Abstract:
An easily expandable and interchangeable library system is achieved by integrating several storage library modules which are specifically designed to allow easy transfer of storage media there between. Each library module is equipped with an integral elevator track which is capable of directing and accommodating the movement of a storage media elevator between the various modules. The storage elevator is appropriately designed to easily travel between the storage library modules, without the need for additional components or additional equipment. The use of wireless communication between an elevator controller and a library controller allows for the controlled movement an interaction of the elevator between library modules, thus creating an expandable library system within which storage capacity can be easily and economically increased without the need for additional equipment.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates to a dynamic information storage and retrieval system, and particularly to an easily expandable library system. More particularly, the invention relates to a library system which is easily expandable by adding additional library modules.  
           [0002]    Advances in manufacturing technologies and system architecture have led to increasingly powerful electronic devices and computers. These electronic devices and computers support features and applications, in which vast amounts of information are processed and stored. Generally, the amount of information is not only vast, but also ever-increasing.  
           [0003]    To provide the information needed by today&#39;s high powered applications, storage technologies have been developed to meet the high capacity data storage needs created. Various storage options include hard disk drives, or drives using removable storage media such as magnetic, optical and magneto-optical media. Although these technologies provide relatively large storage capabilities, ongoing improvement is continually necessary so as to overcome factors limiting storage capacity and performance.  
           [0004]    Data storage libraries, or jukeboxes, are robotically controlled storage devices that have been developed to improve the efficacy of storage by automating nearly all data management functions. Every phase of library operations minimizes human intervention, which is the most common cause of data loss. A traditional tape jukebox consists of a series of bays or slots storing a number of tapes. A robotic picker is computer controlled so that it can move any chosen tape from its storage bay and load the tape onto a tape drive unit. The entire jukebox is housed in a sealed environment to prevent contamination of the tapes. Similar jukebox libraries have also been built for virtually all types of storage media, including optical disks. Because jukeboxes store tens or hundreds of tapes, optical disks, or other media, and because the jukeboxes can automatically swap disks and tapes in and out of the read devices, a single jukebox can effectively store much more information than a single tape drive or optical drive. This makes jukeboxes very advantageous.  
           [0005]    As can be easily appreciated, the capacity of a standard jukebox can be limited by its physical size. Simply stated, only so many tapes or optical media can fit within the prescribed housing size, resulting in a limitation. Obviously, the jukeboxes are available in various sizes, however it is often not economical to buy vastly oversized devices simply for the sake of possible future expansion. Consequently, it would be desirable to create a jukebox system which could easily be expanded to include additional modules which would cooperate with one another.  
           [0006]    In one example of past library systems, a rack mounted library module is used initially to meet the user&#39;s storage needs. When it is desired to expand, a number of library modules are connected to one another via an external conversion mechanism. Some example expansion products include the Stacklink, manufactured by Quantum Corporation of Milpitas, Calif., and the XpressChannel, manufactured by Overland Data of San Diego, Calif. Using these expansion devices, each particular module is its own operating jukebox or library including a picker mechanism and appropriate storage slots. Expandability is achieved through the use of the aforementioned external integration system which is specifically designed and configured to allow tapes to be transferred from one library module to another library module. Essentially, these expansion systems physically tie the various modules together.  
           [0007]    Unfortunately, these expansion systems are specifically designed for the particular expansion being undertaken. For example, if two library modules are to be connected, a specific “two library rail” is required, which is attached to the back of the libraries. Similarly, a specifically configured expansion device is required for three library modules. Further, another module is required for four modules, etc. While these expansion mechanisms do achieve the goal of integrating multiple library modules to one another, they are not easily expandable as a new expansion mechanism is required for each additional expansion. This becomes costly and cumbersome when trying to expand library modules. Furthermore, this does not accommodate the easily removal and replacement of library modules should that be necessary.  
           [0008]    It would be particularly beneficial to devise a system which would allow for the easy integration of multiple library modules, without additional hardware. Further, such a system would be beneficial if it also accommodated the swapping (removal and replacement) of library modules.  
         SUMMARY OF THE INVENTION  
         [0009]    In order to address the above referenced issues related to expandability and module swapping, the present invention provides an integral elevator support, or guide rail within each library module. This elevator support easily allows an elevator mechanism to move storage media between the various library modules without the use of additional components or pieces.  
           [0010]    As mentioned above, the elevator system includes a guide rail or support which is rigidly attached to each library module. This guide rail will include the necessary guide structures (slots) to direct elevator movement within an appropriately constrained area. These guide rails are also designed to provide necessary power to the elevator mechanism during its travel. Additionally, the guide rail also includes gear teeth designed to interact with corresponding gears on the elevator mechanism itself.  
