What is PaaS (Platform as a Service) and IaaS (Infrastructure as a Service)?
Platform as a Service (PaaS) and Infrastructure as a Service (IaaS) are cloud computing service models that allow users to utilize hardware and software resources over a medium such as the internet in the form of a ‘service’. Therefore, to better understand, compare, and contrast PaaS and IaaS, it is imperative to briefly discuss what cloud computing is and how it has helped shape the computing realm into what it is today.
Cloud Computing Overview
Arguably, the initial concept of Cloud computing was proposed by Herb Grosch in the 1950s. He was of the opinion that the entire world would be working out of 15 colossal data centers in the future. The predecessor to cloud computing, utility computing, first employed the infamous ‘cloud’ symbol to represent the medium/infrastructure i.e. the internet on which cloud services were to be offered. The basic premise of using cloud computing systems is referred to as “time sharing”, which originated in the 1960s when access to mainframe computers via multiple terminals was becoming more and more common. This prompted a need to use resources efficiently and get the most out of them. The answer to this was cloud computing. Cloud Computing is described by the National Institute of Standards and Technology (NIST) as:
Cloud computing is a model for enabling ubiquitous, convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction.
The 3 ubiquitous models of  Cloud Computing, IaaS, PaaS and PaaS offer the infrastructure, Platform and Software to the user (developers/IT Managers/CIOs etc.)
The significant attributes of platform-as-a-service and its cost effectiveness have resulted it to be a widespread preference by users over IaaS.
PaaS vs IaaS – A brief analysis
Although IaaS offers the basic infrastructure required to setup a computing cloud such as storage, computing power, network, etc. the end user is still required to do substantial tasks such as manual configuration of the network, storage space, OS, resource management etc. At most, a pre-installed operating system might be installed on the server in an IaaS model. On the other hand, PaaS offers basic hardware as well as software services that allows end users to get straight down to business of developing and testing applications. PaaS providers might also offer automatic resource management service for automatic scaling according to additional need for computing power, storage, etc.
Benefits of PaaS
PaaS is not just limited to the aforementioned attributes. Here are some other  key features of PaaS:
- Unlike IaaS, PaaS has the ability to be deployed much more readily; it gives the user more time to focus on other aspects of development.
- PaaS is simpler to use than IaaS and offers better flexibility to expand or contract resources and test new applications.
- Reducing system administration chores also ensures a better ROI. PaaS improves overall manageability by reducing the hassle of installations and licensing of Software.
- PaaS also has an automatic resource management service so that additional demand for the services results in automatic scaling of the required computing power, storage, etc
- PaaS enables users to build and deploy applications on a hosted infrastructure. This allows them to utilize the highly functional and infinite assets of a managed Cloud infrastructure without even taking control of an IaaS.
- PaaS offers the same control over the service as IaaS but is less costly to manage and use.
