 The last major advance was to use a general-purpose digital computer in place of the analog or custom designed digital computers.Previous missile designs normally used two single-purpose computers; one ran the autopilot that kept the missile flying along a programmed course, and the second compared the information from the inertial platform to the target coordinates and sent any needed corrections to the autopilot.To reduce the total number of parts used in Minuteman, a single faster computer was used, running separate routines for these functions.