VMware has released its first embedded hypervisor.

The new ESX Server 3i runs directly on the server's hardware (refered to as 'bare iron') without requiring an operating system. Users run their virtual machines directly on this software.

Virtualisation users previously had to install their own operating system and install virtualisation software on top of that.

Measuring only 32MB, the embedded hypervisor is 90 per cent smaller than the average operating system and virtual machine combination, VMware claimed.

Its smaller footprint renders it more secure and more stable than mainstream operating systems which offer many features that are needless to the average user, VMware chief executive Diane Greene argued in her opening keynote at VMworld in San Francisco.

XenSource, a maker of software that competes with that of VMware, last week unveiled its own embedded hypervisor.

But where XenSource essentially created a lightweight Linux distribution bundled with its hypervisor, VMware is running without any operating system whatsoever, boasted Greene.

"It's the only hypervisor out there that has absolutely no tie to an operating system," she said.

Server vendors are expected to embed the software with their hardware by connecting a USB memory stick or Flash memory directly to a server.

Loading the hypervisor and base operating system off Flash memory allows for faster deployments of new servers, although it does not offer any benefits in day-to-day operations.

HP is currently shipping servers with a USB connector, and IBM last week unveiled a similar system with its X4 chipset.

During an appearance at Greene's keynote, Dell's marketing chief Mark Jarvis revealed that the firm will start shipping a server optimised for virtualisation by the end of November.

Codenamed Veso, the server offers an SD Memory slot that stores virtualisation software.

In an effort to address the needs of virtualisation workloads, Viso offers twice the memory capacity of a similar Dell server. The system features two of AMD's new 'Barcelona' quad-core processors.

VMware's embedded hypervisor will be available as a standalone product at some time in the future. Server vendors will be able to bundle the software with their systems, the first of which are expected by late 2007 or early 2008.