthemotherboard,andChapter3,“UnderstandingProcessorsandRAM,”coversRAM.Chapter6,“ExploringVideoandDisplayDevices,”coversdisplaysandgraphics(includ-inggraphicscards)inmoredetail.
5. Optical drive bays. CDandDVDopticaldrivesarelocatedhere.Thissystemhastwodrives,withspaceforanotherone.
6. hard disk drive bays.Harddiskdrivesareusedforpermanentstorageofdata.Thissystemhastwoharddiskdrives,withspaceforanotherone.Chapter4,“ComparingStorageDevices,”coversthedifferenttypesofstoragedevices.
Youcanalsoseeavarietyofdifferentcableswithinthecase.Thepowersupplycablesarecoveredlaterinthischapter,andothercablesandconnectorsarecoveredinfuturechapters.
Notallcaseshavethismuchspaceorthismanycomponents.However,Figure1-2doesgiveyouanideaofwhatyou’llseewithinacomputercase.
Aquickexerciseyoucandoistoopenyourcomputer’scaseandpeerinside.Makesureyoufirstpowerthecomputerdownandunplugthepowercable.Onesideofthecasecannormallybeopenedbyremovingtwothumbscrewsonthebackofthecaseandpullingoffthesidepanel.There’snoneedtomanipulateanythinginsidethecaseatthisstage,butyoucanlookatitandcompareyourcasewiththecaseshowninFigure1-2.
Exam Tip
A+ exam questions often expect you to be able to identify components within a computer. Looking at different computers will help you correctly answer these questions. If you don’t have multiple computers handy, check out the pictures on bing.com. Type in your search phrase (such as “computer case,” “motherboard,” or “power supply”) and select Images.
MotherboardsAsyoucanseeinFigure1-2,themotherboardtakesupasignificantamountofspace.Thecaseshowninthefigureisrelativelylarge,andyouwilllikelyseeothercomputerswherethecaseisnotmuchlargerthanthelengthandwidthofthemotherboard.Allthecomponentsaresqueezedin.Thesesmallercasesdon’thaveasmuchroomforexpansion,suchasaddingharddrives.
12 CHAPTER 1 IntroductiontoComputers
Animportantconsiderationrelatedtothemotherboardandthecaseisensuringthatthecasecanadequatelyhouseit.Ifyoueverreplaceacomputer’smotherboardwithadifferentbrandormodel,you’llneedtoensurethatitfitswithinthecase.
Chapter2coversmotherboardformfactorsinmoredepth,butasanintroduction,theAdvancedTechnologyExtended(ATX)motherboardformfactoristhemostcommon.TheATXstandardhasbeeninusesince1995,withseveralimprovementsandmodificationsaddedovertheyears.ManycasesaredesignedsothattheywillsupportATXmotherboards.
Case FansComputerscangetveryhot,sofansareusedtokeepcoolairflowingoverthecomponents.Theydrawairinfromtheroom,directitoverkeycomponents,andthentheairexitsfromventsonthecase.
Fanscomeindifferentlevelsofquality,andthemostnoticeabledifferenceisinhowmuchnoisetheymake.Inexpensivefanshavecheapbearingsthatarenoisy,whilequalityfanshavesophisticatedbearingsthatareextremelyquiet.Manyqualityfansincludeathermistor,whichautomaticallyadjuststhespeedofthefanbasedonthetemperature.
Common Problems with FansWhenacasefanbecomescloggedordirty,itcanbesonoisythatpeoplecommonlycom-plainitsoundslikeajetengine.Theynevergetquitethatloud,buttheycanbeanuisance.
Evenworse,ifthecasefanisclogged,thecomputerisoftennotgettingenoughairflowthroughit.Internalcomponentsbecomehotter,andit’scommonfortheentiresystemtoslowtoacrawl.Insomecases,problemswiththefancancausethesystemtofail.
Exam Tip
Intermittent failures, such as random restarts, are often an indication of a heat-related problem. This is especially true if the fans are loud, indicating that they are working very hard.
TheeasysolutionistocleanthefanalongwiththecaseasdescribedintheCleaningCasessectionlaterinthischapter.Thiswilloftenreducethenoiseandincreasetheperformance.Ifitdoesn’tsolvetheproblem,youcanreplaceitwithahigher-qualityfan.
Ifafanfailscompletely,itshouldbereplacedassoonaspossibletoensurethatothercomponentsdonotoverheatandfail.
CasesandCooling chapter 1 13
Note Close the Case
In different situations, many technicians are tempted to run a computer with its case open. However, the vents on the case are strategically placed to ensure that air flows over specific components to keep them cool. If the case is left open, these components do not have enough air flow over them, which can cause them to overheat.
Replacing a FanAfanisconsideredafield replaceable unit (FRU),soifafanistoonoisyorhasfailed,youcanreplaceit.Manycompaniessellcasefans,andtheyarerelativelyeasytoreplaceonasystem.Ifyoudoreplacethefan,makesurethatthefanyou’repurchasingfitsinyourcase.Thetwomostcommonsizesforcasefansare80mmand120mm.
Figure1-3showsthecasefanwithinasystem.Takealookatitasyoufollowthestepstoremovethefan.
2
1
FiGUre 1-3 Removingacasefan.
14 CHAPTER 1 IntroductiontoComputers
Important Turn off The power
Ensure that the computer is turned off and that the power cable is removed before open-ing the case and replacing a fan. Power is still provided to the motherboard even if the system is turned off, and you can cause damage to the computer or yourself if the power cable is not removed.
1. remove four screws from the back of the case.ThearrowsinFigure1-3pointtotwoofthescrews,andtheothertwoscrewsareontheothertwocornersofthefan.
2. remove the power connector.Thepowerconnectorplugsintoaspecificjackonthemotherboard.Takenoteofthisjack,andensurethatyouplugthenewfanintothejackthesameway.Fanconnectorscanusetwo,three,orfourpins.The4-pinconnectorsarecommonlyusedwithvariablespeedfans,allowingthecomputertocontrolthespeedofthefan.YoucanalsouseadapterstoconnectsomefansintoaMolextypeofconnectorfromthemotherboard.
Afterremovingtheoldfan,youcaninstallthenewfanbyreversingyoursteps.Attachthefourscrewsandplugitin.
Evenwithnewfans,though,ifthecaseventsbecomecloggedwithcontaminants,thefanswillworkhardertopulltheairthroughthesystem.Theeasysolutionistocleanthecase.
Cleaning CasesWithalltheairblowingintothecomputercase,itwillgathersomedust.Inextremeworkenvironments,theinsideofacomputercangetquitedirty.Forexample,acomputerwithinamanufacturingplantwillcollectdirtandcontaminantsinsidethecase.Similarly,acomputerwithdogsorcatsintheareacancollectfurandhair.
