Technicalparameters
1,capacity
Asthedatastorageofcomputersystem,capacityisthemostimportantofharddiskParameters.
Thecapacityoftheharddiskisinmegabytes(MB)orgigabytes(GB),1GB=1024MB,1TB=1024GB.However,theharddiskmanufacturerusuallytakes1G=1000MBinthenominalharddiskcapacity,sothecapacityweseeintheBIOSorwhenformattingtheharddiskwillbesmallerthanthemanufacturer’snominalvalue.
Thecapacityindexoftheharddiskalsoincludesthesingle-diskcapacityoftheharddisk.Theso-calledsinglediskcapacityreferstothecapacityofasinglediskofaharddisk.Thelargerthesinglediskcapacity,thelowertheunitcostandtheshortertheaverageaccesstime.Forusers,thecapacityoftheharddiskislikethememory.Inadditiontosimpleroperations,theWindowsoperatingsystemhasalsobroughtaboutanincreaseinfilesizeandnumber.Someapplicationswilleatuphundredsofmegabytesofharddiskspaceatanytime,andthereisagrowingtrend..Therefore,itiswisetoadvanceappropriatelywhenbuyingharddrives.Inthefirsttwoyears,mainstreamharddriveswere320Gand500G,andlarge-capacityharddrivesabove750Ghavealsobeguntospread.In2007,large-capacityharddrivesof1TBbegantoappear.
2,Rotationspeed
RotationlSpeed(RotationlSpeedorSpindlespeed)istherotationspeedofthemotorspindleintheharddisk,thatis,theharddiskplatterinoneminuteThemaximumnumberofrevolutionsthatcanbecompletedwithin.Thespeedofrotationisoneoftheimportantparametersindicatingthegradeoftheharddisk.Itisoneofthekeyfactorsthatdeterminetheinternaltransmissionrateoftheharddisk,anditdirectlyaffectsthespeedoftheharddisktoalargeextent.Thefastertherotationspeedoftheharddisk,thefastertheharddiskcanfindfiles,andthetransmissionspeedoftherelativeharddiskwillbeimproved.Theharddiskspeedisexpressedinrevolutionsperminute,andtheunitisexpressedasRPM.RPMistheabbreviationofRevolutionsPerminute,whichisrevolutionsperminute.ThelargertheRPMvalue,thefastertheinternaltransferrate,theshortertheaccesstime,andthebettertheoverallperformanceoftheharddrive.
Thespindlemotoroftheharddiskdrivestheplatterstorotateatahighspeed,generatingbuoyancytomaketheheadfloatabovetheplatters.Tobringthesectorofdatatobeaccessedbelowthehead,thefasterthespeed,theshorterthewaitingtime.Therefore,therotationalspeedlargelydeterminesthereadspeedoftheharddisk.
Thespeedofordinaryharddisksforhomeuseisgenerally5400rpmand7200rpm.High-speedharddisksarethefirstchoicefordesktopusers;fornotebookusers,theyaremainly4200rpmand5400rpm,althoughsomecompanieshavealreadyreleased7200rpm.However,itisstillrelativelyrareinthemarket;serverusershavethehighestrequirementsforharddiskperformance.TheSCSIharddisksusedinserversbasicallyuse10000rpm,even15000rpm,andtheirperformanceismuchhigherthanthatofhouseholdproducts.Ahigherspeedcanshortentheaverageseektimeandactualreadandwritetimeoftheharddisk,butwiththecontinuousincreaseoftheharddiskspeed,italsobringsnegativeeffectssuchastemperaturerise,motorspindlewear,andworkingnoise.Thespeedofnotebookharddisksislowerthanthatofdesktopharddisks,whichisaffectedtoacertainextentbythisfactor.Theinternalspaceofthenotebookissmall,andthesizeofthenotebookharddisk(2.5inches)isalsodesignedtobesmallerthanthatofthedesktopharddisk(3.5inches).Thetemperaturerisecausedbytheincreaseinspeedputshigherrequirementsontheheatdissipationperformanceofthenotebookitself;thenoisebecomeslarger,Andmusttakenecessarynoisereductionmeasures,thesehaveputforwardmorerequirementsonthenotebookharddiskmanufacturingtechnology.Atthesametime,theincreaseinspeed,whiletheothersremainunchanged,meansthatthepowerconsumptionofthemotorwillincrease,themoreelectricityisconsumedperunittime,andtheworkingtimeofthebatteryisshortened,sothattheportabilityofthenotebookwillbeaffected.Therefore,notebookharddrivesgenerallyusearelativelylow-speed4200rpmharddrive.
