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 few different categories based on the type of service provided. SaaS (Software as a Service) is the category of cloud computing in which the main resources available as a service are software applications. DaaS is another category in which the user is provided a whole desktop experience (bundle of applications and their associated data) though internet. Other popular categories are PaaS (Platform as a Service) and IaaS (Infrastructure as a Service).
SaaS
SaaS is one of the categories/methodologies 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 main advantage offered for the SaaS user is that he/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 because they 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.
DaaS
DaaS is another category or a specific application of cloud computing. DaaS deals with proving a whole desktop experience over the internet. This is sometimes referred to as desktop virtualization/virtual desktop or hosted desktop because the user is allowed to enjoy the benefits of a complete desktop virtually. Unlike SaaS, DaaS not only provides applications or software, but also provides the associated data produced by the applications. To allow the users to have a certain control over the data, usually a datacenter capable of sharing/isolating data is setup. DaaS’s architecture is multitenant and subscribers purchase the service by paying a monthly subscription fee. Since the service provider is responsible for the storage, backup and the security of data, only a thin-client is necessary to obtain the service. Because these thin-clients are usually low-end computer terminal, which are only responsible for providing a graphical user interface, subscribers’ initial cost for hardware is at minimum. Accessing the desktop is possible independent of the user’s location, network or device.
What is the difference between SaaS and DaaS?
Even though, SaaS and DaaS are two applications/categories of cloud computing, they have their key differences. SaaS focuses on specifically making software applications available over the internet, while DaaS provides the whole desktop experience by providing a bundle of applications and the associated data to the subscriber. Usually, SaaS only provides a single or a couple of applications, while DaaS provides a whole virtual desktop to the user. DaaS users can use a thin-client to obtain the service, while SaaS users need a fat-client. DaaS users are not responsible for the storage/backup of data but SaaS users should usually store and retrieve the data produced by applications, themselves.