[1] : The Free On-line Dictionary of Computing (27 SEP 03)

virtual machine
     
        1. an abstract machine for which an interpreter exists.
        virtual machines are often used in the implementation of
        portable executors for high-level languages.  the hll is
        compiled into code for the virtual machine an intermediate
        language which is then executed by an interpreter written
        in assembly language or some other portable language like
        c.
     
        examples are core war, java virtual machine, ocode,
        os/2, poplog, portable scheme interpreter, portable
        standard lisp, parallel virtual machine, sequential parlog
        machine, snobol implementation language, soda,
        smalltalk.
     
        2. a software emulation of a physical computing environment.
     
        the term gave rise to the name of ibm's vm operating
        system whose task is to provide one or more simultaneous
        execution environments in which operating systems or other
        programs may execute as though they were running "on the bare
        iron", that is, without an eveloping control program.  a major
        use of vm is the running of both outdated and current versions
        of the same operating system on a single cpu complex for the
        purpose of system migration, thereby obviating the need for a
        second processor.
     
        2002-04-15
     
     
see also:
abstract machine interpreter high-level languages intermediate language assembly language c 
core war java virtual machine ocode os/2 poplog 
portable scheme interpreter portable standard lisp parallel virtual machine sequential parlog machine snobol implementation language 
soda smalltalk ibm vm operating system 
cpu 

[2] : The Free On-line Dictionary of Computing (27 SEP 03)

virtual machine
     
         vm an ibm pseudo-operating system
        hypervisor running on ibm 370, esa and ibm 390
        architecture computers.
     
        vm comprises cp control program and cms conversational
        monitor system providing hypervisor and personal computing
        environments respectively.  vm became most used in the early
        1980s as a hypervisor for multiple dos/vs and dos/vse
        systems and as ibm's internal operating system of choice.  it
        declined rapidly following widespread adoption of the ibm pc
        and hardware partitioning in microcode on ibm mainframes
        after the ibm 3090.
     
        vm has been known as vm/sp system product, the successor to
        cp/67, vm/xa, and currently as vm/esa enterprise systems
        architecture.  vm/esa is still in used in 1999, featuring a
        web interface, java, and db2.  it is still a major ibm
        operating system.
     
        home http://vmdev.gpl.ibm.com/.
     
        "history of vm"?, melinda varian, princeton university.
     
        1999-10-31
     
     
see also:
ibm operating system hypervisor ibm 370 esa ibm 390 
control program conversational monitor system dos/vs dos/vse ibm pc 
microcode mainframes ibm 3090 cp/67 web 
java db2 lt;homegt; 

Virtual Machine >> V Words
Virtual Machine, definition of term: Virtual Machine
virtual+machine_pag1.html

Virtual >> V Words
Virtual, definition of term: Virtual
virtual_pag1.html

Machine >> M Words
Machine, definition of term: Machine
machine_pag1.html

Machine Transla >> M Words
Machine Transla, definition of term: Machine Transla
machine+transla_pag1.html

Virtual Image >> V Words
Virtual Image, definition of term: Virtual Image
virtual+image_pag1.html

Virtual Device >> V Words
Virtual Device, definition of term: Virtual Device
virtual+device_pag1.html

Virtual Circuit >> V Words
Virtual Circuit, definition of term: Virtual Circuit
virtual+circuit_pag1.html

Machine Tool >> M Words
Machine Tool, definition of term: Machine Tool
machine+tool_pag1.html

Virtual Focus >> V Words
Virtual Focus, definition of term: Virtual Focus
virtual+focus_pag1.html

Machine Shop >> M Words
Machine Shop, definition of term: Machine Shop
machine+shop_pag1.html

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