Hardware Documentation - Buses - MCA - Links to information about the MicroChannel Architecture (MCA) bus, as used in many IBM PS/2, RS/6000, AS/400, and 370 machines.
Peter H. Wendt - IBM Microchannel Enthusiasts Page including his famous QBMCA Microchannel Adapter Identification Software and hundreds of ADFs for IBM MCA-machines.
Su's PS/2 Page - The effects of M.A.D. Microchannel Addictive Disorder.
Tavi PS/2 Pages - Information about IBM PS/2 machines. Although mainly directed at the MicroChannel systems (model 50 and above) there may be the occasional snippet about the lower end ISA-based systems as well.
What is MicroChannel Architecture? - IBM's answer to the failings of its older PC bus, which is now referred to as the ISA bus, article discusses the problems and short falls it had.