VM - technical definition

(1) See voice mail.

(2) (Virtual Machine) One instance of a virtual machine in a virtual machine environment. See virtual machine.

(3) (Virtual Machine) An IBM mainframe operating system, originally developed by a separate research arm of the company and later adopted as an IBM system product. Starting in the early 1970s, VM was the first virtual machine environment running on IBM mainframes (for more on VM's history, see CP/CMS).

VM runs multiple operating systems, each with their own applications. Typical guest operating systems are any of IBM's mainframe versions of OS, DOS, AIX and Linux. In 2000, IBM introduced z/VM, the first VM version based on IBM's 64-bit z/Architecture. For more information, visit www.vm.ibm.

VM-CP and CMS
VM-CP (VM-Control Program), also called the "VM hypervisor," is the VM master control program that includes the virtual machine functionality. CMS (Conversational Monitor System) is a compact guest operating system that is widely used with VM to provide interaction for one user. Each user communicates with CMS in a separate virtual machine in the computer. See virtual machine.