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云计算毕业设计外文文献

云计算——新兴的计算技术摘要:云计算是涉及通过互联网提供托管服务的总称。

这些服务大致分为三类:基础设施即服务(IaaS)、平台即服务(PaaS)和软件即服务(SaaS)。

云计算这个名字的灵感来自于云符号经常用来代表在互联网上流程图和图表。

这是在继主机计算、个人电脑计算、客户端服务器计算和Web计算之后的第五代计算技术。

本文将围绕云计算进行讨论。

关键词:云计算,IaaS(基础设施即服务),PaaS的(平台即服务),SaaS(软件即服务)1引言云服务有三个鲜明的特点区别于传统的主机服务模式,它们分别是:云服务的出售通常按分钟或小时收取费用;云服务是有弹性的,一个用户可以在不同的时间拥有可多可少的服务;云服务完全由供应商托管(消费者只需要通过个人电脑和互联网就可以使用)。

虚拟化的重大创新、分布式计算的发展,以及高速互联网的建设和经济的衰落,都加速了对云计算的兴趣。

云可以是私有的或公有的。

公有云向互联网上的任何人销售(目前,亚马逊的网络服务是最大的公有云服务提供商)。

私有云是一个专有网络或数据中心,向一部分人提供托管服务。

当服务提供商使用公有云资源来创建自己的私有云,这样的结果被称为虚拟化的私有云。

私有云或公共云的云计算目标是提供方便的、可扩展的计算资源和IT服务[1]。

IaaS(基础设施即服务),像亚马逊提供的Web服务是根据唯一的IP地址和存储块按照客户的需求提供虚拟的服务器实例。

客户使用提供商的API来启动、停止、访问和配置他们的虚拟服务器和存储。

在企业中,云计算能够根据需要进行购买。

PaaS(平台即服务)被定义为托管提供商提供的一套软件开发工具和产品。

开发人员通过互联网在基础平台上开发应用程序。

PaaS的提供者可以使用API,门户网站或门户网站上的软件为客户的计算机进行安装。

(的产物)和GoogleApps都是PaaS的例子。

开发人员需要知道的是,目前还没有云的互操作性和云数据可移植性的标准。

一些供应商可能不会允许客户创建的软件移出提供商的平台。

在SaaS(软件即服务)的云模型中,供应商通过前端门户向客户提供硬件设施、软件产品、以及用户交互。

SaaS是一个很广泛的市场。

服务可以从基于Web电子邮件的目录控制到数据库处理。

由于服务提供商提供的主机应用程序和数据,最终用户从任何地方可以自由地使用该服务。

2云计算的优势云计算具有的优势是什么?(a)最小化的资本开支(b)位置和设备独立性(c)利用和提高能效(d)非常高的可扩展性(e)高计算能力答案:供应商的视角:申请厂商更容易吸引新客户。

(a)提供最低成本的方法和配套应用;(b)能够使用商品服务器和存储硬件;(c)能够降低数据中心的运营成本;(d)一个词概括:经济学。

3云计算的障碍从客户的视角来看,云计算的障碍有:(a)数据安全;(b)很多客户不希望他们的数据迁移到可以信任的“云”上;(c)数据必须进行本地保留;(d)延迟;(e)云可以走多少毫秒;(f)不是实时应用的理想选择;(g)应用程序可用性;(h)无法通过现有的传统应用进行切换;(i)等效的云应用不存在;总结,并非所有的应用程序都要工作在公共云之上。