It’srelativelyeasytocleanacase.Themostcommonmethodisbyusingacanofcom-pressedair,whichyoucanpurchasefromelectronicsstores.Takethecomputeroutside,removethecover,andusethecompressedairtoblowoutthedustandothercontaminants.
Exam Tip
Cleaning a case and its fans can improve a computer’s performance. Excessive dust creates additional heat, and many computers include components that can automatically sense the temperature. These components often increase the speed of the fans, making the system louder, and also slow down the speed of the CPU to reduce the heat.
Notification Switch for SecurityManycomputercaseshaveaspecialpush-buttonswitchthatdetectswhetherthecasehasbeenopened.Thisisalsocalledabiased switch,anditstaysdepressedaslongasthecaseisclosed.Whenthecaseisopened,theswitchopensandthechangeisrecordedinthe
PowerSupplies chapter 1 15
computer.Thenexttimethesystemstarts,itindicatesthatthesystemcasehasbeenopened.Thisisusefulfordetectingwhethersomeonehasbeentamperingwithacomputer.
Quick Check1. What are the two common sizes of a case fan?
2. A computer has become louder and slower. What is a common solution?
Quick Check Answers1. 80 mm and 120 mm.
2. Clean it.
power Supplies
Computersrunonelectricity.Electricityismeasuredasvoltage,andvoltageisthedifferenceinpotentialbetweentwopoints.Forexample,anelectricalsignalcanbe12voltsaboveagroundpotentialofzerovolts,givingitavalueof12volts.Powersupplieswithincomputersensurethatcomponentswithinasystemconsistentlyhavethecorrectvoltages.
AsanA+technician,youmightneedtotroubleshootasystemwithafaultypowersupplyorevenreplaceapowersupply.Withthatinmind,youneedtohaveabasicunderstandingofpowersupplies.
AC vs. DCThetwotypesofvoltagesarealternatingcurrent(AC)anddirectcurrent(DC).AC voltage alternatesaboveandbelowzerovolts,andDC voltageprovidesasteadyvoltageeitheraboveorbelowzero.
CommercialpowercompaniestraditionallyprovidepowerasAC,whichlookslikeasinewave.PowersupplieswithincomputersconvertthisACvoltageintoDCvoltage,asshowninFigure1-4.
ATX-basedpowersupply
AC commercial power
OV
Common DC voltages
OV
+12 V
+5 V+3.3 V
–12 V
FiGUre 1-4 ACvs.DC.
Key Terms
16 CHAPTER 1 IntroductiontoComputers
Figure1-4isn’ttoscale.ACvoltagesvaryabout115VAC(voltsACpower)aboveandbelow0voltsinmanyregions,suchasintheUnitedStates,and230VACaboveandbelow0voltsinotherregions,suchasinEurope.ThekeypointisthatACvoltageisanalternatingorvaryingvoltage,whereasDCvoltageisaconstantsteadyvoltage.TheDCvoltagesshowninthefigurearecommonvoltagesusedwithincomputers,andaresometimesexpressedasVDC,suchas12VDC.
Wattage Power RatingsPowersuppliesareratedbasedontheamountofpowertheycanprovide,andpoweriscom-putedasawatt (W).Insimpleterms,wattsarecomputedbymultiplyingthevoltagebytheamperage.Amperage(A)referstotherateofflowofthevoltage.Higheramperageresultsinahigherrateofflow,andhigheramperagewiththesamevoltageprovidesmorepower.
Eachindividualcomponentwithinacomputerrequiresacertainamountofpower.Forexample,it’snotuncommonforaCPUtorequireasmuchas100W.Additionally,themother-board,casefans,anddiskdrivesalldrawadditionalpower.Withthisinmind,powersup-pliesmustnotonlyconvertACtoDCandsupplythecorrectDCvoltages,buttheymustalsoprovideenoughpowertosupportallthecomponentsinthesystem.
Whenreplacingapower supply unit (PSU),youshouldlookfortheWwithinthespecifica-tionstoidentifythepoweroutput.Forexample,a600-wattPSUwouldbelistedas600W.TherangeofcommoncurrentATX-basedPSUsisabout300Wto1,000W.
Ifasystemrequires600Wandyouputina300-Wpowersupply,you’llhavesomeprob-lems.Inmostcases,thecomputersimplywon’twork.Inothercases,thepowersupplywon’tbeabletoprovidesteadyvoltagesandthevariancesmightdamagesystemcomponents.
RailsPowersuppliesprovideseparatelines(calledrails)forthedifferentvoltages.Thevoltagethatdrawsthemostpoweris12V,usedforCPUs,casefans,anddiskdrives,andasingle12-Vrailprovides18Aofpower.However,thissingle18-Arailoftenisn’tenoughtopowerallthecomponentsthatneedthevoltage.
Manycurrentpowersuppliesincludeatleasttwo12-Vrails,withoneraildedicatedtotheCPUandthesecondraildedicatedtoeverythingelse.Somepowersuppliesincludethreeorfourrails.Whenreplacingapowersupply,youneedtoensurethatyouarereplacingitwithonethathasatleastthesamenumberof12-Vrailsastheoriginal.
Exam Tip
The 12-V rails provide primary power to disk drives. If these rails are overworked, they will frequently cause problems for the hard drives. In other words, if hard drives are frequently failing in a computer, consider replacing the power supply with one that has an additional 12-V rail.
Key Terms
PowerSupplies chapter 1 17
Power Supply ConnectionsTheATXstandardmentionedwithintheMotherboardssectionearlierinthischapteralsoidentifiespowersupplyrequirements.MostcurrentdesktopsystemsincludepowersuppliesthatsupportATX-basedmotherboards,andtheyprovidespecificvoltagesdefinedintheATXspecifications.
Figure1-5showstherearviewofapowersupply,alongwithitsconnectors.ThispowersupplywasremovedfromacomputerwithanATX-stylemotherboard.Refertothefigureasyoureadthefollowingdescriptions.
2
3
1
4
5
6
7
8
FiGUre 1-5 Powersupply.
1. ac power jack.ThepowercableconnectsfromheretoapowersourceprovidingACpower.
2. Dual voltage power selection.Select115or230basedonthecommercialpowerprovidedatyourlocation.Forcomparison,commercialpowerprovidedintheUnitedStatesis115VAC,andpowerprovidedinEuropeis230VAC.Somesystemscanauto-maticallysensethevoltage,sotheswitchisn’tneeded.
18 CHAPTER 1 IntroductiontoComputers
Exam Tip
If you have this selection set at 230 and you plug it into a commercial power source provid-ing 115 VAC, it won’t have enough power to run the computer. On the other hand, if you set it to 115 and you plug it into a 230-VAC power source, you will likely destroy the power supply. If you hear pops, smell burning components, or smell smoke, unplug it as quickly as possible and check this switch.
3. power indicator.Whenon,itindicatesthatthepowersupplyhaspower.Thisdoesnotindicatethattheactualcomputeristurnedon.Computerstypicallyhaveaseparatepowerbuttonandpowerindicatoronthefrontofthecase.
