Relay computers - OR functionality - symbology

From: Dwight K. Elvey <>
Date: Tue Sep 28 20:21:54 2004

>From: "Vintage Computer Festival" <>
>On Tue, 28 Sep 2004, Steve Thatcher wrote:
>> when someone can pick up a logic description and understand it WITHOUT
>> having to figure out what each sytmbol means in the context of the
>> usage, then it is simply more understandable. If I picked up something
>> that had two binary numbers wiht a PLUS sign inbetween, I would not
>> assume that it meant OR, only if you would dig further does the PLUS
>> sign make sense. If you simply said OR, then there is no confusion and
>> it is self documenting. I think Sellam was trying to make this point
>> with regards to symbology.
>Right. What I was getting at is that there were plenty of other symbols
>on the typewriter or keypunch to choose from.
>Having gotten the explanation as to why those operations were chosen, it
>does make sense and is somewhat elegant (I'll reluctantly concede), but
>it's still stupid as far as I'm concerned. Why didn't they use * or X
>for AND then?

Hi Sellam
 Some do use * or X. Would that have helped you? Although, others
seem to to describe things like set theory, I can show a simple
example of the practical use.

 A.(B+C) = A.B + A.C ( just like ordinary math )
 A+(B+C) = (A+B)+C ( again, just like ordinary math )
Other than that, I don't think there is a good reason.
Received on Tue Sep 28 2004 - 20:21:54 BST

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