A virtual machine is a set of resources obtained from UNIX at initialization time that display the functions and characteristics of a D3 computer system, and are shared by several D3 processes.
In this case, a real machine (the UNIX computer system) emulates a virtual machine (the D3 computer system), which then appears to have disk space, tape drives, printers, terminals, users, and the D3 file system and language.
Several virtual machines can coexist on any given single hardware platform.
A virtual machine is identified by a unique key allocated by the System Administrator at install time.
A virtual machine must first be booted (activated) before users can access it. Any user can be connected to any number of virtual machines at any given time.