           [0011]    The elevator mechanism or crawler itself is designed to interact with the guide rail to accommodate its movement. Further, a media holding mechanism is attached to the elevator in order to carry the desired media. In the preferred embodiment, this includes media tape, however accommodations could easily made to handle optical storage disks or other storage media.  
           [0012]    The elevator itself includes a drive motor and appropriate gearing, which will interact with gear teeth on the guide rail so as to carry the elevator along the path defined by the guide rail. Appropriate contacts are provided to carry electrical power to the motor at all points along its travel.  
           [0013]    Also included on the elevator is a control system coupled to the drive motor. As would be expected, this control system directs the actual movement of the elevator as it travels between the various library modules. The control system also includes a communication device which will communicate with a master library controller. In one embodiment, the communication is done through infrared or IR signals. This wireless communication between these components allows for unrestrained movement of the elevator throughout its entire range of travel in a multi-module library system. Naturally, many alternative communication methods could be utilized, including RF, etc.  
           [0014]    It is an object of the present invention to provide a library module with the capability of being easily integrated into a library system including multiple modules. This capability is achieved by providing an integral structure to accommodate a transport mechanism which is specifically configured and designed to transport storage media between the various modules.  
           [0015]    It is a further object of the present invention to provide a library module which can be expanded without the use of additional hardware. In the design of the present invention, only integral components of the library module are necessary to accommodate the expandability of the overall system.  
           [0016]    It is a further object of the present invention to provide continual expansion capability at any time throughout the life of the storage library.  
           [0017]    It is yet another object of the present invention to provide a elevator mechanism to a library module which is specifically configured and designed to carry storage media between various library modules within an overall storage system. The elevator mechanism cooperates with structures within the library module to easily accommodate and guide its movement.  
           [0018]    It is yet another object of the present invention to provide an elevator mechanism which includes communication capabilities so that the operation elevator can easily be controlled as it travels throughout the library system. The communication capabilities are preferably achieved in a wireless fashion, thus accommodating free movement of the library through the entire library system. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]    Further objects and advantages of the present invention can be seen by reading the following detailed description in conjunction with the drawings in which:  
         [0020]    [0020]FIG. 1 is a perspective view of a rack mounted library system;  
         [0021]    [0021]FIG. 2 is a perspective view of a library module;  
         [0022]    [0022]FIG. 3 is a top view of an opened library module;  
         [0023]    [0023]FIG. 4 is a cross-sectional drawing showing a portion of the library module;  
         [0024]    [0024]FIG. 5 is a first perspective view of the elevator assembly;  
         [0025]    [0025]FIG. 6 is a second perspective view of the elevator assembly;  
         [0026]    [0026]FIG. 7 is a perspective view of the elevator mechanism alone;  
         [0027]    [0027]FIG. 8 is a cross-sectional diagram illustrating elevator  110  “bridging the gap” between two library modules; and  
         [0028]    [0028]FIG. 9 is a schematic diagram of the elevator system control devices. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0029]    As is known and understood by those skilled in the art, a data storage libraries can take on many different configurations and layouts depending on the particular needs and design involved. One configuration is a rack-mounted data storage library which is capable of being mounted in a traditional equipment cabinet. Referring to FIG. 1, there is shown one embodiment of a rack-mounted storage library  20  which includes a first library module  22 , second library module  24  and a third library module  26 . Each of these library modules is mounted within a rack or cabinet  28 . As can be seen, cabinet  28  includes two front face rails  30  which have a number of mounting holes  32  therein.  
         [0030]    As can be seen, first library module  22 , second library module  24  and third library module  26  are mounted within cabinet  28  at positions which are immediately adjacent one another. This alignment allows for the exploitation of cartridge sharing functions, which are described further below.  
         [0031]    Referring now to FIG. 2, there is shown a more detailed drawing of a first library module  22 . It is understood that first library module  22 , second library module  24  and third library module  26  are all similarly configured. Consequently, all comments and description regarding the structure of these components are equally applicable to any library module. As can be seen, first library module  22  includes an enclosed housing  40  which includes a front panel  42 , a top panel  44 , a bottom panel  46  (not shown) and a pair of side panels  48 . Front panel  42  is designed to extend beyond side panels  48 , which facilitates rack mounting as shown in FIG. 1.  