3.Accesstime
AverageAccessTime(AverageAccessTime)referstotheheadfromthestartingpositiontothetargettrackposition,andfromthetargettrackThetimerequiredtofindthedatasectortobereadandwritten.
Theaverageaccesstimereflectsthereadandwritespeedoftheharddisk,whichincludestheseektimeandwaitingtimeoftheharddisk,namely:averageaccesstime=averageseektime+averagewaitingtime.
Theaverageseektimeoftheharddisk(AverageSeekTime)referstothetimerequiredfortheheadoftheharddisktomovetothedesignatedtrackonthedisksurface.Thistimeisofcourseassmallaspossible.Theaverageseektimeofaharddiskisusuallybetween8msand12ms,whileaSCSIharddiskshouldbelessthanorequalto8ms.
Thewaitingtimeoftheharddisk,alsoknownasthelatency(Latency),referstothetimethattheheadisalreadyinthetracktobeaccessedandwaitingforthesectortobeaccessedtorotatebelowthehead.Theaveragewaitingtimeishalfofthetimerequiredforthedisctorotateoneround,andshouldgenerallybelessthan4ms.
4.Transferrate
DataTransferRateThedatatransferrateoftheharddiskreferstothespeedatwhichtheharddiskreadsandwritesdata,inmegawordsKnotspersecond(MB/s).Harddiskdatatransferrateincludesinternaldatatransferrateandexternaldatatransferrate.
InternalTransferRate,alsoknownasSustainedTransferRate,reflectstheperformanceoftheharddiskbufferwhenitisnotinuse.Theinternaltransferratemainlydependsontherotationspeedoftheharddisk.
ExternalTransferRateisalsocalledBurstDataTransferRateorinterfacetransferrate.ItisnominallythedatatransferbetweenthesystembusandtheharddiskbufferTheexternaldatatransferrateisrelatedtothetypeofharddiskinterfaceandthesizeoftheharddiskcache.
ThemaximumexternaltransferrateofFastATAinterfaceharddrivesis16.6MB/s,whileUltraATAinterfaceharddrivesreach33.3MB/s.
TheharddiskusingSATA(SerialATA)portisalsocalledserialharddisk,whichisthetrendofPCharddiskinthefuture.In2001,theSerialATACommittee,composedofIntel,APT,Dell,IBM,Seagate,andMaxtor,formallyestablishedtheSerialATA1.0specification.In2002,althoughserialATArelatedequipmenthasnotbeenofficiallylisted,theSerialATAcommitteehaspreemptivelyestablishedtheSerialATA2.0specification.SerialATAadoptsserialconnectionmode.SerialATAbususesembeddedclocksignalandhasstrongererrorcorrectioncapability.Comparedwiththepast,itsbiggestdifferenceisthatitcanchecktransmissioninstructions(notjustdata).Errorsarefoundtobeautomaticallycorrected,whichgreatlyimprovesthereliabilityofdatatransmission.Theserialinterfacealsohastheadvantagesofsimplestructureandsupportforhotswapping.
5.Cache
Cachememoryisamemorychipontheharddiskcontrollerwithextremelyfastaccessspeed.ItisaharddiskBufferbetweeninternalstorageandexternalinterface.Sincetheinternaldatatransferspeedoftheharddiskisdifferentfromthetransferspeedoftheexternalinterface,thecacheactsasabufferamongthem.Thesizeandspeedofthecacheareimportantfactorsdirectlyrelatedtothetransmissionspeedoftheharddisk,whichcangreatlyimprovetheoverallperformanceoftheharddisk.Whentheharddiskaccessesfragmenteddata,itneedstoconstantlyexchangedatabetweentheharddiskandthememory.Withalargecache,thosefragmenteddatacanbetemporarilystoredinthecache,reducingtheloadontheexternalsystemandincreasingthedatatransmissionspeed
Classification
1.Memorycommunication
Therearetwotypes:XTtype(ieDMAmode)andATtype(ieinterruptdrivemode)kind.
2.Magneticheaddrive
Therearetwotypes:steppermotordriveandvoicecoilmotordrive.
Thestructureofthesteppingmotordrivemechanismiscompactandthecontrolissimple,buttheentiredrivingpositioningsystemisopen-loopcontrol,andthesteppingmotorisdrivenbypulsesignals,sothepositioningaccuracyisrelativelylowandtheaccesstimeislonger;
Thevoicecoilmotorisalinearmotor,whichcandirectlydrivetheheadforlinearmotion.Theentirepotatodynamicpositioningsystemisaclosed-loopadjustmentautomaticcontrolsystemwithspeedandpositionfeedback,withfastdrivingspeedandhighpositioningaccuracy.Advanceddiskdrivesgenerallyusevoicecoilmotordriveandservodiskpositioning.
