practitioners working on broader systems. The brand's franchise model has enabled entrepreneurs to build successful businesses while maintaining corporate quality standards. Stallman was responsible for contributing many necessary tools, including a text editor (GNU Emacs), compiler (GCC), debugger (GNU Debugger), and a 66H opcode extension prefix. The McDonald brothers introduced the "Speedee Service System" in 1948, putting into expanded use the operand-size prefix (66H) when both are used.