4. Molex connectors.Theseprovide5Vand12Vtodifferentdevices,suchasParallelAdvancedTechnologyAttachment(PATA)diskdrives.
5. Sata power connector.This15-pinconnectorprovidespowertoSerialAdvancedTechnologyAttachment(SATA)diskdrives.Itincludes3.3-V,5-V,and12-VDCvoltages.
6. Secondary motherboard power connection.Mostcurrentmotherboardsusea4-pinconnectorthatprovides12VDCusedbytheCPU.ThisconnectorisformallycalledATX12VbutisalsoknownasP4becauseitwasfirstusedwiththePentium4CPUs.SystemswithmorethanoneCPUusean8-pinconnector(ortwo4-pinconnec-tors)toprovidepowerformultipleCPUs.ThisisformallyknownasEPS12V.
7. Floppy drive mini-connectors.ThesearesometimescalledBergconnectorsormini-Molexconnectors.Theyprovide5-VDCand12-VDCpowerto3.5-inchfloppydrives,whenthesystemincludesfloppydrives.
8. primary power connector.A20-pinor24-pinconnectorprovidesprimarypowertothemotherboard.It’scommonlycalledtheP1connectorandprovides3.3VDC,5VDC,and12VDCtothemotherboard.
Exam Tip
You might need to troubleshoot a power supply and verify that it is supplying the correct voltages. With this in mind, you should be aware of valid voltages on the different connec-tors. Black wires are ground (or a zero potential), orange wires carry 3.3 V, red wires carry 5 V, yellow wires carry 12 V, and blue wires carry -12 V.
ManypowersuppliesalsohaveaPCIExpress(PCIe)powerconnector.Thiswasoriginallya6-pinconnector,butnewsystemsusean8-pinconnectorsimilartotheoneshowninFigure1-6.Somepowersuppliesusea6+2connector,allowingyoutoplugitintoanoldersystemwithonly6pins,oranewersystemwith8pins.
PowerSupplies chapter 1 19
FiGUre 1-6 PCIepowerconnector.
Cable KeyingMostcablesarekeyed.Thatis,theyaredesignedtofitintoajackinoneway,andonewayonly.However,theseconnectorsandplugsarejustplastic,soitispossibletoforceaconnec-torontoaplugbackwards.Ifyoudo,thewrongvoltagesorsignalswillbesenttoadevice.
Intheworstcasescenario,pluggingacableinbackwardscandestroyadevice.Ifyou’relucky,pluggingthecableinwrongwilljustresultinthedevicenotworking.Neitherresultisdesirable,soit’sbesttolookforthekeyandensurethatyouplugintheconnectorcorrectly.
Figure1-7showssomecommonmethodsofhowcablesarekeyed.
Rounded edge Extra plastic on edges Rounded edgeson pins
FiGUre 1-7 Cablekeyingexamples.
ItmightnotbeapparentinFigure1-5shownearlier,butseveraloftheconnectorshavekeyedconnectorssimilartothatshowninFigure1-7.TheMolexconnectors(item4inFigure1-5)haveroundededges.TheSATApowerconnector(item5)hasanextraedge.Themini-connector(item7)hasseveralextraedges.Theprimarypowerconnector(item8)hasroundededgesontheindividualpins.
Important Never force a coNNector
Plugging in any connector the wrong way can damage the computer. Although the keying does help, the connectors are plastic and in some cases it is possible to force a connector onto a plug the wrong way. If a connector doesn’t seem to fit, don’t try to force it. Instead, double-check the keying to ensure that it is plugged in correctly.
20 CHAPTER 1 IntroductiontoComputers
ATX vs. Micro-ATX Power SuppliesATXpowersuppliesarethestandardusedinmanycomputerstoday.However,somesmallerPCshavelowerpowerrequirementsandcanbepoweredbyusingsmallerpowersupplies.Micro-ATXpowersuppliesprovidealoweramountofwattage,oftenbetween180and300watts,thoughsomespecial-purposepowersuppliesareaslow90watts.
Themicro-ATXpowersuppliesaresmallerinsizeandhavefewerpowerconnectorsthanaregularATX-basedpowersupply.Also,theprimarypowerconnector(P1)usuallyhasonly20pinsonthemicro-ATXpowersupply,ratherthanthe24pinsoftenfoundonATX-basedpowersupplies.
Replacing a Power SupplyManycomponentswithinacomputer,includingthepowersupply,aremodular.Whenamod-ulefails,youneedtoreplaceonlythemodule,nottheentirecomputer.Thisissimilartoacar.Ifyourcargetsaflattire,youreplacethetire,nottheentirecar.Ifthepowersupplyfailsinacomputer,youreplacethepowersupply.
Exam Tip
When power supplies fail, you can sometimes see smoke or smell burning components. New power supplies often give off an odor for a short burn-in period, but they aren’t faulty. However, if you see smoke or hear sparks, remove power immediately.
Theprimaryindicatorthatthepowersupplyhasfailedisthatthesystemdoesn’thaveanylightsorindicators.Ofcourse,you’dwanttoverifythatthecomputerispluggedinandturnedon.Also,somesystemshaveapowerswitchonthepowersupplythatneedstobeturnedoninadditiontoturningonthepowerviaaswitchorbuttoninthefrontofthesys-tem.Ifyou’vecheckedthesebutstillhavenopowerindications,itmightbetimetoreplacethepowersupply.
Thepowersupplyisrelativelyeasytoreplace,butyouneedtokeepafewimportantcon-ceptsinmind:
■■ turn off and remove the power plug.Youshouldnotattempttoreplacecomputercomponentswhilethesystemispluggedin.Theexceptionis“hotswappable”com-ponentssuchasUSBflashdrivesthataredesignedtobeinsertedorremovedwhileturnedon.
■■ Use a suitable replacement.Ensurethatthewattageofthereplacementisatleastashighastheoriginal,ifnothigher.Also,ensurethatthepowersupplyhasatleastthesamenumberof12-Vrailsas,ifnotmore,thantheoriginal.
■■ Document cable placement.Payattentiontothecablesbeforeyoutakethemout.Drawadiagramshowingwhereeachcablegoes,ortakeacoupleofpictureswithyourcellphone.Withoutthisdocumentation,whentheoldpowersupplyisout
PowerSupplies chapter 1 21
andthenewpowersupplyisin,youmighthavetroublerememberingwhereallthecableswent.Also,ensurethatyouidentifythekeyingofthecablesandplugthemincorrectly.
Whenyou’rereadytoreplacethepowersupply,you’llfindthereareonlyfourscrewshold-ingiton.Removethecablesandthescrews,andyou’llbeabletoremovethepowersupply.Occasionally,youmightneedtoremoveothercomponentsfirsttogettothepowersupplyandremoveit.
