Introduction

Abstract

Over the past few years, cloud computing has been receiving much attention as a new computing paradigm for providing flexible and on-demand infrastructures, platforms and software as services. Cloud computing has emerged as a result of combining the benefits of grid computing with those of service-oriented computing to utilize computer resources (data centers) and deliver computer resources as services. In the case of grid computing, computer hardware resources are combined from several organizations to achieve a certain goal (e.g., high performance and reduced costs), while in the case of service-oriented computing, computer software resources are designed and governed in the form of services. With cloud computing, computer resources are designed and governed in the form of services using virtualization techniques (e.g., the creation of virtual instances of the hardware platform, the operating system or the storage of network resources) to automate business logics since distributed systems are available for both public and private sectors. Cloud environments promise several benefits such as reduced expenses and simplicity to service providers and consumers. For instance, it only took 24 h, at the cost of merely $ 240, for the New York Times to archive its 11 million articles (1851–1980) using a cloud service named Amazon Web Services.