Virtuozzo makes a single operating system, either Linux or Windows, appear to be several independent instances of the OS, instances the company calls virtual private servers. That makes it easier for different software applications to run in separate compartments.
The 64-bit support provided by 64-bit x86 processors such as Intel's Xeon and Advanced Micro Devices' Opteron increases the amount of memory a computer can easily use to well over 4GB. Having large amounts of memory, in turn, makes it easier to run many jobs on the same server.
Herndon, Va.-based SWsoft launched Virtuozzo for Linux in 2001; the Windows version came in 2005. The software competes with EMC's VMware, Microsoft's Virtual Server, and the open-source Xen.
Virtuozzo is most popular among Web site hosting companies, which use the software to share the same server with multiple customers. Customers include and RackSpace.
Virtuozzo costs $999 per processor for its 32-bit software and $1,500 for the 64-bit version. The company charges the same for use on dual-core chips, which feature two processing engines on a single slice of silicon. That policy is the same as that used by VMware, Microsoft and BEA Systems, though some software companies charge per processor core and not per processor.
Virtuozzo is not certified to run with Windows or Linux, but the company "has open discussions with a number of companies, including Red Hat, Novell and Microsoft," the company said.