The document discusses cloud computing and different cloud service models including Infrastructure as a Service (IaaS), Platform as a Service (PaaS), and Software as a Service (SaaS). IaaS refers to accessing computer infrastructure resources like servers and storage. PaaS allows accessing platforms and development tools without installing them locally. SaaS delivers software applications through a web browser without installing or managing the software. The cloud offers advantages like scalability, pay-per-use pricing, and reduced maintenance costs compared to locally hosted infrastructure and applications.

1. An Introduction to SaaS and Cloud Computing Ross Cooney

2. The hype Cluster Computing Cloud Computing Grid Computing

3. What is the cloud ? 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?

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

5. SaaS Software as a Service

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

7. Advantages Pay per use Instant Scalability Security Reliability APIs SaaS

8. Examples CRM Financial Planning Human Resources Word processing Commercial Services: Salesforce.com emailcloud SaaS

9. PaaS Platform as a Service

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

11. Popular services Storage Database Scalability PaaS

12. Advantages Pay per use Instant Scalability Security Reliability APIs PaaS

13. Examples Google App Engine Mosso AWS: S3 PaaS

14. IaaS Infrastructure as a Service

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

16. Advantages Pay per use Instant Scalability Security Reliability APIs IaaS

17. Examples Flexiscale AWS: EC2 IaaS

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

19. Common Factors Pay per use Instant Scalability Security Reliability APIs IaaS PaaS SaaS

20. Advantages Lower cost of ownership Reduce infrastructure management responsibility Allow for unexpected resource loads Faster application rollout IaaS PaaS SaaS

21. Cloud Economics Multi-tenented Virtualisation lowers costs by increasing utilisation Economies of scale afforded by technology Automated update policy IaaS PaaS SaaS

22. Risks Security Downtime Access Dependency Interoperability IaaS PaaS SaaS