Patent ID: 7177942

Claim:
A method for adjusting the speed of operation of a channel for communicating with disk drives in a multi ported system organized into a plurality of enclosure services modules comprising: a first channel connected to a first enclosure services module and successively connected to successive enclosure services modules to a last enclosure services module in sequence, a second channel connected to the last enclosure services module and connected, in reverse sequence relative to the first channel, to successive enclosure services modules, to the first enclosure services module, and a bridge controller connected to the first enclosure services module via the first channel and to a last enclosure services module via the second channel, the steps comprising: (a) sending a change speed frame from the bridge controller to the last enclosure services module connected on the first channel which has not undergone the speed change; (b) waiting for an indication on the second channel that the enclosure has attained the changed speed; (c) determining whether the enclosure service module currently undergoing speed change is the first enclosure service module on the first channel; and (d e) repeating the steps (b), (c), (d) and (e) with the enclosure services module which precedes, on the first channel, the enclosure services module currently undergoing speed change if the enclosure services module currently undergoing speed change is not the first enclosure service module on the first channel.