"Desktop virtualization" is still a phrase that means different things to different people. Some speak about access virtualization, such as that offered by Citrix, Microsoft and others, as if it is a form of desktop virtualization. Others would describe application encapsulation and delivery as a form of desktop virtualization. Some would say if there isn't a virtual machine in the picture somewhere supporting a complete encapsulated virtual client/desktop system that it isn't really virtualization. In truth, we're rapidly approaching a time in which there won't really be a desktop at all.
This haggling reminds me of the story of the blind men and the elephant. All of them believe they have a full view even though they only are able to perceive a small part of the animal.
In my view, virtualization is a term that can be applied when and wherever a function is placed in an artificial environment in order to gain some benefit. This can mean obtaining better performance, improved access, greater levels of flexibility and few other things (see Sorting out the different layers of virtualization for more information.)
I've had the opportunity to speak with Purmina Padmanabhan of MokaFive and Andrew McKay of Virtual Computer, Inc. about desktop virtualization, what is required for a useful implementation, and where things are going from here. Although each has a different take on this trend, both would agree that a flexible, scalable management system that makes it possible to easily install, modify and maintain desktop images is a key component.
The challenge these folks and others competing in the same sector face is that the nature of the access device, that is the device individuals use to access applications and data, is rapidly changing. The industry has moved from the use of dumb terminals as the desktop standard to desktop computers to laptop computers and now to a constellation of intelligent devices as the standard.
How will desktop virtualization work if the device on the other end is a smartphone? Most desktop applications need a specific type of processor, operating system, a larger screen and, of course, something that mimics a keyboard and mouse. In many cases, smartphones don't have these attributes. What about the case of the need to access an application and its data using an internet tablet, such as the iPad? Getting a virtual environment to support all of the necessary processors, operating environments, memory and storage configurations, user interfaces and user input devices is really hard and, in the end, possibly not worth the effort.
It is my view that desktop applications are going to gradually be replaced by Web-based applications that may be accessed from anywhere over just about any network using just about any type of device. When local processing or storage is available, it will be used, but they'll be smart enough to use whatever lives in the hands of the person using the application.