Introduction
Incomputerscience,bitisthesmallestunitofinformation,calledbinarybit;itisgenerallyrepresentedby0and1.Byteiscalledabyte,abyteiscomposedof8bits(bit),whichisusedtorepresentacharacterinacomputer.ConversionbetweenbitandByteispossible,andtheconversionrelationshipis:1Byte=8bit(orabbreviatedas:1B=8b);inpracticalapplications,itisgenerallyabbreviated,thatis,1bitisabbreviatedas1b(notethatthelowercaseEnglishletterb),1ByteAbbreviatedas1B(notetheuppercaseEnglishletterB).
bistheabbreviationofbit,thatis,"bit",whichisthesmalleststorageunitininformationtechnology.Onebitrepresentsa"1"or"0".BistheabbreviationofByte,thatis,"byte",whichisasmallstorageunitininformationtechnology.AnEnglishcharacteroccupiesonebyte,andaChinesecharacteroccupiestwobytes.Theconversionbetweenthemis1Byte=8bit,andtheiradvancerateis8.
1MB=1024KB=1048576B(Bisbyte,Byte)
So1Mbps(1megabitpersecond)=0.125MByte/s(0.125megabytespersecond)=0.125MByte/s*1024=128KB/s(128kilobytespersecond)
Thatis1Mbps(megabitspersecond)=1/8MB/s(one-eighthofamegabytepersecond)Seconds)
Incomputernetworksornetworkoperators,generally,theunitofbroadbandspeedisexpressedinbps(orb/s);bpsmeansbitspersecondmeanshowmanybitsofinformationaretransmittedpersecond,Itistheabbreviationofbitpersecond.Infact,1Mbandwidthmeans1Mbps[Itismegabitspersecond(Mbps),notmegabytespersecond(MBps).
Application
Overview
Inouractualwebapplications,whendownloadingsoftware,weoftenseethatthedownloadspeedisdisplayedas128KBps(KB/s),103KB/sandsoon,becausetheunitofthelinebandwidthprovidedbytheISPisthebit,andthegeneraldownloadsoftwaredisplaysthebyte(1byte=8bits),sotheactualvaluecanbeobtainedthroughconversion.However,wecanconvertitaccordingtotheconversionformula:
128KB/s=128×8(Kb/s)=1024Kb/s=1Mb/s,thatis,128KB/s=1Mb/s.
Conversionformula
Itisrecommendedthatusersrememberthefollowingconversionformula:
1B=8b1B/s=8b/s(or1Bps=8bps)
1KB=1024B1KB/s=1024B/s
1MB=1024KB1MB/s=1024KB/s
Writingstandard:Intheactualwritingstandard,BshouldmeanByte(Byte),bshouldrepresentbit(bit),butinordinaryactualwriting,bothbitandBytearemixedasb.Forexample,bothMb/sandMB/saremixedasMb/s,causingpeopleIntheactualcalculation,errorsoccurredduetotheconfusionoftheunits.
Specialreminder
(1)Explanationabouttheconversionofbit(bit)/second(second)andByte(byte)/s(second):Thelineunitisbps,whichmeansbit(bit)/second(second),notethatitisalowercaseletterb;therateunitdisplayedwhentheuserdownloadsontheInternetisoftenByte(byte)/s(second),notethatitisacapitalletterB.Therelationshipbetweenbyteandbitis1Byte=8Bit;inadditiontotheincreasedtransmissionvolumeduetonetworktransmissionprotocolssuchasIPheaderandHTTPheader,whenthedownloadrateof1KByte/sisdisplayed,theactualtransmissionrateofthelineisabout10Kbps.Forexample:whenthedownloaddisplayis50KByte/s,theactualspeedhasreached500Kbps.
(2)Thebroadbandservicerateappliedbytheuserreferstothemaximumtheoreticalratethatcanbeachievedtechnically.Whentheusergoesonline,itisalsoaffectedbytheconfigurationoftheuser’scomputersoftwareandhardware,thelocationofthewebsitebeingbrowsed,andthebandwidthoftheoppositewebsite.Duetotheinfluenceofothercircumstances,theuser'sratewhensurfingtheInternetisusuallylowerthanthetheoreticalratevalue.
(3)Theoretically:2M(ie2Mbps)broadbandtheoreticalrateis:256KB/s(ie2048Kb/s),theactualrateisabout103-200KB/s;(ThereasonisthattheuserComputerperformance,networkequipmentquality,resourceusage,networkpeakperiod,websiteservicecapacity,lineattenuation,signalattenuationandotherfactors.Thetheoreticalbroadbandrateof4M(ie4Mbps)is:512KB/s,andtheactualrateisabout200---440KB/s.
Therelationshipbetweenmegabitsandbits(experimentalproof)
1Mb=106b(bit)
Theexperimentalproofisasfollows:
[Thinking]Iusemyvoicerecordertodoexperiments,recordatacertainkilobitrate(1536kbpsIuse),andthenlookattheremainingrecordablerecordingtimeandremainingdiskspacedisplayedonthevoicerecorder.Becausetheformerisbasedonkilobitrate,thelatterisbasedonkilobytes,andtheconversionofkilobytestobytes,andbytestobitsisnotdisputed(1kB=1024B,1B=8b),soyoucanUsedforexperimentation.[Note:Strictlyspeaking,1MiB=1024KiB,1KiB=1024B,1B=8bit(bitmeansbit,bit,abbreviatedasb)butweareusedtoomittingi.Inthediskcalculation,1GB=1000MBisactuallycorrect.Infact1GiBisequalto1024MiB,butthisisnottheobjectofourdiscussion]
[Recorddata]
Startrecordingat1536kbps,andthesystemdisplaystheremainingrecordingtimeof100Itstopsathours(ie360000s),andinsertingWindowsshowsthattheremainingdiskspaceisequalto65919MB,thatis,67501056KB②
[AssumptionsandAnalysis]
①If1Mbpsisequalto1024kbps,then1kbpsshouldalsobeequalto1024bit/s.Inthisway,1536kbpsisequivalenttooccupying192kBofdiskspacepersecond(1536kb=1536×1024b=1536×1024÷8B=1536×1024÷8÷1024kB=192kB).Multiply192kB/sbytheremainingtime360,000stoget69120000KB①,whichisahugedifferencefromtheremainingdiskspaceof67501056KB②.Thedifferenceisaboutsixordersofmagnitude,andbothare1GB,whichisabsolutelyimpossible.What'smore,thespacerequiredforrecordingforsuchalongtimeislargerthantheremainingspace,whichisevenmoreoutrageous.
②Next,Iassumethat1Mbpsisequalto1000kbps,anditiseasytoget1536kbps=1536000bit=1536000/8B=1536000/8/1024KB.Basedonthiscalculation,theserecordingsoccupy67500000KB③.Next,forcomparison,67501056KB②-67500000KB③=1056KB,whichisaboutafewmegabytes,thenthisisthenormalrange.
[Conclusion]
Proof1Mbps=1000kbps=106bps