Here’s an interesting behind-the-scenes image from the making of Alien. From left, it’s director Ridley Scott, giving some instructions to Ian Holm as science officer Ash, and Sigourney Weaver as warrant officer Ripley. They’re inside another character from the film, the super computer that the crew affectionately (or not) refers to as Mother.
Its actual designation is MU/TH/UR 6000, a 2.1 terabyte mainframe that controls many of the functions of the spaceship Nostromo. Another arm of the ubiquitous Wayland-Yutani corporation, Mother eventually reveals the existence of Special Order 937, which demands the preservation of the alien life form on LV-426, even at the expense of the lives of the Nostromo crew members.