I have located a block diagram for my server. It appears that the I2C bus hangs off the XBUS(?), whatever that is. Perhaps this is why I can't detect anything? >From a description of the Alpha 2100- I don't know if this is the same as mine. "Electrical and architectural restrictions prohibited the interrupt control logic from being directly accessed by either the system bus or the PCI bus. As a result, the interrupt control logic is physically located on a utility bus called the XBUS. The XBUS is an 8-bit slave ISA bus placed nearby the PCI-to-EISA bridge chips." The two pages from the docs are at http://www.jdfiles.org/a.pdf and http://www.jdfiles.org/b.pdf
