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1、Cloud computing for education: Anew dawn?AbstractEducational establishments continue to seek opportunities to rationalize the way they manage their resources. The economic crisis that befell the world following the near collapse of the global financial system and the subsequent bailouts of local ban
2、ks with billions of tax payerswill continue to affect educational establishments that are likely to discover that governments will have less money than before to invest in them. It is argued in this article that cloud computing is likely to be one of those opportunities sought by the cash-strapped e
3、ducational establishments in these difficult times and could prove to be of immense benefit (and empowering in some situations) to them due to its flexibility and pay-as-you-go cost structure. Cloud computing is an emerging new computing paradigm for delivering computing services. This computing app
4、roach relies on a number of existing technologies, e.g., the Internet, virtualization, grid computing, Web services, etc. The provision of this service in a pay-as-you-go way through (largely) the popular medium of the Internet gives this service a new distinctiveness. In this article, some aspects
5、of this distinctiveness will be highlighted and some light will be shed on the current concerns that might be preventing some云计算在教育中的应用迎来新的曙光摘要: 教育机构一直在寻找如 何更加合理的管理教学资源。经济 危机使全球经济系统临近瓦解,随 后地方银行使用纳税人数以亿计的 钱对其支援,随之而来的是教育机 money 构发觉政府对其的投资比之前要缩 减。本文要论述的是在这样的困难 时期,对于缺乏现金支持的教育机 构来说,云计算有可能成为其寻找 的机会之一,它的弹性
6、和按需支付 的费用结构将给教育机构带来巨大 的经济利益(在授权的情况下) 。云 计算是为交付计算服务提供的一种 新型计算规范。这种计算方法依赖 于大量的现存技术, 例如,互联网、 虚拟化、网格计算、Web 服务等等。 按需支付服务通过大量通用的互联 网媒介给这项服务赋予一种新的特 殊性。在本文中,这种特殊性的一 些方面将重点强调,并说明了涉及organizations from adopting it.Keywords: Cloud computing Web services Virtualization Grid computing Small and medium enterprises
7、 (SMEs)IntroductionProviding software as a service is not a new computing practice.Some companies, known as Application Service Providers (ASPs), were providing businesses with software programs as a service via the medium of the Internet during the 1990s. However, such attempts at “ utility computi
8、ng ” did not take off. This was largely attributed to lack of sufficient bandwidth. During that period broadband was neither cheap nor plentiful enough for utilities to deliver computing services with the speed and reliability that businesses enjoyed with their local machines (Carr, 2009). Then came
9、Web services (especially those based on the XML-based SOAP1 message protocol) that represented a model of software delivery based on the notion that pieces of software applications can be developed and then published to a registry where they can be dynamically discovered and consumed by other client
10、 applications over different transport protocols (e.g., HTTP, TCP/IP, etc.) irrespective of the language used to develop those applications or the platforms (e.g., operation systems, Internet servers) on which they are 到防止一些组织采纳它的方面。关键词: 云计算, Web 服务, 虚拟化,网格计算,中小型企业 (SMEs)1、概述 提供软件作为一种服务已不是 新的计算实践了。
11、20世纪 90 年代, 一些以应用服务供应商而著名的公 司通过互联网这个媒介将软件程序 作为一种服务开始提供。然而,并 没有脱离“效用计算”。这主要是由 于缺乏足够的带宽。当时,带宽既 不能廉价获取,也不能像企业使用 本地设备一样,满足实用工具能够 高速而可靠地传递计算服务( Carr, 2009)。随之 Web 服务(特别是基 于可扩展标记语言的 SOAP信息协 议)代表着软件应用的一部分 基于概念的软件传递模式能够得以 开发,并且基于不同传输协议 (如, HTTP, TCP/IP等)的其他客户应用程 序能够发现和使用他们,不用考虑implemented. This was a dramat
