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When you press the main button. BOOM! Interrupt! That is one example. They even had virtualization in the 80's on System / 370 long VMWare came out.

There was the operating systems CMS and CP67 done by the IBM Cambridge Scientific Center for the IBM 360/67 in, right, about 1967. The CP67 was control program 67 and was for virtual machine. CMS was Cambridge Monitor Systems, maybe off and on Conversational Monitor System, and the command-line time-sharing operating system users saw.

CP67 was intended as a means for interactive, time-shared operating system development. So, right, could run CP67 on CP67 -- once that was done 7 levels deep.

The combination CP67/CMS was, for the time, a total dream for a time sharing system.

Stop malicious code? Sure: On CP67 write and run any code, any instructions doing anything you want with any data you want, and you just cannot bother any other users. So, could run malicious code safely.

I used CP67/CMS and PL/I from National CSS Time Sharing in Stamford, CT to schedule the fleet at FedEx. Founder, COB, CEO Fred Smith's remark about the output was "Amazing document" "Solved the most important problem facing FedEx". The Board was pleased and a nice chunk of funding was enabled. It literally saved the company. No, Fred never gave me my promised stock, that once he said would be worth $500,000. Add a few zeros for now.

Since then CP67 was called VM, and for years IBM's internal computing was done on about 3600 mainframes around the world and all running VM/CMS and connected with VNET which was a lot like the Internet except the communications were via bisync lines and the routing was done by the mainframes themselves. No, that setup didn't depend on Systems Network Architecture (SNA). Yes, there were a lot of fora!

The advantages of running on VM were too good to pass up, so eventually essentially all production IBM mainframes were running their operating systems as guests on VM on the bare metal.

In virtual machine, IBM was way out in front.

They still are.

When I started learning how OS/400 work, now IBM i. I was quite interested to see the execution model of having everything stored as bytecode, with a JIT kernel doing AOT compilation at install time.

Something that is kind of being done on the Android and Windows worlds, attempted on Oberon and Inferno, but not with the extent that the OS/400 does it.

http://virtualirfan.com/history-of-interrupts

So no on that one.

Visualiation? You mean virtualization. That was a given, Turing should be credited with that, after all the whole idea of a universal Turing machine is that it can emulate any other Turing machine (including another universal one).

VM is not really an emulation. If the guest's code is just user level code, then it just runs as usual directly in the hardware processor. But if in the guest's code there is a privileged instruction, that is, an instruction reserved for an operating system, then the VM gets an interrupt and, then, decides if VM wants to execute the privileged instruction on behalf of the guest. To make this all efficient, there is some hardware called virtual machine assist.

It goes back even farther than the 1980s. IBM's virtualization product, VM/370, was released in 1972.[1] The development of it happened in the late 1960s on a special version of the 360 that had virtual memory support.[2]

[1] https://en.wikipedia.org/wiki/VM_%28operating_system%29

[2] https://en.wikipedia.org/wiki/CP/CMS

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