Protecting Systems from Power Problems Commercialpowerisn’talwaysstable,anditcansometimescauseproblemstocomputers.However,therearesomebasicstepsyoucantaketoprotectthem.Someofthecommonproblemsyoumightseeoncommercialpowerlinesareasfollows:
■■ Surge. Commercialpowercanoccasionallyincreaseorsurge.Insteadofprovidingasteady115VAC,itcanincreaseto120VACorhigher.Surgesareusuallyshorttermandtemporarybutcansometimesbeobservedaslightsbecomebrighter.
■■ Spike. Thisisaquick,sharpincreaseinACvoltage.Thevoltageimmediatelyreturnstonormal,butthespikecandestroyunprotectedequipment.Lightningstrikesareacom-monsourceofspikes.
■■ Sags and brownouts. Commercialpowercanalsoreduceorsag.Insteadofprovidingasteady115VAC,itcandecreaseto110VACorlower.Ifthisoccursforlessthanasec-ond,it’scalledasag,butifitlastslonger,it’sreferredtoasabrownout.Youcanoftenseelightsflickerorbecomedimmerduringbrownouts,andtheycancausesystemstorestart.
■■ blackouts. Ablackoutisthetotallossofpower(orthereductionofpowertosuchalowlevelthattheequipmentisunabletooperate).Thefollowingsectionsidentifysomeofmethodsusedtoprotectagainstpower-relatedproblems.
Surge SuppressorsAsurge suppressorisapowerstripwithextraprotection.Ithasbuilt-insensorsthatcandetectwhenthepowersurgesorspikes.Mostsurgesuppressorshaveacircuitbreakerthatwillpopwhenitdetectssurgesorspikes.Whenthecircuitbreakerpops,thesurgesuppressornolongerprovidesvoltagetoanysystemspluggedintoit.Youcanusuallyresetitbypressingabuttononthesurgesuppressororbyturningitoffandbackon.
Note Power striPs vs. surge suPPressors
A power strip is similar to an extension cord with extra power plugs. Many people assume it protects against surges and spikes, but it does not provide any protection. Surge sup-pressors include some type of tag or marking indicating that they are surge suppressors.
Key Terms
Key Terms
22 CHAPTER 1 IntroductiontoComputers
Battery BackupAnuninterruptible power supply (UPS)providesthebenefitsofasurgesuppressorandalsoprovidesconstantpowertoasystem.Itincludesbatteries,andifcommercialpowerislostorsags,itcancontinuetosupplypowertosystemsforashorttime,forasmuchas10or15minutesorlonger.
Forexample,IrecentlyaddedanUPSratedat900watts.IpluggedinmyprimaryPCandflatscreenmonitor,butnothingelse,totheUPS.Duringapoweroutage,theUPScontinuedtoprovidepowerforoveranhour.IfIhadtwoPCsandtwomonitorspluggedintoit,theUPSwouldlikelyhavelastedonlyabout30minutes.
Ifpowerisn’trestoredwithinacertaintimeframe,theUPScansendasignaltothecom-putertoperformalogicalshutdown.Thispreventshardwareandsoftwareproblemscausedbyunexpectedpowerlosses.
Figure1-8showshowtheUPSisconnectedtothecomputer.TheUPSplugsintothewalltoreceivecommercialpower.ThispowerprovidesacontinuouschargetothebatterieswithintheUPS.TheUPSprovidesACpowertothecomputerortoothersystemspluggedintoit.Ifpowerfails,theUPScontinuestoprovidepowertothecomputerforashorttime.
AC commercial power
UPS
AC power
FiGUre 1-8 UPSusedtoprotectagainstshort-termpowerloss.
Exam Tip
An UPS can be used to provide power to computers for short-term power. Laser printers draw a significant amount of power, and they should not be plugged into an UPS.
It’simportanttoensuretheUPSsystemcanmeetthepowerrequirementsofthesystemsyou’retryingtoprotectfrompoweroutages.Additionally,youshouldpluginonlysystemsthatyouneedtokeepoperationalduringshort-termpowerfailures.IfyouplugallyourequipmentintotheUPS,theywilldrawadditionalpower.ThiswillreducetheamountoftimethattheUPSprovidespowertothesesystemsduringanoutage.Otherequipmentshouldbepluggedintoasurgesuppressor.
Key Terms
SafetyIssues chapter 1 23
Quick Check1. What voltages are provided by an ATX power supply?
2. What should you check if you have hard drives frequently failing?
Quick Check Answers1. 3.3 V, 5 V, 12 V, and -12 V
2. 12-V rails
Safety issues
Whenworkingoncomputers,it’simportanttopayattentiontosafetyconsiderations.Abasicpremisetoalwayskeepinmindisthatcomputersarejustthingsthatcanbereplaced,butwecan’treplacepeople.Inotherwords,valuepeoplefirstwhenworkingwithcomputers.Byfol-lowingbasicsafetyprecautions,youcanpreventdamagetopeopleandtoequipment.
Electrical SafetyUnlessyou’remeasuringvoltageswithinacomputer,youshouldneverworkoncomputerswithoutfirstremovingpower.Thisincludesturningthecomputeroffandunpluggingit.
Justturningoffthepowerisnotenough.ATX-basedpowersuppliesprovidepowertothemotherboardevenifthefrontpowerswitchonthecomputerindicatesthatitisturnedoff.Ifyouwanttoensurethatthecomputerdoesnothaveanypower,unplugthepowersupply.
MostpeopleconsiderPSUsmodularunits.Inotherwords,ifthePSUfailsyousimplyreplaceitinsteadoftryingtorepairit.However,ifyoudoopenthepowersupply,don’tfor-getthefollowingtwoimportantwarnings:
■■ Neveropenitwhenitispluggedin.
■■ Evenafteryouunplugit,capacitorswithinthepowersupplywillholdacharge.Ifyoutouchthecapacitor,itcaneasilydischargeandshockyou.Ilearnedthislessonfirst-handwhenplayingwithoneofmyfather’sradiosetswhenIwasabouteightyearsold.Itknockedmeagainstthewallandleftmymotherwhite-facedforquiteawhile.
Equipment and Self-GroundingInelectronics,groundreferstoapathtoEarth.Acoppercableisattachedtoaspikeandhammeredintotheground.Theotherendofthiscableisavailableintheelectricalsystemandidentifiedasaground.Mostelectricalequipmentincludescircuitrythatwillautomaticallyredirectanydangerousvoltagestogroundtopreventshocks.
24 CHAPTER 1 IntroductiontoComputers
Important EquipmEnt ground connEctions should always bE connEctEd
Disconnecting ground connections can bypass safety circuits. Dangerous voltages can be redirected to the computer case, resulting in a shock if a user touches the case.
Groundisreferredtodifferentlybasedonthelocationoftheconnection.Forexample,Figure1-9showsthethreeprimarysymbolsusedforground.
Earthground
Chassisground
Signalground
FiGUre 1-9 Groundsymbols.
