Patent Publication Number: US-2007124019-A1

Title: Scalable composite rectangular/cylindrical automated data storage library system

Description:
FIELD OF THE INVENTION  
      The invention relates to automated data storage library systems and in particular to a scalable composite rectangular/cylindrical library system that provides a simple and flexible architecture for serving various customer needs.  
     PROBLEM  
      It is a problem in the field of automated data storage library systems to provide a simple, inexpensive method to incrementally increase the data storage capacity of the library system while also retaining an acceptable access time to retrieve a data storage element and mount it in a data read/write device.  
      Automated data storage library systems function to provide a host computer with access to a plurality of data storage elements (such as tape cartridges, tape cassettes, disks, and the like). The automated data storage library system includes an array of data storage locations, each of which houses a data storage element, and uses a robotic mechanism to move the data storage element between its storage location and a read/write device. There are two architectures used in automated library systems: cylindrical and rectangular.  
      The cylindrical architecture of an automated data storage library system provides an array of data storage locations that are arranged in a cylindrical shape. The robotic mechanism may either be stationary while the cylindrical array of data storage locations rotates or the robotic mechanism may rotate around or within the cylindrical array of data storage locations. In the case where dual concentric cylindrical arrays of data storage locations are employed, the robot may rotate between the two cylinders at the same time. The use of a cylindrical array of data storage locations, or dual concentric cylinders of data storage locations, provides a high density data storage capacity for an automated data storage library system. However, a problem with this architecture is that the user can not incrementally increase the data storage capacity of the library system. Once the cylindrical array of data storage locations is fully occupied, the customer cannot expand the capacity of the automated library system without adding an entire new library, with a full complement of data storage locations and complete robotic mechanism. Therefore, there is no ability to incrementally increase the storage capacity of these library systems. A further limitation of this architecture is that the speed of the data storage element retrieval operation is limited by the use of a single robotic mechanism. To gain speed results in the use of expensive robotic mechanisms.  
      The more common automated data storage library system architecture is the rectangular architecture, in which the data storage locations are configured in a flat plane in the horizontal and vertical directions (also termed an X-Y configuration). The robotic mechanism travels on a continuous horizontal track along the face of this array of data storage locations and includes a retrieval mechanism that travels vertically up and down to transport the data storage elements between a data storage location and a selected read/write device. The capacity of these rectangular automated data storage library systems, while not as dense as the cylindrical architecture, can be incrementally increased by linearly attaching additional data storage modules to the existing array of data storage modules. In this manner, the capacity of the automated data storage library system can be managed in discrete blocks, as the needs of the customer change.  
      A first problem with attaching additional data storage modules in a linear mode to an existing rectangular library system is the complexity required for the interconnection among the data storage modules. A typical rectangular architecture automated data storage library system  10  is shown in  FIG. 3  and includes a robotic mechanism  30  that travels along the X-axis on a set of stationary horizontal tracks  32 ,  34  to serve an existing set of data storage modules  14 ,  16 ,  18 . To add an expansion module  12  that includes a plurality of data storage locations requires extension of the horizontal tracks  32 ,  34  on which the robotic mechanism  30  travels into the added data storage module  12 . This change requires modification of the drive system, additional cabling to accommodate the extended distance traveled by the robotic mechanism  30 , and precise alignment of the expanded linear horizontal tracks  32 ,  34  in all three dimensions. In addition, as data storage modules are added to the automated data storage library system  10 , the access time for the robotic mechanism to retrieve a data storage element and mount it in a data read/write device increases. One traditional solution to this access time problem is the addition of an additional robotic mechanism  30 , operating on the same set of stationary horizontal tracks  32 ,  34 . The use of multiple robotic mechanisms  30  on the same set of tracks results in another problem of coordinating the operation of the multiple robotic mechanisms  30  to ensure that there are no collisions and that all data storage locations are served.  
      Thus, existing automated data storage library systems either cannot incrementally expand their data storage capacity or can do so, but at the cost of complexity required to expand the automated data storage library system, the increased access time to retrieve a data storage element and mount it in a data read/write device, and the need to coordinate the operation of multiple robotic mechanisms, operating on the same set of stationary horizontal tracks.  
