Maxtor 6800 manual Glossary, Access Time

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GLOSSARY

Glossary

A

ACCESS

Toobtaindatafrom,orplacedatainto,RAM,aregister,ordatastoragedevice.

ACCESS TIME

Theintervalbetweentheissuingofanaccesscommandandtheinstantthatthetarget datamaybereadorwritten.Accesstimeincludesseektime,latencyandcontroller overheadtime.

ADDRESS

Anumber,generallybinary,distinguishingaspecificmemberofanorderedsetof locations.Indiskengineering,theaddressmayconsistofdrives(unitaddress),radial positions(cylinderaddress),orcircumferentialposition(sectoraddress).

ALLOCATION

Aprocessofassigningdesignatedareasofthedisktoparticularfiles.

ALTERNATE TRACK

Asparetrackusedintheeventthatanormaltrackbecomesdamagedorisunusable.

ANALOG

Asignalorsystemthatdoesnotusedigitalstatestoconveyinformation.Asignalmay haveanynumberofsignificantstates(values),contrastedtodigitalsignalswhichcan onlyhavetwostates.

ANSI

AmericanNationalStandardsInstitute.

APPLICATION PROGRAM

Asequenceofprogrammedinstructionsthattellthecomputerhowtoperformsome end-usertask,suchasaccountingorwordprocessing.

AREAL DENSITY

Bitdensity(bitsperinch)multipliedbytrackdensity(tracksperinch)orbitspersquare inch.

ASYMMETRY

Adistortionofthereadbacksignalwhichisshownindifferentintervalsbetweenthe positiveandnegativevoltagepeaks.

AUXILIARY MEMORY

Memoryotherthanmainmemory;generallyamass-storagesubsystemcontainingdisk drivesandbackuptapedrives,controller(s)andbuffermemory(alsocalledperipheral memory).

AVERAGE ACCESS TIME

Theaveragetimetomakeallpossiblelengthaccesses(seeks).

AVERAGE SEEK TIME

Theaveragetimetomakeallpossiblelengthseeks.Atypicalmeasureofperformance.

B

BAD BLOCK

Ablockthatcannotstoredatabecauseofamediaflaw.

BIT

Anabbreviationforbinarydigit,ofwhichtherearetwo(0and1).Abitisthebasic dataunitofmostdigitalcomputers.Abitisusuallypartofadatabyteorword,butbits maybeusedsinglytocontrolorreadlogic“on-off”functions.Thefundamentalunit information,oftenusedlooselytorefertoacircuitormagnetizationstateataparticular instantintime.

BIOS

AcronymforBasicInput/OutputSystem.ThefirmwareareaofaCPUthatcontrols operationsthroughthesystembusandtotheattachedcardsandperipheraldevices.

BPI

Acronymforbitsperinch.Seebitdensity.

BLOCK

Agroupofbyteshandled,stored,andaccessedasalogicaldataunit,suchasan individualfilerecord.

BUFFER

Atemporarydatastorageareathatcompensatesforadifferenceindatatransferrates and/ordataprocessingratesbetweensenderandreceiver.

BUS

Acollectionoffunctionallyparallelconductorsthatformsaninterconnectionbetween functionalblocksinadigitaldevice.Alengthofparallelconductorsthatformsamajor interconnectionroutebetweenthecomputersystemCPU(centralprocessingunit)and itsperipheralsubsystems. Dependingonitsdesign,abusmaycarrydata,addresses, power,andmore.

BYTE

Anorderedcollectionofbitstreatedasaunit.Mostoften,abyteisunderstoodto consistofeightbits.Onebyteisnecessarytodefineanalphanumericcharacter.

C

CACHE

Randomaccessmemory(RAM)usedasabufferbetweentheCPUandthediskdrive.

CAPACITY

Theamountofdata,usuallyexpressedinbytes,whichcanbestoredinagivendevice orportionofsame.

CENTRAL PROCESSING UNIT (CPU) Theheartofthecomputersystemthatexecutesprogrammedinstructions.Itincludes thearithmeticlogicunit(ALU)forperformingallmathandlogicoperations,acontrol sectionforinterpretingandexecutinginstructions,internalmemoryfortemporary storageofprogramvariablesandotherfunctions.

CHANNEL

Acollectionofelectroniccircuitsusedintheprocessofwritingandreading informationtoandfrommagneticmedia.

CHARACTER

Anorderedcollectionofbitsrepresentingoneofasetofpredefinedsymbols.Oftenthe termisusedinterchangeablywithbyte,butthisisinexact.

