Despite these concerns however the world's largest companies still actively promote and routinely hype the value of cloud computing without mentioning the myriad of risk associated with this platform, despite its continual maturation from a security and stability standpoint .
An example of this is type of hype is when Microsoft's Steve Balmer described cloud computing as the next frontier and Dr. Ajei Gopal verified that the cloud is there to alter everything. Joe Tucci, the CEO of EMCCorp described the impact of cloud computing as "We're now going through what I believe is pretty much going to be the biggest wave in the history of information technology." These claims of corporate executives must be balanced against reality and the fact that these platforms require a continual focus on quantifying and validating trust on the one hand  and designing the systems to ensure a higher level of content agility and flexibility on the other . The National Institute of Standards and Technology (NIST) defined cloud computing as a model for allowing "convenient on-demand network access to a shared collection of customizable resources such as services, storage, applications, networks and servers that can be quickly provided and issued with minimal management effort or interaction with service provider.
Cloud computing history began in the nineties through the development of World Wide Web. Using the Mosaic browser, internet-based computing started. Using a business perspective, it provided virtual shopping experience and chain integration. The aspect of e-business obtained a foothold in almost any company. As a significant side-effect, users became used to this leading-edge technology whilst seeking for information, performing online shopping, chatting with family and family, watching movies online or handling bank accounts. The following generation of cloud services was inspired by consumer experiences, accessible 24/7, an intuitive user interface that does not need training and comprehensive self-services from opening a new back account to purchasing holiday packages. Technology changed to produce a comprehensive interactive web interfaces and service-to-service interaction. It also went far beyond business applications and this includes social networks and collaboration tools. This clearly changed the way business people acquire and share information while some companies including Amazon and Google took advantage of such trends through offering their storage and computing capacity to consumers and business users.
As of today, the attention surrounding cloud services in the company focuses on these forms of techniques and sourcing alternatives for IT capabilities -- IT as a service. Through the use of standardized, highly virtualized infrastructure and applications, this new strategy can encourage higher degrees of consolidation which reduce costs.
2.0 Cloud Models
3.1 Cloud Delivery Models
When people hear the word "cloud computing," things that come first to their mind are the giants such as Amazon, Google, Twitter, YouTube, Facebook and Salesforce.com. They are called public cloud because they are providing resources for free or rent. This also includes storage capacity and increasing array of business applications and services. Learning the differences between the private, public and hybrid model as well as community cloud is a common method of understanding the cloud.
Private Cloud: a specific organization solely operates their respective private clouds. It can be maintained by the organization itself or by a third party, which means it could be on premise or off premise. On premise means that the owner is based inside the office of the organization and their private cloud is maintained by their own IT staff. The organization has the complete control over the infrastructure, data center and services. Off premise is based outside the organization, taking advantage of the expertise of the third party provider such as hosting facility. Off-premise approach is for those organizations that do not have needed expertise or resources to build and maintain their own data center. One good example of private cloud is Microsoft Private Cloud. In addition, private cloud, whether off-premise or on-premise is entirely dedicated to the needs of the organizations and not of the public. Another difference between large-scale corporate data centers and private clouds is in terms of governance model. The cloud model recognizes that the customers are actually the "business." The risks associated with the operation are in the IT side rather than the business idea. The new challenge here for the IT is not only the cost center but as