The field of virtualizing desktops is in ferment, with a wide array of new ideas being tried out. Startup MokaFive has launched its own approach.

If you listen to VMware or Citrix Systems, chances are you will arm yourself with a set of powerful central administrative consoles and servers, along with the ability to virtualize thousands of end users at a time as you build out their virtual desktop infrastructure (VDI).

Three-year-old MokaFive, coming out of research at Stanford University, is a 30-employee startup that thinks there's a simpler way.

Last week it launched MokaFive Virtual Desktop Solution 1.0. As opposed to VDI, its emphasis lies in generating desktops at a central location, then allowing them to run on a desktop or laptop, regardless of whether that unit remains connected to a central server.

The MokaFive approach is also the opposite of a thin-client approach. It assumes there's both a memory device and a CPU available, and that after the download the connection may be cut. MokaFive is targeting mobile workers, such as members of the enterprise sales force, as its first customers.

That option exists under some circumstances with the large vendors' virtual desktop infrastructures, but for the most part, VDI assumes the end users' devices will remain connected to central servers. VDI in some instances encourages thin clients, which have no hard disks or other lasting memory device.

The MokaFive approach allows a kind of free-roaming spilt in responsibility between central IT and end users. Documents and files generated by users will for the most part stay on their own devices. The core desktop is examined and updated on the end user device to keep it in conformance with central rules and regulations, said John Whaley, CTO and co-founder of MokaFive.

"The users can be as disconnected as they want to be," he said. "We allow central management combined with remote execution."

MokaFive divides the user's virtual desktop into "system state" and "user state." As the user starts up his virtual machine, system state checks in with a central server to see if any updates have occurred to the operating system or key applications. If they have, the changes and only the changes get downloaded to the VM resident on the PC, called a LivePC.

The user state, which consists of the data, files, and documents generated by the end user, is isolated on the user's machine and doesn't check with central management. User data may be uploaded periodically to a replication server for backup purposes. The approach minimizes dependence on central servers and might allow an end user to go for days without contact with a data center server.

There's an immediate drawback to the approach. MokaFive is generating VMware Server virtual machines, called Live PCs, and modifying their file format for their journey to the end-user desktop. This introduces yet another VM file format that will be incompatible with other VM formats and management software from VMware, Citrix Systems, Microsoft, and open source Xen. Nevertheless, with the modifications, LivePCs may be compressed and encrypted, so that downloads can be more efficient and secure. A LivePC can be up and running on the end user's desktop as soon as 100 MB have arrived -- in some cases, faster than a laptop can boot itself up, said Whaley. The approach includes MokaFive Predictive Fetch, which anticipates what applications and data the user will need next and downloads them in background.

When the user is done with a desktop session, that image of the desktop, which might include a virus or worm that the user has inadvertently picked up, is flushed from the system and the next boot goes back to a clean LivePC image stored on the user's disk drive or other memory device. Because of MokaFive's ability to compress the desktop, it can be fitted on a USB device and quickly loaded onto a Windows, Macintosh, or Linux computer.

The MokaFive user first has to download a MokaFive Player in which a Live PC virtual machine will run. Player is the equivalent of the Adobe Reader installed on user desktops for reading documents in the Adobe's PDF file format, said Whaley. MokaFive Creator generates virtual desktops on a central server, MokaFive Player runs them on the user's desktop, and MokaFive Service Management Console allows for their remote supervision and updating. Even though the user may be disconnected, his VM will be updated with the latest security patches and operating system changes as he logs back into headquarters, where the Rejuvenation feature of the management console brings his VM back into conformance with the latest version.

Given the light "updating" workload of the central server, "You don't need an expensive server hardware infrastructure. That's the biggest difference," said Whaley.

One early user of the approach is a health care plan that equips doctors in a hospital with a USB device that contains their desktop, which can be activated on any laptop or PC in the hospital as they make their rounds. If the USB device is lost, no patient data is exposed because it's been encrypted.

In addition, if someone finding the device plugs it into a PC and attempts to use the virtual machine, the Rejuvenation feature detects the device and downloads a "poison pill" that kills the VM and erases its data.

Road warriors or work-at-home employees represent "a nightmare to IT administrators" trying to guarantee the security of the data they work with. With MokaFive virtual desktops, some of the worry goes away, Whaley said.

MokaFive Virtual Desktop Solution is available immediately for free download in its express version and offers cost-savings even in its paid version, said Whaley. A professional version is available for a $79 to $99 annual subscription.