Electrical computers and digital processing systems: memory – Storage accessing and control – Specific memory composition
Reexamination Certificate
2001-06-07
2003-04-15
Kim, Matthew (Department: 2186)
Electrical computers and digital processing systems: memory
Storage accessing and control
Specific memory composition
C711S202000, C711S220000
Reexamination Certificate
active
06549979
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a technique for the mapping of addresses to mass storage devices mounted in a mass storage device mounting system.
2. Brief Description of Related Prior Art
Network computer systems generally include a plurality of geographically separated or distributed computer nodes that are configured to communicate with each other via, and are interconnected by, one or more network communications media. One conventional type of network computer system includes a network storage subsystem that is configured to provide a centralized location in the network at which to store, and from which to retrieve data. Advantageously, by using such a storage subsystem in the network, many of the network's data storage management and control functions may be centralized at the subsystem, instead of being distributed among the network nodes.
One type of conventional network storage subsystem, manufactured and sold by the Assignee of the subject application (hereinafter “Assignee”) under the tradename Symmetrix™ (hereinafter referred to as the “Assignee's conventional storage system”), includes a plurality of disk mass storage devices (e.g., disk drives) configured as one or more redundant arrays of independent (or inexpensive) disks (RAID). The disk devices are controlled by disk controllers (commonly referred to as “back end” controllers/directors) that may communicate (i.e., exchange data and commands) with the disk devices via Small Computer System Interface (SCSI) protocol communication channels. The disk controllers are coupled via a bus system to a shared cache memory resource in the subsystem. The cache memory resource is also coupled via the bus system to a plurality of host controllers (commonly referred to as “front end” controllers/directors). The disk controllers are coupled to respective disk adapters that, among other things, interface the disk controllers to the disk devices. Similarly, the host controllers are coupled to respective host channel adapters that, among other things, interface the host controllers via channel input/output (I/O) ports to the network communications channels (e.g., SCSI, Enterprise Systems Connection (ESCON), or FC based communications channels) that couple the storage subsystem to computer nodes in the computer network external to the subsystem (commonly termed “host” computer nodes or “hosts”).
In the Assignee's conventional storage system, the disk devices are grouped together into respective sets, and each set of disk devices may be controlled by respective pair of disk controllers. If one of the disk controllers in the respective pair fails, the other (i.e., redundant) disk controller in the pair may assume the duties of the failed disk controller, and thereby permit the set of disk devices to continue to operate, despite the failure of the failed disk controller.
Also in the Assignee's conventional storage system, the disk devices are placed in respective housings and stored in one or more chassis. The chassis may include a multiplicity of sets of slots for receiving respective housings within which the respective disk devices are placed. The chassis may also include an electrical back plane having a multiplicity of electromechanical connectors. The connectors may be mated with respective electromechanical connectors of the housings to electrically and mechanically couple the disk devices to the chassis.
In general, two types of commercially-available disk devices may be mounted in the chassis used in the Assignee's conventional storage system: “low profile” and “half-high” form factor disk devices. With the exception of their respective heights, a low profile form factor disk device (hereinafter “LP device”) may have identically the same dimensions as a half-high form factor disk device (hereinafter “HH device”). An LP device may have a height of 1 inch; an HH device may have a height of 1.6 inches.
At present, the storage capacity of a HH device may be approximately twice that of a LP device. However, the speed with which data may be read from or written to a HH device may be slower than the speed with which data may be read from or written to a LP device.
Only two types of chassis may be used in the Assignee's conventional storage system. One type of chassis is configured to receive and mount only LP devices, and the other type of chassis is configured to receive and mount only HH devices. Thus, in the Assignee's conventional storage system, a single chassis cannot contemporaneously receive and store both LP and HH devices; instead, all of the disk devices stored in a single chassis must have a single form factor (i.e., LP or HH).
This is unfortunate, since, given the above-described relative differences in the capabilities of HH and LP devices, in certain practical applications of a data storage system, it may be desirable to employ in an individual chassis combinations of both HH and LP devices that, when taken together, may permit the overall performance of the system to be improved. Also unfortunately, since an individual chassis used in the Assignee's conventional data storage system is unable to receive and store disk devices having multiple different form factors, this inherently reduces the design flexibility of the data storage system. Thus, it would be desirable to provide a mass storage device mounting system that may use a single type of chassis that is able to contemporaneously receive and store disk mass storage devices that have different form factors (e.g., receive and store combinations of both HH and LP devices).
Additionally, it has been proposed to replace with FC protocol communication channels the SCSI communication channels that permit communication among the disk devices and disk controllers in the Assignee's conventional data storage system, in order to increase the speed with which such communication may be performed. According to this proposal, each such FC communication channel may comprise a serial, unidirectional, FC communication ring or loop system.
It would also be desirable to provide a technique that may be used to assign FC communication loop addresses to mass storage devices mounted in one or more of the aforesaid type of chassis (i.e., the chassis that is able to receive and store contemporaneously disk devices having multiple different form factors). It would also be desirable to provide such a technique that would permit a maximum number of mass storage devices to be used in a single such FC loop, and would reduce the possibility that human error and/or addressing conflicts may be introduced into the addresses assigned to the mass storage devices.
SUMMARY OF THE INVENTION
In accordance with the present invention, a technique is provided for mapping/assigning addresses to mass storage devices in a mass storage device mounting system that overcomes the aforesaid and other disadvantages of the prior art. More specifically, in one embodiment of the present invention, a method is provided for assigning numerical addresses to mass storage devices mounted in a mass storage device mounting system. The mounting system may be of the type, disclosed in the aforesaid copending U.S. patent application Ser. No. 09/877,808, entitled “Mass Storage Device Mounting System,” filed concurrently with the subject application. As is disclosed in said copending application, this type of mounting system includes one or more electrical cabinets or chassis, and is able to mount different respective configurations of mass storage devices. Each of the chassis in the mounting system is able to contemporaneously receive and store a respective combination of disk mass storage devices. The respective combination of disk mass storage devices may include both HH and LP devices.
The method of this embodiment of the present invention may include assigning a first subset of the numerical addresses to a first subset of the mass storage devices mounted in a first chassis in the mounting system. A second subset of the numeri
Elmore Stephen
EMC Corporation
Gunther John M.
Gupta Krishnendu
Kim Matthew
LandOfFree
Address mapping in mass storage device mounting system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Address mapping in mass storage device mounting system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Address mapping in mass storage device mounting system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3035702