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Thefirstautomaticcalculatorwasinventedin1642byBlaisePascal.However,noneofdevisesshouldbecomparedtoacomputerbecausetheycouldbeprogrammed.Acomputermustnotonlycalculateautomatically,butitshouldalsobepossibletoprogrammeit.Thefirststepinthisdirectionwastakenin1801whenJosephMarieJacquardinventedapunchcardthatcouldbeusedforweaving.Thecardmadesurethatthethreadswentthroughintherightorder.Thisisimportant,becausecomputersusecodesinordertowork.
By1883,CharlesBabbageinventedthemajorpartsofthemechanicalcomputer.
DIFFERENTTYPESOFCOMPUTERS;
Past,Present,Future
∙COLOSSUSCOMPUTER
TheColossuswasagiantcomputerbuildbyBritishSecretServiceduringWorldWarII.ItwasbuildbyanengineercalledTommyFlowers,andusedvacuumtubestoperformthecalculations.ColossuscomputerswereusedbytheBritishtobreaktheGermancodes.Theyweretheworld’sfirstprogrammable,digital,electronic,computingdevices.
∙Z3COMPUTERS
TheZ3computerwasbuildbyKonradZuse,between1936and1941,inGermany.Itwasfirstreliable,freelyprogrammable,workingcomputerintheworld,andwascompletelyconstructedfrom2000relays.TheZ3containedalmostallofthefeaturesofmoderncomputer.ThesuccessofZuse’sZ3isoftenattributedtoitsuseofthesimplebinarysystem–thatis,allthedataisstoredintheformofjust2numbers,0and1.
∙HARVARDMARK-I
Manyconsiderthatthemoderncomputereracommencedwiththefirstlarge-scaleautomaticdigitalcomputer,whichwasdevelopedbetween1939and1944.Thisdevice,thebrainchildofHarvardgraduateHoward.H.Aiken,wascommonlyreferredtoastheHarvardMark–Iwasconstructedoutofswitches,relays,rotatingshafts,andclutches,andwasdescribedassoundinglikea‘roomfulofladiesknitting.’Themachinecontainedmorethan750,000components,was15meterlong,2.4metertall,andweighedapproximately5tons.
∙ATANASOFF–BERRYCOMPUTERS
TheAtanasoff–BerryComputerwastheworld’sfirstelectronicdigitalcomputer.ItwasbuildbyJohnVincentAtanasoffandCliffordBerryatlovastateuniversityduring1937–42.Itincorporatedseveralmajorinnovationsincomputing.Themachinewascapableofsolvingupto29simultaneouslinearequations.Themachinewas,however,theimplementthreecriticalideasthatarestillpartofeverymoderncomputer.Itusedbinarydigits,itperformedallcalculationsusingelectronicsratherthanwheelsormechanicalswitches,anditorganized
∙MICROCOMPUTERS
Microcomputershaveamicroprocessorastheircentralprocessingunit,andarethereforerelativelysmallinsize.Whentheyhaveakeyboardandmonitor,theyareusedaspersonalcomputers,whichistypeofcomputerthatyouhaveinyourhome.
∙LAPTOPCOMPUTERS
Alaptopcomputerornotebookcomputerisasmalllightweightcomputerthatyoucancarryaroundeasily.Itcanperformallthefunctionsofaregularcomputer,andhasbuildinkeyboard,pointingdeviseandalightweight,non–bulkyscreen.Laptopcomputerscanrunbothonbatteriesandfromanexternaladaptorthatchargesthebatterywhilesuppingpower.Ifyouhavealaptopcomputer,youcanworkonitwhiletravelingorevenyouareoutdoors.
∙DESKTOPCOMPUTERS
Adesktopcomputerisasmallcomputerthatyoucanusefromafixedpowersource.Itgetsitsnamefromafactthatitissmallenoughtofitonatableordesk.Desktopcomputershaveseparatekeyboardsandscreens,andcomeinavarietyofstylesandmodels.
∙POCKETPC
ApocketPCisascaleddownversionofafullsizedcomputerthatyouuseinhomeoroffice.Althoughtheyarethesizeofasmalldiary,pocketPCsarepropercomputers.Theyhavemanyofcapabilitiesoffullsizecomputers,andcanrunsophisticatedsoftwareapplications.Theyarecompactenoughtofitinyourshirtpocket…hencetheclevername.
∙TABLETPC
AtabletPCiscrossbetweenanotebookPC,andahandheldcomputer.Itisaflat–panelportablePCinaformofaslate.Youcanenterinformationbytypingthescreenwithastylus,orelectronicpen.Youcanusethependirectlyonthescreenjustasyouwouldamousetodothingslikeselect,drag,andopenfiles.Youcanalsouseitaplaceofakeyboardtohandwritenotesandcommunications.Unlikeatouchscreen,thetabletPCscreenonlyreceivesinformationfromthisspecialpen.
∙HANDHELDCOMPUTER
Ahandheldcomputerisaportablecomputerthatissmallenoughtobeheldonehand.Theyareaboutthesizeofspectaclecase,andacapableofstoringthousandsofaddress,appointmentandmemos.So,theyarealsocalledPersonalDigitalAssistantsorPDAs.Handheldcomputershaveextremelysmallscreensandkeyboards.Today,thekeyboardhasbeenreplacedwithanelectronicpeninsomehandheldcomputers.Youcanconnectahandheldcomputertoadesktopcomputertoexchangeinformationbetweenthetwo.
