Platform as a Service (PaaS)
PaaS provides
pre-installed
web and database servers so
that you can publish and run
web application without worrying
about server setup.
Infrastructure as a Service (IaaS)
IaaS provides you basic virtual
compute infrastructure resources
like CPU, Memory, Disk Storage
attached to blank VMs with
allowing you to install OS
Software as a Service (SaaS)
SaaS is a software delivery model
here users are not responsible for
supporting the application or any
of the components.