12、ic improvement over the services provided by ASPs which relied on proprietary (and hence un-portable) software.The advent of Web services promised many exciting possibilities. Some of these promised possibilities initially received a great deal of attention and were a frequent subject of media discu
13、ssions and futuristic scenarios (sometimes amounting to “ hype”) such as the ability to automate the process of discovery, binding, and invocation of Web services on the Internet without human intervention (Manes, 2004; Nakhimovsky & Myers, 2004). One technology analyst and author (David Chappell) i
14、n 2003 even doubted if there was a business case for Web services (Chappell, 2003).However, Web services are nowhere near achieving the full potential that was hoped for. Nevertheless, the technology is being implemented successfully (and commercially) by many of the big players such as eBay, Amazon
15、 and Google (Iskold, 2006). Furthermore, the technology has also created the foundation for a new Enterprise Application Integration (EAI) paradigm known 用于开发应用程序的语言或他们运 行的平台(如,操作系统,因特网 服务器)。这种信任所有 (因此包括 非便携的)软件的 ASP提供的服务 有了戏剧性的改善。Web 服务的出现使许多的不可 能变为了可能。最初这受到了大量 的关注,并成为了媒体频繁讨论的 话题,未来的情境(不排除“炒作”) 能够没
16、有人的介入因特网 Web 服 务的调用能够自动发现进程、连接 ( Manes,2004;Nakhimovsky & Myers,2004)。一个技术分析家兼作 者(David Chappel)l 2003 年甚至怀 疑是否这是一项有关 Web 服务的 商业案例( Chappell,2003)。然而, Web 服务并没有像我们 所期待的那样发挥出全部的潜力。 然而,这项技术正在被许多大的玩 家所成功的实现,例如 eBay,亚马 逊,谷歌( Iskold,2006)。此外, 技术也能够为新的企业应用集合as Service-Oriented Architecture (SOA). The exte
17、nsible XML-based nature of SOAP has enabled many organizations to expose some of their legacy and disparate systems as Web services in order to achieve total integration of their systems (Clark, 2007; Flinders, 2007; Mohamed, 2007).Most importantly, SOAP-basedWebservices arenowbeing used in the deli
18、very of some aspects of a new computing paradigm (namely cloud computing) which not only promises to deliver software remotely but also other computing-related functionality thanks also to other relatively new technologies such as virtualization2 and grid computing.3What is cloud computing? There se
19、ems to bemany definitions of cloud computing around. A study by McKinsey (the global management consulting firm) found that there are 22 possible separate definitions of cloud computing. In fact, no common standard or definition for cloud computing seems to exist (Grossman, 2009; Voas & Zhang, 2009)
20、. A more commonly used definition describes it as clusters of distributed computers (largely vast data centers and server farms) which provide on-demand resources and services over a networked medium (usually (EAI)范例打造基础,如面向服务 架构( SOA)。SOAP 可扩展的基于 XML的特性作为 Web 服务能够使许 多组织机构展示一些他们的难以维 护及不同的系统,从而达到系统的
21、完全集成( Clark, 2007;Flinders, 2007;Mohamed,2007)。最重要的是,基于 SOAP的 Web 服务用来一种新的计算模式(即云 计算)的某些方面的递送,而不仅 承诺远程递送软件,还有其他与计 算相关的功能,这便不能忽视如虚 拟化及网格计算这些新技术。2、什么是云计算? 现在似乎有许多有关云计算的 定义。 Mckinsey(一个全球企业管 理咨询公司)的一项研究发现可能 有 22 种云计算的定义。 实际上, 并 没有一个通用的标准或定义来定义 云 计 算 ( Grossman , 2009 ; Voas&Zhang,2009)。一个较为普遍 的定义将云计算描述
22、为作为分布式the Internet). The term “ cloud”was probably inspired by IT text books illustrations which depicted remote environments (e.g., the Internet) as cloud images in order to conceal the complexity that lies behind them.However, by understanding the type of services offered by cloud computing, one b