     SOLUTION  
      The present scalable automatic data storage library system solves the above described problems and provides an advance in the art of automated data storage library systems by providing a composite rectangular-cylindrical architecture that overcomes the problems with existing library systems. The scalable automatic data storage library system includes a base unit housing having an array of data storage locations mounted in a rectangular form factor along a back wall of the housing and at least one read/write device. An X-Y-Z robotic mechanism located in the base unit includes a stationary vertical shaft (Y-axis) on which is mounted on a horizontal track (X-axis), located in front of the array of data storage locations, and movable in the vertical direction along the stationary shaft. The horizontal track extends from one end of the base unit housing to the other end of the base unit housing, for transporting individual data storage elements between their assigned data storage locations and the read/write devices. The robotic mechanism includes a rotatable gripper that moves end-to-end on the horizontal track and swivels on a pivot about an axis that is parallel to the vertical shaft to provide access to all interior surfaces of the base unit housing where data storage locations reside, reaching in the Z-axis direction to access the data storage elements.  
      The base unit may include at least one access door located on the front wall of the base unit housing, which may contain additional data storage locations. These doors also provide the operator with access to the robotic mechanism for maintenance purposes, access to the read/write devices for manual operation and access to data storage locations for bulk loading and unloading of data storage elements. The front of the base unit housing may include a stationary panel incorporating one or more I/O ports, each containing a removable magazine of data storage locations. The I/O ports allow the operator to import and export one or more magazines of data storage elements without interrupting the operation of the robotic mechanism. The rotatable gripper also accesses the data storage locations in the access doors and within the magazines to move data storage elements between the I/O ports and the array of data storage locations. A control panel can be mounted on the front of the base unit housing to allow the operator to control the operation and configuration of the base unit.  
      An expansion module, comprising a rotary carousel having a plurality of columns of outwardly facing data storage locations arranged around the circumference of the carousel, can be connected to either end of the base unit to allow the robotic mechanism to access the data storage elements that are stored in the data storage locations in the expansion module. Installation of the expansion module only requires the removal of the end cover of the base unit housing and the attachment of the expansion module to the base unit housing. There are no additional tracks or robotic mechanisms to install since the rotatable gripper mechanism reaches into the expansion module to retrieve a data storage element but the horizontal track does not need to extend into the expansion module, so the expansion of the scalable automated data storage library system is a simple process. The data storage element retrieval time is not impacted by the addition of the expansion module since the robotic mechanism has no additional travel distance to reach the carousel of data storage locations and the rotation of the carousel overlaps with the movement of the robotic mechanism in the base unit. Thus, the expansion module presents only one column of data storage locations at a time to the rotatable gripper mechanism, which rotates to align with the column of data storage locations as it is being simultaneously translated in the horizontal and vertical directions to be positioned opposite a selected data storage location in the column of data storage locations. An interface in the expansion module allows a control processing system within the base unit to control and coordinate the operation of the robotic mechanism and the rotary carousel.  
      To further increase the storage capacity of the scalable automated data storage library system, a second expansion module may be connected to the other end of the base unit housing. Alternatively, an expansion module may be centrally located between two base units wherein each robotic mechanism within each base unit has access to the shared storage locations within the expansion module. The combination of expansion module(s) and base unit(s) can be architected in many configurations, to thereby incrementally increase the storage capacity of the scalable automated data storage library system. In all of these configurations, each robotic mechanism travels only within the original extent of their base unit and the rotatable gripper mechanism reaches into the adjacent expansion module(s) to move data storage elements between the expansion module(s) and the read/write device(s) within the base unit. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  illustrates a top down view of implementation details of the present scalable automated data storage library system;  
       FIGS. 2A-2B  illustrate perspective and schematic views, respectively, of the present scalable automated data storage library system;  
       FIG. 3  illustrates a prior art automated data storage library system with banks of tape cartridge storage locations;  
       FIG. 4A  illustrates a perspective view of a base unit according to the present scalable automated data storage library system and  FIG. 4B  illustrates a perspective view of the interior of the scalable automated data storage library system showing the front wall and the robotic mechanism;  
       FIG. 5  illustrates a perspective view of the interior of the scalable automated data storage library system with the covers and front panel removed, showing the back wall and the robotic mechanism;  
       FIG. 6  illustrates a top view of the base unit with the left and right front doors in a closed location;  
       FIG. 7  illustrates a top view of the base unit with the left and right front doors in an open location;  
       FIG. 8  illustrates the I/O ports located on the center panel between the left and right front doors with the magazine carrier shown outside the ports;  
       FIG. 9  illustrates a perspective view of an expansion module according to the present scalable automated data storage library system;  
       FIG. 10  illustrates a perspective view of the rotary carousel;  
       FIG. 11  illustrates a top view of the base unit robotic mechanism with respect to the rotary carousel within the adjacent expansion module according to the present scalable automated data storage library system;  
       FIGS. 12A and 12B  illustrate a top view and a perspective view, respectively, of a sample configuration of the present scalable automated data storage library system;  
       FIGS. 13A and 13B  illustrate a top view and a perspective view, respectively, of another sample configuration of the present scalable automated data storage library system;  
       FIG. 14  illustrates a top view of the present scalable automated data storage library system in a star configuration;  
       FIG. 15  illustrates a schematic block diagram of an operational configuration of the present scalable automated data storage library system; and  
       FIG. 16  illustrates a schematic block diagram of another alternative operational configuration of the present scalable automated data storage library system. 
