We are always picking sides, our favorites! Today there is a growing debate on where application virtualizationshould be performed, 'client side' or 'server side'. The concept of separating the application from the underlining OS can be done on the client (Desktop/laptop) and on the server.

Many references to application virtualization (http://virtualfuture.info/2008/06/virtualfuture-appchart/) are usually about client side application virtualization. Products like SoftGrid, ThinApp, InstallFree and  XenApp application streaming (the application virtualization feature within XenApp) are mainly referring to the client side of virtualization. All these products do a great job of server side virtualization also.  In many XenApp installations customers are using server slide application virtualization to improve the return on their XenApp investment. From what I've seen there are more server side implementations of application virtualization, now the idea of client side application virtualization is getting into the spotlight.

There seems to be a debate brewing as to which is the best way to go - client side or server side? Do you run the traditional server based model of computing and delivery apps to users from the server or is it better to deliver  and run the apps as close as possible to the user on their PC? The good news is that application virtualization is applicable to both client and server side, so at the end of the day as long as you are looking at virtualization your applications you are heading in the right direction. Can you get the best of both world? The ideal scenario would be to prepare your applications for virtualization once and then decide later as to where would be the best place to execute the application, client side or server side. Even better would be a system that can decide based on policy, users connectivity or application usage controls where to vertualize, at the client or the server. The ultimate would be a system that can change where the application is virtualized and executed, based on the above scenarios - so in one instance you run your application on the client, and then, say, when you're, outside the corporate firewall, you would run the same application from the server. Of course you want to only use one instance of the virtualized application in both cases.

XenApp is an application delivery system that uses both client side and server side application virtualization to deliver applications in the most optimal way depending on policy. The application hub within XenApp stores the profiled applications and delivers the same application to the client or the server. Anytime the application is modified or needs to be updated, you only need to make the changes to the profile in the application hub and the virtualized application on the client and/or server is updated automatically. You can profile and store all your Windows applications in the application hub. Additionally XenApp works with Microsoft 'SoftGrid' application virtualization and other application virtualization technologies. XenApp is the overall delivery system for all windows applications. For example if you are using SoftGrid as your application virtualization technology that's fine, the XenApp delivery system still works in the exactly the same way, even more you can mix both SoftGrid and XenApp virtualized applications within the XenApp application delivery system. So if there is a specific feature within application virtualization you need, or you have already bought an application virtualization technology or you prefer a specific application virtualization vendor; you can use a specific application virtualization technology within the XenApp application delivery system.

The next version of XenApp which will also be on the Windows Server 2008 platform will provide even more features to enable application virtualization with XenApp. You should be using both sides of application virtualization; enabling all your Windows applications for all your users. You no longer need to decide which application virtualization side you are on, you can be on both sides, delivery the best of all worlds.

Are you working on both sides?