∙ULTRAMOBILEPC
Theultra-mobilePCorUMPCisasmall,mobilecomputerthatrunsontheWindowsVistaoperatingsystem.TheUMPCgoesanywhere,andcanbeusedanytime,justlikeamobilePC.TheUMPChasmanyadvantages.Itissmallerandlighterthantraditionallaptopcomputersandhasmultipleinputmethodsliketoughscreen,tabletpen,theUSBkeyboardandothers.Itcanalsooperateondifferentsystems.
∙SUPERCOMPUTERS
Thefastestandmostpowerfulcomputersavailableataparticulartimearecalledsupercomputers.Supercomputersareveryexpensiveandemployedforspecializedtasksthatrequiredimmenseamountofmathematicalcalculations.TheNewYorkWorld,referringto
tabulatorsmanufacturedbyIBM,coinedthetermsupercomputerin1929.Tomoderncomputerusers,thesetabulatorswouldprobablyappearawkwardandslow.Intheconstantlychangingtheworldofcomputing,itshouldcomeasnosurprisetolearnthatmostsupercomputersareconsideredtobe‘super’onlyfewyears,infact,today’ssupercomputerwillbecometomorrow’sordinarycomputer!
∙MINISUPERANDSUPERMINICOMPUTERS
Aminisupercomputerissupercomputerthatisaboutaquartertoahalfasfastasthemostpowerfulsupercomputers,butcostmuchless.Aminisupercomputeraminicomputerwithhighperformancecomparedtoordinaryminicomputers.
∙BIOLOGICALCOMPUTER
Biologicalcomputersarespecialtypesofmicrocomputersthatarespecificallydesignedtobeusedformedicalapplications.Thebiologicalcomputerisplantedinsidethebodyandismainlyusedfortaskslikemonitoringthebody’sactivities,ordiagnosingandtreatingdiseases.Biologicalcomputersareimportantbecausetheyenableadoctortofocuson,findatreatonlydamagedordiseasedcells.
∙QUANTUMCOMPUTERS
Wealreadyknowthatabitisafundamentalunitofinformationwhichisrepresentedasa0or1indigitalcomputer.Ordinarycomputersinterruptinformationaccordingtothewellunderstoodlawsofclassicalphysics.Inquantumcomputer,fundamentalunitofinformationiscalledquantumbitorqubit.Aquantumcomputerobeysthelawsofquantummechanicswhichareverydifferentfromclassicalphysics.Scientistshavealreadybuiltbasicquantumcomputersthatcanperformcertaincalculations,butapracticalquantumcomputerisstillyearsaway.
∙DNACOMPUTERS
DNAordeoxyribonucleicacidmolecules,materialourgenesaremadeof,havethepotentialtoperformcalculationsmanytimesfasterthantheworld’smostpowerfulhumanbuiltcomputers.AcomputerthatusesDNAtostoreinformationandperformcomplexcalculationsiscalledaDNAcomputer.Itwasin1994thatUniversityofSouthernCaliforniacomputerscientistLeonardAdelmansuggestedthatDNAcouldbeusedtosolvecomplexmathematicalproblems.Whilestillintheirinfancy,DNAcomputerswillbecapableofstoringbillonsoftimesmoredatathanyourpersonalcomputer.
∙OPTICALCOMPUTER
Anopticalcomputerisacomputerthatuseslightinsteadofelectricity.Anopticalcomputerusesphotonstomanipulate,storeandtransmitdata.Youalsoknowthemodernelectriccomputerusetransistors.Inopticalcomputerselectroniccomponentsarereplacedwithopticalonesand‘opticaltransistors’mustbeused.Opticalcomputertechnologyisstillinearlystages.
∙CHEMICALCOMPUTERS
Achemicalcomputerisanunconventionalcomputerbasedonasemi–solidchemical‘soup,’wheredataisrepresentedbyvaryingconcentrationofchemicals.Thecomputationsareperformedbynaturallyoccurringchemicalreactions.Sofar,itstillinveryearlyexperimentalstage,butmayhavegreatpotentialforthecomputerindustry.
∙NANOCOMPUTER
Ananocomputerisacomputerthatismicroscopicsize.Itissmallerthanmicrocomputer,whichissmallerthanminicomputer.Wecanalsosayitisacomputerwhosefundamentalpartsarenobiggerthanafewnanometers.Itiscommonlyusednanotechnologywhichisthebuildingofextremelysmallmachines.
∙WETWARECOMPUTERS
Awetwarecomputerisanorganiccomputer.Organicrefersanythingthatisderivedfromlivingorganisms.Awetwarecomputerisfromlivingneurons,whicharecellsfoundinbrain,spinalcolumnandnerves.Awetwarecomputerissometimescalledanartificialorganicbrainoraneurocomputer.Awetwarecomputerhasalreadybeenconstructedfromleechneurons.
∙SHOECOMPUTERS
Ashoecomputerisatypeofcomputerthatuseslawlevelelectricalimpulsesemitte
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