Re: Groups!
I was a "system programmer" back in those days, which meant I was responsible for installing software updates from IBM. Thus I was told the passcode to unlock the door into the hallowed raised-floor room. One day, while attempting to make a backup copy of the main "procedure library" I accidentally got the cards in reverse order and copied an empty disk pack (remember those?) on top of the active library. I had to go to the tape library room (remember those?), get out the last backup tape, and restore the procedures disk. Without the procedures file, all operations grind to a halt in an IBM shop of those days so the actual "operators" stood around glaring at me as I did this.
So even the hallowed priests can mess up.