Meaning
Thestoragecapacityofthealgorithminthedatastructurereferstothemaximumstoragespacerequiredduringtheexecutionofthealgorithm.Itincludesthefollowingthreeparts:1.Thespaceoccupiedbytheinputdata;2.Thespaceoccupiedbytheprogramitself.3Spaceoccupiedbyauxiliaryvariables.
Storageunit
Thisistheproblemofthestorageunitofinformationinthecomputer:
Amongthem1024=2^10(2tothe10thpower,convenientforbinarycalculation)
1bit=1bit(bitabbreviatedasbpayattentiontolowercase)
1byte(ByteabbreviatedasBpayattentiontouppercase)=8bits(bit)
1Kilobyte(KB,Kforshort)=1024bytes(B)
1Megabyte(MB,Mforshort)=1024kilobytes(KB)
1gigabyte(GB,Gforshort)=1024megabytes(MB)
1terabyte(TB,Tforshort)=1024gigabytes(GB)
1piebyte(PB)=1024terabytes(TB)
1exabyte(EB)=1024piebytes(PB)
1zettabyte(ZB)=1024exabytes(EB)
1Yaobyte(YB)=1024zettabytes(ZB)
ThestorageunitthatwecangenerallyuseisalsoItcanonlyreachterabytes(TB).
Thecommonlyusedcomputermemoryis2GB,4GB,8GB,16GB.Commonlyusedharddrivesare500GB,1TB,1.5TB,and2TB.
Mobilephonememoryiscommonlyused2G,3G,4G,andmobilephonememorycardsarecommonlyused8G,16G,32G,64G,128G.Thiscardisoptional.
Thereare1G,2G,4GM,8G,16Gmemorycardsfordigitalcameras.
Newrecord
AlthoughthePCstoragefieldaroundusisalreadydominatedbyharddisksandevensolid-statestorage,manycompanies,medical,governmentandotherfieldsthatrequirelarge-capacitylong-termstorage,Thetapedrivestillhasroomforitssurvival.TheIBMZurichLaboratoryinSwitzerlandannouncedafewdaysagothattheyandJapan'sFujifilm(Fujifilm)companyhavecreatedanewstoragedensityrecordinthefieldofmagnetictape.
ThestoragedensityofthistapesampledemonstratedbyIBMreaches29.5Gbpersquareinch,whichis39timesthatofcommontapedrives.Thestoragecapacityofeachreeloftapesupportedbythistechnologycanreach35TB,whichis44timesthatofthefourth-generationIBMLTOtape.
Toachievethisbreakthrough,researchershaveappliedanumberofnewtechnologies.ThefirstistheNANOCUBICtapeprovidedbyFujifilm,whichusesbariumferriteasamagneticmediumtoincreasethestoragedensity.NextistheprecisemagneticheadpositioningtechnologydevelopedbytheIBMZurichLaboratory,whichhasincreasedthenumberoftracksonthetapeby25times.Thenewsignalprocessingalgorithmreducesreadandwritenoiseandincreaseslinearstoragedensityby50%.Coupledwiththeapplicationofgiantmagnetoresistancetechnology,today'srecordstoragedensityhasfinallybeenachieved.
Databasestoragecapacity
ThedifferencebetweenAccessandSQLdatabasesisverybig.Oneisadesktopdatabaseandtheotherisenterprise-leveldata.However,Ifeelthatitisnotnecessarytobefamiliarwiththesedetails.Itisbesttolearnandmasterinpractice!
Pleaserefertothedetailedparameterdifferencesbetweenthefollowingtwodatabases:
ACCESS2000Chineseversionspecifications:
Attributemaximumvalue
MicrosoftAccessdatabase(.mdb)Thefilesizeis2Gbytes.However,sincethedatabasecanincludelinkedtablesinotherfiles,itssizeisactuallyonlylimitedbytheamountofavailablestoragespace.
Thenumberofobjectsinthedatabase32,768
Modules(includingformsandreportswhoseHasModulepropertyisTrue)1,000
Thenumberofcharactersintheobjectnameis64
p>Thenumberofcharactersinthepasswordis14
Thenumberofcharactersintheusernameorgroupnameis20
Thenumberofusersis255
MicrosoftAccessprojectgeneralSpecifications:
MaximumAttributes
ThenumberofobjectsintheMicrosoftAccessproject(.adp)is32,768
Modules(includingformswiththeHasModuleattributeasTrue)andReport)1,000
thenumberofcharactersintheobjectname64
MicrosoftAccessdatabasetablespecifications:
attributemaximum
tablenameThenumberofcharactersis64
Thenumberofcharactersinthefieldnameis64
Thenumberoffieldsinthetableis255
Thenumberofopentablesis2,048.Theactualnumberoftablesthatcanbeopenedmaybeless,becauseMicrosoftAccessalsoneedstoopensomeinternaltables.
Thesizeofthetableis1Gbytes.
Thenumberofcharactersinthetextfieldis255
Thenumberofcharactersintheremarkfieldis65,535inputthroughtheuserinterface,andinputthroughtheprogramItis1Gbytes.
ThesizeoftheOLEobjectfieldis1Gbytes
Thenumberofindexesinthetableis32
Thenumberoffieldsintheindexis10
ValidThenumberofcharactersinthesexmessage255
Thenumberofcharactersinthevalidityrule2,048
Thenumberofcharactersinthetableorfielddescription255
Thenumberofcharactersintherecord(ExceptformemofieldsandOLEobjectfields)2,000
Thenumberofcharacterssetbythefieldpropertiesis255