Was the mother board invented for another purpose?

Answer 1

No. Motherboards are related to "backplanes" that have been around for as long as the telephone system, nearly 100 years. All this refers to is a piece or hardware that is usually flat intended to hold a bunch of electrical or electronic components that need to be wired together. Backplanes usually lacked any active electronics and just consisted of a series of connectors designed to connect <i>other</i> boards holding components together. A PC could consist of a backplane and a CPU card, a card with RAM, a card with a video controller and so forth. Many early PCs were constructed this way (see S100 bus computers). When makers of early PCs were figuring out how to get started, they realized that this could be expensive. Why not put all the usual basic components together on <i>one</i> board and save on expensive connectors and space. The mother of all motherboards, the god daughter of earlier examples like the IMSAI and Altair computers, was the IBM PC. This became a standard and broke free of IBMs control fairly early in the game.