雲端運算上的服務雲端伺服架構整體雲端運算的架構雲端服務架構圖U02-5TopLevel:雲控制器CloudController(CLC),儲存控制器WalrusStorageController(WS3)MiddleLevel:叢集控制器ClusterController(CC),儲存區塊ElasticBlockStorage(EBS)EndLevel:節點控制器NodeController雲端伺服系統的組成雲端的特徵商業運作模式何謂作業系統?Asetofprogramsthatmanagecomputerhardwareresourcesandprovidecommonservicesforapplicationsoftware.(wikipedia)Managingsystemresources:ProcessmanagementMemorymanagementInput/Output(Device)managementDatamanagementBasicComponentsofOperatingSystem:KernelDevicedriversFilesystemApplicationsupportinglibrariesCommandprocessor(Shell)OperatingsystemtypesrelatedtothisCloudComputing:DistributedOperatingSystemNetworkOperatingSystemClusterOperatingSystemCloudComputing–ThesharedpoolofconfigurablecomputingresourcesExamples:NetworksServersStorageApplicationsServicesTheoperatingsystemresponsibleformanagingthelowlevelcloudresourceshidingthecloudinfrastructuredetailsfromapplicationprogrammerscoordinatingthesharingoftheresources相似處ResourcemanagementProvidesComputingservicesStorageservicesCommunicationservices相異處LargescaleManagescloudinfrastructureSupportsaverylargenumberofusersProvidescomputingpowerintheformsofvirtualmachineMapreduceforcloudcomputingenvironmentEventualconsistencypermitautonomousresourcemanagementcontinueoperatingdespitelossofnodesbeoperatingsystemandarchitectureagnosticsupportmultipletypesofapplicationsprovidedecentralizedandscalablemanagementsupportaccountingonresourceusageAvirtualmachineisasoftwareimplementationofamachine(computer)thatexecutesinstructionslikeaphysicalmachineCPU虛擬化記憶體虛擬化I/O虛擬化儲存虛擬化網路虛擬化虛擬化[23]就是在一個實體主機可以同時運行多個作業系統，每個作業系統可以自主執行其應用程式。虛擬化技術[24]可分為伺服器虛擬化、桌面虛擬化、網路虛擬化以及儲存虛擬化，這邊談的是前兩者。雲端計算的基礎之一就是虛擬化，即是多部虛擬機VMs透過虛擬層Hypervisor做CPU、memory、IOdevices的emulation。伺服器虛擬化又區分為全虛擬化旁虛擬化硬體支撐的虛擬化全虛擬化(FullVirtualization)–VMwareESXServer[25]為代表。一個“可執行代碼翻譯”(binarytranslation)方法將這些指令的可執行代碼轉變為一系列新的指令順序可以得到硬體虛擬化支援；全虛擬化的hypervisor(即ESX)將硬體平臺上的所有的輸入輸出設備也都虛擬化了，它含有所有這些設備驅動器。例如VMwareESX/ESXiServer、