System for determining configuration of devices installed on a computer

Abstract

In a system that executes the method according to the invention, each slot on the system bus is individually enabled at start-up and each address of an address range is read to determine whether an expansion board is installed in the slot and is responding to a read from that I/O address. If the data value returned by the I/O read is not equal to the undriven value of the data bus, then it is known that the expansion board is responding to that I/O address. Otherwise, a second read of the I/O address is performed, and the values of certain control lines on the system bus are latched to determine whether an expansion board is driving those lines in response to the I/O read. If so, again it is known that an expansion board is responding to a read from that I/O address. Otherwise, the system then performs a further special I/O read to determine the data bus response time. If the response time is faster than the response time of an undriven bus, it is known that an expansion board is responding to this I/O address. In this way, an I/O address map is created for each expansion board. This map is then used to determine the system configuration by comparing the map to standard signatures of known boards. The system configuration is the passed to standard configuration software.