biff
The Unix command that announced new mail in your terminal, named after a dog that barked at the postman.
John Foderaro wrote biff at UC Berkeley around 1980, and it travelled out into the world with BSD Unix. biff y turned notifications on, biff n turned them off. The actual work fell to the comsat daemon: on delivery it was poked, found the user's terminal and printed the sender and first few lines straight over whatever they happened to be doing.
The name comes from Biff, a dog belonging to Heidi Stettner at Berkeley who, as the story goes, barked whenever the mail carrier arrived. Its graphical successor xbiff showed a mailbox whose flag went up. Every modern push notification is essentially the same idea, with the same talent for interruption.