Abstract: In a highly available storage system, an enclosure includes first and second power supplies, and first and second controller boards. Each of the first and second controller boards includes first and second serial bus controllers. First and second serial buses are coupled to both of the first and second serial bus controllers on each of the first and second controller boards. The first serial bus is coupled to the first power supply, while the second serial bus coupled to the second power supply. The first and second serial buses are used for exchanging enclosure management and environmental information between the first and second power supplies and the first and second controller boards. The first and second serial buses are coupled to isolation switches so that redundant modules can operate if a serial bus controller fails.

Abstract: A module for a storage system is capable of accessing disk drives in a particular order regardless of its orientation. The module accesses the drives in the same order whether it is installed in a first orientation or in a second, inverted orientation. The module includes a plurality of disk controllers. Each disk controller is coupled to one or more disk drives. The disk controllers are mounted on the module so that when the module is coupled to the disk drives in a first orientation, the disk controllers are coupled to the disk drives in a particular order. When the module is coupled to the disk drives in a second orientation inverted relative to the first orientation, the disk controllers are coupled to the disk drives is the same particular order.

Abstract: Disk drives in a storage system are spun up in sequential stages. During each sequential stage a number of disk drives is spun up based on parameters related to the power requirements of the system. The parameters include the maximum current for the storage system, the number of disk drives currently in steady state, the steady state current required for a disk drive, and the spin up current required for a disk drive. High availability features are provided as further aspects of the spin up mechanism.

Abstract: Described is a system and method of designing a length of an electrical trace used to implement a point-to-point serial link for conveying a digital signal between a transmitter and a receiver. A trace segment of the electrical trace is identified. The trace segment has a first endpoint determined by a first impedance discontinuity on the point-to-point serial link and a second endpoint determined by a second impedance discontinuity on the point-to-point serial link. A restricted length is calculated for the trace segment based on a propagation delay of the signal along the trace segment and a frequency of the signal. A length of the trace segment is set to be unequal to the restricted length.