OpenVZ

OpenVZ is an Operating System-level server virtualization solution, built on Linux. OpenVZ creates isolated, secure virtual environments — VEs (otherwise known as virtual private servers, or VPSs) on a single physical server enabling better server utilization and ensuring that applications do not conflict. Each VE performs and executes exactly like a stand-alone server; VEs can be rebooted independently and have root access, users, IP addresses, memory, processes, files, applications, system libraries and configuration files.

http://openvz.org/

Sun's UltraSparc T1 processor use OpenVZ - http://news.zdnet.co.uk/software/0,1000000121,39285296,00.htm