    
    
     DETAILED DESCRIPTION  
      The present scalable automated data storage library system summarized above and defined by the enumerated claims may be better understood by referring to the following detailed description, which should be read in conjunction with the accompanying drawings. This detailed description of the preferred embodiment is not intended to limit the enumerated claims, but to serve as a particular example thereof. In addition, the phraseology and terminology employed herein is for the purpose of description, and not of limitation.  
      Scalable Automated Data Storage Library System  
       FIG. 1  illustrates a top down view of implementation details of one embodiment of the present scalable automated data storage library system  100  which consists of a base unit  200  and two expansion modules  300 .  FIG. 2A  illustrates a perspective view of the present scalable automated data storage library system  100  while  FIG. 2B  represents a schematic view of the present scalable automated data storage library system  100 .  FIG. 5  illustrates a perspective view of the base unit  200  of the scalable automated data storage library system  100 , illustrating the interior with the covers and front panel removed, showing the back wall and the robotic mechanism.  
      The automated data storage library system  100  is connected to one or more host computers  101 ,  102  via control path  223 , and base unit  200  is operable to mount data storage elements  242  into read/write devices  260  to enable the host computers  101 ,  102  to control the operation of the read/write devices  260  to read and write data on to and from the rewriteable media contained within the data storage elements  242  via data path  222 . The automated data storage library system  100  includes a base unit housing  202  having an array of data storage locations  241  mounted in a rectangular form factor along a back wall  240  of the housing  202  and at least one read/write device  260 . An X-Y-Z robotic mechanism  400  includes a stationary vertical shaft  410  on which is mounted a horizontal track  430 , located in front of the array of data storage locations and read/write devices  260 . The horizontal track  430  extends from one end  421  of the base unit housing to the other end  422  of the base unit housing, for transporting individual data storage elements  242  between their assigned data storage locations  241  and the read/write devices  260 . The robotic mechanism  400  includes a rotatable gripper  450  that traverses horizontal track  430 , which moves in a vertical direction on the vertical shaft  410 . The rotatable gripper  450  swivels about an axis that is parallel to the vertical shaft  410  to provide access to all interior surfaces of the base unit housing where data storage locations  241  and read/write devices  260  reside, reaching in the Z-axis direction to access the data storage elements  242 .  
      This embodiment of the scalable automated data storage library system  100  includes a base unit  200 , interconnected via local control path  221  to two expansion modules  300 , one connected to the base unit  200  at either end thereof. Alternatively, a single expansion module  300  can be connected to the base unit  200 . The expansion module  300  comprises a rotary carousel  310  having a plurality of columns of outwardly facing data storage locations  341  arranged around the circumference (surface  320 ) of the rotary carousel  310  and can be used to incrementally increase the storage capacity of the base unit  200  without requiring the addition of any robotic mechanism. The side cover  301  in  FIG. 4A  of the base unit housing  202  ( FIGS. 4A &amp; 5 ) is removed when the expansion module  300  is connected to the base unit  200  to allow the base unit robotic mechanism  400  to access the data storage locations  341  located within the expansion module  300  without modifying or extending the horizontal track  430  of the existing robotic mechanism  400  of the base unit  200 . Therefore, the present scalable automated data storage library system  100  eliminates the addition of hardware, cabling, and the expenditure of the time to implement complex alignment procedures and modifications required for expanding prior art data automated data storage library systems by allowing the base unit robotic mechanism  400  to access storage locations  341  within the expansion module  300 .  
