1、UNIT18 Cloud Computing 18-1 Technical Part18-2 Reading Material 18-1 Technical Part 18-1-1 Definition Cloud computing is Internet-based computing,whereby shared resources,software and information,are provided to computers and other devices on-demand,like the electricity grid.18-1-2 Introductions 1.D
2、evelopment of Cloud ComputingCloud computing is the next revolution of computing technologies following mainframes and PCs.This revolution is both from standalone server-based computing to distributed computing in terms of technology,and from“box”to service in terms of business model.IP has changed
3、the communications industry.The cloud computing technology may change the information and communications technology(ICT)industry.Figure 18-1 shows the development of cloud computing.And now we are facing the next technology revolution which is cloud computing,this is not only the technology revoluti
4、on,but also a business model revolution in ICT industry.And we can see the huge potential of this market which has 500 billion US dollars cloud services revenues.Figure 18-1 The development of cloud computing 2.Categories of Cloud ComputingCloud computing is a general term for anything that involves
5、 delivering hosted services over the Internet.These services are broadly divided into three categories:Infrastructure-as-a-Service(IaaS),Platform-as-a-Service(PaaS)and Software-as-a-Service(SaaS).A cloud can be private or public.A public cloud sells services to anyone on the Internet.(Currently,Amaz
6、on Web Services is the largest public cloud provider.)A private cloud is a proprietary network or a data center that supplies hosted services to a limited number of people.When a service provider uses public cloud resources to create their private cloud,the result is called a virtual private cloud.P
7、rivate or public,the goal of cloud computing is to provide easy,scalable access to computing resources and IT services.Below Figure 18-2 shows the category of cloud computing.Figure 18-2 The category of cloud computing3.Characteristics and Main Function of Cloud Computing Device and location indepen
8、dence enable users to access systems using a web browser regardless of their location or what devices they are using(e.g.,PC,mobile phone).As infrastructure is off-site(typically provided by a third-party)and accessed via the Internet,users can connect from anywhere.Virtualization technology allows
9、servers and storage devices to be shared and utilization be increased.Applications can be easily migrated from one physical server to another.Centralization of infrastructure in locations with lower costs(such as real estate,electricity,etc.).Peak-load capacity increases(users need not engineer for
10、highest possible load-levels).Utilization and efficiency improvements for systems that are often only 1020%utilized.Reliability is improved if multiple redundant sites are used,which makes well-designed cloud computing suitable for business continuity and disaster recovery.Scalability and Elasticity
11、 via dynamic(“on-demand”)provisioning of resources on a fine-grained,self-service basis near real-time,without users having to engineer for peak loads.Performance is monitored and consistent and loosely coupled architectures are constructed using web services as the system interface.Maintenance of c
12、loud computing applications is easier,because they do not need to be installed on each users computer and can be accessed from different places.4.Perspectives on the CloudJust as in the early days of the Internet,the cloud definition is best-suited to include a public cloud(external,like the Interne
13、t)and private clouds(internal,like intranets).Private clouds will be used by companies that do not want to have their IT-related services available to external customers but that do want to leverage the delivery and acquisition model the cloud enables.This has several implications:The cloud is a mec
14、hanism that supports alternative delivery and acquisition models(ADMs)of multiple types(for example,grid,utility and SaaS)in that anything and everything can be offered as a service.The cloud is more than just SaaS in that everything as a service(XaaS)would be a more appropriate appellation.Through
15、the cloud,we can get services that are primarily hardware based where the software is an integral part of the delivery,not a specific value proposition in itself.Storage as a service is an example of this.SaaS is an ADM and can be delivered through the cloud just as any other service can.To say that
16、 SaaS and the cloud were the same would be a limited view.The Internet and potentially the Web are necessary for the existence today of the cloud but are not solely definitive of it.There must be a deliberate delivery of service to constitute cloud computing.(In the future,some other globally distri
17、buted network may supplant the Internet in this capacity to support cloud computing.)Internal clouds can exist using Internet/Web technologies but must also include the intentional ADM of XaaS to internal customers and private partners.This is what distinguished these internal clouds from the one pu
18、blic cloud.18-1-3 Application Case or Example 1.Case 1:Application of virtual DesktopOne typical application scenario is to provide virtual desktop Cloud choice.This can be provided to Large Enterprise/SME/Or individuals.The Figure 18-3 shows the typical application of the virtual desktop.Figure 18-
19、3 The application of virtue desktop Comparing with the traditional desktop:PC processing capability(including CPU and hard disk)is centralized to the data center.PCs are replaced with TCs,which do not require strong processing and storage capabilities.The cloud data center provides each TC with a vi
20、rtual computer.Resources are shared by all TCs.Any idle resources allocated to a TC can be used by other TCs.Resource allocation is performed according to actual requirements based on the uniform management platform of cloud computing shared by all TCs.Any idle resources allocated to a TC can be use
