Digital circuits and analog devices

Eric Smith spacewar at
Fri Dec 2 00:18:38 CST 2016

On Thu, Dec 1, 2016 at 10:59 PM, Tony Duell <ard.p850ug1 at> wrote:

> It's one of Don Vonada's laws. I am pretty sure I first read them in
> 'Computer Engineering', that book produced by DEC. I think the
> original is 'Digital circuits are made from analog parts'
> Another of the laws is 'There is no such thing as ground' which

That's where I saw them also.  The full set from the book (any typos are

Vonada's Engineering Maxims

1. There is no such thing as ground.
2. Digital circuits are made from analog parts.
3. Prototype designs always work.
4. Asserted timing conditions are designed first; unasserted timing
conditions are found later.
5. When all but one wire in a group of wires switch, that one will switch
6. When all but one gate in a module switches, that one will switch also.
7. Every little pico farad has a nano henry all its own.
8. Capacitors convert voltage glitches to current glitches (conservation of
9. Interconnecting wires are probably transmission lines.
10. Synchronizing circuits may take forever to make a decision.
11. Worse-case tolerances never add -- but when they do, tehy are found in
the best customer's machine.
12. Diagnostics are highly efficient in finding solved problems.
13. Processing systems are only partially tested since it is impractical to
simulate all possible machine states.
14. Murphy's Laws apply 95 percent of the time. The other 5 percent of the
time is a coffee break.

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