pioneered in 1966 with the IBM CP-40 and CP-67, predecessors of the VM family. Examples outside the mainframe field include Parallels Workstation, Parallels Desktop for Mac, VirtualBox, Virtual Iron, Oracle VM, Virtual PC, Virtual Server, Hyper-V, VMware Fusion, VMware Workstation, VMware Server (discontinued, formerly called GSX Server), VMware ESXi, QEMU, Adeos, Mac-on-Linux, Win4BSD, Win4Lin Pro, and Egenera vBlade technology. Hardware-assisted virtualization In hardware-assisted virtualization, the hardware provides architectural support that facilitates building a virtual machine monitor and allows guest OSes to be run in isolation. Hardware-assisted virtualization was first introduced on the IBM System/370 in 1972, for use with VM/370, the first virtual machine operating system offered by IBM as an official product. In 2005 and 2006, Intel and AMD provided additional hardware to support virtualization. Sun Microsystems (now Oracle Corporation) added similar features in their UltraSPARC T-Series processors in 2005. Examples of virtualization platforms adapted to such hardware include KVM, VMware Workstation, VMware Fusion, Hyper-V, Windows Virtual PC, Xen, Parallels Desktop for Mac, Oracle VM Server for SPARC, VirtualBox and Parallels Workstation. In 2006, first-generation 32- and 64-bit x86 hardware support was found to rarely offer performance advantages over software virtualization. Operating-system-level virtualization In operating-system-level virtualization, a physical server is virtualized at the operating system level, enabling multiple isolated and secure virtualized servers to run on a single physical server. The "guest" operating system environments share the same running instance of the operating system as the host system. Thus, the same operating system kernel is also used to implement the "guest" environments, and applications running in a given "guest" environment view it as a stand-alone system. The pioneer implementation was FreeBSD jails; other examples include Docker, Solaris Containers, OpenVZ, Linux-VServer, LXC, AIX Workload Partitions, Parallels Virtuozzo Containers, and iCore Virtual Accounts. See also Amazon Machine Image Desktop virtualization Linux containers Native development kit Paravirtualization Storage hypervisor Universal Turing machine Virtual appliance Virtual backup appliance Virtual disk image Virtual DOS machine (VDM) Virtual machine escape References Further reading James E. Smith, Ravi Nair, Virtual Machines: Versatile Platforms For Systems And Processes, Morgan Kaufmann, May 2005, , 656 pages (covers both process and system virtual machines) Craig, Iain D. Virtual Machines. Springer, 2006, , 269 pages (covers only process virtual machines) External links Sandia National Laboratories Runs 1 Million Linux Kernels as Virtual Machines The design of the Inferno virtual machine by Phil Winterbottom and Rob Pike Operating system technology Programming