Maxtor 5120 manual Read Gate Signal

R

RANDOM ACCESS MEMORY (RAM)

Memorydesignedsothatanystoragelocationcanbeaccessedrandomly,directlyand individually.Thisiscontrastedtosequentialaccessdevicessuchastapedrives.

READ

Toaccessastoragelocationandobtainpreviouslyrecordeddata.Tosensethepresence offluxreversalsonmagneticmedia.Usuallyimplementedsuchthatadynamicflux amplitudewillcauseaproportionalelectricaloutputfromthetransducer.

READ GATE SIGNAL

Adigitalinputsignalwhichcausesthedrivecircuitrytorecoverdata.

READ ONLY MEMORY (ROM)

Aformofmemorywhichcannotbechangedinformaloperationalmodes.Many differenttypesareavailable.RAMisusedforpermanentinformationstorage. ComputercontrolprogramsareoftenstoredinROMapplications.

READ/WRITE HEAD

Therecordingelementwhichwritesdatatothemagneticmediaandreadsrecorded datafromthemedia.

RE-CALIBRATE

Theactionofmovingtheheadofadiskdrivetocylinderzero.

RECOVERABLE ERROR

Areaderror,transientorotherwise,fallingwithinthecapabilityofanECC mechanismtocorrect,orabletoovercomebyrereadingthedatainquestion.

ROTATIONAL LATENCY

Theamountofdelayinobtaininginformationfromadiskdriveattributabletothe rotationofthedisk.

RUN-LENGTH LIMITED

Anencodingprocessthatrepositionsdatabitsandlimitsthelengthofzerobitsinorder tocompressinformationbeingstoredondisks.

RUN-LENGTH LIMITED ENCODING

Arecordingcode.Sometimesmeanttodenote“2.7RLL”whichcansignify1.5times thebitsasMFM,giventhesamenumberoffluxreversalsinagivenlinealdistance.

S

SECTOR

Alogicalsegmentofinformationonaparticulartrack.Thesmallestaddressableunitof storageonadisk.Tracksaremadeofsectors.

SECTOR PULSE SIGNAL

Adigitalsignalpulsepresentinhardsectoreddriveswhichindicatesthebeginningofa sector.Embeddedservopatternorotherprerecordedinformationmaybepresenton thediskwhensectorisactive.

SEEK

Arandomaccessoperationbythediskdrive.Theactofmovingasetofread/write headssothatoneofthemisoverthedesiredcylinder.Theactuatororpositionermoves theheadstothecylindercontainingthedesiredtrackandsector.

SEEK COMPLETE SIGNAL

Adigitalsignallevelwhichindicatesthatthepositionerisnotmovingandislocated overacylinderoroffsetposition.

SEEK TIME

Theamountoftimebetweenwhenasteppulseorseekcommandisissueduntilthe headsettlesontothedesiredcylinder.Sometimesismeasuredwithoutsettlingtimes.

SEQUENTIAL ACCESS

Thewritingorreadingofdatainasequentialordersuchasreadingdatablocksstored oneaftertheotheronmagnetictape.Thisiscontrastedtorandomaccessof information.

SERVO BURST

Amomentaryservopatternusedinembeddedservocontrolsystemsusuallypositioned betweensectorsorattheendofatrack.

SERVO CONTROL

Atechniquebywhichthespeedorpositionofamovingdeviceisforcedinto conformitywithadesiredorstandardspeedorposition.

GLOSSARY

SERVO HEAD

Amagneticheaddesignedspecificallyforaccuratelyreadingservodata.

SERVO PATTERN

Areadbacksignalthatindicatesthepositionofaheadrelativetoatrack.

SERVO SURFACE

Arecordingsurfaceinamulti-surfacediskdrivethatonlycontainscontrolinformation whichprovidestiming,headposition,andtrack-followinginformationforthedata surfaces.

SERVO SYSTEM

Anautomaticsystemformaintainingtheread/writeheadontrack;canbeeither“open loop,”“quasi-closedloop,”or“closedloop.”

SERVO TRACK

Atrackonaservosurface.Theprerecordedreferencetrackonthededicatedservo surfaceofadiskdrive.Alldatatrackpositionsarecomparedtotheircorresponding servotrack todetermine“offtrack”/”ontrack”position.

SETTLING TIME

Thetimeittakesaheadtostopvibrating,withinspecifiedlimits,afteritreachesthe desiredcylinder.

SILICON Semiconductormaterialgenerallyusedtomanufacturemicroprocessorsandother integratedcircuitchips.

SMALL COMPUTER SYSTEM INTERFACE (SCSI)

Anintelligentinterfacethatincorporatescontrollerfunctionsdirectlyintothedrive.

S.M.A.R.T. CAPABILITY Self-MonitoringAnalysisandReportingTechnology.Predictionofdevice degradationand/orfaults.

SOFT ERROR

Adataerrorwhichcanbeovercomebyrereadingthedataorrepositioningthehead.

SOFT SECTORED

Atechniquewherethecontrollerdeterminesthebeginningofasectorbythereading offormatinformationfromthedisk.Thisiscontrastedtohardsectoringwherea digitalsignalindicatesthebeginningofasectoronatrack.

SOFTWARE

Applicationsprograms,operatingsystems,andotherprograms(asopposedto hardware).

SPINDLE

Therotatinghubstructuretowhichthedisksareattached.

SPINDLE MOTOR

Themotorthatrotatesthespindleandthereforethedisks.

SPUTTERED MEDIA

Magneticdiskortapethathasthemagneticlayerdepositedbysputteringmeans.

STEPPER MOTOR

Amotorthathasknowndetentpositionswheretherotorwillstopwiththeproper controlinsomecases.Thedigitallycontrolledmotormovestheheadpositionerfrom tracktotrackinsmall,step-likemotions.

STORAGE CAPACITY

Theamountofdatathatcanbestoredinamemorylocation,usuallyspecifiedin kilobytesformainmemoryandfloppydrivesandmegabytesformassstoragedevices.

STORAGE DENSITY

Usuallyreferstorecordingdensity(BPI,TPI,oracombinationofthetwo.)

STORAGE LOCATION

Amemorylocation,identifiedbyanaddresswhereinformationmaybereador written.

STROBE OFFSET SIGNAL

AgroupofdigitalinputsignallevelswhichcausethereadPLLand/ordatadecoderto shiftthedecodingwindowsbyfractionalamounts.Oftenearly/latearemodifiedwhen twosignalsareused.

GL – 5