IaaS (Infrastructure-as-a-service) is not a new technology, and it is what formerly known as hardware as a service and now got the name IaaS. In SaaS the software can be used as a service and the remote computer can just make use of the services by paying, and in PaaS the platform will be provided to customer as a service by the cloud service providers. But in IaaS, the users are using the cloud provider's machines. Another term for this type of computing is everything as a service. That is, the users are using a virtualized server and running software on it.