      Base Unit  
       FIG. 4A  illustrates a perspective view of a base unit according to the present scalable automated data storage library system and  FIG. 4B  illustrates a perspective view of the interior of the scalable automated data storage library system showing the front wall and the robotic mechanism.  FIG. 6  illustrates a top view of the base unit with the left and right front doors in a closed location.  
      The base unit  200  may include one or more front access doors  212 ,  214  on the front wall  210  to permit bulk loading and unloading of data storage elements and to provide access for maintaining the internal robotic mechanism. The center front panel  216 , located between the left and right front access doors,  212  and  214  respectively, may also include a control panel  220  to allow the operator to configure, to control the operation of, or obtain status from, the data automated data storage library system base unit  200 . The center front panel  216 , shown in  FIGS. 4A and 8 , may also include one or more I/O ports  500  for importing and exporting a magazine of data storage elements as is described below.  
      Internally, the base unit  200  includes rack space for operational components such as a power supply and a control processing system including memory for controlling operation of the base unit  200  and interconnected expansion modules  300 . Base unit  200  also includes a back wall  240  of data storage locations  241  for housing a plurality of data storage elements  242  and data read/write devices  260  as illustrated in  FIG. 5 . Additional storage locations may be located on the interior center front panel  216  and on the interior of the left and right front access doors,  212  and  214  respectively ( FIG. 4B ). In this example, a robotic mechanism  400  moves the data storage elements  242  among the back wall  240  of data storage locations, the center front panel  216 , including the I/O ports  500 , and the right and left doors  212  and  214  and the data read/write devices  260 . The rotatable gripper  450  attached to the robotic mechanism  400  swivels about an axis that is parallel to the vertical shaft  410  to provide access to all interior surfaces of the base unit housing where data storage locations  241  and read/write devices  260  reside, reaching in the Z axis direction to access the data storage elements  242 .  
       FIGS. 6 &amp; 7  illustrates a top view of base unit  200  with the right side door  212  and the left side door  214  in a closed and an open position, respectively. As illustrated, the robotic mechanism  400  travels between the data storage locations  241  located on the back wall  240  and the data storage locations  241  that are located on the center front panel  216 , left front access door  212 , and the right front access door  214 . The rotatable gripper  450  swivels about an axis that is parallel to the vertical shaft  410  to provide access to the data storage locations located on the front panel  210  and the data read/write devices  260  located in the back wall  240 .  
      Input/Output Ports  
      The center front panel  216  illustrated in  FIG. 4A  includes a control panel  220  for configuring and controlling the operation of and obtaining status from the base unit  200  and includes one or more input/output (I/O) ports  500  for importing and exporting data storage elements. The I/O ports  500  are located on the center panel  216 , between the left and the right front access doors,  212  and  214 , respectively.  
      The I/O ports  500  provide an alternative method of inserting and extracting data storage elements  242  without interrupting the operation of the base unit  200 . The data storage elements  242  may be housed in a magazine  502 - 508  as illustrated in  FIG. 8  for importing and exporting data storage elements into and out of the base unit  200 . The I/O ports make use of a tilt mechanism to enable an operator to slide a magazine  502 - 508  into the I/O ports  500 , then close the I/O port  500  to enable the robotic mechanism  400  to access the data storage elements contained therein. One or more magazines  502 - 508  may be removed from the base unit  200  as illustrated in  FIG. 8  to allow the operator to insert and/or extract one or more data storage elements into or from the magazines  502 - 508 . While the base unit  200  is illustrated and described with four I/O ports  500  in the center front panel  216 , the base unit  200  may be configured for an alternative number of I/O ports in alternative locations on the front panel  216  of the base unit  200 .  
