ENABLING RELIABLE COMMUNICATION BETWEEN AN ACCESSOR AND A TAPE LIBRARY
A method is disclosed in one embodiment of the invention as including physically transporting tape cartridges in a tape library using an accessor. The method further enables communication between the accessor and the tape library using a flexible cable assembly. The flexible cable assembly includes a flexible channel and multiple twisted wire pairs loosely routed through the flexible channel. The multiple twisted wire pairs independently and substantially freely move within the flexible channel.
1. Field of the Invention
This invention relates to electrical cables, and more specifically to high flex-life electrical cables for transmitting high bandwidth signals.
2. Background of the Invention
A tape library is an automated data storage system used to store data on magnetic tape cartridges. A tape library typically includes tape drives for reading and writing information to magnetic tape cartridges, access ports for entering and removing cartridges from the tape library, and a moving robot (i.e., an accessor) to physically transport tape cartridges between storage cells, drives, and access ports. The robotics associated with the accessor enable the accessor to move in left and right directions (X-motion) and up and down directions (Y-motion). The accessor typically includes motors and controller cards that require power and the ability to communicate with a stationary library controller.
To transmit electrical power and data signals between a stationary library controller and a moving accessor, one option is to use a cable assembly comprising flat parallel conductors, such as is used in the IBM 3494 and 3584 tape libraries. Although effective, flat parallel conductors have limited signal bandwidth and noise immunity as a result of the flat straight conductors. Thus, if bandwidth requirements continue to increase, this technology will eventually reach its limit. Another option is to use moving contacts that slide on fixed conductors like those used in the Sun-STK SL08500 tape library. This solution has various drawbacks such as contact wear, noise generation, limited bandwidth, and the limited number of signals that can be transmitted using this approach. Yet another option is to use non-contact means for transmitted power and electrical signals such as by using inductive coupling or wireless communication. Although effective to eliminate wires, this solution may require addressing issues such as electromechanical complexity, power transmission efficiency, electromagnetic compatibility (EMC), and radio frequency interference (RFI). This solution may also require isolating the communication signal from other wireless systems for security purposes or to prevent interference.
In view of the foregoing, what is needed is a flexible cable assembly to efficiently transmit electrical power and data signals between a stationary library controller and a moving tape library accessor. Ideally, such a flexible cable assembly would provide high-bandwidth signal capability and high noise immunity. The flexible cable assembly would also ideally have a very high flex life.
SUMMARYThe invention has been developed in response to the present state of the art and, in particular, in response to the problems and needs in the art that have not yet been fully solved by currently available apparatus and methods. Accordingly, the invention has been developed to provide an electrical cable assembly to efficiently transmit electrical power and data signals between a stationary library controller and a moving tape library accessor. The features and advantages of the invention will become more fully apparent from the following description and appended claims, or may be learned by practice of the invention as set forth hereinafter.
Consistent with the foregoing, a method is disclosed in one embodiment of the invention as including physically transporting tape cartridges in a tape library using an accessor. The method further enables communication between the accessor and the tape library using a flexible cable assembly. The flexible cable assembly includes a flexible channel and multiple twisted wire pairs loosely routed through the flexible channel. The multiple twisted wire pairs independently and substantially freely move within the flexible channel.
In order that the advantages of the invention will be readily understood, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments of the invention and are not therefore to be considered limiting of its scope, the invention will be described and explained with additional specificity and detail through use of the accompanying drawings, in which:
It will be readily understood that the components of the present invention, as generally described and illustrated in the Figures herein, could be arranged and designed in a wide variety of different configurations. Thus, the following more detailed description of the embodiments of the invention, as represented in the Figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of certain examples of presently contemplated embodiments in accordance with the invention. The presently described embodiments will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout.
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To enable the movement of tape cartridges between the storage slots 200 and the tape drives 202, the accessor 204 may include a gripper and pivot assembly 212 that moves up and down on an accessor mast 214. Similarly, the accessor 204 may travel in left and right directions along a track 216. This dual movement enables the gripper and pivot assembly 212 to move in both X and Y directions. This X-Y movement allows the gripper and pivot assembly 212 to transport tape cartridges between the storage slots 200 and the tape drives 202. In certain embodiments, the gripper and pivot assembly 212 includes a reading device, such as a bar code scanner, to read identifying information on each tape cartridge.
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The independent and free movement allows stresses in the twisted wire pairs 702 to be relieved as bending occurs by allowing the twisted pairs 702 to move freely within the channel 704. The instant inventors have found that the independent and free movement of the twisted wire pairs 702 within the channel 704 significantly improves the flex life of the wire 702. Furthermore, the twisted wire pairs 702 (when used to transmit communication signals) support much higher bandwidth and provide much higher noise immunity than flat parallel conductors or other conventional types of wire. The twisted pairs 702 also offer advantages in terms of noise immunity, bandwidth, and security compared to prior art solutions that use moving contacts that slide on fixed conductors, or use non-contact means such as inductive coupling or wireless communication to transmit power and electrical signals.
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The instant inventors have found that the flexible cable assembly 300 described in
The apparatus and methods disclosed herein may be embodied in other specific forms without departing from their spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.
Claims
1. A method comprising:
- physically transporting tape cartridges in a tape library using an accessor; and
- enabling communication between the accessor and the tape library using a flexible cable assembly, the flexible cable assembly comprising: a flexible channel; and a plurality of twisted wire pairs loosely routed together through the flexible channel, the plurality of twisted pairs independently and substantially freely moving within the flexible channel.
2. The method of claim 1, wherein the flexible channel comprises a flexible track and a retention membrane to substantially enclose the flexible track.
3. The method of claim 2, wherein at least one of the flexible track and the retention membrane are fabricated from plastic.
4. The method of claim 2, further comprising forming at least one of slits and apertures in the flexible track to impart flexibility thereto.
5. The method of claim 1, further comprising using the plurality of twisted wire pairs to transport at least one of communication signals and electrical power.
6. The method of claim 1, further comprising providing at least one power cable in the flexible channel in addition to the plurality of twisted wire pairs.
7. The method of claim 6, further comprising isolating the plurality of twisted wire pairs and the at least one power cable within the flexible channel.
8. The method of claim 7, wherein isolating the plurality of twisted wire pairs and the at least one power cable comprises providing a partition element in the flexible track.
9. The method of claim 1, wherein the ends of the plurality of twisted wire pairs are substantially fixed relative to one another to enable connectors to be attached thereto.
10. The method of claim 9, wherein the ends of the plurality of twisted wire pairs are laminated to enable connectors to be attached thereto.
Type: Application
Filed: Jun 2, 2013
Publication Date: Oct 17, 2013
Inventors: Chester David Holden (Tucson, AZ), Michael Philip McIntosh (Tucson, AZ), George G. Zamora (Vail, AZ)
Application Number: 13/907,931