Thediscdiameterandcapacityare5.25inches,3.5inches,2.5inches,1.8inchesand1.3inches,andthesmallestisthesizeofafingernail.
Fromtheappearancesize,therearethreetypes:full-height,half-heightandthin.
Structure
Theharddiskisoneofthemostimportantmemoryinacomputer.Mostofthesoftwareneededforthecomputertofunctionproperlyisstoredontheharddrive.Becausethestoragecapacityofharddiskislarge,itisdifferentfrommemoryandopticaldisk.Harddisksarestoragedevicesbasedonhardrotatingdisksusedoncomputers.Itstoresandretrievesdigitaldataonaflatmagneticsurface.
Magnetichead
Themagneticheadisthemostexpensivecomponentintheharddisk,anditisalsothemostimportantandcriticalpartoftheharddisktechnology.Thetraditionalmagneticheadisanelectromagneticinductionmagneticheadthatcombinesreadingandwriting.However,harddiskreadingandwritingaretwocompletelydifferentoperations.Forthisreason,thistwo-in-onemagneticheadmustbedesignedwithbothreadingandwriting.Thesetwocharacteristicsresultinthelimitationofharddiskdesign.MRmagneticheads(Magnetoresistiveheads),thatis,magnetoresistivemagneticheads,useaseparateheadstructure:writeheadsstillusetraditionalmagneticinductionheads(MRheadscannotperformwriteoperations),andreadheadsusenewMRheads.Theso-calledinductivewritingandmagnetoresistivereading.Inthisway,duringthedesign,thedifferentcharacteristicsofthetwocanbeoptimizedseparatelytoobtainthebestread/writeperformance.Inaddition,theMRheadsensesthesignalamplitudethroughchangesinresistanceratherthanchangesincurrent,soitisverysensitivetosignalchanges,andtheaccuracyofreadingdataisalsoimprovedaccordingly.Andsincetheamplitudeofthereadsignalhasnothingtodowiththetrackwidth,thetrackcanbemadeverynarrow,therebyincreasingthediscdensityto200MB/inch2,whilethetraditionalmagneticheadcanonlyreach20MB/inch2,whichisalsoanMRheadThemainreasonforbeingwidelyused.MRheadshavebeenwidelyused,andGMRheads(GiantMagnetoresistiveheads)madeofmaterialswithamulti-layerstructureandbettermagnetoresistiveeffecthavegraduallybecomepopular.
Track
Whenthediskisspinning,iftheheadisheldinoneposition,eachheadwilldrawacirculartrackonthesurfaceofthedisk.Thesecirculartracksarecalledtracks.Thesetracksareinvisibletothenakedeyeatall,becausetheyareonlysomemagnetizedareasonthedisksurfacethataremagnetizedinaspecialway,andtheinformationonthediskisstoredalongsuchtracks.Adjacenttracksarenotclosetoeachother.Thisisbecausewhenthemagnetizationunitsaretooclose,themagnetismwillaffecteachother,andatthesametimeitwillalsocausedifficultiesforthemagneticheadtoreadandwrite.A1.44MB3.5-inchfloppydiskhas80tracksononeside,andthetrackdensityontheharddiskismuchgreaterthanthisvalue,usuallytherearethousandsoftracksononeside.
Thesurfaceofthediskiscoatedwithamagneticmediumforrecording,andwhatappearsunderthemicroscopeisamagneticparticle.Thepolarityoftinymagneticparticlescanbequicklychangedbythemagnetichead,andcanbemaintainedstablyafterthechange.Thesystemdistinguishes0or1inthebinarysystemthroughchangesinmagneticfluxandmagnetoresistance.Itispreciselybecausealloperationsareperformedundermicroscopicconditions,soiftheharddiskissubjectedtoexternalforceshockswhilerunningathighspeed,itmaycauseirreversibledatalossduetotheheadslapsonthesurfaceofthedisk.Inaddition,theuniaxialanisotropyandvolumeofthemagneticparticleswillobviouslyaffectthethermalstabilityofthemagneticparticles,andthelevelofthermalstabilitydeterminesthestabilityofthemagneticparticlestate,thatis,thecorrectnessofthestoreddata.Sexandstability.However,theuniaxialanisotropyandvolumeofmagneticparticlescannotbeincreasedblindly.Theyarelimitedbythewritefieldthatthemagneticheadcanprovideandthesignal-to-noiseratioofthemedium.
