Cloud computing is a style of computing in which resources are made available over the internet. Most often these resources are extensible and highly visualized resources and they are provided as a service. Cloud computing is broken down in to three categories as follows. SaaS (Software as a Service) is the category of Cloud computing in which the main resources available as a service are software applications. Other two categories are PaaS (Platform as a Service) and IaaS (Infrastructure as a Service).
What is Cloud Computing?
As mentioned above, Cloud computing offers the internet user to access the resources as services. Since they are available through internet, any user with standard HTTP medium can access these resources in the cloud. Advantage the user has while using a resource available over the cloud is the fact that he is not required to have the knowledge, expertise or the control over the cloud specifically, the infrastructure which support the various resources. Essentially, a cloud provides separation between resources and the user’s computer. This means that the user’s computer may have very minimal software (web browser running on a minimal operating system) or data in order to handle the acquired resources. The main principle behind cloud computing is that the providers would create and host their solutions on the cloud so that multiple users can obtain them on demand. And these solutions could be infrastructure, software or platform. And based on these three types of resources, cloud computing is divided in to three parts as Paas, SaaS and IaaS (as explained above). There can be public or private clouds. Public clouds provide its resources to everyone over the internet while private clouds provide proprietary resources to a limited number of people.
What is SaaS?
SaaS is one of the categories/methodologies of Cloud computing. In other words, SaaS could be identified as an application of Cloud computing. As mentioned above, resources available as a service through SaaS are specifically software applications. Here, an application is shared across multiple clients using the “one-to-many” model. The advantage offered for the SaaS user is that she can avoid installing and maintaining software and can free herself from complex software/hardware requirements. The provider of SaaS software, also known as hosted software or on-demand software, will take care of the security, availability and performance of the software becuase they are run on the provider’s servers. Using a multitenant architecture, a single application is delivered to millions of users through internet browsers. Customers do not require upfront licensing while providers are enjoying a lower cost because they are maintaining just one application. Popular SaaS software are Salesforce.com, Workday, Google Apps and Zogo Office.
Difference between Cloud computing and SaaS?
Even though, Cloud computing and SaaS are used interchangeably, they do not refer to the same concept. Cloud computing is a style of computing in which resources are made available over the internet while SaaS is one of the methodologies/ applications/ categories of Cloud computing. Cloud computing is the big picture which deals with delivering any type of resource over the internet while SaaS focuses on specifically making software applications available over the internet. To make the differentiation more clear, Cloud computing is rather a broad term which covers a wide spectrum of services while SaaS is just a one area that Cloud computing enables and powers.