Bill:  I hope you don't mind if I enjoyed this discussion and just jumped
in.  I just thought you might be interested to know that the box with the X
had several meanings in different standards over the years.  But one which
may interest you is the case where the box with the X inside represented a
"LOGICAL NOT" function and was used in fluid logic systems.  Fluid logic
was used in "XP" (explosion proof) - another use for the X- requirements
such as Class 1, Division 1, Group C.  I believe you may know that it was a
system of air logic modules, i.e., AND< NAND, OR, NOR, NOT...
GE picked up the symbol and used it in their "STATIC LOGIC BLOCKS", which
were RTL logic functions made with discrete components and put on a male
octal tube type plug.  They  used the symbol to represent a logical not for
a long time.  The  STATIC LOGIC BLOCKS had some interesting functions like
a "SEALED AND", and "RETENTIVE MEMORY".  They were rudamentary, but They
did lend themselves to some pretty sophisticated automation in their day.
Richard :-)     ----------
> From: Bill Cornutt <bill@CORNUTT.COM>
> To: PICLIST@MITVMA.MIT.EDU
> Subject: Re: [OT] XT -> crystal
> Date: Monday, May 25, 1998 7:44 PM
>
> ----------
>
> > > Bill, what has X
> > > representing 'trans' got to do with 'crystal'?
>
> Marco,
>
> Nothing, I was just showing that some things are not logical.
>
> But I did like the crisscross information.  And now I
> have a reasion for 'Xmas'.
>
> Is a box with a X in it the symbol for a crystal?
> If so, that brings up the question, "Which came first,
> the box or the X?"  (this is a variation of the classic
> American (USA), English? question, "Which came first,
> the chicken or the egg?"  Which is not at all the same as
> "Why did the chicken cross the road?"  Which brings us
> back to crisscross.)
>
> I've learned to over come reality,
>
> Bill C.   bill@cornutt.com