         [0032]    Front panel  42  includes a cartridge loading opening  50  which allows data storage cartridges to be inserted into the interior of housing  40  and accommodates the population of this library module  22 . In order to accommodate the disk cartridge sharing capabilities of the present invention, housing  40  also includes an opening  52  positioned in the top panel  44  thereof. Opening  52  has a pair of cover mount rails  54  positioned on either side of the opening to accommodate the attachment of a cover plate  56  (not shown). A pair of cover screw attachment holes  58  are also shown in cover mount rails  54 . As can be appreciated, these holes accommodate the attachment of cover plate  56 .  
         [0033]    As mentioned above, the first library module  22  (and all library modules contained within a rack mounted library system) are configured to allow storage cartridges to be transferred between the various modules. The first portion of the structure which accommodates this features is the opening  52  in top panel  44 . It should be understood, although not shown in FIG. 2, that a similar opening exists in bottom panel  46  which again is configured to allow a removable cover plate to be attached thereto.  
         [0034]    As mentioned above, each library module includes the ability to house and manipulate a number of media storage elements. It will be understood that the present invention is not limited to any specific type of storage media, and could be implemented with any media type, such as magnetic tape, and storage disks, including optical, magneto optical, magnetic disks, etc. Traditionally, the library includes a number of storage locations or storage bins, at least one media drive for reading the storage media, and pickers/placer mechanisms to transport the storage media. Additionally, some mechanism is typically necessary to allow media to be inserted or imported into the library module for use.  
         [0035]    Referring now to FIGS. 3 and 4, there are shown a top view of first library module  22  with the top panel  44  removed. Further, shown in FIG. 4 is a sectional view showing certain interior components of first library module  22  shown from section line  4 - 4  of FIG. 3.  
         [0036]    As mentioned above, library module  22  includes a media storage drive  70  along with a storage bin  72  which is configured to have a plurality of storage slots  74  therein. Also contained within first library module  22  is a picker/placer mechanism  80  which is configured to transport media elements from storage slots  74  to media drive  70 . Picker/placer  80  travels along a guide rail  82  located along a back portion of library module  22 . An import mechanism  86  is provided at a front portion of library module  22 . Import mechanism  86  allows library module  22  to be populated by receiving and appropriately placing media elements within first library module  22 . This involves a coordinated effort between picker/placer  80  and the library module controller (not shown) to appropriately receive and place media elements in the desired storage slot  74 .  
         [0037]    The library modules of the present invention are easily incorporated into a storage library system which can include multiple library modules. In the embodiment shown in FIG. 1, three such library modules are utilized. In order to incorporate these multiple modules into one library system, accommodations are made to allow a media transport to carry media elements between the various modules. In order to accomplish this, an elevator system  100  is incorporated into the library system. As can be seen in FIGS. 3 and 4, library system  100  is positioned adjacent storage bin  72  so as to easily cooperate with picker/placer  80 . As can be anticipated, this allows picker placer  80  to remove the particular storage media carried by elevator system  100  and place it in a desired storage slot  74 , or directly to media drive  70 .  
         [0038]    Referring now to FIGS.  5 - 7 , elevator system  100  is shown in more detail. At a general level, elevator system  100  includes a support track or support rail  102  which is rigidly attached to the housing  40  of library module  22 . Elevator system  100  also includes a climber or elevator  110  which is adapted to interact with elevator support track  102 . Climber  110  includes a drive motor  112  and related gearing  114  which is designed to interact or cooperate with related track gears  104 . Both motor  112  and gearing  114  are attached to coupling support  116  which is designed to interact with guiding slots  106  in elevator support track  102 . More specifically, a number of tabs or protrusions  118  are specifically designed to fit within guiding slots  106  as climber  110  travels along elevator support track  102 .  
         [0039]    Attached to coupling support  116  is a media transport bin  130  which is configured to receive and transport the particular storage media being used in library system  20 . In this particular embodiment, media transport bin  130  is configured to receive and carry a magnetic tape cartridge. Media transport bin  130  has a substantially rectangular housing forming a rectangular opening  132  therein.  
         [0040]    On a backside of coupling support  116  is located a controller housing  140  which contains an elevator controller  142  and communication devices  144 . Controller  142  will direct the operation of elevator system  100  and achieve appropriate movement and direction. FIG. 8 is a schematic drawing illustrating the electrical connection and control operation for elevator system  100 .  
         [0041]    As mentioned above, controller housing  140  contains communication devices  144  which provide the necessary link to a library system controller  150  contained within library system  20 . In one embodiment of the present invention, communication is achieved via radio frequency signals transmitted between elevator controller  142  and library system controller  150 . Based on the signals received, and programming logic within controller. Library controller  150  obviously includes similar communication device  154 . Alternative communication methods could include infrared or visible light signals. While wireless communication is obviously preferable, systems could be incorporated to have wired communication depending on the number of modules included.  