23、egins to understand what this new approach is all about. The following is a list of the three main types of services that can be offered by the cloud4:? Infrastructure as a Service (IaaS): Products offered via this mode include the remote delivery (through the Internet) of a full computer infrastruc
24、ture (e.g., virtual computers, servers, storage devices, etc.);? Platform as a Service (PaaS): To understand this cloud computing layer one needs to remember the traditional computing model where each application managed locally required hardware, an operating system, a database, middleware, Web ser
25、vers, and other software. One also needs to remember the team of network, database, and system management 计算机(大规模的数据中心和服务 器群)的集群通过网络媒介(通常 为因特网)提供按需服务的资源和 服务。“云”这个词可能是受 IT 文 字书籍的插画灵感,描述了云图远 程环境(如互联网)掩盖其背后的 复杂性。然而,了解云计算所提供的服 务类型,便可开始理解这种新方法 的全部内容。下面是云提供服务的 三种主要类型:基础设施即服务( IaaS):通 过这种方式提供产品,包括一个完 整的计算机
26、基础设施(如虚拟计算 机,服务器,存储设备等)的远程 递送(通过互联网);平台即服务 (PaaS):要想理 解云计算的这个层面,那么一方面 需要记住传统计算模型中,每个应 用程序分别负责管理的本地所需的 硬件、操作系统、数据库、中间件、 Web 服务器和其他软件。另一方面experts that are needed to keep everything up and running. With cloud computing, these services arenowprovided remotely by cloud providers under this layer;? Softwa
27、re as a Service (Saas): Under this layer, applications are delivered through themediumof the Internet as a service. Instead of installing and maintaining software, you simply access it via the Internet, freeing yourself from complex software and hardware management. This type of cloud service offers
28、 a complete application functionality that ranges from productivity (e.g., office-type) applications to programs such as those for Customer Relationship Management (CRM) or enterprise-resource management.Before proceeding any further at this stage, a word of caution is necessary. One must not assume
29、 that cloud products offered by any of the above services are likely to work out-of-the-box. In some cases they might. Google Apps, a messaging and collaboration cloud platform from Google, is probably one good example of those out-of-the-box products (even though it does require some level of confi
30、guration nevertheless). Many of the products that are offered by those three types of cloud services will require some 也要记住网络、数据库及系统管理 的专家团队,他们保证了一切都正 常建立和运转。有了云计算,云提 供商依据本层来提供这些服务; 软件即服务 (SaaS):在这一 层,应用程序作为一种服务通过互 联网这个媒介进行传递。与安装和 维护软件部同,你只要通过简单的 互联网访问,从复杂的软件和硬件 管理中解脱出来。这种云服务的类 型提供了一个整的应用程序功能, 从生产率(
31、如办公类)应用程序到 一些客户关系管理( CRM)或企业 资源管理的程序。在这个阶段进行任何一步之 前,以下的注意是十分必要的。不 必假设云产品提供上述任何一种服 务,它有可能是即开即用的。 Google 应用程序、 Google 的消息传送和合 作云平台是很好的一个即开即用产 品的例子(即使它确实需要一些配 置级别)。许多产品由三种类型的云degree of programming (by the user or indeed the cloud provider) in order to access the functionality that exists in those servi
32、ces. Cloud providers will have created their own APIs (application pro-gramming interfaces) so that software developers can use them to create client applications in order to access that functionality. Currently, some of those APIs are proprietary; an issue which will be revisited later when examini
33、ng some of the limitations of cloudcomputing. However, some are based on open source standards such as SOAP or REST .To demonstrate how those services can be utilized and the processes involved in their utilization (in a very simplified manner), a hypothetical example can be given. Take, for example
