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Platform as a service (PaaS) is a category of cloud computing services that provides a platform allowing customers to develop, run, and manage web applications without the complexity of building and maintaining the infrastructure typically associated with developing and launching an app.〔Brandon Butler, (“PaaS Primer: What is platform as a service and why does it matter?” ) ''Network World'', February 11, 2013.〕〔(“Understanding the Cloud Computing Stack: SaaS, PaaS, IaaS,” ) Rackspace, October 22, 2013.〕〔William Y. Chang, Hosame Abu-Amara, Jessica Feng Sanford, ''(Transforming Enterprise Cloud Services )'', London: Springer, 2010, pp. 55-56.〕 PaaS can be delivered in two ways: as a public cloud service from a provider, where the consumer controls software deployment and configuration settings, and the provider provides the networks, servers, storage and other services to host the consumer's application; or as software installed in private data centers or public infrastructure as a service and managed by internal IT departments.〔Judith Hurwitz, Marcia Kaufman, Fern Halper and Dan Kirsh, (“What Is Platform as a Service (PaaS) in Cloud Computing?” ) ''Hybrid Cloud For Dummies'', Hoboken, NJ: John Wiley & Sons, 2012.〕〔(【引用サイトリンク】url=http://csrc.nist.gov/publications/nistpubs/800-145/SP800-145.pdf )〕 ==Development and uses== Fotango, a London (Old Street) based company owned by Canon Europe launched the world's first public platform as a service known as 'Zimki'. Developed in 2005 with a beta launch in March 2006 and a public launch at EuroOSCON in 2006.〔Zimki, hosted JavaScript environment, http://radar.oreilly.com/2006/09/zimki-hosted-javascript-enviro.html〕 Zimki was an end to end JavaScript web application development and utility computing platform that removed all the repetitive tasks encountered when creating web applications and web services. All aspects of infrastructure and operations from setting up servers, scaling, configuration, security and backups were done automatically by Zimki. Zimki introduced the tagline 'Pre-Shaved Yaks' 〔What is a pre-shaved Yak, https://www.flickr.com/photos/zimki/243779431/in/photostream/〕 to describe the removal of all these repetitive tasks.〔Pre Shaved Yaks, http://archive.ianwinter.co.uk/2007/09/25/zimki-is-no-more/〕 Zimki was a pure play 'pay as you go' platform which enabled developers to build and deploy applications without incurring any start-up costs on a true utility based computing platform. Charging was done on storage used, network traffic and JSOPs (Javascript Operations). It provided a multi-tenant platform where developers created entire applications (front and back end through SSJS) using a single language - Javascript, with all development, billing, monitoring and application control exposed through APIs〔Fotango Opens its APIS, http://www.prnewswire.co.uk/news-releases/fotango-opens-its-zimki-customer-api-153777895.html〕 and a range of component services from a NoSQL object store to Message Queue services.〔Fotango Opens its Zimki Customer API, http://www.prnewswire.co.uk/news-releases/fotango-opens-its-zimki-customer-api-153777895.html〕 Furthermore, all functions within Zimki could be exposed as web services and Zimki provided billing analysis down to individual functions. Whilst the Zimki platform was rapidly growing and Fotango was profitable, the parent company decided this area was not core 〔A personal journey, http://blog.gardeviance.org/2009/04/there-and-back-again-personal-journey.html〕 and the service was closed in Dec 2007.〔Zimki Shuts Down, http://blog.gerv.net/2007/09/zimki_shuts_down/〕 At the time of its closure, Zimki had several thousand developer accounts and had demonstrated the technical viability of Platform as a Service but also provided the first example of the perils of being dependent upon a single provider.〔Zimki closure shows the perils of hosted web platforms, http://www.itwriting.com/blog/337-zimki-closure-shows-the-perils-of-hosted-web-platforms.html〕 This risk had been highlighted in July 2007, when the CEO gave a presentation on Zimki at OSCON 2007 which announced that Zimki would no longer be open sourced and discussed the future of what was then called Framework as a Service (later renamed to Platform as A Service) covering the importance of a market of providers based upon an open source reference model 〔OSCON Keynote 2007, http://mais.uol.com.br/view/v1xaxe2lamb3/oscon--commoditisation-of-it-and-what-the-future-holds-0402D4B10386?types=A〕 In April 2008, Google launched App Engine, with a free trial version limited to 10,000 developers.〔Jack Schofield, (“Google angles for business users with ‘platform as a service’,” ) ''The Guardian'', April 16, 2008.〕 This was said to have "turned the Internet cloud computing space into a fully-fledged industry virtually overnight."〔Dion Hinchcliffe, (“Comparing Amazon’s and Google’s Platform-as-a-Service (PaaS) Offerings,” ) ZDNet, April 11, 2008.〕 The original intent of PaaS was to simplify the code-writing process for developers, with the infrastructure and operations handled by the PaaS provider. Originally, all PaaSes were in the public cloud. Because many companies did not want to have everything in the public cloud, private and hybrid PaaS options (managed by internal IT departments) were created.〔Mike Kavis, (“Top 8 Reasons Why Enterprises Are Passing On PaaS,” ) ''Forbes'', September 15, 2014.〕 PaaS provides an environment for developers and companies to create, host and deploy applications, saving developers from the complexities of the infrastructure side (setting up, configuring and managing elements such as servers and databases). PaaS can improve the speed of developing an app, and allow the consumer to focus on the application itself. With PaaS, the consumer manages applications and data, while the provider (in public PaaS) or IT department (in private PaaS) manages runtime, middleware, operating system, virtualization, servers, storage and networking.〔〔Sean Ludwig, (“An ugly duckling no more: Why Platform-as-a-Service is poised for huge growth,” ) VentureBeat, October 8, 2012.〕 Development tools provided by the vendor are customized according to the needs of the user.〔Andrea Peiro, (“Keep Your Head in the Cloud,” ) ''Inc.'', January 2009.〕 The user can choose to maintain the software, or have the vendor maintain it.〔 PaaS offerings may also include facilities for application design, application development, testing and deployment, as well as services such as team collaboration, web service integration, and marshalling, database integration, security, scalability, storage, persistence, state management, application versioning, application instrumentation, and developer community facilitation. Besides the service engineering aspects, PaaS offerings include mechanisms for service management, such as monitoring, workflow management, discovery and reservation.〔M. Boniface, (“Platform-as-a-Service Architecture for Real-Time Quality of Service Management in Clouds,” ) ieee.org, May 2010.〕〔Chen, Tse-Shih, et al. "Platform-as-a-Service Architecture for Parallel Video Analysis in Clouds." Advances in Intelligent Systems and Applications-Volume 2. Springer Berlin Heidelberg, 2013. 619-626.〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「platform as a service」の詳細全文を読む スポンサード リンク
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