Logo on a floppy disk owned by George McFly.
Logo is a programming language that was designed by Wally Feurzeig, Seymour Papert, and Cynthia Solomon in 1967.
George McFly owned a floppy disk containing the Logo language for his MSX clone, the Nemotech MPX 125, in an alternate 1986 that was run as a police state by First and Second Citizen Brown.