At Macworld Expo in San Francisco yesterday, Moka5 released a free public beta of Moka5 for Mac, a Mac OS X version of software for automatically distributing and updating virtual machines over a network or distributing via USB storage device. The release version will be available during the second quarter. The beta is compatible with the company's Windows and Linux versions.

Moka5 for Mac beta enables VMware Fusion users to create and configure LivePCs, virtual machines containing an operating system and applications and settings, but which have some special attributes. A proprietary live compression technology also enables users to run a LivePC from a USB flash memory device.

Unlike ordinary virtual machines, LivePCs are "self healing:" every time the LivePC is rebooted, any malware or accidental damage to the system is eliminated as the operating returns to its original state, but users' documents and preference settings are retained.

For instance, in a demonstration, the user changed the Windows XP desktop picture and infected the system with a virus that rendered the system unusable. A simple reboot of the LivePC virtual machine restored the system without the virus, but retained the modified desktop picture.

Administrators can configure what will be saved and what will be discarded upon reboot of the VM. But exactly how the software can distinguish between system and user data is not something Moka5 is willing to talk about.

"That's the secret sauce," said John Whaley, a co-founder of Moka5. The sauce came out of the work that Whaley and others did as graduate students at Stanford University.

A VMware spokesperson said that have been working with Moka5 and its LivePC technology to help the company roll out Moka5 on all of the platforms VMware supports.

Another special attribute of LivePCs is an automatic compression scheme that can contain a Windows XP virtual machine in 100 MB of storage space. This makes LivePCs good for streaming over networks when updating a LivePC after the administrator makes changes, like installing or removing software in the VM or making configuration changes. Moka5 only moves the changes to a LivePC over a network when updating, not the entire virtual machine

The compression technology also enables a user to run one or more LivePCs directly from a USB flash drive that is only a few gigabytes in capacity. Doing so conserves notebook battery power on notebooks. It also creates the secure situation of running a virtual machine without installing anything on the host computer.

LivePCs are cross-platform, and can automatically install and update LivePC on multiple Windows, Mac, and Linux client machines over a network. On Mac clients, the LivePCs run in VMware Fusion. On Windows PCs, the LivePCs can run in the free VMware Player.

Moka5 for Mac and run any operating system that VMware supports in a LivePC, including Mac OS X Server. Mac clients can also run LivePCs created with Moka5 for Windows. The user interface is a simple palette that lists the available LivePCs next to buttons to turn them on and off.

Last month, Moka5 issued a "preview release," which was something of a pre-beta, less robust version.

If you’ve tried the Moka5 for Mac beta what you think of it.