Patent ID: 6816915
Filing Date: 2004-11-09
Classification: G06F

Abstract:
A method for automatically discovering topology map of an I/O subsystem, the I/O subsystem being coupled to one or more host computers and including one or more peripheral buses, a set of peripheral devices, and a set of expanders, each expander having a valid expander address and being arranged to couple a pair of the peripheral buses, the peripheral devices and the one or more host computers being coupled to the peripheral buses, the method comprising:a) selecting, by a host computer, a peripheral device as a target device and writing a set of entries to the selected target device, each entry written having an expander address field initialized to an invalid expander address for storing an expander address; b) selecting, by the host computer, the target device and reading the set of entries from the target device; c) for each expander coupled between the host computer and the target device, writing the valid expander address associated with the each expander to one of the expander address fields in the set of entries that contain invalid expander addresses; d) receiving, by the host computer, the set of entries such that the set of the valid expander addresses in the set of entries indicates identity of associated expanders coupled between the host computer and the target device; and e) repeating operations a) to d) for each of the other peripheral devices as the target device so as to discover the topology map of the entire I/O subsystem.