Cloud computing is a fast-growing technology that provides hard- ware, networks, storage, services and interfaces as a service through a network (Miller, 2008). The utilities are provided either as separate components or as a complete platform to meet the user's demand. Thus, cloud users enjoy all the computing components as a service, instantly and dynamically. The key char- acteristics of cloud computing include on-demand self-service, ubiquitous net- work access, location and device independence, rapid elasticity and pay-per-use (Shroff, 2010). This chapter discusses the basic concepts of cloud computing and outlines the motivation for this thesis.
PRELIMINARIES
When cloud compting originated, it targeted only three major services (Leavitt, 2009): Software-as-a-Service (SaaS), Platform-as-a-Service (PaaS), Infrastructure-as-a-Service (IaaS). In recent times, this has become a myth with anything being provided as a service i.e. XaaS has dawned. However, IaaS and SaaS have still not lost their place as IaaS practically provides every comput- ing resource and gives users the ability to perform any task without any physical resource from their side whereas SaaS attracts users by providing them with soft- wares to perform any task, giving them a lot of leisure time by saving the time taken for developing such softwares. The following subsections highlight the concepts of cloud computing which are necessary for understanding the work in this thesis.