It looks more like a paper weight than a PC. A chromed 3.5-inch-square box, open on one end, captures a new form of desktop virtualization.

The Pano is designed to run the output from a Windows virtual machine, running elsewhere on a networked server. The Pano passes the user interface information from the server to the screen at the user's desktop. Call it a blocky thin client.

The Pano was launched Monday by Pano Logic, a Menlo Park, Calif., startup. It contains no memory, no disk drive, nor any processor except for a simplified form of silcon, a field programmable gate array. The array can be embedded with some program logic, along with switches and interconnects to peripheral devices. It's just smart enough to convey the Windows' user interface elements to a desktop display and send back any mouse clicks or keyboard entries to a central server.

Nick Gault, CEO of Pano Logic and one of the founders of XenSource, in an interview called it "a no-software computer."

The Pano strips away nearly everything found on a traditional desktop PC. And its small size makes the thin clients from manufacturers such as Wyse Technology and Hewlett-Packard seem like Sumo wrestlers. Pano requires 5 watts of power, or about 3% of what an average PC requires, said Gault.

The sole user action to start the Pano is to press the little triangular start button on its chrome top, its only visible control. Pano Logic will put the small boxes on an enterprise desktop for $15 a month ($180 a year per user) or $300 to $350 for a lifetime license.

As with other forms of desktop virtualization, end user software is cheaper to maintain with all the applications and operating systems running on central servers, administered by IT staff. "When there's no software on the desktop, desktop security problems tend to disappear," said Gault.

Hundreds of desktops run by Panos would require two central servers to sustain them. One would be the virtualization server generating VMware ESX Server virtual machines and running Windows XP or Windows Vista in them. A second server, the Pano Management Server, sits between the virtualization server and the Pano desktops. Its job is to supply connections as needed to end users seeking to link to an enterprise's Microsoft Active Directory, an LDAP directory, or other enterprise resources. Its installation is covered by the price paid for Pano desktops.

The need for two central servers, each with complex software, makes the no-software desktop more complicated than it first appears. But Gault said Affinity Bank, a unit of the Affinity Group in Ventura, Calif., is equipping its branch offices with Panos as a way to deliver desktop applications.

Once started, the Pano units can present additional options to their users with a follow-up touch of the triangular button. They can be programmed through the central server to offer a rollback to a good instance of Windows from a frozen session. They can offer different operating system environments to the same desktop. Or they can offer role-based desktops, with different combinations of applications.

The versatility illustrates how virtualization revamps thinking on how desktops can be managed, Gault said. Such management is made possible by fast networks with plenty of capacity. With devices such as disks and CPUs running on central servers instead of inside desktop machines, "the network has become the computer bus," tying the display at the desktop to its missing elements out on the network, he said.

Pano currently runs only with VMware's ESX Server hypervisor, but "we are hypervisor agnostic," Gault said. He made no commitments to support open source Xen or Microsoft's upcoming Viridian hypervisor within a foreseeable timeframe.

The Pano will become generally available by the end of September.