Sectors
Eachtrackonthediskisequallydividedintoanumberofarcs.Thesearcsarethesectorsofthedisk.Asectorcanstore512bytesofinformation.Whenthediskdrivereadsandwritesdatatothedisk,itmusttakethesectorastheunit.1.44MB3.5-inchfloppydisk,eachtrackisdividedinto18sectors.
Cylinder
Aharddiskisusuallycomposedofasetofoverlappingdisks,eachdisksurfaceisdividedintoanequalnumberoftracks,andfromtheouteredge"0"startswiththenumber,andthetrackswiththesamenumberformacylinder,whichiscalledthecylinderofthedisk.Thenumberofcylindersonadiskisequaltothenumberoftracksonadisk.Sinceeachdisksurfacehasitsownhead,thenumberofdisksurfacesisequaltothetotalnumberofheads.Theso-calledCHSoftheharddisk,namelyCylinder(cylinder),Head(head),Sector(sector),aslongasthenumberofCHSoftheharddiskisknown,thecapacityoftheharddiskcanbedetermined,andthecapacityoftheharddisk=thenumberofcylindersandthenumberofsectors.Thenumberis512B.
Howtouse
Whentheharddiskisworking,neverforciblyturnoffthepower.Turningoffthepowerwhentheharddiskisworkingwillcausephysicaldamagetotheharddiskanddataloss.Inaddition,therearehigh-speedrunningpartsintheharddisk.Ifthehigh-speeddiskisshutdownforcibly,thehigh-speeddiskwillsuddenlystop,andifitisturnedonimmediatelyaftertheshutdown,itismorelikelytocausedamagetotheharddisk.Sodon'tturnonthecomputeragainimmediatelyaftershuttingdown.Turnitonagaininatleasthalfaminute.
Whentheharddiskisworking,trytoavoiditsshock,becausethedistancebetweenthemagneticheadandthemagneticdiskisveryclose.Ifitissubjectedtoseverevibration,themagneticheadwillhitthemagneticdisk,andthemagneticheadmayscratchthemagneticdisk.Chipsmayalsocausecompletedamagetothehead,makingtheentireharddriveunusable.
Intheprocessofusingtheharddisk,manyusersoftencompressinthe"diskspacemanagement".Usethisprogramtocompresstheharddisk.Thiswillcausethecompressedvolumefiletocontinuetogrow.Theteamalsosloweddown,andthenumberofreadsandwritesincreased,whichwouldaffecttheheatgenerationandstabilityoftheharddisk.Soitwillleadtoareductioninservicelife.So,iftheharddiskisenough,thereisnoneedtousethisprogram.
Correctmaintenance
Theharddiskisveryafraidofdust.Ifdustisattractedtothecircuitboard,itwillcausetheharddisktoworkunstableorcausedamagetointernalparts.Thefunctionalworkingstatusoftheharddiskhasagreatrelationshipwiththelifeandtemperature.Ifthetemperatureistoohighortoolow,theclockfrequencyofthecrystaloscillatorwillchange,whichwillcausethecircuitcomponentstomalfunction.Ifthetemperatureistoolow,itwillcausetheairThemoisturecondensesonthecomponent,causingashortcircuit.
Secondly,wewillorganizeyourharddriveregularly.Thiswillincreasethespeedofyourharddrive.Iftherearetoomanyjunkfilesontheharddisk,thespeedwillslowdownandthetracksmaybedamaged.However,donotcleanupintwodays,asthiswillalsoreducethelifeoftheharddrive.
Finally,itisanti-virus.Virusesarethebiggestthreattothefilesstoredontheharddrive.Therefore,wefoundthatthevirusshouldberemovedintimeandtrynottoformattheharddisk.
Theabovearesometipsforusingandmaintainingharddrives.Ifeveryonecandothis,yourharddriveswillbemoredurable.
Mattersneedingattention
1.Don’tshutdownsuddenlyduringwork
Whentheharddiskstartstowork,itusuallyspinsatahighspeed.Amongthem,ifwesuddenlyturnoffthepowerhalfway,itmaycauseviolentfrictionbetweentheheadandtheplattersanddamagetheharddisk.Therefore,wemustavoidasuddenshutdown.Whenshuttingdown,youmustpayattentiontowhethertheharddiskindicatoronthepanelisstillflashing.Onlyaftertheindicatorstopsflashingandtheharddiskreadandwriteends,youcanturnoffthecomputer'spowerswitch.
2.Preventdustfromentering
Dustcancausegreatdamagetotheharddisk.Thisisbecauseinadustyenvironment,theharddiskiseasytoattractThedustparticlesintheaircauseittoaccumulateontheinternalcircuitcomponentsoftheharddiskforalongtime,whichwillaffecttheheatdissipationoftheelectroniccomponents,causingthetemperatureofthecircuitcomponentstorise,causingleakageorburningofthecomponents.
