Patent ID: 7702819

Claim:
A storage system coupled to a computer, comprising: a first unit having a first interface and able to control a read command and a write command of data to and from said computer; a plurality of second units each having cache memory and the ability to temporarily store data sent from said first unit, the plurality of second units being coupled with said first unit; a third unit having a second interface and able to transfer or to receive data to or from said plurality of second units and being able to send data to a disk drive, the third unit being coupled with said plurality of second units; a first path coupling said first unit to a second unit A of said plurality of second units; a second path coupling said first unit to a second unit B of said plurality of second units; a third path coupling said third unit to said second unit A; and a fourth path coupling said third unit to said second unit B, wherein said first path is not intersecting said second path, the third path, nor said fourth path except for at an end point connecting said first path to said first unit; said second path is not intersecting said first path, the third path, nor said fourth path except for at an end point connecting said second path to said first unit; said third path is not intersecting said first path, the second path, nor said fourth path except for at an end point connecting said third path to said third unit; said fourth path is not intersecting said first path, the second path, nor said third path except for at an end point connecting said fourth path to said third unit.