摘要：This paper consists of four major sections: The first section is a literature review of cloud computing and a cost model. The next section focuses on detailed overviews of cloud computing and its levels of services: SaaS, PaaS, and IaaS. Major cloud computing providers are introduced, including Amazon Web Services (AWS), Microsoft Azure, and Google App Engine. Finally, case studies of implementing web applications on IaaS and PaaS using AWS, Linode and Google AppEngine are demonstrated. Justifications of running on an IaaS provider (AWS) and running on a PaaS provider (Google AppEngine) are described. The last section discusses costs and technology analysis comparing cloud computing with local managed storage and servers. The total costs of ownership (TCO) of an AWS small instance are significantly lower, but the TCO of a typical 10TB space in Amazon S3 are significantly higher. Since Amazon offers lower storage pricing for huge amounts of data, the TCO might be lower. Readers should do their own analysis on the TCOs.
