distinction between SAAS, PAAS, IAAS

The chararistics of cloud computing are offered in different service models, these models deliver their services to different types of users. In the figure shown below the type of user per service model is shown. The service models are also called the cloud stack.


Figure 1 Cloud computing stack (Schuller, 2010)


Software as a Service (SaaS): is cloud computing layer where users simply make use of a web-browser to access software that others have developed, maintain and offer as a service over the web. At the SaaS level, users do not have control or access to the underlying platform and infrastructure that is being used to host the software. Salesforce’s Customer Relationship Management and Google gmail are popular examples that use the SaaS model of cloud computing.(Armbrust, et al., 2009)

Platform as a Service (PaaS): is the layer where applications are developed using a set of programming languages and tools that are supported and provided by the PaaS provider. PaaS provides developers with a high level of abstraction that allows them to focus on developing their applications. Developers can provide their customers with an custom developed application without the hassle of defining and maintaining the infrastructure. Just like the SaaS model, users do not have control or access to the underlying infrastructure being used to host their applications at the PaaS level. Google App Engine and Microsoft Azure are popular PaaS examples.(Boniface, et al., 2009)


Infrastructure as a Service (IaaS): is the lowest layer where users use computing resources such as databases, CPU power, memory and storage from an IaaS provider and use the resources to deploy and run their applications. In contrast to the PaaS model, the IaaS model allows users to access the underlying infrastructure through the use of virtual machines which automatically can scale up and down. IaaS gives users more flexibility than PaaS as it allows the user to deploy any software stack on top of the operating system. However, flexibility comes with a cost and users are responsible for updating and patching the operating system at the IaaS level. Amazon Web Services’ EC2 and S3 are popular IaaS examples.(Murphy, Abraham, Fenn, & Goasguen, 2009)



SaaS – software application delivered trough cloud computing techniques

PaaS – development platform delivered trough cloud computing techniques

IaaS – – CPU en storage delivered trough cloud computing techniques



Armbrust, M., Fox, A., Griffith, R., Joseph, A., Katz, R., Konwinski, A., et al. (2009). Above the clouds: A berkeley view of cloud computing. EECS Department, University of California, Berkeley, Tech. Rep. UCB/EECS-2009-28.

Boniface, M., Nasser, B., Papay, J., Phillips, S., Servin, A., Yang, X., et al. (2009). Platform-as-a-Service Architecture for Real-time Quality of Service Management in Clouds.

Murphy, M., Abraham, L., Fenn, M., & Goasguen, S. (2009). Autonomic Clouds on the Grid. Journal of Grid Computing, 1-18.

Schuller, S. (2010). Cloud stack http://www.saasblogs.com/images/uploads/2008/12/cloud_stack.gif

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