IS-DOS v1.0 1985 Intelligent Software Ltd The Base 1985 The Adventure Workshop Deadline 1986 Infocom The Island 1985 The Adventure Workshop Seastalker 1984 Infocom Zork 1 - The Great Underground Empire 1984 Infocom Zork 2 - The Wizard of Frobozz 1984 Infocom Zork 3 - The Dungeon Master 1984 Infocom