4云计算的体系结构云计算架构及其实现的定义非常强调UNIX哲学,具备开发人员必须遵循的一系列规则,确保云计算将很容易地实施,并且保证应用程序对用户的优势。

虽然有很多Unix哲学的定义,规则和原则,他们都有一个共同的信念:建立一个协同工作的事物。

通过UNIX哲学,设计云计算架构的开发商必须记住的是只有一个应用程序并且至少有一个输出。

云计算可能是由不同的阶段组成,但这些阶段是以实现在线申请一致的计算为目标。

数据中心和服务器农场提出了应用程序的需求。

可以说,许多硬件可以被用来支持一个进程,但这些都应该确保该应用程序有足够的后备设备计划。

云计算的应用程序也被认为是由安全性和性能监测组成的。

通过云计算架构的正确执行,应用程序将能够为用户提供7×24小时的服务。

5云计算安全安全是企业的最关注的问题之一。

不管业务有多大,或者有多小,都应该采取必要的安全措施。

不同的安全漏洞通常会引来不同意图的攻击。

一个单一的安全问题可能意味着数百万元的企业,可能会突然就无法正常经营了。

安全措施对于云计算是非常必要的[3]。

从互联网启动的应用程序更容易受到攻击[3]。

局域网的应用程序比部署在外网的应用程序安全性好。

这是云计算的独特情况。

云计算的实现可能需要数百万的资金用于基础设施的建设和应用程序的开发,但仍置于不同类型的攻击之中。

5.1保护用户除了以上的问题之外,云计算或者任何网络形式的应用程序都应该考虑保护其用户。

开发者应该保证用户相关的数据不会被错误的获取。

这里有两种方案保证云计算的安全:限制用户的访问和认证。

(a)限制性访问可能来自简单的用户名和密码,但是云计算的应用程序不仅应立足于这些挑战。

IP的特定应用和用户访问的时间只是云计算安全应予以执行的一些措施。

限制用户访问的挑战在于限制用户的访问权限。

每个用户必须手动指派安全检查,以确保限制通行不同的文件。

(b)证书对于用户的认证也同样重要。

开发商必须开放其提供安全认证的专家或公司。

这是一种被不同类型的攻击测试用户的方式。

这常常是云计算外部安全检查面对的可以公开公司秘密的难题,但是这必须以确保其用户的安全为前提。

5.2数据安全除了对用户受到不同类型攻击的保护,数据本身应该得到保护。

在这方面,硬件与软件都会起到作用。

而且,认证在数据安全方面是非常必要的。

另一方面,计算机硬件需要不同类型的安全考虑。

数据中心的位置选择不仅要考虑是否靠近控制器和用户,而且还需要考虑其外部安全问题(甚至是保密)。

数据中心应该得到保护,可以适应不同类型的天气条件,能够抵御会造成物理损坏的火灾等自然灾害。

对于添置应用程序有关的硬件,某些硬件必须增加安全性。

其中之一是手动关机,以防止信息的进一步访问。

虽然数据可以由其他应用程序控制,但是数据也会流失除非立即关机。

5.3恢复和调查云计算安全不应只注重预防本身。

充足的资源,也应侧重于恢复,如果真的发生不幸就会罢工。

即使在灾难发生时,某些计划必须到位,以确保每个应用都能复苏。

该计划并不一定要把重点放在单独攻击的软件上,如某些外部灾害天气情况应该有单独的恢复计划。

当一切都已经恢复,供应商及受理申请的公司应通过一些途径调查问题的原因。

通过调查,可以发现该事件导致的原因,甚至采取法律的行动,如果安全受到故意破坏。

实施云计算,安全是最困难的任务之一。

它不仅要求能够从软件方面抵御各种形式的攻击,而且在硬件方面也要能够起到作用。

攻击造成灾难性的影响只需要一个安全漏洞,所以它始终是每个人面临的安全性挑战。

6云计算的挑战云计算应用的挑战主要在于应用程序可以处理的请求数量[2]。

尽管这个问题有了数据中心的建议,没有正确开发阿杜应用程序也会遇到门槛。

为了解决这一问题,开发者使的元数据来为用户提供个性化的服务,以及数据处理。

通过元数据,个性化的要求将被接纳,并会得到妥善落实。

元数据还保证在正常运行时间的交易数据请求将会得到延缓如果开发商选择这样做。

7云计算的未来云计算可能是一些企业和消费者比较新的概念。

但是即使一些企业刚开始采用,也能获益于云计算的优势。

很多行业巨头都已经开始期待着下一个云计算阶段。

云计算的未来应高度考虑在任何行业的企业。

云计算的能够完全适应任何一个行业的可能性正在慢慢开始出现。

如果一个企业不考虑在云计算时代的未来,面临的挑战以及云计算的优势可能无法得到合理和充分利用。

Cloud C omputing-The Emerging Technology of C omputingPratima Manhas,Shaveta ThakralECE Dept,Manav Rachna International,University(MRIU),Faridabad,IndiaABSTRACT:Cloud computing is a general term for anything that involves 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).The name cloud computing was inspired by the cloud symbol that's often used to represent the Internet in flowcharts and diagrams.It is the5th generation of computing after mainframe,personal computer,client server computing and the web.In this certain application,limitation and future scope of this technology was discussed.KEY WORDS:Cloud computing,IaaS(Infrastructure-as-a-Service),PaaS(Platform-as-a-Service),SaaS (Software-as-a-Service)1IntroductionA cloud service has three distinct characteristics that differentiate it from traditional hosting.It is sold on demand,typically by the minute or the hour;it is elastic--a user can have as much or as little of a service as they want at any given time;and the service is fully managed by the provider(the consumer needs nothing but a personal computer and Internet access).Significant innovations in virtualization and distributed computing,as well as improved access to high-speed Internet and a weak economy,have accelerated interest in cloud computing.A cloud can be private or public.A public cloud sells services to anyone on the Internet.(Currently, Amazon 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.Private or public,the goal of cloud computing is to provide easy,scalable access to computing resources and IT services[1].Infrastructure-as-a-Service like Amazon Web Services provides virtual server instances with unique IP addresses and blocks of storage on demand.Customers use the provider's application program interface(API) to start,stop,access and configure their virtual servers and storage.In the enterprise,cloud computing allows a company to pay for only as much capacity as is needed,and bring more online as soon as required.Platform-as-a-service in the cloud is defined as a set of software and product development tools hosted on the provider's infrastructure.Developers create applications on the provider's platform over the Internet. PaaS providers may use APIs,website portals or gateway software installed on the customer's computer. ,(an outgrowth of )and Google Apps are examples of PaaS.Developers need to know that currently,there are not standards for interoperability or data portability in the cloud.Some providers will not allow software created by their customers to be moved off the provider's platform.In