Introduction
ForeignOrigin
In1965,JohnGlenn,theoverseassalesdirectorofDECCompany,shippedthePDP-8totheUKandfoundthat"miniskirts"werepopularonthestreetsofLondon"(Mini),thegirlsarevyingtoputonskirtsshorterthantheknees,livelyandlight,lookingsocharmingandmoving.HesuddenlydiscoveredtheconnectionbetweenthePDPandtheminiskirt,andthenewsmediaimmediatelyacceptedtheidea,jokinglycallingthePDP-8a"minimachine.""Mini"means"small".Thiskindofmachineissmallandexquisite,withalengthof61cm,awidthof48cm,andaheightof26cm.Putitonaslightlylargertable,anditlookslikea"miniskirt".The"SlimLady".Itspricewasonly$18,500,whichwaslowerthananycompany'scomputerproductsatthetime.ItsoonbecametheleadingproductforDEC'sprofitandtriggeredaminiaturizationrevolutioninthecomputermarketatthattime.Differentfromlaterservers,theminicomputerusesthehost/dumbterminalmode,andeachmanufacturerhasitsownarchitecture,whichisincompatiblewitheachother.
Domesticdevelopment
AndUNIXservers,whicharetheminicomputersusedintheChineseindustry,areinthemiddle-to-high-endpositionintheservermarket.UNIXservershaveauniquearchitecturethatdistinguishesX86serversandmainframes.Basically,UNIXserversofvariousmanufacturersusetheirownUNIXversionoftheoperatingsystemanddedicatedprocessors.Forexample,IBMusesPowerprocessorandAIXoperatingsystem,SunandFujitsu(Fujitsu)useSPARCprocessorarchitectureandSolarisoperatingsystem,HPusesItaniumprocessorandHP-UXoperatingsystem,andInspurusesEPICprocessorarchitectureandK-UXoperatingsystem;thepastCompaqcompany(whichhasbeenmergedintoHP)processorarchitectureusesAlpha.Userswhouseminicomputersgenerallyvaluethesecurity,reliability,verticalscalability,andexcellentprocessingcapabilitiesofUnixoperatingsystemsanddedicatedservers,aswellashighconcurrentaccess.
Manufacturers
Currently,themajormanufacturersofUNIXserversareIBM,HP,Oracle(acquiredSUN),Inspur,andFujitsu.TypicalmachinesareIBM'sRS/6000,Power8,Power9,HP'sSuperDome,RX9800,RX9900,andInspur'sTissotK1950.SUNandHPhavesomehigh-endminicomputers,suchasHP’sSuperDome2,asproductsthatcompetewithmainframes(Mainframe),buttheyarecompatiblewithmainframessuchasIBMZseriesandUnisysClearPathintermsofsystemarchitectureandprocessinglogic.Withacompletelydifferenttechnicalsequence,hstillbelongstothecategoryofminicomputers.
Features
Technology
Thetechnologiesgenerallyusedinhigh-endIBMminicomputersare:RISC-basedmulti-processorarchitecture,megabytecache,SeveralgigabytesofRAM,hundredsofGBofdiskstorageondedicatedI/OchannelsusingI/Oprocessors,anddedicatedmanagementprocessors.Theyaresmallinsizeandair-cooled,sotherearenospecialcoolingpipelinerequirementsonthecustomersite.
Features
Thereisabigdifferencebetweenminicomputersandordinaryservers(alsoknownasPC-SERVER).ThemostimportantpointisthehighRAS(Reliability,Availability,Serviceability(highreliability,highavailability,highserviceability)features.
RASistheabbreviationofthethreeEnglishwordsReliability,Availability,andServiceability.Theyreflectthethreefamouscharacteristicsofhighreliability,highavailability,andhighserviceabilityofcomputers.Theirspecificmeaningsareasfollows:
Highreliability(Reliability):Thecomputercancontinuetorun,nevershutdown.
Highavailability(Availability):importantresourcesarebackedup;potentialproblemscanbedetected,andtasksrunningonitcanbetransferredtootherresourcestoreducedowntimeandmaintaincontinuousproductionOperation;withreal-timeonlinemaintenanceanddelayedmaintenancefunctions.
Highserviceability(Serviceability):Real-timeonlinediagnosis,preciselocationofthefundamentalproblem,andaccurateandquickrepair.