A Cloud is a graphical representation of Network / Internet

Five Key Cloud Attributes: 

1. Shared / pooled resources 
   
2. Broad network access
   
3. On-demand self-service
   
4. Scalable and elastic
   
5. Metered by use

1. IaaS: Infrastructure as a Service :-Consumer can provision computing resources within provider's infrastructure upon which they can deploy and run arbitrary software, including OS and applications.
2. PaaS: Platform as Service :- Consumer can create custom applications using programming tools supported by the provider and deploy them onto the provider's cloud infrastructure.
3. SaaS: Software as Service :- Consumer uses provider’s applications running on provider's cloud infrastructure

Note: This download only have PPT there is another full seminar on Cloud Computing present here.