<human>:  What are the differences between the four principal cloud computing service models: IaaS, PaaS, SaaS, and CaaS?
<bot>: The four principal cloud computing service models, Infrastructure as a Service (IaaS), Platform as a Service (PaaS), Software as a Service (SaaS), and Container as a Service (CaaS) differ in the type of services they provide. IaaS provides virtualized computing resources, raw computing services such as CPU and RAM, that are configurable and scalable. PaaS gives developers the ability to create, deploy and manage applications without having to provision or manage the underlying infrastructure. SaaS offers a complete software solution, with the all backend infrastructure being managed by the service provider. And finally, CaaS offers developers the ability to more quickly create, deploy and manage cloud-based applications and services within containers, providing a layer of abstraction from the underlying hardware and promoting rapid development.