Last week I began to discuss MojoPac from RingCube, which uses operating system virtualization to create a Windows XP virtual machine on a host PC running XP.

Virtualizing the operating system rather than the hardware results in big performance gains. RingCube claims hardware virtualization overhead can be as high as 40% of processor cycles, while the MojoPac operating system virtualization has an overhead of about 0.4%. The company also claims a low memory overhead -- about 30MB compared with hardware virtualization, which starts at around 1GB.

MojoPac, in effect, shares the host operating system. This not only means you can run games from a MojoPac system, but it also gets around licensing problems because there is only one copy of the host operating system. Sorry Bill.

When a MojoPac system is running you are either in the MojoPac environment or in the host environment. Whichever you are in occupies the whole display, although programs running in both environments continue to execute and you have full clipboard sharing.

I mentioned last week that MojoPac requires administrator access to run. If this level of privilege isn’t possible, RingCube now has a tool called Usher that, once installed, allows MojoPac to run with whatever privileges the current user has.

Last week I referred to the MojoPac product that runs off USB-interfaced devices as “MojoPac” — this has recently been rebranded as “MojoDrive.”

MojoDrive is marketed under the banner of Enterprise MojoPac, a suite of virtualization solutions that also includes MojoStation. MojoStation is like MojoDrive but can be installed in a local hard-disk subdirectory, allowing for much improved performance.

Even more interesting is that with RingCube’s configuration tool, MojoAdmin, you can create installers for your own pre-configured and locked-down versions of MojoDrive and MojoStation.

For example, you could build an installer that creates a MojoDrive or MojoStation that requires a name and password to install, when running disables switching back to the host operating system, doesn’t allow new applications to be installed, requires authentication against Active Directory, blocks printing on the host’s printers, disables print screen and clipboard sharing, and requires host antispyware and antivirus software.