34、, a typical university with an IT infrastructure that caters for the needs of students, teaching staff and management, research staff and software developers (e.g., Web developers). As illustrated in Fig. 1, demand for IT services in this environment is directed to the IT Services Department (pictur
35、ed in the middle) whose job is to:服务提供,需要一定程度的编程(用 户或实际的云提供商)来访问现有 服务的功能。云提供商将创建他们 自己的应用程序接口,从而软件开 发者能够使用它们去创建客户端应 用程序来访问这些功能。目前,一 些应用程序接口是私有的;当测试 云计算的局限性时将重新审查的问 题。然而,一些应用程序接口是基 于开源标准的,如 SOAP和 REST。为了展示如何利用这些服务并 且了解如何利用的过程(用一个非 常简化的方式),我们给出了一个假 设的例子。例如,一个典型的拥有 IT 基础设施的大学为学生、教职工 和管理者,研究院及软件开发者提 供所需(
36、如 Web 开发商)。如图 1 所示,在这种环境下, IT 服务需求 是针对 IT 服务部门(如图中间所示) 的,他们的工作为:图 1 :一个典型大学的 IT 服务主要使用者 简图? provide students and staff with software (e.g., email accounts, operating systems, productivity applications, malware detectors and cleaners, etc.) and hardware (e.g., PCs, Servers, etc.);? provide researcher
37、s and postgraduate students with the required special software and hardware to run experiments that are likely to involve a great deal of processing and computation;? provide Web developers with the development tools needed to write and host Web applications.Many aspects of this arrangement can be m
38、igrated to the cloud as demonstrated in Fig. 2. For example, students, administrative staff and lecturers can be made to use the services of providers of SaaS and IaaS clouds. These services will be ideally accessed through thin clients.6 Any software launched by these groups of people resides on th
39、e servers of the SaaS cloud provider and is accessed online. Any requirement for disk space or additional hardware (e.g., a virtual提供给学生及教职工软件 (如,电子邮件账户,操作系统, 生产率应用程序,恶意软件监控器 及清理工具等)及硬件(如,个人 电脑,服务器等);提供给研究员及硕士研究生 所需的特殊软件和硬件,用来操作 可能包含大量的处理及计算的实 验;提供给 Web 开发商编写及 管理 Web 应用程序的开发工具。各种安排的许多方面都能够迁 移到云下,如图
40、2 所示。例如,学 生、行政人员和讲师能够使用软件 即服务及基础设施即服务类型的云 提供的服务。这些服务将理想地通 过瘦客户端进行访问。任何软件由 用户所在的 SaaS 云提供者的服务PC or a virtual Server) is executed immediately online by the IaaS cloud provider. The same situation applies to the developers category in this scenario. Developers can now use all the software they need for
41、 their development online and all the hardware for hosting their applications through a PaaS cloud provider. Finally, researchers whose projects require a great deal of processing power and/or additional server capacity can do so at the click of a button through an IaaS cloud provider.器启动,并且在线访问。任何桌
42、面和额外的硬件(虚拟个人电脑或虚拟服务器)需求由 IaaS云提供商在线即时执行。在这个方案中,相同的情况适用于开发商的策略。通过PaaS云供应商,开发者现在能在线使用所有他们开发时所需的所有软件及硬件托管他们的应用程序。最后,研究员的项目需要具有大量处 理能力和额外服务器容量,也能够 仅仅点击按钮便可从 IaaS云提供商那里获得。图 2:一个典型的大学所中使用的云计算 服务,及 IT 服务的主要使用者简图Some analysts dispute the validity of attaching the title “ new paradigm ” to cloud computing ar
43、guing that this approach is largely dependent on existing technologies and approaches such as utility computing, distributed computing and centralized data centers. Cloud computing s only innovation,一些分析家争论给云计算附上新范式”有效性,这种方式要极大的依靠现存的技术和方法,如效用计算、分布式计算和集中的数据中心。根据这种观点,云计算仅仅according to this view, is that it combines and integrates these approaches( Weinhardt, Anandasivam, Blau, & Ster, 2009).However, the notion of providing a wide array of computingrelated services on the fly on a pay-as-you-go basis opens many opportunities for the providers of
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