IBM Microchannel Bus Architecture
Suppose you gave a party and no one came.
Microchannel was IBM's proprietary 32-bit bus design that improved over the PC's 16-bit bus. Also, IBM was rather miffed that there were so many PC "clones", so they insisted on licensing the Microchannel architecture to third-party manufacturers.
Unfortunately, the licensing fees inflated the prices of third-party cards, hampering sales.
One of Microchannel's "features" was its "jumperless" design. The earlier Industry Standard Architecture (ISA) cards had jumpers and dip switches that required opening the case to set. Coordination of interrupts and addresses had to be done manually. Microchannel, for the most part, succeeded in making configuration easier.
Since IBM was licensing Microchannel, they could assign a unique card id number to each card so that the correct "option file" could be identified and loaded to configure the cards. The problem with that approach was that one needed a piece of software for each Microchannel card. For us vintage collectors, it means that once we acquire an old Microchannel card, we have to identify it and then find the matching option file before we can use the card.
I've collected several option files, which I plan to post here as time permits. But for now, here's a Microchannel card identification utility that I've found useful. IDMCA.ZIP. This utility and several other cool tools can be found at Tavi PS/2 Pages.