Disc storage subsystem having improved reliability

#The present invention relates generally to disc storage subsystems, and more particularly, but not by limitation, to a disc storage subsystem having redundant controllers for improved reliability.

#A disc storage subsystem generally includes a housing in which a plurality of disc drives are stored in removable carriers. Each disc drive includes a connector that interfaces with a corresponding connector of a midplane card to provide data communication therebetween. A controller, stored in a rear portion of the housing, includes an electrical connection with the midplane card for data communication with the disc drives. External processing electronics, such as a host computer, can access the data stored in the disc drives through the controller.

#Each disc drive of the subsystem includes a data interface, through which the data stored therein is accessed. One such data interface is the Advanced Technology Architecture (ATA) data interface. This data interface can be serial (SATA) or parallel (PATA) data interface. The ATA data interface only provides single channel communication with the disc drive. Thus, disc storage subsystems using such ATA disc drives include only one controller, through which the data can be accessed by a host computer.

#FIGS. 1 and 2 are simplified exploded perspective views of a disc drive storage subsystem that includes a midplane mounting assembly in accordance with embodiments of the invention.

#FIG. 3 is an isometric view of a disc drive.

#FIG. 4 is an exploded view of a conventional disc drive carrier.

#FIGS. 1 and 2 are exploded perspective views of a disc drive storage subsystem 100 in accordance with embodiments of the invention. Disc storage subsystem 100 generally includes a housing 102, one or more disc drive assemblies 104 each including a disc drive 106, a pair of controllers 108, one or more intermediate electronic components 110, and a midplane card 112. Disc storage subsystem 100 generally includes multiple disc drive assemblies 104. Only a single disc drive assembly 104 is depicted in FIGS. 1 and 2 to simplify the illustration. Additionally, FIGS. 1 and 2 are further simplified by not showing cooling fans, power supplies, and other conventional components of disc storage subsystem 100.

#As will be discussed in greater detail below, the controllers 108 (individually labeled 108.1 and 108.2) and intermediate electronic component 110 operate to improve the reliability of disc storage subsystem 100. In operation, one or more external host computers access data stored in the disc drives 106 through controllers 108 and the intermediate electronic components 110. Each intermediate electronic component 110 determines which controller 108 is provided data access to a particular disc drive 106 by opening and closing data communication paths between the disc drive 106 and each of the controllers 108. In the event that one of the controllers 108 fails, data stored in the disc drives 106 can still be accessed by the host computer through the remaining active controller 108. In this manner, the reliability of disc storage subsystem 100 is improved.

#Disc drive assemblies 104 each include a disc drive 106 that is contained in a carrier 114. FIG. 3 is an isometric view of an example of a disc drive 106 that can be used with disc storage subsystem 100. Disc drive 106 includes a housing with a base 116 and a top cover (not shown). Disc drive 106 also includes a disc pack 118, which is mounted on a spindle motor (not shown) by a disc clamp 120. Disc pack 118 includes a plurality of individual discs, which are mounted for co-rotation about central axis 122. Each disc surface has an associated disc head slider 124 which is mounted to disc drive 106 for communication with the disc surface. In the example shown in FIG. 3, sliders 124 are supported by suspensions 126, which are in turn attached to track accessing arms 128 of an actuator 130. Actuator 130, shown in FIG. 3, is of the type known as a rotary moving coil actuator and includes a voice coil motor, shown generally at 132. Voice coil motor 132, under the control of servo electronics 134, rotates actuator 130 with its attached heads 124 about a pivot shaft 136 to position heads 124 over a desired track along an arcuate path 138 between a disc inner diameter 140 and a disc outer diameter 142.