21、d by other TCs.Data on desktops are run and stored on the data center.Users can remotely access their desktops over various terminals.Therefore,users do not need to stop the running applications and can replace terminals in hot swapping mode shared by all TCs.Any idle resources allocated to a TC can
22、 be used by other TCs.Terminals and information are separated.Data are stored and processed at the background.The data transmitted to the terminal is only the result refreshed on the screen.Terminal No-hard-disk designing terminals,so they cannot store server data.Block physical interfaces for possi
23、ble data disclosure on the user side,which actually support only input and output of mouse and keyboard instructions(other applications can be enabled by the environment system administrator for special requirements).Access Control TC authentication effectively prevents illegal TCs from accessing th
24、e system.Each host and the ID of each ROM card are bound together.This ensures uniqueness of the TC legality.User identity can be authenticated with the help of the multi-factor authentication method,such as using user fingerprint and user password for authentication Data Transfer Virtual channels s
25、upport application control and management,such as Print control,File sharing management,USB port mapping,management,Flow media application management.User computing node has automatic backup and restoration functions.This ensures seamless switchover when hardware is faulty.Data fragments are backed
26、up in different physical areas and automatic restoration function can be implemented for any physical storage faults.2.Case 2:Application of Private Cloud Current Situation is that the IT server is deployed in silo mode,resource need to be configured according to max-use;server utilization is low an
27、d the cost is high,and the standalone system reliability is low.By SPC(Service Private Cloud)mode,all applications and services can be deployed in a Unified hardware platform.One VM is allocated to Applications.Hardware resource can be shared and the resource can be automatically switched between Ap
28、plications.Cost on hardware would be saved and the system reliability and availability based on the whole platform would be high.We can take Heath cloud built in Shanghai as an example,which is the first health cloud in China.See below Figure 18-4 shows the structure of Shanghai heath cloud.Figure 1
29、8-4 The deployment of Shanghai Health Cloud 18-2 Reading Material 18-2-1 Reading Comprehension Cloud ComputingCloud computing is a style of computing in which dynamically scalable and often virtualized resources are provided as a service over the Internet.Users need not have knowledge of,expertise i
30、n,or control over the technology infrastructure in the“cloud”that supports them.Cloud computing can be confused with grid computing(“a form of distributed computing whereby asuper and virtual computer is composed of a cluster of networked,loosely-coupled computers,acting in concert to perform very l
31、arge tasks”),utility computing(the“packaging of computing resources,such as computation and storage,as a metered service similar to a traditional public utility such as electricity”)and autonomic computing(“computer systems capable of self-management”).Indeed,many cloud computing deployments as of 2
32、009 depend on grids,have automatic characteristics,and bill like utilities but cloud computing tends to expand what is provided by grids and utilities.Some successful cloud architectures have little or no centralized infrastructure or billing systems whatsoever,including peer-to-peer networks such a
33、s Bit Torrent and Skype,and volunteer computing such as SETLhome.Furthermore,many analysis are taken to stress the evolutionary,incremental pathway between grid technology and cloud computing,tracing roots back to Application Service Providers(APIs)in the year 1990s and the parallels to SaaS,often r
34、eferred to as application on the cloud.Some are of the persuasion that the true difference between these terms is marketing and branding;that the technology evolution was incremental and marketing evolution discrete.Words&Expressionscloud computing 云计算scalable adj.可升级的，可扩展的 infrastructure n.基础设施，基础结
35、构 confused adj.混淆的，混乱的grid computing 网格计算 loosely-coupled adj.松散耦合的 capable adj.有能力的，有技能的 deployment n.展开，部署，调度 whatsoever pron.无论什么 analyst n.分析家，化验员SaaS n.软件服务化 persuasion n.信仰，说服，劝说 incremental adj.增加 discrete adj.离散expertise n.专门知识或技能 18-2-2 Exercises I.Multiple Choices1.Users of cloud computing
36、 should have the qualities including _.A.Knowledge of the technology infrastructure.B.Expertise in the technology infrastructure.C.Control over th technology infrastructure.D.None of the above is necessary.2.Which of the Following would NOT be confused with cloud computing?A.Grid computing.B.Utility
37、 computing.C.Autonomic computing.D.Parallel computing.3.Which of the following is not an example of centralized infrastructure or billing systems not found in some successful architectures?A.BitTorrent.B.Skype.C.SETIhome.D.MS.4.According to the passage,what is stressed by many analyses?A.The differe
38、nce between cloud computing and utility computing.B.Why cloud computing depend on grids.C.The pathway between cloud computing and grid technology.D.The difference between cloud computing and grid computing.5.What is the true difference between the terms mentioned in the last paragraph?A.The architec
39、ture.B.The theory.C.The process.D.The marking and branding.II.Read&Translate.1.Cloud computing is a style of computing in which dynamically scalable and often virtualized resources are provided as a service over the Internet.2.Cloud computing can be confused with grid computing(“a form of distribute
40、d computing whereby asuper and virtual computeris composed of a cluster of networked,loosely-coupled computers,acting in concert to perform very large tasks”),utility computing(the“packaging of computing resources,such as computation and storage,as a metered service similar to a traditional public utility such as electricity”)and autonomic computing(“computer systems capable of self-management”).3.Some are of the persuasion that the true difference between these terms is marketing and branding;that the technology evolution was incremental and marketing evolution discrete.
