Microsoft will support both Linux and Solaris in its next version of Virtual Server. But virtually, on top of Windows. At the same time, the interim release of the product was renamed Virtual Server 2005 R2, rather than "Service Pack 1" because it will include significantly more changes than a usual service pack, said Zane Adam, director of marketing in the Windows Server division of Microsoft. The software giant typically offers service packs and interim releases called "R2s" between major updates to its server products. Those "enhancements" include support for Linux and Solaris - technology that Microsoft is developing with the help of some of its partners, although Adam refused to say which. Virtual Server 2005 R2 also will include 64-bit support, which allows more virtual machines to run on one server. It will feature better performance for virtual machines in memory-intensive applications, as well as higher availability through new clustering technologies, Adam said.