VMware’s Workstation 6.5, its desktop virtualization widgetry, hit general availability Monday. The latest upgrade of the nine-year-old software, VMware’s original product, can be used to toggle between windows on different virtual machines and debug multi-tier applications while productivity apps run on the same computer.

The company, which calls it the “gold standard” and “the only choice for serious technical desktop virtualization users,” claims it accelerates software development and testing, provides rapid provisioning and resetting of multi-tier environments, enables pre-production testing of new desktop and server applications in secure, easy-to-manage virtual machines and allows users to run any application on their preferred operating system.

It supports Windows, Linux, NetWare, Solaris x86 and FreeBSD. Installing Windows and Linux guest operating systems and VMware Tools can be done unattended once a checklist is filled out.

Complements of a so-called Unity feature, rev users can run applications in virtual machines alongside applications on their normal desktop. VMware says the desktop of the virtual machine disappears and applications appear as a normal window in the rest of the user’s environment. Color coding of Unity application windows is said to make it easy to run multiple versions of the same application across different virtual machines.

VMware Workstation 6.5 lets users record a VM’s entire programmatic execution – every CPU instructions, every memory page and every disk write – over time and then replay the recording to reproduce the exact behavior and state of the virtual machine to help analyze and debug hard-to-reproduce software defects until they are fixed.

VMs can also be encrypted and run with the VMware Player for improved data security or Personal Pocket ACE virtual machines can be created that the user can take on the road with a USB thumb-drive.

The upgrade is free to users. It lists for $189.