1. Lecture 9: What is cloud computing Chapter 1 of the Second Reference Book

2. Significance of Cloud Computing A research from IDC predicts that the cloud will generate nearly 14 million new jobs worldwide by 2015 [TopStories at Microsoft.com, March 5, 2012].

3. In the state of Georgia, Silver lining, a cloud computing company is in the process of adding 900 new jobs in Atlanta [Atlanta Business Chronicle, Feb. 1, 2013]

4. Defintion of Cloud Computing In a simplest sense, Cloud represents a network and, more specifically, the global Internet Cloud Computing is the use of computational resources that are hosted remotely and delivered through the Internet

5. There are many definitions of Cloud Computing. (e.g., definition by Gartner, Forrester, Wikipedia, the 451 Group, Nist)

6. Definition by NIST Cloud Computing is a model for enabling convenient, on-demand network access to a shared pool of conifgurable computing resources (e.g., networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction.

7. None of the definitions is universally accepted. Each definition emphasizes some aspects of cloud computing, but do not provides a complete description.

8. Why using “cloud” In order to understand cloud computing, one obvious place to start is the cloud metaphor itself. Why we don’t call it forest computing or ocean computing.

9. A cloud has long been used in network diagrams to represent a sort of black box where the interfaces are well known but the internal routing and processing is not visible to the network users. A cloud, by nature, is opaque A could is typcially very large and distant. Furthermore, clouds may be overlapping; they may dynamically intersect or split.

10. Key attributes of cloud computing Off-Premise Elasticity Flexible billing Virtualization Service delivery Universal access Simplified management Affordable resources Multi-tenancy Service level management

11. Key attributes of cloud computing Off-Premise: the service is hosted and delivered from a location that belongs to a service provider. - The service is deliverred over the public Internet - Computing processes occure outside the company firewall.

12. Elasticity: cloud computing provides an elastic provisioning mechanism for resource allocation, so that resources can be scaled both up and down very rapidly on demand.

13. Flexible Billing: Cloud computing typically charges users by fine-grained metering of resource usages.

14. Virtualization: cloud services are usually offerred through an abstracted infrastructure, which leverage various virtualization mechanisms.

15. Service delivery: cloud functionality is often available as a service. Typically the services offer programmatic interfaces in addition to the user interfaces.

16. Universal access: Pooled resources are available to anyone authorized to utilize them; Location independence and high levels of resilience allow for an always connected user experience.

17. Simplified management: - Administration is simplified through automatic provisioning to meet scalability requirements; - user self-service expedites businesss process; - programmatically accessible resources facilites integration into enterprise management frameworks

18. Affordable resources: The cost of resources is dramatically reduced for two reasons: - From the user side, there is no requirement for captial expenditures on fixed purchases - From the service provider side, the economy of scale of the service providers allow them to optimize their cost structure with commodity hardware and fine-tuned operational procedures that are not easily matched by most companies.

19. Multi-tenancy: The cloud is used by many organizations (tenants). It can protect and isolate each tenant from all others.

20. Service-level management: Cloud services typically offer a service-level definition that sets the expectation with the customer as to how robust that service will be.

21. Related Concepts Service-oriented architecutre (SOA) Grid computing Web 2.0

22. Service-oriented architecture (SOA): SOA decomposes the information technology landscape of an enterprise into loosely coupled functional primitives called services. These services implement single actions and may be used by many different business applications.

23. SOA and Cloud Computing are two independant notions. - SOA is an architecture, which is technology independent. Cloud computing can be a good means of implementing a SOA design

24. Grid Computing: It refers to the use of many interconnected computers to solve a problem through highly parallel computaiton. There are conceptual similarity between grid and cloud computing. - Both involve large interconnected systems of computers - distribute their workload - blur the line between system usage and system ownership.

25. There are also distinctions between these two computing models - Grid computing is typically used in scientific environment where a job typically requires a huge number of computer processing cycles. It allocates resources in a bath mode. - Cloud computing is typically process many small tasks simutaneously. It uses real-time resource allocation.

26. Web 2.0: It refers to the web as not only a static information source for browser access but a platform for web-based communities to facilitate user participation and collaboration. There is no intrinsic connection between cloud computing and web 2.0. - Cloud computing is a means of delivering services - Web 2.0 is a class of services that may be deliverred in many different ways.

27. History of cloud computing Amazon was arguably the first company to offer an extensive and thorough set of cloud- based services. Why it is Aamzon?

28. Amazon started as an online book store in 1995. It later diversified its product portfolio to include a wide range of categories. It also brokered transactions for fee and developed a successful ecosystem of partnership.

29. As Amazon grew, it had to invest larger and larger data center to support its business. Its data center was provisioned to guarantee the computing capacity in holiday season. However, this overprovisioning resulted in the idle of a major share of its data center for 11 out of 12 months.

30. In order to turn their weakness into an opportunity, Amazon lanuched Amazon Web Services that sold some of their idle capacity to other organizations. Organizations can take advantage of Amazon’s secure and reliable infrastructure at reasonable prices without making any financial and strategic commitment.