'motherboard' etymology

[Jon Elson]

On 02/28/2016 06:32 PM, Jules Richardson wrote:
>
> Does anyone know the origins of the term 'motherboard'?
>
> I've always associated it with computers and assumed that 
> it started appearing somewhere around 1980, with the 
> fading out of passive backplane systems and arrival of 
> machines which put more functionality onto a 'core' PCB 
> into which other cards were plugged. I don't recall ever 
> seeing it used when referencing earlier big iron, but 
> maybe I've just missed it.
>
Computers existed way before 1980, and had many boards 
plugged into wire-wrapped backplanes or motherboards.    I'm 
guessing the terminology was company-specific.  IBM had 
their own name for EVERYTHING, for instance.  They did NOT 
use the term motherboard, as far as I know.  The SMS systems 
like 709x, 1401, etc. had totally passive backplanes.  The 
SLT systems (System/360, 1130/1800, etc.) had passive 
backplanes, but the local interconnect was done mostly with 
etched traces on multilayer PC boards, which also 
distributed power to the cards.  They just called these 
backplane sections "boards" and the SLT circuit boards that 
plugged into them were "cards".  Not sure where I first saw 
the term motherboard, or if it really implied it had 
substantial active circuitry on it.

Jon