Relay computers - OR functionality

From: Vintage Computer Festival <>
Date: Tue Sep 28 05:29:07 2004

On Tue, 28 Sep 2004, Dwight K. Elvey wrote:

> >> In my logic, 'A' would indicated the normally opened contact an 'a'
> >> would be the normally closed contact for relay A. I'll use + to
> >> indicate OR and . to indicate AND.
> >
> >You already lost me. You may as well have used ! and $ instead of A and
> >a.
> >
> >:)
> >
> >P.S. C programming convention (which most people would relate to
> >immediately) says that next time you should use & for AND and | for OR.
> I'm sorry, people doing logic have been using + and . a
> lot longer than C has been using & and |. I specifically stated
> what I would use. Look at most any pre-C math book and
> you'll most likely see the + and . used for OR and AND.

What Genius decided that + should be OR, as opposed to AND, which seems
actually logical and not counter-intuitive?

> These are just symbols until one applies meaning to them. I

Right, but it's hard to work around ingrained meanings that have been with
you since 1st grade.

> I don't see the issue with using upper and lower case to
> indicate normally close or normally open? What difference
> does it make how one represents it?

None, I just felt like pointing out that whoever decided to use the plus
sign for OR was most likely insane.

Sellam Ismail                                        Vintage Computer Festival
International Man of Intrigue and Danger      
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Received on Tue Sep 28 2004 - 05:29:07 BST

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