Technologies in 2001: A Space Odyssey well, such as a nervous breakdown—as Hal did in the film. Clarke noted that, contrary to popular rumor, it was a complete coincidence that each of the letters of Hal's name immediately preceded those of IBM in the alphabet. The meaning of HAL has been given both as "Heuristically programmed ALgorithmic computer" and as "Heuristic ALgorithmic computer". The former appears in Clarke's novel of "2001" and the latter in his sequel novel "2010". In computer science, a heuristic is a programmable procedure not necessarily based on fixed rules, producing informed guesses often using trial-and-error. The results can be false such
2001: A Space Odyssey (novel) a Space Shuttle launch, the adhesive sauces used to keep food firmly in place on one's plate, and even the zero-gravity toilet. Over the course of the novel, several minor characters either appear very briefly or are named only in passing, including other man-apes, spaceflight staff, lunar station security, and "Discovery" crew members. Among the novel's minor characters, some of the more consequential are listed below (often having direct film equivalents, or else being recurring characters in the "Odyssey" novel series). A sequel to the book, entitled "", was published in 1982 and adapted as a motion picture in 1984.