Cloud computing, which was coined in late 2007, currently emerges as a hot topic due to its ability to offer flexible dynamic IT infrastructures, services and most of all innovative platforms to develop applications. Amazon, Google, Microsoft and several other organizations played a key role in the development of cloud computing by modernizing their data centers after the dot-com bubble, having found that the new cloud architecture emerged as an essential internal performance enhancement. Cloud computing is a term adopted to represent both a platform and type of application. A cloud computing platform dynamically provisions, configures, reconfigures servers as needed through virtualization, or virtual machines (VMs).

Virtualization, or virtual machines (VMs), is a method for creating one computer into many. It offers web applications, such as a contact manager for sales, a document manager for storage, version tracking of files, workspaces for sharing information over the Internet, and project management software. Moreover, organizations with extensive batch-oriented responsibilities can get returns as promptly as their programs can scale. This flexibility and agility of resources, without spending the expense for large scale, is unique in the history of information technology and only provided by cloud computing.

The Innovative Computing Technology - Cloud Computing

Basically, in a simple sense, cloud computing can be said as using the internet to access someone else's software running on someone else's hardware in someone else's datacenter. Cloud computing commits to utilizing computing resources that are otherwise owned and provided by a third-party provider. They feature on-demand provisioning and pay-as-you-go resource billing, with minimal up-front investment. It is focused on providing cost-effective computing power over the internet, including virtual private networks (VPN). From the perspective of a reasonable cloud proponent, cloud services minimize the capital expense of computing, tie operating expense to actual use, and reduce staffing costs.

The Cloud Deployment Models

Public cloud: Public cloud or external cloud describes cloud computing in the traditional mainstream sense, whereby resources are dynamically provisioned on a fine-grained, self-service basis over the internet, via web applications/web services from an off-site third-party provider who bills on a fine-grained utility computing basis. The cloud infrastructure is made available to the general public or a large industry group and is owned by an organization selling cloud services. Examples: Amazon Elastic-Compute-Cloud, IBM's Blue- Cloud, Sun Cloud, Google AppEngine.

Community cloud: A community cloud may be implemented where numerous organizations have related specifications and attempt to share infrastructure. With the expenses expanded over more infrequent users than a public cloud (but more than a single tenant) this prospect is more expensive but may contribute a higher level of privacy, or policy compliance. Examples of community cloud include Google’s "Gov Cloud".

Hybrid cloud: The term "Hybrid Cloud" has been utilized to join two separate clouds together (public, private, internal or external), or a fusion of virtualized cloud server examples used concurrently with physical hardware. The common definition of the term "Hybrid Cloud" is presumably the application of physical hardware and virtualized cloud server examples collectively to produce a single shared service. Two cloud models that have been combined are more accurately called a "combined cloud". A hybrid storage cloud uses a blend of public and private storage clouds. Hybrid storage clouds are usually beneficial for archiving and backup purposes, enabling local data to be replicated in a public cloud.

Private cloud: A private cloud is a critical model of cloud computing that includes a well-defined and secure cloud-based environment in which only the particularized client can operate. As with other cloud models, private clouds will present computing power as a service within a virtualized environment using underlying provisions of physical computing resources. However, under the private cloud model, the cloud (the pool of resources) is only accessible by a single organization providing that organization with greater control and privacy.

How Can Enterprises Choose The Right Cloud Deployment Model

Available Budget for Service Deployment Model: Available additional budget for deploying a particular service delivery model: public, private, hybrid, or community. The three scale measures are Low (Limited funds available), Medium (Adequate funds available), and High (Abundant funds available).

Required Level of Data Privacy and Security: Level of data privacy and security, needed by the organization adopting cloud computing. The three scale measures are: Low (little need for data privacy and security), Medium (moderate need for data privacy and security), and High (much need for data privacy and security).

Required Level of User Control: Degree of control to manage a particular cloud service needed by the organization adopting cloud computing. The three scale measures are: Low (little need for managing the service by the user), Medium (moderate need for managing the service by the user), and High (much need for managing the service by the user).

Level of Industry Integration: Level of integration with business partners, needed by the organization adopting cloud computing. The three scale measures are Low (little integration with business partners), Medium (medium integration with business partners), and High (high integration with business partners).

Further, before developing an appropriate set of rules of expertise of the knowledge domain, the authors chose six types of commonly required services (RS) for which a decision of the appropriate service delivery and deployment models is needed. The chosen six types of required services are:

• Readymade Software (RMS): Standard software such as email system, payroll application, ERP system, etc.
• Custom Developed Software (CDS): Any software with nonstandard requirements that an organization wishes to build. For example, a decision support system to support customer services.
• Web Hosting (WH): Hosting and maintaining an organizational website.
• Data Storage (DS): Storage of any kind of organizational data for backup and recovery, archiving, document management, etc.
• Network Server (NS): A computer server used for storing and running databases, mail, or business applications.
• Computer Network (CN): A computer network used for establishing an intranet and/or extranet. According to Merritt (2004), it is possible in certain cases to fit logical relationships (rules of expertise) into a database, if one can structure these relationships in a tabular format.

Cloud computing is a developing computing standard that is increasingly adopted because of the multiple benefits and use cases. Prominent leaders in the industry, such as Google, Amazon, and Microsoft have contributed their leadership in developing cloud computing. But still, there are many questions have left without an answer and indeed the most important one is security. IT technicians are spearheading the challenge, while academia is a bit slower to react. There are several groups out there, such as the Cloud Security Alliance or the Open Cloud Consortium, which was formed to explore the opportunities offered by cloud computing. This is because new technologies and abilities may result in additional development of the cloud computing model. From cloud deployment models to three cloud service models, there is always something about the cloud that pushes organizations to adopt cloud and enhance their operations.