Multivac is the name of a fictional supercomputer appearing in over a dozen science fiction stories by American writer Isaac Asimov. Asimov's depiction of Multivac, a mainframe computer accessible by terminal, originally by specialists using machine code and later by any user, and used for directing the global economy and humanity's development, has been seen as the defining conceptualization of the genre of computers for the period (1950s–1960s). Multivac has been described as the direct ancestor of HAL 9000.