Cloud Computing is emerging as a promising cost efficient computing paradigm which professionals believe is an absolutely new trend and will represent next level of internet evolution. Though the presence of Cloud computing is ubiquitous, it still lacks consensus on a proper definition and classification of the major Clouds in effect today. It also suffers from major criticism of being a hype/fad and some researchers claim that it is just an extension of already established computing paradigms. This chapter attempts to deal with such criticisms by comprehensively analyzing the Cloud definitions and diagnose the components of the same. It performs a comprehensive study of more than 30 definitions given by Cloud computing professionals and published in research papers. These definitions are then analyzed under more than fifteen components, each of which is discussed in the chapter. This study is backed by empirical work, to understand Cloud computing from different angles and come up with a comprehensive definition. It also analyses the present Cloud service providers and the level of services they provide to bring about a clear picture of Cloud computing. Based on the comparison, the pending issues in Cloud computing are discussed.
TopIntroduction
With Gartner predicting the Cloud computing market to reach $150.1 billion in 2013, the entire IT industry is looking upon Cloud computing as the most powerful computing paradigm of the future. The growing complexity of the computational world in terms of processing large volumetric data resulted in a need of a cost-efficient model that could support the processing using clusters of commodity computers. Cloud computing has evolved as a computing paradigm to support such data processing. According to Dean and Ghemawat (2008), Google maintains more than 20 terabytes of raw web data which is quite tough to process using distributed computing. Cloud computing can handle massive data at this level and render services on the demand using pay-for-use models.
Put in simple terms, the concept of Cloud computing is that computing resources will reside somewhere other than the computer room and that the users will connect to it using the resources as and when required. In effect, it displaces the infrastructure to the network so that the overall cost with respect to the management of hardware/software resources is reduced (Hayes, 2008). It appears to be highly disruptive technology (Bhaskar et al., 2009) hinting to the future where computation moves from local computers to centralized facilities operated by third party compute and storage utilities (Foster et al., 2008).
Many argue that Cloud computing is not a new paradigm and that its concept is based upon some already known and established computing paradigms. It is argued that way back in 1961, it was predicted by John McCarthy that “computation may someday be organized as public utility”. It is said also that Cloud computing draws on basic concepts of virtualization, utility computing or distributed computing (Aaron, 2007; Kai, 2008; Dejan, 2008). This chapter tries to understand all aspects related to Cloud computing and understand how it is different from the existing paradigms.
Variety of technologies related to Cloud computing makes the overall concept a very confusing one (Kai, 2008). There is a little consensus on the definition of Cloud computing (Foster et al., 2008) and the confusion about the term makes it a general term for any solution that allows outsourcing concerning the infrastructure and all kinds of hosting (Luis et al., 2009). Also, it is well known fact that Cloud computing is not the first technology that has come under criticism of being a buzzword/hype. According to Gartner’s Hype Cycle (Gartner, 2008) technology evolves from over-enthusiasm through a period of disillusionment to a gradual understanding of technology relevance and the role in a market/domain. It can be clearly seen that Cloud Computing falls in the first stage of the hype cycle which is termed as positive hype. To avoid confusion resulting from this stage, this study attempts to diagnose Cloud computing and to bring out all possible associated aspects.
A clear analogy of Cloud computing can be drawn with Grid computing which faced the same issue of lack of a crisp definition. There were some accepted definitions like Foster (Foster et al., 2001; Foster et al., 2002), according to which the aim of Grid computing was to enable resource sharing and coordinated problem solving in dynamic, multi-institutional virtual organizations. However, there was no consensus on the same. Grid computing as a paradigm can also be observed under Gartner’s Hype cycle. Figure 1 reveals the popularity of Cloud and Grid computing in terms of the number of searches being made worldwide.
Figure 1. Google search trends for grid computing and cloud computing