Relay computers - OR functionality - symbology - test-drb@ccmp.vtda.org

28 Sep 2004

...
 From: "Vintage Computer Festival"
&lt;vcf(a)siconic.com&gt;

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.
Dwight