[time-nuts] D term (was no subject)

Poul-Henning Kamp phk at phk.freebsd.dk
Mon Jan 26 15:15:12 EST 2015

In message <5E5E892CF8A2440FBF18FFAD000B65FD at NewComputer>, "Lee Mushel" writes:

>I'm fairly sure that Jim is right.   I never had to worry about PID machine 
>control before the late sixties and by the mid-seventies the concepts were 
>firmly in place and in use.

The basic math of PID has been around for about 100 years.  The invention
of the servo (and synchro/resolver) is what makes its day...

>>> Almost all mechanical "governors" er pure P.
>> Maxwell strikes again
>> http://upload.wikimedia.org/wikipedia/commons/b/b1/On_Governors.pdf
>> definitely more than P controllers..

I said "Almost all"... :-)

Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

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