What operating system did the McDonald brothers develop before McDonald's became a global brand?

The McDonald brothers developed the Speedee Service System before McDonald's became a global brand.

Richard and Maurice McDonald created the system at their restaurant in San Bernardino, California. It used a restricted menu, standardized food preparation, assembly-line methods, and self-service principles to increase speed and consistency.

The approach became a foundation for the modern fast-food model. Ray Kroc later expanded McDonald's through franchising, but the operating concept originated with the brothers rather than with the later corporate expansion. The system's name also inspired Speedee, an early McDonald's mascot.

The Speedee Service System should not be confused with a later slogan or logo. It was primarily an operating and production method, although its emphasis on speed influenced the restaurant's early branding and advertising. Its principles helped make McDonald's recognizable as a standardized chain rather than a collection of unrelated local restaurants.