CLOSED LOOP

Acontroltechniquethatenablesthepositioningsystemtocorrectoff-trackerrorsin realtime.Theactualheadpositionismonitoredandcomparedtotheidealtrack positiontodetermineanypositionerrorthatmightbeoccurring.Thisinformationis thenusedtoproduceacorrectionsignal(feedback)thatgoestothepositionertocorrect theerror.(Seealsotrackfollowingservo).

CLOSED LOOP SERVO

Aservocontroltechniquethatusespositionfeedbacktocorrectoff-trackerrors.See TrackFollowingServo.

CLUSTER

ThesmallestallocatableunitofdiskstorageallowedbyMS-DOS;eachFATentry representsonecluster.

CONTROLLER

Anelectronicdeviceforconnectingoneormoremassstorageperipherals(rigiddisk drives,tapedrives,andopticaldiskdrives)totheinput/outputcircuitsofahost computer.Controllersvaryincomplexity,withmoresophisticatedunitsabletobuffer andschedulecommands,correctdataerrors,andbypassmediadefectswithouthost intervention.

CONTROLLER

AminiatureCPUdedicatedtocontrollingaperipheraldevice,suchasadiskdrive, tapedrive,videodisplayterminal,orprinter.Thecontrollerexecutescommandsfrom thecentralprocessingunitandreissuescommandstotheperipheraldevice.

CORRECTABLE ERROR

AnerrorthatcanbeovercomebytheuseofErrorDetectionandCorrection.

GL – 1

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Contents HA RD Drive Produc T MA Nual DiamondMax Before You Begin U T I O NContents Product Specifications Handling and InstallationAT Interface Description Host Software InterfaceService and Support Interface CommandsGlossary Figures Introduction Maxtor CorporationManual Organization AbbreviationsSignal Conventions ConventionsKey Words NumberingDiamondMax 6800 Key Features Product DescriptionProduct Features Functional / InterfaceOn-the-Fly Hardware Error Correction Code ECC Logical Block AddressingDefect Management Zone DMZ Software ECC CorrectionRead-Ahead Mode Cache ManagementBuffer Segmentation Automatic Write Reallocation AWRMajor HDA Components Subsystem Configuration Jumper Location/ConfigurationCylinder Limitation Dual Drive SupportProduct Specifications Drive ConfigurationPerformance Specifications Models and CapacitiesPhysical Dimensions Parameter Standard MetricPower Requirements Power Mode DefinitionsEPA Energy Star Compliance Environmental LimitsReliability Specifications Shock and VibrationRadiated Electromagnetic Field Emissions EMC Compliance Safety Regulatory ComplianceCanadian Emissions Statement Handling and Installation Hard Drive Handling PrecautionsPre-formatted Drive Important NoticeUnpacking and Inspection Multi-pack Shipping ContainerRecommended Mounting Configuration Physical InstallationRepacking Handling Precautions Tools for InstallationSystem Requirements Drive Identification InformationGeneral Requirements Hard Drive IdentificationSystems Using Cable Select Installing 5.25-inch Mounting Brackets and RailsInstalling in a Device Bay Mounting Drive in SystemAttaching Interface and Power Cables Attaching System CablesSetting the Bios Cmos System SetupBios Cmos Parameters Hard Drive Preparation System Hangs During Boot AT Interface Description Interface ConnectorPin Description Summary PIN Name Signal Name Signal Description Pin Description TableTiming Parameters Mode PIO TimingDMA Timing Mode MIN MAX Ultra DMA TimingSustained Ultra DMA Data In Burst Device Terminating an Ultra DMA Data In Burst Initiating an Ultra DMA Data Out Burst Device Pausing an Ultra DMA Data Out Burst Device Terminating an Ultra DMA Data Out Burst Error Register Features RegisterHost Software Interface Task File RegistersSector Count Register Sector Number RegisterCylinder Number Registers Device/Head RegisterCommand Register Command Name Command Code Parameters Used SDH SummaryControl Diagnostic Registers Alternate Status RegisterDevice Control Register Digital Input RegisterReset Handling Reset and Interrupt HandlingInterrupt Handling Interface Commands Set Feature CommandsRead Sectors Read CommandsRead Verify Sectors Read DMA Read MultipleWrite Commands Set Multiple ModeWrite Sectors Write Verify SectorsWrite Multiple Write DMASet Feature Commands Set Features ModePower Mode Commands Sleep Mode Initialization Commands Identify Drive15-8 = PIO data transfer mode = Write Cache enabled Initialize Drive Parameters Execute Drive Diagnostic Seek, Format and Diagnostic CommandsFormat Track A.R.T. Command Set Execute S.M.A.R.TService and Support Service PolicyNo Quibble Service SupportCustomer Service MaxFax ServiceInternet Access Time GlossaryCylinder Zero Gigabyte GB Logical Block Addressing Read Gate Signal THIN-FILM Media
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