April Fools Practical Day Jokes
A group of us were novice UNIX hacks working for our department of computer science, all on similar terminals. I had written a small program that would transmit a single character at a time to another terminal. (No big deal, but no one else had tried it.) One guy was typing away, and I was making his cursor "wiggle" by pressing the forward and reverse arrow keys. He exclaimed that something was wrong with his cursor. Another guy picked up on this, and explained that the cursor beam must be loose. He gave the right side of the first guy's (John's) terminal a good hard whack, I transmitted a carriage return. John laughed, but actually sat there typing in (some text), and whacking the side of the terminal every time he needed a carriage return, FOR SEVERAL MINUTES. Needless to say, we were hysterical.
The second guy, (Tim), says "John, watch this!" and put his hand under John's desk and gave the underside of the desk another whack: I transmitted a "HOME" character, moving the cursor to the top of the screen, again as if the whack had moved the cursor. John continues typing, whacking the bottom and side of the terminal whenever he needs cursor motion. Tim smacks the top of the terminal and I transmit a CLEAR key: it looked as if the characters have been "knocked off" the screen. John is just about the get the lab manager when we clue him in.
I once had a job as a COBOL programmer. A particular program was to input no more than 20 items from an operator, and them produce the appropriate report from them. I asked my boss what the program should do if the operator wanted more than 20 items to appear in the report. He said, oh, that will never happen. But what if it does, I asked. Gruffly, he said, have it notify the operator.
This particular machine had a seriously loud bell (control G) that sounded like a real bell, plus it was fairly easy to make the screen flash off and on. I coded it to flash and ring the alarm for a minute. I tried it once and it was truly alarming. I never heard if anybody tried to enter more than twenty items, but it is something I think about from time to time ...