VMware has released the second beta of its virtualisation software, Fusion 2.0, adding features such as multiple backups, mirrored folders and support for Mac OS X Server 10.5.

Fusion is one of the two available virtualisation programs for the Macintosh - the other is Parallels Desktop for Mac - that lets users of Intel-based Macs run Windows, Linux and other operating systems on their machines.

According to Fusion 2.0 Beta 2's release notes and a blog posted to the VMware site, users can now take and manage multiple "snapshots," VMware's term for saved versions of a virtual machine (VM). Fusion 1.0 and Beta 1 of Fusion 2.0 allowed only one snapshot per VM. A new auto-protect tool has also been added, which takes snapshots at user-set intervals.

Other changes and additions include improvements to Unity, the Mac-Windows integration feature that lets users run Windows applications in Mac-style windows and launch Windows-formatted files with Mac applications; and to the virtual machines' support for DirectX 9.0 3D acceleration.

VMware continued to warn users of possible problems with the beta implementation of 3D acceleration, however. "Performance may still vary, depending on your graphics card and game requirements," the company told Windows gamers.

Beta 2 also lets users mirror important folders in Windows XP and Vista -- Desktop, My Documents, My Music and My Pictures - by mapping them to the corresponding folders in Mac OS X. It is also the first version of Fusion to support Mac OS X Server 10.5.

Fusion 2.0 Beta 1 was released nearly three months ago; VMware, however, has not set a schedule for shipping the final product.

"We're not publicly stating a [release] timetable," said Pat Lee, a VMware senior product manager. "But we're really happy with the feature set in the beta." Lee also declined to say how many betas VMware had planned for Fusion.

Fusion 2.0 Beta 2 can be downloaded free of charge from the VMware site. Current Fusion users will receive the update at no charge when it ships.