      Expansion Module  
       FIG. 9  illustrates a perspective view of the expansion module  300 , which includes a rotary carousel  310  having a plurality of outwardly facing data storage locations  341 , shown in  FIG. 10 , for housing a plurality of data storage elements  242 . The expansion module  300  may also include left and right front doors  330 ,  331  for bulk loading of data storage elements  242  and windows  332 ,  333  for viewing the operation of the rotary carousel  310 . The expansion module  300  is connected to an end of the base unit  200  as illustrated in  FIG. 1  to increase the storage capacity of the scalable automated data storage library system  100 . The rotary carousel  310  includes a plurality of outwardly facing data storage locations  341  on the outer surface of a cylindrical drum  320 , creating a cylinder having a plurality of facets as illustrated in  FIG. 10 . The connection of the expansion module  300  to the base unit  200  includes an interface between the carousel drive mechanism (not shown) and the base unit processor (not shown) to allow the base unit processor to control the rotational movement of the rotary carousel  310 . The side cover  301  (shown in  FIG. 4A ) of the base unit  200  is removed and replaced on to the end of expansion module  300  to allow the robotic mechanism  400  to access the data storage locations  341  on the rotary carousel  310  without requiring precise and critical alignment of the openings.  
      The rotary carousel  310  within the expansion module  300  provides storage locations for housing a plurality of data storage elements in an array of rows and columns. When the data storage elements are ½ inch magnetic tape cartridges (such as LTO or SAIT), an 18-facet rotary carousel  310  may include data storage locations for up to 1072 half-inch tape cartridges. A robotic mechanism is not required for the expansion module  300 ; instead, the robotic mechanism  400  of the adjacent base unit  200  accesses the data storage elements in the rotary carousel  310  for moving data storage elements between the rotary carousel data storage locations  341  and the base unit data read/write devices  260 . The rotatable gripper mechanism  450  of the robotic mechanism  400  reaches, in a combined X-axis and Z-axis motion, a minimal distance into the expansion module  300  as illustrated in  FIG. 11  to provide access to the data storage locations  341  without requiring an extension of the robotic mechanism track  430  into the expansion module  300 . In other words, access of data storage locations in the expansion module  300  by the base unit robotic mechanism  400  does not require additional tracks, extension of cabling or modification of the robotic mechanism drive system. Therefore, the present scalable automated data storage library system  100  eliminates the complex hardware additions or alignment procedures and modifications required for expanding prior art data automated data storage library systems.  
      Robotic Mechanism  
      The robotic mechanism  400  is located within the base unit  200  and has vertical and horizontal motions and includes a rotatable gripper mechanism  450 . Referring to the top view of the base unit  200  and adjacent expansion module  300  of  FIG. 11 , the rotatable gripper mechanism  450  swivels about an axis that is parallel to the vertical shaft  410  and reaches along the Z axis to provide access to all interior surfaces of the base unit housing where data storage locations reside: in the rear wall  240 , the front panel  210  and also the surface  320  in the rotary carousel(s)  310  within the adjacent expansion module(s)  300 .  
      Horizontal track  430  extends the length of the base unit  200  from the left side  421  to the right side  422  as illustrated in  FIGS. 5 &amp; 11 . When the adjacent expansion module  300  is attached to the base unit  200 , the horizontal track  430  is not extended into the expansion module  300 . However, the rotatable gripper mechanism  450  reaches a minimal distance into the expansion module  300  to allow the rotatable gripper mechanism  450  to access data storage elements  242  housed in the rotary carousel  310  as illustrated in  FIG. 11 .  
      Scalable Automated Data Storage Library System Configurations  
      The present scalable automated data storage library system  100  provides a base unit  200  which can be configured to include a combination of data read/write devices  260 , data storage locations  241  for housing data storage elements  242 , including I/O ports  502 - 508 . The expansion module  300  includes a plurality of data storage locations  341  for housing a corresponding plurality of data storage elements  242 . For installation, a left or right side cover of the base unit housing is removed and an open side of the expansion module  300  is connected to an open side of the base unit  200 . Removing a side cover  301  of the base unit housing exposes the rotary carousel  310  for access by the robotic mechanism  400 . The rotary carousel drive system is controlled by a base unit processor to rotate the rotary carousel  310  to the desired location. A combination of the rotation of the rotary carousel  310  and the swivel and reach of the rotatable gripper mechanism  450  form an effective method for moving data storage elements  242  from the adjacent rotary carousel  310  to a data read/write device  260  within the base unit  200 . The movement of the rotary carousel  310  and the robotic mechanism  400  may be concurrently executed.  
