Operating system software of a prototype autonomous vehicle is presented in this paper. The prototype Autonomous Vehicle employs binary camera vision for navigation and is differentially steered. The software is a top-down design, modular in architecture to facilitate software maintenance and continual enhancement. At this present stage of development, it contains several parameter definition files and close to 50 major sub functions/sub function groups besides the main supervisory module. The subroutines range from system validation (data acquisition in real-time) and equipment calibration, image data filtering and processing to the driving and steering of the vehicle. The control codes are developed using the Borland Turbo-C compiler.