The Evolution of Corporate Computing: From SaaS to DaaS

By Jeff Fisher
published: Tuesday, July 22 2008

Software as a service (SaaS)-which lets organizations access applications on-demand over the Web instead of programs locally installed on a desktop-is a proven, viable application delivery model. Typically used for customer relationship management (CRM), Web analytics and e-services applications, its appeal is evident in research that finds nearly three-quarters of large organizations have adopted or plan to adopt SaaS, and in predictions that SaaS will make up almost 25 percent of the $120 billion U.S. software market by 2010.* 

However, SaaS is not the end game.  In mid-size and enterprise markets, SaaS is a stepping stone to DaaS (desktops as a service) where not just singular applications, but entire desktops will be consumed as an outsourced, subscription service. 

This evolution, already underway, is due as much to the acceptance of SaaS as it is to the fast-growing interest in virtual desktops as a network service, the challenges and high costs that enterprises incur when building their own virtual desktop infrastructures (VDI), and the ready availability of high-speed bandwidth.  In fact, Gartner predicts that by 2011, early adopters will purchase 40 percent of their IT infrastructure as a service.  A good part of this will focus on the desktop-the most costly, difficult and time-consuming part of the infrastructure to maintain-where virtual, rather than physical, desktops will be consumed as a service.

SaaS and DaaS:  The Similarities

The evolution from SaaS to DaaS makes perfect sense.  They enable many of the same benefits:

• Outsourced, subscription service handled as OPEX instead of CAPEX:  Unlike traditional software and desktops, which are purchased through capital budgets and whose value depreciates over time, SaaS and DaaS are usually procured through operating budgets using monthly subscriptions or transaction-based pricing, which lets your organization match the amount of service purchased to actual use.

• No internal deployment or support risks: Your IT organization is not burdened with deploying, upgrading or maintaining the infrastructure that delivers SaaS or DaaS, enabling it to focus on more strategic projects while eliminating the cost and technology risks inherent in large-scale implementations.

• Rapid provisioning:  Because you no longer have to purchase, test, install and deploy the technologies enabling SaaS or DaaS, you can quickly provision applications and/or desktops to end users through your service provider.

• Simple scaling up or down:  It is easy to add or remove users, desktops and application rights.  IT no longer has to go through tedious, time-consuming uninstall or reharvest processes, and instead of paying for unused applications or desktops that you own, you simply eliminate (and stop paying for) unnecessary subscriptions.

• Liberate users from specific computing devices:  Users are no longer tied to particular computers; they can access their applications or desktops from virtually any device and any location, enabling them-and your company-to be much more flexible, mobile and productive.

It's also important to note that SaaS and DaaS also require a persistent network connection, which may limit their use to certain groups of workers.  If the network goes down, DaaS users will be unable to access their desktops, while SaaS users will be unable to access any applications delivered as a service.  However, technologies currently under development will accommodate these users in the future.

How SaaS and DaaS Differ

While the above characteristics have contributed to SaaS' adoption and the increasing interest in DaaS, significant differences between the two approaches are compelling organizations to evolve beyond software as a service to outsourced desktops, where service providers own and operate the physical infrastructure that powers virtual desktops while enterprises retain control over the provisioning, management and licensing of the virtual desktops they use.

• SaaS tradeoff:  SaaS provides cloud-hosted delivery at the expense of the existing client application model. While SaaS makes sense and has been proven for a number of client-facing applications, only certain classes of applications have been converted into SaaS models; the wholesale replacement of rich Windows applications for enterprises is just not feasible.  Conversely, DaaS marries the benefits of a cloud-hosted service with the traditional rich Windows client experience.

• Integration and personalization:  Integrating SaaS applications with other, existing applications is quite challenging because of the differences in where they reside and how they're delivered.  In addition, IT organizations cannot customize SaaS applications to the same extent as traditional applications.  These issues don't exist with DaaS because a user's entire desktop, including all the applications, is kept intact.  Applications interact, and can be customized, the way they always have in traditional client computing environments.

• Degree of statelessness:  DaaS makes a user's entire desktop stateless.  The complete Windows environment-including the applications-roams with the user anytime, anywhere.  SaaS only provides statelessness one application at a time. 

• Control and security:  In a DaaS model, user identity, application servers and organizational data are stored in the enterprise data center, giving you the control and security required.  With SaaS, however, data is hosted, along with the application, in the provider's data center, potentially compromising security.

• Architecture supported:  SaaS offerings tend to be browser based.  DaaS supports all Windows client application architectures (i.e. Win32, .NET, browser based, etc.), allowing organizations to leverage the investments they've made building in-house applications.

• Hosting location flexibility:  SaaS is 100% cloud-hosted.  DaaS can be hosted either in the cloud (where the physical infrastructure resides in the service provider data center) or in the enterprise data center as a managed service, or both.  Companies that have distributed, global infrastructures or that are highly regulated, such as healthcare and financial services organizations, may prefer the managed DaaS model. Businesses that are more centralized or that have less data center capacity may opt for the cloud-hosted DaaS model.  Despite the configuration, with DaaS the physical resources are owned and operated by the service provider.

SaaS has proven the feasibility and merits of consuming applications as a service.  But it represents the tip of the iceberg, a small portion of what is possible by outsourcing non-strategic aspects of the IT infrastructure.  By evolving to DaaS, organizations can realize orders of magnitude greater flexibility, cost savings, security and productivity benefits.