         [0042]    In order to provide power to motor  112  and controller  142 , power connections are provided on coupling support  116 . Specifically, a first power connector  160  and a second power connector  162  are provided. These power connectors interact with power strips incorporated into elevator track  102 . More specifically, elevator rail  102  includes a first power slot  122  and a second power slot  124 . These power slots contain conducting material which provide the necessary power signals to the elevator  100 . As expected, this would traditionally include a ground signal and a positive power supply signal.  
         [0043]    Referring again to FIG. 1, it can be seen that the various library modules (i.e., first library module  22 , second library module  24  and third library module  26 ) are all located relatively close to one another. With the appropriate housing openings  52  aligned with one another, and the common geometry of the various library modules, elevator system  100  is capable of transporting storage media between the various library modules. As mentioned above, the configuration of the various library modules causes each elevator track  102  to be aligned with one another. Consequently, multiple elevator tracks  102  aligned with one another would create a semi-continuous rail system along which elevator  110  could travel. Naturally, some gaps exist between the various elevator tracks  102 . The ability to bridge these gaps is achieved by the configuration of gears  114  and coupling support  116 . More specifically, gears  114  includes a drive gear  170 , a first travel gear  172  and a second travel gear  174 . As can be seen in FIG. 7, first travel gear  172  and second travel gear  174  are spaced a distance apart. In practice, this distance is sufficient to allow elevator system  110  to bridge any existing gap between the various library modules. Similarly, coupling support  116  is sufficient in size and configuration to bridge the existing gaps.  
         [0044]    The step of bridging gaps between library modules is further illustrated in FIG. 8. More specifically, an elevator support track  110  for first library module  22  and a elevator library track  110  for second library module  24  are shown. As can be seen, the elevator support rails  110  are aligned with one another and closely spaced to allow consistent travel of elevator  110 .  
         [0045]    As can be seen, the top panel  44  of first library module  22  is adjacent the bottom panel  46  of second library module  24 . The rack mounted systems are designed and configured so that a minimum distance exists between these two library modules when appropriately mounted. This minimizes the gap that elevator  110  must bridge during its travel between modules.  
         [0046]    Coupling support  116  is sized to be substantially larger than the gap which must be bridged during this operation. Consequently, during any point in travel coupling support  116  will be sufficiently coupled with elevator support track  102  so that its movement is closely guided. Additionally, first travel gear  72  and second travel gear  74  are sufficiently spaced so that at least one travel gear will continuously be engaged with the gears  104  on elevator support track  102 . As can be seen from this figure, the movement of elevator  110  across the gap is easily achieved through the appropriate placement and configuration of components—specifically first travel gear  172 , second travel gear  174 , and coupling support  116 .  
         [0047]    In operation, the elevator will be largely controlled by the library controller  150 . A schematic drawing of the control system is shown in FIG. 9. When library controller  150  determines it is necessary for a cartridge to be moved from one module to another, appropriate communication signals will be transmitted via library communication device  154  to elevator controller  142 . Upon receipt of such signals, elevator controller  142  will cause motor  112  to be appropriately actuated, thus causing the movement of elevator  110 . Elevator controller  142  will then cause elevator  110  to proceed to the desired location. In the library system, at least one proximity switch  146  may be utilized to control the precise positioning of elevator  110 . Once at position, library controller  150  will actuate the related systems, such as picker/placer  80 , causing the appropriate movement of storage media. This may include the placement of a storage cartridge within media transport bin  130 , or, the removal of a storage cartridge therefrom.  
         [0048]    In order to provide necessary communication, elevator controller  142  will provide appropriate signals back to library controller  150 , indicating that elevator  110  is in an appropriate position. Likewise, other information could be communicated back to the library controller, such as cartridge information, etc. For example, each cartridge could include an identifier which could be read by a sensor on the elevator. This could then be communicated back to library controller  150 . Example identifiers may include bar codes, RFID chips, etc.  
         [0049]    While a proximity switch  142  is mentioned above, it is understood that positioning of elevator  110  could be accomplished via several mechanism. For example, tracking of motor operation would also allow positioning of elevator  110 . Further, micro-switches or optical sensors could also be utilized.  
         [0050]    Those skilled in the art will further appreciate that the present invention may be embodied in other specific forms without departing from the spirit or central attributes thereof. In that the foregoing description of the present invention discloses only exemplary embodiments thereof, it is to be understood that other variations are contemplated as being within the scope of the present invention. Accordingly, the present invention is not limited in the particular embodiments which have been described in detail therein. Rather, reference should be made to the appended claims as indicative of the scope and content of the present invention.