Developing all the necessary drivers needed by PC users has proven to be one major challenge. Another roadblock may be persuading PC vendors to ship and support these hypervisors with their hardware, according to research firm Gartner.
Citrix and VMware were expected to ship their respective products, XenClient and Client Virtualisation Platform, before the end of 2009. Now VMware hopes to have something out by the end of 2010. Citrix is waiting for the results of an ongoing closed beta test before committing to any dates, according to Dave Austin, Citrix's director of product marketing in Europe, the Middle East and Africa.
A bare-metal hypervisor, also known as a type 1 hypervisor, runs directly on system hardware rather than on top of a host operating system. That allows one or more operating systems to run on top of the hypervisor as virtual machines.
Desktop virtualisation allows corporate IT departments to easily ensure a standard operating environment for all users, but the current approach requires that the desktop environment be networked to a server where the virtual OS is actually running. With bare metal desktop hypervisors, performance is improved because the system is running locally, not over a network, and users are also able to work offline.
They would also allow companies to create a standardised operating system image that can be rolled out on all desktops, and then updated and managed centrally. For it to work, the PCs need to be compatible with Intel's vPro technology.
Currently, there are a couple of issues delaying the two companies, according to Mark Margevicius, research director for client computing at Gartner.
From a technical perspective, the development of bare metal hypervisors for client side virtualisation is made more complex by the plethora of components the hypervisor must interact with on the PC. So drivers have proved to be a big challenge for VMware and Citrix, Margevicius said.
And the vendors agree: you have to take into account networking, Bluetooth, graphics hardware, and other common client side components, according to Austin. In the server world, where bare-metal hypervisors have been around for ten years, the hardware compatibility list is much shorter and well-defined, according to Fredrik Sjöstedt, VMware's director of product marketing in Europe, the Middle East and Africa.
There aren't just technical challenges that have to be sorted out. PC vendors will have to support the products, and bare metal hypervisors aren't necessarily beneficial, according to Margevicius. That's because they may make it easier and cheaper for companies to switch vendors when they can build a standardized desktop image that is independent of the hardware. They can change the vendor, but the image stays the same, Margevicius said.
"If the costs come down, customers will be doing bids on PC hardware on a weekly basis," said Margevicius.
There is a different side to that argument, according to Sjöstedt. He agreed that bare metal hypervisors will make it easier to replace PCs. But that doesn't necessarily mean companies will be switching vendors all the time. It could also help organisations upgrade to PCs with the latest processors more easily than they can now, Sjöstedt said.
How PC vendors will see the issue remains to be seen. Both virtualisation companies have Intel in their corner. VMware is in talks with the PC vendors, but hasn't got any deals in the bag that it can announce, according to Sjöstedt. Citrix is in the same position: some hardware vendors are interested, but that isn't anything the company can disclose publicly, a Citrix spokesman said via email.
For the CIO, bare metal hypervisors could let them entertain the idea of having users buy and bring their own PCs to work, according to Margevicius. A personal and a work operating system could run side by side, and be completely separated from each other.
The bare-metal hypervisor will definitely make the process of letting users buy their own PC or Mac much easier, according to Austin. One thing administrators could do that they can't with any other platform is to send out "a kill pill" from a central location when a user leaves the organisation, he said.
VMware is seeing the same trend toward user-owned PCs, but has decided to approach it with a different product. It's accelerating development of a host-based virtual desktop solution for employee-owned PCs called View Manager Local Mode, according to Scott Davis, CTO for VMware's Desktop Business Unit.
Bare-metal hypervisors and employee-owned PCs are a bad fit because the IT department would have to bring in the computer, wipe it and then install the hypervisor, according to Davis. Bare metal hypervisors are a better fit on devices that are owned by the company, and, for example, located at remote office or branch office locations.
"I have talked with a couple of oil refineries. They want managed end-points out on the rigs, where the network isn't robust enough for VDI and there is no IT personnel," said Davis.
VMware will ship View Manager Local Mode before Client Virtualization Platform. But VMware isn't saying when; "soon" is as far as Davis will go.