You can do virtualization also using z/VM operating system, each user has its own VM. It still stores all the users password in plain text inside a DIRECTORY f

You can do virtualization also using z/VM operating system, each user has its own VM. It still stores all the users password in plain text inside a DIRECTORY file that resides on the maintenance userids. I've seen it 100% of the time I did support on one of those systems.