The part number, or part #, was given to each program developed for the TI-99/4A. It allowed for a comprehensive yet simple way to catalog the software made for the system. Most publishers created their own part numbering system, but would stay with the same naming algorithm once devised. For example, Texas Instruments part number for Solid State SoftwareTM Command Modules followed the same pattern. They all began with the letters "PHM" followed by 4 digit number (example PHM 3027).