the software-as-a-service cloud model,the vendor supplies the hardware infrastructure,the software product and interacts with the user through a front-end portal.SaaS is a very broad market.Services can beanything from Web-based email to inventory control and database processing.Because the service provider hosts both the application and the data,the end user is free to use the service from anywhere.2Benefits of Cloud Computing(a)Minimized Capital expenditure(b)Location and Device independence(c)Utilization and efficiency improvement(d)Very high Scalability(e)High Computing powerA.VendorPerspectiveEasier for application vendors to reach new customers(a)Lowest cost way of delivering and supporting applications(b)Ability to use commodity server and storage hardware(c)Ability to drive down data center operational cots(d)In one word:economics3Barriers to Cloud ComputingA.Customer Perspective(a)Data Security(b)Many customers don’t wish to trust their data to“the cloud”(c)Data must be locally retained for regulatory reasons(d)Latency(e)The cloud can be many milliseconds away(f)Not suitable for real-time applications(g)Application Availability(h)Cannot switch from existing legacy applications(i)Equivalent cloud applications do not existNot all applications work on public clouds4Architecture of cloud computingCloud computing architecture and its implementation is strongly defined by the Unix Philosophy.It’s basically a set of rules and principles that developers would have to follow to ensure that cloud computing would be easily implemented and the application would be for the advantage of the user.Although there are many definitions,rules and principles for Unix Philosophy,they all point out to one belief:build one thing and make sure it works consistently.Through the Unix Philosophy,developers who design the architecture for cloud computing have to remember that they there only to support only one application or at least an output. Cloud computing could be composed of different stages but these stages are geared towards the consistent computing of the online application.Keeping up with the demands of the application is the data centers and server farms.It could be said that too much hardware could be used to support a single process but these are implemented to ensure that theapplication would have as many back-up plans as it could have.Applications from cloud computing is also implemented with the thought of consistent security and performance monitoring.Through proper implementation of cloud computing architecture,the application will be accessible24/7with a new100% uptime for their users.5Security on cloud computingSecurity is one of the biggest concerns of businesses in any form.Whether a business is a small brick-and-mortar or a multi-million online ventures,security should be implemented.Exposing the company to different security flaws is always inviting to different elements with malicious intent.A single security strike could mean millions of dollars for businesses and might single handedly close the business down.Proper implementation of security measures is highly recommended for cloud computing[3].The mere fact that the application is launched through internet makes it vulnerable to any time of attack[3].An application available in LAN(Local Area Network)only could even be infiltrated from the outside so placing an application over the internet is always a security risk.This is the unique situation of cloud computing. Implementation of cloud computing could require millions of dollars in infrastructure and applications development but it still places itself at risk for different types of attacks.A.Protecting the UsersAbove everything else,cloud computing or any type of online application format should consider protecting its users.Developers should make sure that data related to the user should not be mishandled and could be extracted just by one.There are two ways to ensure cloud computing security:restrictive user access and certifications.(i)Restrictive access could come from simple username/password challenge to complicated CAPTCHA log in forms.But applications in cloud computing should not only base itself on these challenges.IP specific applications and user time-outs are only some of the security measures that should be implemented.The challenge in restrictive user access is to limit the access privilege of the user.Each user will have to be assigned manually with security clearance to ensure limitation of access to different files.