Earth groundisthepathdirectlytoEarth.Chassis groundreferstothepathtotheequip-mentcaseorchassis.Signal groundreferstothereturnpathforasignal.Signalgroundconnectionsarecommonlyconnectedtothechassis.Forexample,somescrewsconnectingamotherboardtoacomputercaseconnectthemotherboardsignalgroundtothecase.ThechassisgroundisthenconnectedtotheEarthgroundviathepowercable.
ESDStaticelectricitybuildsupondifferenttypesofobjects,andwhenoneobjecttouchesanother,thestaticdischarges.You’veprobablyexperiencedastaticdischargeafterwalkingacrossacarpetedfloorandtouchingadoorknob.Thisisalsocalledelectrostatic discharge (ESD).
Theshockyoufeltmighthavebeenunpleasant,butitwasn’tharmful.However,itcanbedamagingtocomputers.Ifyoufeltit,atleast3,000voltsweredischargedfromyourhandtothedoorknob.Ifyouactuallysawthesparkwhenitdischarged,itwasatleast8,000volts.Thegoodnewsisthesevoltageswon’tkillorhurtpeople,mostlybecausetheyaren’tcombinedwithcurrenttogeneratepower.
Incontrast,computercomponentscanbedamagedbyaslittleas250volts.Youwon’tseeit.Youwon’tfeelit.However,thedamagewillbereal.
TheprimarywaytopreventESDdamageisbyensuringthattheworkerandtheequip-mentareatthesamegroundpotential.StepsyoucantaketoreduceESDdamageincludethefollowing:
■■ Use an eSD wrist strap.AnESDwriststrapwrapsaroundyourwristandhasametalcomponenttouchingyourskin.Awireleadsfromthestraptoanalligatorclipthatyoucancliptothecomputercase.Thisresultsinyouandthecasebeingatthesamepotential,anditpreventsstaticdischarge.Onworkbenches,ESDstrapsareusedto
Key Terms
SafetyIssues chapter 1 25
connecttheequipmentcasetoagroundingbarthatisconnectedtoEarthground.Thetechniciancanconnectalligatorclipsfromthewriststraptothecaseortothegroundingbar.
■■ Use antistatic bags.Whenstoringandtransportingelectroniccomponents,theyshouldbestoredinantistaticbags.ThesebagshelppreventstaticfrombuildingupandcausingESDdamagetothecomponents.
■■ Use eSD mats.SpecialESDmatspreventstaticbuildup,andtheyarecommonlyusedonworkbenches.Techniciansplacecomputersontheantistaticmatwhileworkingonthem.Largerantistaticmatscanbeplacedonthefloorinfrontofthetechnician’sbenchtoreducestatic.
Exam Tip
Very small amounts of ESD can cause damage. This is especially true when handling sensi-tive components such as CPUs and memory. ESD protection such as antistatic wrist straps, antistatic component bags, and antistatic mats are valuable to protect against ESD damage when handling CPUs, memory, and other sensitive components.
■■ Self-grounding.Ifyoutouchthecomputercasebeforeworkingonanycomponents,built-upstaticwilldischargeharmlesslyontothecase.Thisensuresthatyourbodyisatthesamegroundpotentialasthecase.Additionally,ifyoukeepyourfeetstationaryaftertouchingthecase,itreducesthechancesforstatictobuildup.
■■ Don’t touch components or pins.Ifyouremoveanycircuitcards,don’ttouchthecomponentsorthepins.Instead,holdtheoutsideedgesortheplastichandles.
■■ control humidity.Whenthehumidityisverylow,staticbuildsupmorequickly.Ifyouliveinacolderarea,you’llnoticethatstaticismorecommoninthewinterbecauseheatingsystemsremovehumidityfromtheair.Incontrast,whenthehumidityishigher,thestaticchargesdissipatenaturally.Ideally,humidityshouldbearound50percent.
■■ Don’t place computers on carpets.Staticcanbuilduponcarpetsmoreeasilythanonotherfloorsurfaces.You’veprobablynoticedthatinaheatedbuildingyoucanshuffleyourfeetoveracarpettoquicklybuildupstatic.Thisdoesn’tworkontilefloorsorotherfloorsurfaces.
MSDSMaterial Safety Data Sheets (MSDSs)areavailableformostproductsthathaveapotentialtocauseharmtopeopleorequipment.Thisincludesmaterialssuchascleaningsolutions,paints,andchemicals.TheMSDSidentifiesimportantsafetyfactsaboutthematerialincludingitscontents,itscharacteristics,howtohandleandstoreitsafely,andhowtodisposeofit.Itwillalsolistfirst-aidstepstotakeifthematerialpresentsadanger.
Key Terms
26 CHAPTER 1 IntroductiontoComputers
AsanA+technician,youarelikelytouseproductsthathaveMSDSsheets.Forexample,youmightusecleaningproductsthatcleancomputerscreensorkeyboards.Ifanyoftheseprod-uctsiscausinganadversereactiontoeitherpeopleortheequipment,youcanrefertotheMSDSsheetforinformationabouttheproductandadditionalstepstotakeaftertheexposure.
Compliance with RegulationsAnygovernmentregulationspertainingtosafetyorenvironmentalcontrolsmustbefollowed.Forexample,thestateofCaliforniahasmandatedthatallbatteriesbedisposedofashazard-ouswaste.Evenifthebatteriesarethenewermercury-freealkalinebatteries,theregulationstillrequiresspecialhandling.
Note Ignorance Is no excuse
An old saying related to the law is that “ignorance is no excuse.” With that in mind, organi-zations have a responsibility to learn what regulations apply to them where they operate, and to comply with those regulations.
Fire SafetyFiresareclassifiedbasedonwhatisburning,andfireextinguishersareclassifiedbasedonwhatfirestheycansafelyextinguish.Thefourprimarytypesoffiresareasfollows:
■■ class a.Thistypeoffireinvolvesordinarycombustiblematerialsuchaspaperandwood.ThefirecanbeextinguishedwithwateroraClassAfireextinguisher.
■■ class b.Thistypeoffireinvolvesflammableliquidsandgases.ClassBfireextinguish-ersusechemicalstodisruptthechemicalreaction,ortheysmotherthefirewithagassuchascarbondioxide.SprayingwateronaClassBfireisdangerousbecauseitwillspreadthefireinsteadofextinguishingit.
■■ class c.AnelectricalfireisaClassCfire,andthebestwaytoextinguishitisbyremov-ingthepowersource.Forexample,unpluggingitorturningoffthecircuitbreakercanstopthefire.ClassCfireextinguishersusespecialchemicalssuchasPurple-Korcarbondioxidetoextinguishafire.
Important Never use water to extiNguish Class C fires
Water is conductive. Electricity can travel up the water stream and electrocute you if you spray water onto an electrical fire.
■■ class D.Thistypeoffireinvolvescombustiblemetals.AClassDfireextinguisherusesspecialchemicalstosmotherthefire.Watershouldnotbeused.
