This document provides an introduction to Software as a Service (SaaS), Platform as a Service (PaaS), and Infrastructure as a Service (IaaS) cloud computing models. It defines cloud computing as providing on-demand access to IT resources and applications from the internet without requiring technical knowledge of the underlying infrastructure. The three main cloud service models - SaaS, PaaS, and IaaS - are described along with their advantages of pay-per-use pricing, instant scalability, security, reliability and APIs. Popular commercial examples for each service model are also listed.

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
• APIsIaaS

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
• InteroperabilityIaaS
PaaS
SaaS