A list of electrical engineering maxims by DEC Engineer Don Vonada:
- There is no such thing as ground.
- Digital circuits are made from analog parts.
- Prototype designs always work.
- Asserted timing conditions are designed first; unasserted timing conditions are found later.
- When all but one wire in a group of wires switch, that one will switch also.
- When all but one gate in a module switches, that one will switch also.
- Every little picofarad has a nanohenry all its own.
- Capacitors convert voltage glitches to current glitches (conservation of energy).
- Interconnecting wires are probably transmission lines.
- Synchronizing circuits may take forever to make a decision.
- Worse-case tolerances never add — but when they do, they are found in the best customer’s machine.
- Diagnostics are highly efficient in finding solved problems.
- Processing systems are only partially tested since it is impractical to simulate all possible machine states.
- Murphy’s Laws apply 95 percent of the time. The other 5 percent of the time is a coffee break.
Source: Computer Engineering: A DEC View of Hardware Systems Design, 1978, Digital Press, Chapter 1, “Seven Views of Computer Systems”, by C. Gorgon Bell, J. Craig Mudge, and John E. McNamara, Table 5