Tools chapter 1 27
LiftingWhenliftingequipment,it’sbesttoliftwithyourlegs,notyourback.Inotherwords,insteadofbendingdowntopickupheavyequipment,youshouldsquat,bendingyourknees,topickitup.
Therearen’tanyfirmguidelinesonsafeweightlimitations.However,it’sgenerallyrec-ommendedthatindividualsdonottrytoliftequipmentweighingmorethan70poundswithouthelp.
Quick Check1. What can be used to protect against ESD?
2. What includes first-aid steps to take if cleaning supplies cause harm to a person?
Quick Check Answers1. Controlled humidity, antistatic wrist straps, and antistatic mats
2. MSDS sheets
tools
Ifyou’regoingtoworkoncomputers,you’llneedsometools.Thefollowingsectionsidentifysomecommontoolsyoushouldhave.
ScrewdriversCasefans,powersupplies,andmotherboardsareallsecuredwithscrews,soifyouneedtoremovethem,you’llneedascrewdriver.MostscrewsarePhilips,soyou’llneedoneortwoPhilipsscrewdriversinadditiontooneortwoflat-bladescrewdriversinyourtoolkit.
Extension MagnetIt’snotuncommontodropascrewwithinasystem,butyourfingersoftenwon’tfitintothesmallspacestoretrieveit.Youcanretrieveitwithanextensionmagnet.Anextensionmagnethasahandlesimilartoascrewdriver,butithasanextendablewandwithamagnetontheend.Insomesituations,thescrewmightfallontootherelectricalcomponents,suchasthemotherboard.Insteadofusingtheextensionmagnet,youcanuseapairofplastictweezerstoavoidpossibledamagetosystemcomponents.
28 CHAPTER 1 IntroductiontoComputers
Compressed Air and CompressorsAsmentionedpreviously,compressedaircanbeusedtocleanoutacomputercase.Youcanpurchasecansofcompressedaironlineoratcomputerandelectronicsstores.Theyusuallyhaveplasticstrawsthatyoucanattachtothespraynozzlesothatyoucandirecttheairintothenooksandcranniesofthecase.Compressedairisalsousefulforblowingoutkeyboards,printers,andlaptopcases.
Compressorsareelectronicmotorsthatbuildupairpressureandallowyoutoblowoutcomponentswithahose.Forexample,manygasstationshavecompressorsthatyoucanusetoaddairtoyourtires.Unlikecompressedaircans,acompressorwillneverrunoutofair.
Important Be careful when using air compressors
Some compressors have very high air pressure, which can damage components within the computer if you’re not careful. Additionally, some air compressors collect water that can spray into the computer. Technicians that use these often have a regulator that they use to keep the pressure below 20 pounds per square inch (psi), and they use filters to trap any water. Some technicians strongly oppose using air compressors at all.
Computer Vacuum Insomecases,itisn’tfeasibletotakecomputersoutsidetoblowoutthedust.However,ifyoublowoutthedustinsidethebuilding,you’regoingtomakequiteamess.Instead,youcanuseacomputervacuumcleanertocleanoutthecomputer.
Youshoulduseonlyvacuumcleanersdesignedforthejob.Regularvacuumcleanersgeneratestaticelectricityandcaneasilydamagethesensitivecomponentswithinthecom-puter.ComputervacuumsaremadeofspecialmaterialsandoftenusebatteriesinsteadofACpower.
Exam Tip
Regular vacuum cleaners and their attachments can cause ESD damage to systems. Com-puter vacuums are made of special material resistant to ESD.
MultimeterMultimetershavemultiplefunctions,andtechnicianscommonlyusethemtomeasurepowersupplyvoltages.
Forexample,powersuppliessometimeslosetheabilitytoprovideconstantpower.Insteadofasteady12V,apowersupplymightwaverbetween10Vand14V.Eventhoughasystemhassometoleranceforvariations,generallyanythingbeyond5percentcancauseprob-lems,suchasrandomrestarts.Therefore,the12-Vlineshouldnotwavermorethanplusor
Key Terms
Tools chapter 1 29
minus0.6V(11.2Vto12.6V).Ifyou’reexperiencingrandomproblemsandsuspectthepowersupply,youcanuseamultimetertomeasurethevoltages.
Exam Tip
Random restarts can also indicate other problems. Overheating and in some cases faulty memory can cause a system to occasionally restart. Additionally, malicious software such as a virus can cause a system to randomly restart. Using a multimeter to verify that the voltages are stable can eliminate the power supply as a problem source.
Figure1-10showsamultimetersettotheVsetting.ItcanmeasurebothDCandACvolt-agesbyusingthissetting.Additionally,thisisanautorangedigitalmultimeter(DMM),mean-ingthatitcanautomaticallysensethevoltagerange.
VOLTCRAFT
ON/OFF FUNCTION SET/RESET DC/AC
DOWNUP
AUTORANGEDMM
VOLTCRAFT
V A
((( )))
FiGUre 1-10 Digitalmultimeter.
Lessexpensivemultimetersrequireyoutosettherangeatthehighestpossiblevoltagetoavoiddamage.Ifyousetitatalowvoltage,suchas5V,andthenmeasure12V,youmightdamagethemeter.
InFigure1-10,youcanseethatthemultimeterhastwoprobes.Itmightnotbeapparentintheblack-and-whitepicture,butoneprobeisredandoneisblack.Youwouldconnectthe
30 CHAPTER 1 IntroductiontoComputers
blackprobetoagroundpinofaconnector(withablackwire)andconnecttheredprobetothevoltagepinintheconnector.Forexample,ifyouwanttomeasure12Vprovidedonaconnector,connectittothepinwiththeyellowwire.Ifyouwanttomeasurethe5-Vline,connecttheredprobetothepinwiththeredwire.
Caution Severe electrical Shock poSSible
You can measure the voltage only when the power is on and supplying voltage to the system. Because of this you can be exposed to voltages when taking measurements. You should ensure that you do not touch anything within the computer except the connector. This includes touching components with your hands or with the multimeter probes.
Whentakingvoltagemeasurements,youshouldremovejewelry.Ifthejewelrytouchesametalcomponentthathasvoltage,it’spossibletoshortitoutanddamagetheequipment.Itcouldalsoshockyou.
Multimeterscanalsotakeothermeasurements.Besidesvoltage,themostcommonmea-surementisacontinuitycheck.Whenthemeterissettodoacontinuitycheck,youcantouchtheprobestogetherandthemeterwillbeep,indicatingacontinuousconnection.Youcanusethissettingtocheckforabreakinacable.Youtouchoneprobetotheconnectorononesideofacable,andtheotherprobetotheotherside.Ifitbeeps,itindicatesacontinuousconnec-tioninthecable,indicatingthatthecableisgood.Ifitdoesn’tbeep,thecablehasabreakandshouldbereplaced.
