VERSAbus
The VERSAbus bus was created in 1979 by Motorola for use on Motorola MC68000-based systems. Although it was not used by many products (although the Power 6/32 did), it was influential as the inspiration for the electrical functionality of the VMEbus, used in many minicomputers and specialist computers.
The first section of 'Installing and Operating 4.3BSD-tahoe UNIX on the Tahoe' (link below) contains a moderately detailed description of the VERSAbus: it has a 32-bit data path, and can use 16-bit, 24-bit, or 32-bit addresses (see the document for details). Since the VERSAbus is principally used as an input/output bus, it must also support interrupts, but nothing on this has yet been found.
VERSAbus cards, in common with many card systems of that era (such as DEC standard cards), used etch fingers on one edge of the card, to make electrical contact with the bus; they measured 14.5 by 9.25 inches.
