The operating system computer was a JC8520, which was running a version of MS-DOS. All commands had to be typed in correctly or nothing would happen. While operating the plant, several commands had to be entered every shift, since the owners didn't purchase a very automated package.
In the interview for the data center job, I was asked if I had any experience with Windows. I didn't understand the question because I wasn't aware they were talking about a computer operating system! So, I replied at the office building I worked in there were outside contractors who cleaned the windows.
After my reply all seven of the interviewers were all grinning and I was aware I said something they weren't looking for. One of the men politely told me Windows was a computer operating system. My reply was, "Oh, I see."
When I returned home I told my wife what happened and we shouldn't get our hopes up. To my utter shock, a week later I was offered the job, which I took and after some training, learned something I didn't know before.