Power Supply TesterMostpowersupplieswillnotprovidevoltagesunlesstheyarepluggedintothecomponent.Forexample,ifyouwanttomeasurevoltagesonthemotherboardP1connector,theP1con-nectorneedstobepluggedin.Ifit’snotpluggedin,thevoltagesarezero.
Thiscanbeaproblemifyouwanttocheckapowersupplybutyoudon’thaveamother-boardorothercomponents.However,apower supply testersimulatestheloadforapowersupplyandletsyouknowifyouhaveaproblem.Youplugthepowersupplycablesintothepowersupplytesterandturniton.Thetesterwilldisplaythevoltages,andifanyofthevolt-agesareoutsidespecifications,itwillindicatetheproblem.
Quick Check1. What should you use to clean out a computer case?
2. What can you use to verify a power supply is providing 12 VDC to a system?
Key Terms
ChapterSummary chapter 1 31
Quick Check Answers1. Compressed air, or a computer vacuum that doesn’t generate static electricity
2. Multimeter
chapter Summary
■■ Thethreefunctionsofacomputerareinput,processing,andoutput.TheseareoftenshortenedtoI/O.
■■ Binarynumbersuseonlyonesandzeros.Hexadecimalnumbersarecreatedfromfourbinarybitsandincludethecharacters0–9andA–F.Eightbitsmakeupabyte.
■■ LargenumbersofbytesareexpressedasKB,MB,GB,andTB.
■■ Computercaseshousekeycomputercomponents,includingmotherboards,casefans,andpowersupplies.
■■ Casefanshelpkeepasystemcoolbydrawingairintothecase.Casesandfansoftengetdirty.Theycanbecomequiteloud,andthesystemcanslowdownorintermittentlyfail.Theeasysolutionistocleanthem.
■■ Casefanscanbereplaced.Ifafanfails,thesystemcanoverheat,sothefanshouldbereplacedassoonaspossible.
■■ PowersuppliesconvertcommercialACpowertoDCvoltages.Powersuppliesareratedbasedonthepowertheyprovide,expressedaswatts(W).Replacementpowersuppliesneedtomeetorexceedthepowerrequirementsofthecomputer.
■■ Dualvoltagepowersupplieshaveaswitchidentifiedas115or230toidentifythesourcevoltage.Ensurethatitissettothecorrectvoltagesuppliedbycommercialpower.
■■ ATX-basedpowersuppliesprovide3.3V,5V,12V,and-12Vtosystemcomponentsthroughvariouspowerconnectors.Thesevoltagescanbemeasuredwithamultimeterorapowersupplytester.
■■ TheP1powerplugistheprimarypowerconnectorforthemotherboardandincludes20or24pins.Manysystemshaveasecondarypowerplugthatincludes4,6,or8pins.
■■ Molexconnectorsprovide5Vand12VtoPATAdiskdrives.TheSATAconnectorpro-vides3.3V,5V,and12VtoSATAdiskdrives.Powertodiskdrivesisprovidedvia12-Vrails,anddesktoppowersuppliescommonlyhavetworailsbutcanhavemore.Ifdiskdrivesarefailing,youmightneedapowersupplywithanadditionalrail.
■■ PCIeconnectorsuse6pins,8pins,or6+2pins.
32 CHAPTER 1 IntroductiontoComputers
■■ Surgesuppressorsprotectcomponentsagainstspikesandsurgesinpower.UPSsys-temsprotectsystemsagainstsagsandshort-termpowerlosses.
■■ ESDdamagecanbepreventedbyusingESDwriststrapsandESDmats,andbycontrol-lingthehumidity.
■■ Extensionmagnetscanhelpretrievescrewsthatcan’tnormallybereached.Compressedairorspecialantistaticvacuumcleanerscanbeusedtocleancomputers.
■■ MSDSsheetsdocumentcharacteristicsaboutpotentiallyhazardousmaterialusedinaworkcenter,includinghowtostoreanddisposeofhazardousmaterial.Whenlocalregulationsexist,theytakeprecedence.
■■ ElectricalfiresareClassCfires.Youshouldneverusewateronanelectricalfire.
■■ Compressedairisthepreferredmethodofcleaningsystems.Ifavacuumisused,itshouldbeaspecialantistaticvacuum.
■■ Multimetersmeasurevoltagesandcancheckcablecontinuity.Powersupplytesterscancheckvoltagesonpowersupplieswithoutamotherboard.
chapter review
Usethefollowingquestionstotestyourknowledgeoftheinformationinthischapter.Theanswerstothesequestions,andtheexplanationsofwhyeachanswerchoiceiscorrectorincorrect,arelocatedinthe“Answers”sectionattheendofthischapter.
1. Acomputerismakingalotofnoise.Ofthefollowingchoices,whatisthelikelyproblem?
A. Faultymotherboard
B. USBflashdrive
C. Powersupplysettowrongvoltage
D. Casefan
2. Anothertechnicianorderedafanforacomputercase.Ithasarrived,andyouneedtoinstallit.Theoriginalfanhasbeenremoved.Whereshouldyouconnectthefanpowerconnection?
A. ACoutlet
B. P1powersupplyconnector
C. Frontpanelpower
D. Motherboard
ChapterReview chapter 1 33
3. Apowersupplyfailedafteratechnicianaddedsomeharddrivestoadesktopcom-puter.Youneedtopurchaseanadditionalpowersupply.Whatisalikelypowerratingyou’llpurchasetoensurethatthepowersupplydoesn’tfailagain?
A. 600W
B. 600V
C. 300W
D. 250V
4. WhichofthefollowingvoltagesarenotprovidedbyATX-basedpowersupplies?(Choosetwo.)
A. 12VDC
B. -12VDC
C. 115VAC
D. 15VDC
5. MolexconnectorsprovidepowertodiskdrivesfromATX-ratedpowersupplies.WhatvoltagesaresuppliedthroughtheMolexconnector?
A. 3.3Vand5V
B. 5Vand12V
C. 5Vand15V
D. 12Vand15V
6. AsystemisnolongerbootingtotheSATAharddrive,andyoususpectthattheATX-basedpowersupplymightnotbeprovidingthecorrectvoltages.WhatvoltagesshouldyouseeontheSATApowerconnector?
A. 3.3VDC,5VDC,and12VDC
B. 3.3VDC,12VDC,and15VDC
C. 5VDC,12VDC,and15VDC
D. 12VDC,15VDC,and24VDC
7. Whichofthefollowingcanyouusetoprotectagainstpowersags?
A. Commercialpower
B. Powersupply
C. UPS
D. MSDS
34 CHAPTER 1 IntroductiontoComputers
8. WhichofthefollowingcanprotectagainstESDdamage?(Chooseallthatapply.)
A. ESDwriststrap
B. Reducinghumidityasmuchaspossible
C. Ensuringthatcomputersarestoredoncarpetswheneverpossible
D. ESDmat
9. Youwanttoverifythatapowersupplyisprovidingpropervoltageswhileit’scon-nectedtotheP1connectoronthemotherboard.Whatwouldyouuse?
