|IBM PS/2 FAQ | What is
Micro Channel Architecture (MCA for short) is a bus that was developed by IBM in 1986/1987 for use in IBM's new Personal System/2 series of computer.
The bus was very advanced for its time(and still is) because it could have adapters addressing sizes of 8-bit, 16-bit and 32-bit. Adapter Description Files(ADF) are used to auto configure the adapters connected to the bus. No need for jumpers or dip switches. The first version of the MCA bus ran at 10Mhz and was capible of transfering 20MB/sec. The later version which came around in 1992 ran at speeds up to 40Mhz and transfering 40MB/sec. And the last version as used in the Pentium models of the 9595 and PC Server 500 was capible of 80MB/sec at 32-bit streaming and 160MB/sec at 64-bit streaming.