Patent ID: 8397002

Claim:
A storage system comprising: a plurality of storage devices including at least one first type storage device and at least two second type storage devices, an expander device which is coupled to the first type storage device via a first physical link having a first level transmission rate, and coupled to the second type storage devices via second physical links each having a second level transmission rate which is lower than the first level transmission rate, a controller, which is coupled to the expander device via a third physical link having the first level transmission rate, including a multiplexing circuit which is configured to multiplex first data and second data to multiplexed data, each of the first data and the second data is to be stored in the second type storage devices, and transferring third data to be stored in the first type storage device without multiplexing the data; and wherein the expander device is configured to determine whether data, which is sent from the controller, is multiplexed or not based on a predetermined parameter indicating that the data is multiplexed, wherein, when the expander device receives the multiplexed data and the predetermined parameter, a demultiplexing circuit, in the expander device, is configured to demultiplex the multiplexed data to the first data and the second data, and send the first data and the second data via the second physical links to the second type storage devices in parallel, and wherein, when the expander device receives the third data from the controller that is not multiplexed, the expander device is configured to send the third data via the first physical link to the first type storage device.