Inaddition,dustmayalsoabsorbmoisture,corrodetheelectroniccircuitsinsidetheharddisk,andcausesomeinexplicableproblems.Therefore,althoughthevolumeofdustissmall,theharmtotheharddiskcannotbeunderestimated.Therefore,itisnecessarytomaintainenvironmentalsanitationandreducethehumidityanddustcontentintheair.Remember:generalcomputeruserscannotdisassembletheharddiskcoverbythemselves,otherwisethedustintheairwillentertheharddiskandscratchthediskorthemagneticheadwhenthemagneticheadreadsorwrites.
3.Topreventthetemperaturefrombeingtoohighortoolow
Temperaturealsoaffectsthelifeoftheharddisk.Acertainamountofheatisgeneratedwhentheharddiskisworking,andthereisaheatdissipationproblemduringuse.Thetemperatureshouldbe20～25℃,toohighortoolowwillcausetheclockfrequencyofthecrystaloscillatortochange.Temperaturecanalsocausefailureofharddiskcircuitcomponents,andmagneticmediacanalsocauserecordingerrorsduetothermalexpansion.Ifthetemperatureistoolow,themoistureintheairwillbecondensedontheintegratedcircuitcomponents,causingashortcircuit;whenthehumidityistoohigh,thesurfaceoftheelectroniccomponentsmayabsorbawaterfilm,oxidizeandcorrodetheelectroniccircuit,resultinginpoorcontactorevenshortcircuit,Itwillalsocausethemagneticforceofthemagneticmediumtochange,causingdatareadingandwritingerrors;toolowhumidity,itiseasytoaccumulatealargeamountofstaticchargegeneratedbytherotationofthemachine,whichwillburnouttheCMOScircuit,attractdustanddamagetheheadandscratchthedisk.piece.Inaddition,trynottoplacetheharddiskclosetostrongmagneticfields,suchasspeakers,speakers,motors,radios,mobilephones,etc.,soasnottodamagethedatarecordedbytheharddiskduetomagnetization.
Causeoffailure
1.Harddiskcoolingfan
Consideringtheheatdissipationeffect,manypeoplehaveinstalledtheharddiskfortheircomputerHarddiskcoolingfans,butsomelow-endfans,itsvibrationisquiteobvious,cantransmitthevibrationtotheharddisk,inthelongrun,itwilldefinitelyhaveanimpactonthelifeoftheharddisk.
Second,CD-ROMdrive
ThereadingspeedofmainstreamCD-ROMdriveshasreachedmorethan50timesspeed.Vibrationwilldrivetheresonanceofthechassis,therebyaffectingtheworkoftheharddisk.Andthiskindofhigh-speedrotationgeneratesalotofheat,andtheopticaldriveissoclosetotheharddrive,theheatreleasedfromtheopticaldrivewillsurelyincreasethetemperatureoftheharddrive.
3.Dust
Dustdamagestheharddisk.Thedustdepositedontheharddiskcircuitboardwillseriouslyaffectthechiponthecircuitboard.Theheatdissipationcausesthetemperatureofthecomponentsonthecircuitboardtorise,whichinturncausesthechiptooverheatandburn.Inaddition,ifdustabsorbsmoisture,itiseasytocauseashortcircuit.
Four.Staticelectricity
Intheprocessofrepairingthecomputer,manypeopleholdtheharddiskwiththeirhands,butindryweather,people’sTensofthousandsofvoltsofstaticelectricitymayaccumulateonyourhands,andthestaticelectricityonyourhandsmaybreakdownthechipsonthecircuitboardandcausetheharddisktomalfunction.
V.Low-levelformatting
Ifthecomputerharddiskhasbadsectors,manynetizenshaveadoptedlow-levelformattingmeasures.Infact,low-levelformattingaffectstheharddisk.Thedamageislarge,itmaycausethespreadofbadsectorsonthedisk,andevencausethelossofharddiskparameters,makingtheharddiskunusable.
Six.Powersupply
Alow-qualitycomputerwillcausetheharddisktobedisturbedbyvoltagefluctuations,especiallywhentheharddiskisreadingandwritingoperations,ifThereisaproblemwiththepowersupply,andaharddiskcanbescrappedinaninstant.
Seven,magneticfield
Becausetheharddiskisadevicethatreliesonmagneticmediatorecorddata,ifitisinterferedbythemagneticfieldoftheexternalenvironment,itmaycausethediskDataislost,soitshouldbeasfarawayfromthemagneticenvironmentaspossible.