云计算中云主机的“经济性”分析

云计算在发展初始就有专家指出其具有“经济性”的特点。云主机是云计算在基础设施即服务（1aaS）层面的典型产品，现今已经可以通过网络订购云主机的服务。通过考察一个IT项目的例子，利用亚马逊公司的云主机服务（EC2）报价作为参考，将客户自购物理服务器及使用的成本与采用云主机服务的成本进行分析和对比，使用5％的贴现率来计算该IT项目的净现值（NPV），评估自购设备和使用云主机服务的经济效果，得出在当前使用云主机服务的经济效益。

The Cost Effectiveness Analysis of Cloud Hosting in Cloud Computing

Cost effective is deemed as basic char- acter of Cloud-Computing, when Cloud-Computing emerging. Cloud hosting is a typical IaaS （Infras- tructure as a Service） layer product among Cloud- Computing architecture. This article discusses the cost of purchasing physical servers from market and the cost of renting Cloud Hosting service from Amazon. Finally it evaluates different solution and deduces economic meaning of cloud computing based on NPV result.