The term gave rise to the name of IBM's VM operatingsystem 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use of VM is the running of both outdated and current versions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.