"Not long ago, commentators were referring to
mainframes as dinosaurs, heading for extinction. IBM's mainframe
revenues were clearly in decline and high-end Unix servers,
including even IBM's own variety, were threatening its existence.
Things were looking decidedly grim for the dinosaurs. That was
until the dinosaurs did a deal with the Linux penguin. According to
popular mythology, this is how it happened.
A group of developers in one of IBM's German Labs decided to run
Linux under VM, provoked by a member of the Linux community who
wanted to see Linux run everywhere. IBM invented VM, which stands
for Virtual Machine, in the 1960s to allow users to test new
releases of the operating system without disturbing the current
version. It developed over the years and saw a good deal of usage
as an operation OS. VM was thus the easiest and fastest way of
getting the penguin to run with the dinosaur.
Legend has it that several IBM executives got to know about the
Linux project and advised the developers involved to desist. They
didn't, it just turned into a skunk works. They got Linux working
and demonstrated the running of thousands of Linux instances on the
mainframe. Because the educational world became interested, IBM
executives changed their minds. Then, IBM looked at the Linux
market and decided that it wanted in and suddenly mainframe Linux
became part of the strategy."