Hardware speed selection behind a disk array controller

A system for adjusting the speed of operation of a channel for communicating with disk drives in a multi ported system, comprising:

• a disk array controller having a first channel;
• and
• a plurality of enclosures, each having an enclosure services module from which the first channel is formed in sequence from a disk array controller to a first enclosure services module of a first enclosure and between first enclosure services modules of successive enclosures to a last enclosure,
• each one of the plurality of enclosure services modules having a port bypass device which makes a data rate determination of incoming data.

A system for adjusting the speed of operation of a channel for communicating with disk drives in a multi ported system, comprising:

• a disk array controller having a first channel and a second channel;
• and
• a plurality of enclosures, each enclosure having first and second enclosure services modules, a first channel being formed in sequence from a disk array controller to a first enclosure services module of a first enclosure and between first enclosure services modules of successive enclosures to a last enclosure and a second channel being formed in reverse sequence from the disk array controller to a second enclosure services module of the last enclosure and between second enclosure modules of successive enclosures to the first enclosure, the system operating according to the method having the steps of
• detecting by a device associated with a corresponding first one of the plurality of enclosure services modules the data rate of incoming data from the disk array controller;
• comparing the data rate of the incoming data with the current data rate in the enclosure services module;
• changing the data rate of the enclosure services module to that of the data rate of the enclosure services module;
• and
• checking the validity of the incoming data.

A system for passing a signal to a chain of electrically connected devices having two channels, comprising

• a controller device;
• and
• a plurality of subservient devices, each subservient device being able to determine the data rate of incoming data,
• wherein the controller device is connected both in an open chain manner to the subservient devices in a forward order and in a physically separate reverse order.