I don't know anything about IBM operating systems, but I understand that older versions of System/370 are free and can be run on PCs via this famous emulator:

I don't know anything about IBM operating systems, but I understand that older versions of System/370 are free and can be run on PCs via this famous emulator: http://www.hercules-390.eu/ http://www.hercules-390.eu/ IBM absolutely hates that software.