Micro Channel architecture

data channel architecture of IBM, standard for data transfer between expansion cards and the motherboard

Micro Channel Architecture (in practice almost always shortened to MCA) was a proprietary 16- or 32-bit parallel computer bus created by IBM in the 1980s for use on their new PS/2 computers.
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<architecture> (MCA) IBM's proprietary 32-bit bus, used in high-end PS/2 personal computers. Micro Channel is designed for multiprocessing. It eliminates potential conflicts that arise when installing new peripheral devices. MCA is *not* compatible with either EISA or XT bus architecture so older cards cannot be used with it.
As with the ROM BIOS in the first IBM PCs, figuring out the Micro Channel's secrets has been an arduous task of reverse engineering ever since the PS/2 line was announced. Consequently, the MCA has never become as wide spread as the competing EISA standard.
(1996-08-16)