(ii)Certifications are also important for user certification.Developers have to open their application to security specialists or companies that provide certifications for security.This is one way of assuring users that the application has been fully tested against different types of attacks.This is often the dilemma for cloud computing as external security checks might open the company secrets on cloud computing.But this has to be sacrificed to ensure the security of their users.B.Data SecurityAside from user protection against different types of attacks,the data itself should be protected.In this aspect,the hardware and software linked to cloud computing should be scrutinized.Again,a certification is highly desired in this part of cloud computing.The hardware component for cloud computing on the other hand requires a different type of security consideration.The location of data center should not only be selected because of its proximity to controllers and intended users but also on its security(and even secrecy)from external problems.The data center should be protected against different types of weather conditions,fire and even physical attacks that might destroy the center physically.With regards to the hardware component in relation to the application,certain manual components have to be available for increased security.Among them is manual shutdown to prevent further access of the information.Although data could be controlled with another application that data could be infiltrated unless the application is shutdown immediately.C.Recovery and InvestigationCloud computing security should not only focus itself on prevention.Ample resources should also be focused on recovery if the unfortunate event really strikes.Even before disaster happens,certain plans have to be in place to ensure that everyone will be working in unison towards recovery.The plans do not have to be focused on software attacks alone–certain external disasters such as weather conditions should have separate recovery plans.When everything has been recovered,developers and the company handling the application should have the means to investigate the cause of the problem.Through investigation,certain conditions that lead to the event could be realized and insecurities could be discovered.Even legal actions could be done if security has been breached on purpose.Security is one of the most difficult task to implement in cloud computing.It requires constant vigilance against different forms of attacks not only in the application side but also in the hardware components.Attacks with catastrophic effects only needs one security flaw so it’s always a challenge for everyone involved to make things secured.6Challenges in cloud computingThe challenge for applications in cloud computing is largely based on the number of requests the application could handle[2].Although this factor could be highly suggested by the data center,the application will usually have a threshold if they are not properly written.To deal with this concern,developers use metadata to enable personalized services to their users as well as data processing.Through metadata,individualized requests will be entertained and will be properly implemented.Metadata also ensures uptime of transaction as data requests will be slowed down if the developer chooses to do so.7Future of cloud computingCloud computing may be a relatively new concept for some businesses and consumers.But even though some businesses are only starting to adopt and realizing the advantages of cloud computing,industry giants are already looking forward to the next big step of cloud computing.The future of cloud computing should be highly considered by businesses in any industry.The possibility of full adaptation of cloud computing by almost any industry is slowly starting to happen.If a business will not consider their future in cloud computing,the challenges as well as the advantages of cloud computing may not be addressed and fully harnessed.References[1]Toby Velte,Anthony Velte,Robert Elsenpeter.“Cloud Computing,A Practical Approach”,Mcgraw-Hill Education,2009.[2]Ronald Krutz and Russell Vines.“Cloud Security:A Comprehensive Guide to Secure Cloud Computing”, Wiley Publishing Inc,2010.[3]John Rittenhouse and James Ransome.“Cloud Computing:Implementation,Management,and Security”, CRC Press2010.。

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