This is a great question! And like all really great questions it has a simple and thought provoking answer. There are some associated questions I would like to also address here.
1. When was virtualization invented?
2. How did virtualization differ at invention from what we have now?
I know there is a whole group of you out there thinking tat you already know the answer to this question. If you are thinking that the answer is VMware you would be………….
wrong! Sorry folks vmware wasn’t even a dream in a child’s mind when virtualization was born.
The right answer is IBM.
Yes that’s right the IBM’ers were responsible for the Virtualization revolution. The really cool thing is that they came up with this revolutionary concept before there were even PC’s. We have to go all the way back to the mid 60’s and early 70’s to find the roots of virtualization. There wasn’t even Microsoft for crying out loud. It was the days of the mainframe.
So up in Boston , Ma. IBM had a research and development facility called the Cambridge Scientific Center and those guys really thought long and hard about how to get the most out of those giant (by the standards of the day) mainframe machines. The capacity to run multiple operating systems and stacks of applications was certainly there but there was this problem.
IBM had a set of code that managed OS access to hardware that was called the “Supervisory code” or the “supervisor” for short. There was a 1 to 1 relationship from supervisor to OS. As such running multiple OS’s on a single Supervisor was not functionally possible without some degree of abstraction above the supervisor.
The problem was solved by adding another layer of code above the supervisor to provide the necessary abstraction for the operating systems. Because the code ran atop the supervisor it was given the title “Hyper-Visor.” The term persists today more than 40 years later.
IBM released the CP/CMS operating system in the early 1970’s as the first to be commercially available with built in virtualization functionality. They didn’t stop there! IBM continued to develop technologies for Virtualization for the next 40 years.
The thing that really makes you sit back and go Hmmmmmmmmmm…….. is that IBM not only pioneered virtualization but there were no competitors in this space for more than 20 years. Connectix and VMware don’t hit the scene until the late 1990’s. In the world of technology if you get a 20 year head-start on your competition it might as well be forever. And yet here we are.
Home Work: Read the history article at : http://en.wikipedia.org/wiki/Timeline_of_virtualization_development
Next time we will talk about the 2 types of hypervisors spawned from the IBM’ers and the possible benefits and drawbacks of running each of the types.