      While  FIG. 1  illustrates the base unit  200  and two expansion modules  300  connected linearly, the simplicity of the construction of the base unit  200  and expansion module  300  allow alternative configurations. For example, an expansion module  300  may be located in a corner with a base unit  200  located on each side of the expansion module  300  in an L-shaped configuration as illustrated in  FIGS. 12A and 12B . The configuration of  FIGS. 12A and 12B  may be expanded by adding an expansion module  300  next to one of the base units  200  or by adding an expansion module  300  adjacent to each of the two base units  200  as shown in  FIGS. 13A and 13B . Alternatively, a single expansion module  300  may be connected with up to four base units  200  in a star configuration as illustrated in  FIG. 14 . In this configuration, each base unit robotic mechanism has access to the plurality of data storage elements housed within adjacent expansion modules  300 .  
      Operationally  
      As shown in  FIG. 15 , one embodiment of the automated data storage library system  600  can consist of two base units  602  and  604  which are connected with a shared expansion module  603 . The automated data storage library system  600  is also connected to one or more host computers  610 - 613  via control paths  623 ,  624  and is operable to mount data storage elements  242  into data read/write devices  651 ,  652  to enable the host computers  610 - 613  to control the operation of the data read/write devices  651 ,  652  to read and write data on to and from the rewriteable media contained within the data storage elements  242 . When two or more base units  602  and  604  are connected with an expansion module  603  as illustrated in  FIG. 15 , the processors  641 ,  642  in the two base units  602 ,  604  function in a master-slave configuration. In other words, host processor  610  communicates with processor  641  which, in turn, controls the operation of the processor  642  and the rotation of the rotary carousel  631 , within the expansion module  603 , via control path  621  to enable the data storage elements to be loaded into the data read/write devices  651 ,  652 . As base units  606  and/or carousels  605  are added, as shown in  FIG. 16 , to the automated data storage library system  600 , the processor  641  is interconnected with the processor  643  located in the added base unit  606 . The master processor  641  may include self-learning software to allow the master processor  641  to determine the configuration of the added base unit(s) and/or the added expansion module(s).  
      More than one host computer  610 - 613  may control the robotics and utilize the storage capacity of the automated data storage library system  600 , as illustrated in  FIG. 15  via data path  622  and local control path  621 . In the example of  FIG. 15 , the storage capacity of the automated data storage library system  600  may be partitioned between the first host  610  and a second host  612 . The first host  610  communicates with the processor  641  of base unit  602  and a second host  612  communicates with the processor  642  of the base unit  604 . Base unit  602  controls the operation of the other base unit  604  and the rotation of the rotary carousel  631  within expansion module  603  via control path  621 . First host  610  has access for reading and writing data to and from the data storage elements that are located within the base unit  602 , expansion module  603  and base unit  604 . The first host  610  can access data storage elements that are located within the base unit  602  and expansion module  603  via data path  622  to data read/write device  651  and can also separately access data storage elements  242  that are located within the base unit  604  and expansion module  603  via data path  622  to data read/write device  652 . The second host  612  also can have access for reading and writing data to and from the data storage elements that are located within the base unit  602 , expansion module  603  and base unit  604 . The second host  612  can access data storage elements that are located within the base unit  602  and expansion module  603  via data path  622  to data read/write device  651  and can also separately access data storage elements  242  that are located within the base unit  604  and expansion module  603  via data path  622  to data read/write device  652 . The partitioning of the data storage locations within expansion module  300  can be managed to satisfy the data storage needs of the various host computers. For example, a subset of the data storage locations within expansion module  300  can be dedicated for the use of host computer  610 , and other subsets of data storage locations within expansion module  300  can be dedicated for the use of each of host computers  611 - 613 .  
      This system configuration of  FIG. 15  can be expanded by the addition of base unit  606  and expansion module  605  as shown in  FIG. 16  so that host  610  may also access the data storage elements within the base unit  604  and second expansion module  605  via the local control path  621  and data path  622  to data read/write device  652  and separately access the data storage elements within the base unit  606  and second expansion module  605  via data path  622  to data read/write device  653 . Similarly, hosts  614 - 615  can access data storage elements using the partitioning described above with respect to host  610 .  
      Summary  
      It is apparent that there has been described a scalable automated data storage library system that fully satisfies the objects, aims, and advantages set forth above. While the scalable automated data storage library system has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and/or variations can be devised by those skilled in the art in light of the foregoing description. Accordingly, this description is intended to embrace all such alternatives, modifications and variations as fall within the spirit and scope of the appended claims.