2. Definition
“Cloud computing is an emerging computing technology that uses the internet and central remote servers to maintain data and applications”.

3. The underlying concept of cloud computing dates back to 1960, when John McCarthy opined that "computation may someday be organized as a public utility"; indeed it shares characteristics with service bureaus that date back to the 1960s.
The actual term "cloud" borrows from telephony in that telecommunications companies, who until the 1990s primarily offered dedicated point-to-point data circuits, began offering VIRTUALPRIVATE NETWORK (VPN)´ services with comparable quality of service but at a much lower cost.

4. The cloud symbol was used to denote the demarcation point between that which was the responsibility of the provider from that of the user. Cloud computing extends this boundary to cover servers as well as the network infrastructure.
Cost is claimed to be greatly reduced and capital expenditure is converted to operational expenditure. Device and location independence enable users to access systems using a web browser regardless of their location or what device they are using

5. In General
An Internet based Computing environment where you pay only for resources that you use
A set of pooled computing resources delivered over the internet
Resource allocation can be adjusted

6. Cloud Computing Defined
In its simplest form, cloud computing consists of shared computing resources that are virtualized and accessed as a service, through an API.
The cloud enables users in an organization to run applications by deploying them to the cloud, a virtual datacenter.

7. The physical resources may reside in a number of locations inside and outside of an organization: on local hardware, in an enterprise data center, or at remote or managed service providers on a pay-to-use basis.
Cloud computing resources are offered as a service on an as-needed basis, and delivered by IP-based connectivity, providing highly scalable, reliable on- demand services with agile management capabilities.

8. Cloud Application Characteristics
Because cloud computing is related to a number of other technologies, it is best defined by the presence of a number of characteristics. These represent ideals that people want for the applications that run on the cloud:
Incremental Scalability. Cloud environments allow users to access additional compute resources on-demand in response to increased application loads
Agility. As a shared resource, the cloud provides flexible, automated management to distribute the computing resources among the cloud's users.

9. Reliability and Fault-Tolerance
Reliability and Fault-Tolerance. Cloud environments take advantage of the built-in redundancy of the large numbers of servers that make them up by enabling high levels of availability and reliability for applications that can take advantage of this.
Service-oriented. The cloud is a natural home for service-oriented applications, which need a way to easily scale as services get incorporated into other applications.
Utility-based. Users only pay for the services they use, either by subscription or transaction-based models.

10. Shared. By enabling IT resources to be consolidated, multiple users share a common infrastructure, allowing costs to be more effectively managed without sacrificing the security of each user's data.
SLA-driven. Clouds are managed dynamically based on service-level agreements that define policies like delivery parameters, costs, and other factors.
APIs. Because clouds virtualize resources as a service they must have an application programming interface (API).

11. Related Technologies
Although the term 'cloud computing' is relatively new, the technologies that make it possible have been used for some time.
For example, cloud computing is enabled by grid computing, virtualization, utility computing, hosting and software as a service (SaaS). Yet these technologies differ from cloud computing in the following ways:

12. Grid Computing:
Originally designed for computationally intensive batch applications, grid computing was developed as a way to share computers and data.
Modern grid computing technologies have evolved as a way to harness inexpensive servers in a data center to solve a variety of business problems.
Traditionally, grids have lacked the automation, agility and simplicity characterized by cloud computing

13. Virtualization: Hosting:
Virtualized infrastructures are available on-demand and capable of supporting multiple users, but lack the automation required for the self-managing, self-healing property of the cloud.
Hosting:
Hosting services provide space on servers for use by clients as well as providing IP-based connectivity, typically in a data center. Because hosting does not enable on-demand, elastic scalability, it cannot be considered cloud computing.

14. Utility Computing:
In the utility computing model, computing resources like applications, infrastructure and storage are packaged and sold as a service, with users paying only for what they consume, like electricity.
In many respects, cloud computing is closely related to the utility computing model, with cloud computing being a broader concept that relates to the underlying architecture in which the services are designed.

15. SaaS:
Although Software-as-a-Service offerings are often hosted on true clouds, SaaS is an application as a service and cloud computing is IT infrastructure as a service.

16. Public Clouds vs. Private Clouds
Public and private clouds are two different types of cloud computing available today and each offers distinct advantages for businesses.
A public cloud computing environment is open for use by the general public, which could include individuals, corporations or other types of organizations.
Amazon Web Services and Google's AppEngine are examples of a public cloud.

17. The public cloud offers startups and SMBs an opportunity to take advantage of the scalability, agility and automated management of the cloud by essentially renting computing resources and avoiding costly hardware expenditures.
However, security and compliance are serious issues with public cloud computing and are among the factors driving the adoption of private clouds.
For example, Amazon's S3 service was recently down for six hours dues to an increased volume of authenticated calls, which pushed the authentication service over its maximum capacity before Amazon could solve the issue.

18. In contrast, a private cloud computing environment exists within the boundaries of an organization, typically for its exclusive usage.
Often, private clouds are driven by C-level executives' concerns about the security and reliability of public clouds, since private clouds can deliver many of the benefits of public cloud computing, without the downside.
Interest in private clouds is also driven by IT departments' attempts to develop utility-like IT environments, where computing resources and applications can be provisioned with greater efficiency

19. While private clouds solve the issues of security and reliability by keeping data safely behind an organization's firewall, their development requires initial hardware investments and in- house expertise.