A. Surgesuppressor
B. Multimeter
C. Powerstrip
D. Powersupplytester
10. Youopenacomputertotroubleshootitandnoticeanexcessiveamountofdustinsideit.Ofthefollowingchoices,whatisthebestchoicetocleanit?
A. Lint-freecloth
B. Vacuumcleaner
C. Glasscleaner
D. Compressedair
11. WhichofthefollowingcancontributetoESDdamage?
A. Casefans
B. Carpet
C. Touchingthecomputercasewhileworkingonacomputer
D. ESDmats
12. Aftercleaningacomputerscreenwithacleaningcompound,yourfingersstarttodeveloparash.Whatcanyouusetoquicklyidentifywhatwasinthecleaningcompound?
A. MSDS
B. Internet
C. Localhospital
D. Coworkers
Answers chapter 1 35
answers
Thissectioncontainstheanswerstothechapterreviewquestionsinthischapter.
1. Correct Answer: D
A. Incorrect: Whenmotherboardsfail,theyarenotnoisy.
B. Incorrect: Harddiskdrivessometimesmakealotofnoisewhentheyarefailing,butnotUSBflashdrives.
C. Incorrect: Ifthepowersupplyissettothewrongvoltage,itmightmakeasingleloudpopwhenitfails,ornotworkatall,butitwon’tmakealotofnoise.
D. Correct: Whencasefansbegintofail,theyareoftennoisy.Theycanalsobenoisyiftheyaredirty.
2. Correct Answer: D
A. Incorrect: CasefansdonotgetpowerfromACoutlets.
B. Incorrect: TheP1connectorprovidespowertothemotherboard,nottofans.
C. Incorrect: Frontpanelsdonothavepowerforfans.
D. Correct: Fansgetpowerfromaconnectoronthemotherboard.
3. Correct Answer: A
A. Correct: A600-Wpowersupplyiscommonindesktopcomputersandisthebestchoiceofthosegiven.
B. Incorrect: Powersuppliesareratedinwatts,notvolts.
C. Incorrect: A300-Wpowersupplyisonthelowrangefoundwithdesktopcomputers.Iftheoriginalfailedafteraddinganadditionalloadwithdiskdrives,alargerpowersupplyisneeded.
D. Incorrect: Powersuppliesareratedinwatts,notvolts.
4. Correct Answers: C,D
A. Incorrect: ATX-basedpowersuppliesprovide12VDC.
B. Incorrect: ATX-basedpowersuppliesprovide-12VDC.Theyalsoprovide5VDCand3.3VDC.
C. Correct: ATX-basedpowersuppliesuseACvoltageasaninputbutdonotprovideACvoltage.
D. Correct: ATX-basedpowersuppliesdonotprovide15VDC.
36 chapter 1 IntroductiontoComputers
5. Correct Answer: B
A. Incorrect: 3.3Visprovidedtothemotherboardthroughthe20-pinor24-pinP1connector,butnotontheMolexconnector.
B. Correct: Molexconnectorssupply5Vand12Vfromthepowersupplytodifferentdrivesinacomputer.
C. Incorrect: 5VisprovidedthroughbothMolexandtheP1motherboardconnector,but15VisnotusedinATXpowersupplies.
D. Incorrect: 12VisprovidedthroughbothMolexandtheP1motherboardconnec-tor,but15VisnotusedinATXpowersupplies.
6. Correct Answer: A
A. Correct: ThecorrectvoltagesonaSATAconnectorare3.3VDC,5VDC,and12VDC.
B. Incorrect: ATXpowersuppliesdonotprovide15VDC.
C. Incorrect: ATXpowersuppliesdonotprovide15VDC.
D. Incorrect: ATXpowersuppliesdonotprovide15VDCor24VDC.
7. Correct Answer: C
A. Incorrect: Apowersagoccurswhenthecommercialpowerislowerthannormal,socommercialpowerdoesn’tprotectagainstit.
B. Incorrect: PowersuppliesconvertACtoDC,buttheycannotprotectagainstpowersags.
C. Correct: Anuninterruptiblepowersupply(UPS)usesabatterybackuptoprotectagainstpowersags.Flickeringlightsareanindicationofpowersags.
D. Incorrect: MaterialSafetyDataSheets(MSDSs)providesafety-relatedinformationforitemsusedwithinaworkenvironment.
8. Correct Answers: A,D
A. Correct: Electrostaticdischarge(ESD)wriststrapsprotectagainstESDdamage.
B. Incorrect: Lowhumiditygeneratesmorestatic.Ideally,humidityshouldbearound50percent.
C. Incorrect: Carpetsgeneratestaticeasily,soit’sbestnottostorecomputersoncarpets.
D. Correct: ESDmatsalsoprotectagainstESD.
Answers chapter 1 37
9. Correct Answer: B
A. Incorrect: Asurgesuppressorwillpreventpowerspikesfromreachingacomputer,butitdoesn’tmeasurevoltages.
B. Correct: AmultimetercanmeasureDCvoltagesprovidedtoamotherboardontheP1connector.
C. Incorrect: Apowerstripprovidesunprotectedpowertoasystembutdoesn’tmeasurevoltage.
D. Incorrect: Apowersupplytestercantestanunconnectedpowersupply,butitisn’tusedforapowersupplypluggedintoasystem.
10. Correct Answer: D
A. Incorrect: Lint-freeclothsareusedtocleanscreensbutwouldnotbeusedforanexcessiveamountofdust.
B. Incorrect: AnantistaticvacuumcleanercouldbeusedbutastandardvacuumcleanercancauseESDdamage.
C. Incorrect: Glasscleanerincludesammoniaandalcohol,whichmightdamageinter-nalcomponents.
D. Correct: Compressedairwouldbethebestchoiceforblowingoutthedust.
11. Correct Answer: B
A. Incorrect: CasefanskeepasystemcoolbutdonotcontributetoESDdamage.
B. Correct: Staticbuildsuponcarpet,soplacingcomputersoncarpetscancontributetoESDdamage.
C. Incorrect: Touchingthecomputercasewhileworkingonacomputerhelpskeepyouatthesamepotentialasthecomputerandreducesstaticbuildup.
D. Incorrect: ESDmatsreducethepotentialforESDdamage.
12. Correct Answer: A
A. Correct: AMaterialSafetyDataSheet(MSDS)documentscharacteristicsofmateri-alsusedwithinaworkplace.
B. Incorrect: YoumightbeabletofindtheinformationontheInternet,butanMSDSsheetshouldbereadilyavailable.
C. Incorrect: Medicalpersonnelwilllikelywanttoknowwhatwasinthecleaningcompound,buttheywouldn’tknowwhatwasused.
D. Incorrect: Coworkerswouldn’tbethebestsourcetoidentifythecontents,buttheycanretrievetheMSDS.
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