Everything you wanted to know about the Cloud but were too afraid to ask II: SaaS, IaaS, PaaS

Estimated reading time: 6 minutes

I dont care if my cloud computing architecture is powered by a grid, a mainframe, my neighbours desktop or an army of monkeys, so long as its fast, cheap and secure (Sam Johnston)

This is the second part of the post on Cloud Computing on ZyncroBlog, explaining the tree basic concepts in the Cloud: SaaS, PaaS and IaaS.

Software as a Service (SaaS)

SaaS is the service based on the idea of having a software that you pay a provider for in installments, instead of buying it outright, and that is not installed in the customer’s machines. The software is hosted in central servers so that its operation is available over the internet. Also know as “on-demand software ”, it currently is the most popular form of cloud computing, due to its high flexibility, quality and scalability, offering lower maintenance costs. The SaaS provider is responsible for hosting the application and the data, while the end user is free to use the service from anywhere, at any time. SaaS is very effective in reducing costs as it provides access to applications normally at a much lower price than purchasing a software license, thanks to an installment payment model (monthly, quarterly, yearly…). With SaaS, users can forget about having to  install and update the software.

Some examples of SaaS providers are: CRM Salesforce.com, Marketo, Akamai, Taleo or Zyncro of course.

Platform as a service (PaaS)

PaaS refers to a development platform for programmers. End users write their own code and the PaaS provider loads this code and presents it on the Web. PaaS providers offer services to develop, test, implement, deploy and maintain applications on a single integrated development environment. They also provide a certain level of support in designing and developing applications. PaaS offers a quick, cost-efficient model for developing and rolling out applications. The PaaS provider manages updates, patches and other routine system maintenance tasks. PaaS is based on a subscription model where users only pay for what they use. Users can use the resources they need without having to worry about the complexity of the platform where they are developing.

Some PaaS providers are: Windows Azure, Google App Engine, Force.com, GigaSpaces

Infrastructure as a Service (IaaS)

IaaS delivers computer infrastructure as a fully externalized service. Users can buy the infrastructure according to requirements at a specific point in time, instead of purchasing the planned infrastructure to be used in a couple of months. IaaS operates using the same model as the previous “pay on-demand” services to ensure that users only pay for what they are using.

The idea of “machine virtualization enables IaaS providers to offer almost unlimited servers to customers and optimize storage machines. IaaS users can have access to a high level of infrastructure and IT resources that would be extremely costly if they were acquired outright.

The benefits of IaaS include:

  • dynamic scaling
  • usage-based pricing
  • reduced costs
  • and access to superior IT resources.

IaaS is also occasionally called Hardware as a Service (HaaS). For a SME or a start-up, one of the most difficult things to achieve is to keep capital spending under control. Moving their infrastructure to the Cloud enables them to scale as if they actually owned their own hardware and datacenters.

Some IaaS providers are: Amazon EC2/S3, Cloud Scaling, Rackspace

Much of the information presented here was taken from http://www.cloudtweaks.com, a web that I fully recommend for learning more about these concepts.