20. Cloud Features Highly virtualized and standardized infrastructures
Massive scalability
Fault tolerant & highly reliable
Intra- & Inter- cloud load balance
Instant application development

21. Cloud Benefits
Simplified, more efficient IT and application management
Deliver more applications to large number of users
Excellent service quality
Higher utilization at reduced cost
Time-to-market

22. No need to install or update SW or HW; access from any browser
Unlimited use
Always on
Access from anywhere
Many services to choose from

23. Types of Cloud Offerings:
Bare Operating System
Web or Portal Infrastructure
Applications
Web Services
Database Services
Customizable Application Services

24. Bare Operating System- RackspaceCloud
Formerly Mosso, a division of Rackspace
Provide various Linux Distributions
Also Support “Sites”
Web Server, Both Linux and Windows
O/S Managed by hosting service

25. Web or Portal Infrastructure - Microsoft
SharePoint Online
Rich Portal Capabilities
Excel Services
Forms Services
Visio Services
Access Services
Business Data Services
Search Services

26. Applications – Google Apps
Pre-built, fully functional applications
Mail
Calendar
Word Processing
Dynamic Web Pages
Etc.

30. Expand your Infrastructure!
Buy new servers, increase your software costs, provision more data centre capacity!!

31. Look to the cloud!
Pay for the bandwidth and server resources that you need. When your push is done then turn the whole thing off!

33. What is Cloud Computing? IT as a service
Cloud allows access to services without user technical knowledge or control of supporting infrastructure
Best described in terms of what happened to mechanical power over 100 yrs ago
Now computers are simple devices connected to the larger cloud
Data processing, storage and software applications that used to run locally are now being supplied by big central computing stations. They're becoming, in essence, computing utilities.
What is
Cloud Computing?

34. What is Cloud Computing
“Cloud” is simply a metaphor for the internet
Users do not have or need knowledge, control, ownership in the computer infrastructure
Users simply rent or access the software, paying only for what they use
Simple Introduction to Cloud Computing

35. History of Cloud Computing
Concept dating back to the 1960’s by John McCarthy, a computer scientist, brought up the idea that "computation may someday be organized as a public utility”
Idea that revolutionized Cloud Computing: Moving from clustering computing to grid computing
- Clustering
- Grid
“In some ways, the cloud is a natural next step from the grid-utility model,” said Frank Gens, an analyst at the research firm IDC

36. What Technologies is Cloud Computing Replacing :
Cloud computing is replacing large Corporate Data Centers and unnecessary, expensive private server infrastructure.
Web 2.0, SaaS, Enterprise and government users are adopting cloud computing because it eliminates capital investment in hardware and facilities as well as reduces operations labor

37. Uses Helps to use applications without installations.
Access the personal files at any computer with internet access.
This technology allows much more efficient computation by centralizing storage, memory, processing and band width.

38. Layers
A cloud  client consists of computer hardware and/or computer software that relies on cloud computing for application delivery

39. Infrastructure as a Service
SaaS
Software as a Service
PaaS
Platform as a Service
IaaS
Infrastructure as a Service

40. Increasingly popular with SMEs No hardware or software to manage
Software delivery model
Increasingly popular with SMEs
No hardware or software to manage
Service delivered through a browser
SaaS

41. SaaS Examples CRM Financial Planning Human Resources Word processing
Commercial Services:
Salesforce.com
cloud

42. PaaS Platform delivery model
Platforms are built upon Infrastructure, which is expensive
Estimating demand is not a science!
Platform management is not fun!

43. PaaS
Examples
Google App Engine
Mosso
AWS: S3

44. IaaS Computer infrastructure delivery model
Access to infrastructure stack:
Full OS access
Firewalls
Routers
Load balancing

45. IaaS
Examples
Flexiscale
AWS: EC2

46. Applications
Cloud application services or “Software as Service(SaaS)” deliver ‘Software’ as a service over the Internet, eliminating the need to install and run the application on the customer’s own computer and simplifying maintenance and support.

47. Platform
Cloud platform services or “Platform as a Service (PaaS)” deliver a computing platform and/or solution stack as a service, often consuming cloud infrastructure and sustaining cloud applications. It facilitates deployment of applications without the cost and complexity of buying and managing the underlying hardware and software layers

48. Infrastructure
Cloud infrastructure services or "Infrastructure as a Service (IaaS)" delivers computer infrastructure, typically a platform virtualization environment, as a service. Rather than purchasing servers, software, data center space or network equipment, clients instead buy those resources as a fully outsourced service. The service is typically billed on a utility computing basis and amount of resources consumed (and therefore the cost) will typically reflect the level of activity. It is an evolution of virtual private server offerings.

49. Server
The servers layer consists of computer hardware and/or computer software products that are specifically designed for the delivery of cloud services, including multi-core processors, cloud-specific operating systems and combined offerings

50. Development Models COMMUNITY CLOUD:
 A community cloud may be established where several organizations have similar requirements and seek to share infrastructure so as to realize some of the benefits of cloud computing. With the costs spread over fewer users than a public cloud,
this option is more expensive but may offer a higher level of privacy, security and/or policy compliance. Examples of  community cloud include Google's "Gov
Cloud”.

51. Hybrid Cloud & Private Cloud
A hybrid cloud environment consists of multiple internal and/or external providers "will be typical for most enterprises". By integrating multiple cloud services, users may be able to ease the transition to public cloud services

52. Private cloud:
Private cloud and Internal cloud are expressions that some vendors have recently used to describe offerings that emulate cloud computing on private networks. These products claim to "deliver some benefits of cloud computing without the pitfalls", capitalizing on data security, corporate governance, and reliability concerns. They have been criticized on the basis that users "still have to buy, build, and manage them" and as such do not benefit from lower up-front capital costs and less hands-on management