I was one of a number of junior sysprogs at CERL back in 1980. We had an office / bullpen upstairs where we would go and take care of business, usually during the non-prime time hours after 10 PM. And, of course, we would leave our terminals signed on, because we were all well-behaved junior sysprogs and would never dream of derfing one of our compatriots.
"Derfing" was what you did to someone who left their terminal logged in. You'd head out, find a public notesfile, leave a message saying "I am a derf", and let everyone ridicule them.
What can I say? We were young computer nerds. :) And we would never derf one another.
Until the evening when Kevin Nortrup walked out of the room for a few minutes and we dumped a "I am a derf" note into Pad using his terminal. Now once you had responded to a note, the original poster could no longer delete it, but we didn't quite manage to get a response in before Kevin returned, saw he had just been derfed, and angrily deleted the note, logged off, and headed off to work somewhere else.
I had inherited PLATO Notes from John Matheny when he'd moved on to CDC in Mpls and I knew many secrets. One of them was that there was an editor that a system programmer could use to resuscitate a deleted note. And so I did. And then we responded to it. And there was much rejoicing in the junior sysprog room.
Of course, Kevin discovered that we'd undeleted his note. And it didn't take him long to figure out that he could delete the note using the same tool that I'd used to undelete it. So he did.
I put the note back.
Kevin scrambled the pointers to the note in the file. Poor form, as that might damage the whole notesfile.
Well, this meant war. One of my compatriots logged into the enforcer, which allowed him to watch what program Kevin was in and to log him out if he tried to go somewhere we didn't want him to go -- such as the Notes editor. I bounced in and undeleted the note again, restoring the pointers that I had carefully copied down, having anticipated Kevin's most recent move.
Kevin saw the note was back, headed for the Notes editor, and we bounced him out. Several times, in fact.
Meanwhile, various readers of Pad were greatly amused to see the derf note appear and disappear and appear again. Obviously, the systems programmers were at play.
Finally, Kevin took advantage of the fact that he had a key to the console room. He went there, logged onto the console -- where we could not boot him out of a program -- and deleted the note once and for all.
Of course, this was all much too good of a story.
The thing was, none of the utilities that we used were logged. But everything that you did from the console was logged, so the only person who left fingerprints was Kevin. And when the owner of Pad, who was not so much a fan of Kevin's, complained about the abuse of his file with the system editors, Kevin was the one who got the stern lecture.
Not too much later, John Matheny added a logging feature to the system Notes editor.
And we did not play that game any more. :)