A few years ago Citrix launched the first version of XenClient. With this launch a big supplier (Citrix) started a product virtualizing the operating system on client hardware. When Citrix launches the technical people love the technique, but many people are/were wondering which business needs such products will fulfill. Although several suppliers followed, even Microsoft announced the availability of Hyper-V in the Windows 8 client; still the technique is not really adopted and is not hyped like other virtualization techniques. In this article I will describe my opinion why I think Client Hypervisors will become important, but by other reasons than current often used.

Not: More Operating Systems on one client

When the client hypervisor is discussed one of the most used demos is to show 2 virtualized machines running on one physical client simultaneously. While this is the big strength for server hypervisor and technically this is cool to do this on client, this is not the reason why Client Hypervisors will become important within enterprise customers. Just think how many people in a company needs two operating systems? That is a real small group if there are any workers, who really need that out of business needs. The only way this could be usable is with the Bring Your Own Device (BYOD) principle, where the client hypervisor can be used to start the company operating system on a personal device. However I don’t think may companies will take this approach when using BYOD mainly out of security- and maintenance standpoint. You need to really administrate which OS (MAC addresses) are allowed in the company’s network to let this work; while the advantaged of BYOD for the end-users are gone (they cannot use their personal operating system during the time there are inside the company). With BYOD I expect that the company will provide a Hosted Desktop (with some technique like Microsoft RDS, Citrix XenApp/XenDesktop, VMware View or another SBC/VDIO product) then providing an image directly to the client device.

Not: Offline VDI

The second reason why client hypervisors are useful is the so called technique Offline VDI. The vision behind is that the end-user will work the whole day in the office in a VDI Desktop running in the data center. When the users wants to go home the VDI will be download to the (portable, I assume) device, so he can continue with his work at home. To get the whole VDI image locally, you need definitely lots of bandwidth (again assuming that the end-user does not want to wait for hours before he can go home, while in that time the work was already finished). So the user is located in a main office, but sufficient links. Why should that user work on the VDI system then? Just let him work locally on his machine, we don’t need to synchronize the operating system and applications, only the data is relevant for synchronization. That’s easier, saves bandwidth, complexity and does not annoy the end-user with a waiting time when he wants to go home.

Yes: Single Image Creation

Actually the virtualization of the client is not that difficult, this is already possible for a long time on the server virtualization. Also the basic of the hypervisor is not the big challenge; the big challenge is supporting all kind of different hardware available in the client. Especially sound, video, LAN cards and similar are those which are the difficult ones. Those devices are replaced quickly by the system manufacturers and the client hypervisor should know them all to function. It becomes even more complicated when direct access to the video card is required for the best (3D) performance. But when the driver challenge has been solved Client Hypervisor has a big advantage comparing with current deployment techniques. The IT Department does not have to care about new drivers that should be embedded in the image every time a new desktop or laptop is purchased. When the device is supported by client hypervisor the image can be easily brought to the device and without any additional steps the device is up and running. One single image will prevent lots of the challenges nowadays seen in deploying Fat Client and could/will bring us back to the future (see my article PDI for more information about that topic).

The question is will the driver issue be solved? And there is exactly where Microsoft comes into play. Is Microsoft will deliver a full featured Client Hypervisor, than drivers are not the case anymore (because current Windows knows most drivers and otherwise they can be developed quickly by the supplier and embedded in the hypervisor by the device manufacturer).

Yes: Singe Image Management

This is actually a logical step when you only have a single image available, but this needs some cooperation with other features or products. Currently the operating system is still installed in the virtual machine and once it’s installed it should be maintained as a regularly installed operating system. However combining the Client Hypervisor with a technique that knows/support image update management into existing enrolled images would be the next step.

Think of the advantages of Citrix Provisioning Services (OS streaming) with a full local cache possibility combined with Client Hypervisor. This will get us to a real flexible, easy to maintain solution that will be real cost effective (in comparison with current traditional Fat Client models and VDI).

Yes: Single Desktop Management

Even one step further is combining the Client Hypervisor with other techniques for example VDI. Although I think that VDI infrastructures can also be accomplished using Server Based Computing solutions Microsoft RDS or Citrix XenApp I can think of situations where many portable workstations are used that you would virtualized workstations for the other workers. When this is the case you would like to use the concepts and tools to maintain the infrastructure. In other words the singe image (preferable including Single Image Management) should be deployed and maintained using one (software) product.

This will then became a solution that will suit all 100% of the workers within the company. Something that currently none current product can offer. And that is something that all companies are still looking for.


In this article I described my opinion why I think Client Hypervisors will become important in infrastructures. Although I don’t believe this will become important by the current supplies reasons why a client hypervisor should be used, but other reasons (which can be accomplished by developing the (concept) of the product). Feel free to leave your opinion with the comments section below this article.