The document outlines NASA's rules for project managers, divided into categories. It discusses two specific rules categories: hardware and software. For hardware, it notes that no hardware is truly previously flown, and that equipment usually works differently than designed. For software, it emphasizes treating software like hardware with quality control. It also notes the difficulty of detecting software flaws and importance of contingency plans. Knowledge comes from testing, but models have flaws, and only the computer truly knows today's complex systems.