Seymour Cray, (the pre-eminent American computer designer for about 3 decades until his death) hit upon the idea of creating a computer from a limited number of standardized logic/function boards rather than hundreds or thousands of separate specialized and different circuits. This is the actual prototype where he tested that idea.

This machine begat the 1604, the 160, and eventually the 6600 supercomputer.

The idea adapted over time to incorporate integrated circuits (as opposed to discrete components) on a limited number of standardized circuit boards, and then as chip density grew, this eventually gave way to a complete computer on a chip.