Abstract:
A media library appliance comprises optical disc handling robotics developed for dual standard slim drives in a vertical orientation. The disc handling robotics comprise a disc transfer assembly for transferring discs to and from a rotatable circular carousel surrounding the optical drives. Each slim drive resides in a separate field-replaceable unit (“FRU”) that can be replaced by a customer in the field without powering down the appliance. The FRU includes various features that allow accurate 3-axis alignment and registration of the optical drive within the appliance.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application 61/051,770, filed on May 9, 2008, and incorporated by reference herein in its entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    This invention pertains in general to handling optical discs and replacement of disc drives used in data storage systems. 
         [0004]    2. Description of the Related Art 
         [0005]    Various designs of optical disc libraries are known. For example, U.S. Pat. No. 4,984,228 to Agostini entitled “Dual Drive Changer for Records,” issued Jan. 8, 1991, describes a system wherein an annular-shaped magazine for the storage of discs surrounds two disc drives. The magazine rotates relative to the disc drives, which allows dual mechanisms to load/unload the discs to/from the drives from/to the magazine. 
       SUMMARY 
       [0006]    Embodiments of the invention provide methods and systems for handling optical discs in a media library appliance and for replacing optical drives in the field. In one embodiment, the media library appliance comprises optical disc handling robotics developed for dual standard slim drives in a vertical orientation. Each slim drive resides in a separate field-replaceable unit (“FRU”). 
         [0007]    In one embodiment, the disc handling robotics comprise a disc transfer assembly for transferring discs to and from a rotatable circular carousel surrounding the optical drives. The carousel rotates around the optical drives until the appropriate disc is aligned with an optical drive. A pusher arm pushes the outer trailing edge of a disc to roll or slide the disc into the optical drive. A knife may move into an active position to push the disc further into the optical drive and prevent any undesired untimely unloading of the disc from the drive or attempted loading of another disc when the drive is occupied. Upon unloading, the knife may also assist with pushing an ejected disc away from the drive and into the carousel. 
         [0008]    In another embodiment, each FRU houses a standard optical slim drive that can be replaced by a customer in the field without powering down the appliance. The FRU includes various features that allow accurate 3-axis alignment and registration of the optical drive within the appliance. In some embodiments, the FRU includes a latch that locks the FRU into the appliance. By depressing the latch release button through the FRU handle, the FRU can be easily lifted out of the appliance for replacement by the handle using one or more fingers. An optional feature of the disc transfer assembly blocks access to the latch release button for a functional FRU, thus preventing replacement of the wrong FRU. 
         [0009]    The present invention has various embodiments, including as a computer implemented process and as computer apparatuses. The features and advantages described herein are not all-inclusive. Many additional features and advantages will be apparent to one of ordinary skill in the art in view of the drawings and detailed description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  illustrates the optical disc handling system of a media library appliance, in accordance with one embodiment. 
           [0011]      FIGS. 2A-C  illustrate loading a disc into an optical drive of a media library appliance, in accordance with one embodiment. 
           [0012]      FIGS. 3A-C  illustrate unloading a disc from an optical drive of a data storage appliance, in accordance with one embodiment. 
           [0013]      FIGS. 4A-B  are views of an example of a field-replaceable unit (“FRU”), in accordance with one embodiment. 
           [0014]      FIGS. 5A-B  are views of another example of a FRU, in accordance with one embodiment. 
           [0015]      FIGS. 6A-B  are views of an example of a FRU positioned for insertion in the media library appliance, in accordance with one embodiment. 
           [0016]      FIG. 7A  illustrates the alignment of two FRUs positioned for insertion in the data storage appliance, in accordance with one embodiment. 
           [0017]      FIG. 7B  illustrates the FRUs in operational positions within the media library appliance, in accordance with one embodiment. 
           [0018]      FIG. 8  illustrates an optional feature of the disc transfer assembly, in accordance with one embodiment of the invention. 
       
    
    
       [0019]    The figures depict embodiments of the present invention for purposes of illustration only. One skilled in the art will readily recognize from the following discussion that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the invention described herein. 
       DETAILED DESCRIPTION OF THE EMBODIMENTS 
     1. Overview of the Media Library Appliance 
       [0020]    Embodiments of the invention include a media library appliance used to read and/or write data stored on a plurality of optical discs within the library.  FIG. 1  illustrates the optical disc handling system of a media library appliance  100 , in accordance with one embodiment. Whereas the front  110  and back  111  sides of the appliance  100  are illustrated, the left side, right side, and top portions of the housing of the appliance  100  are removed in  FIG. 1  so that the arrangement of the interior components of the appliance  110  can be viewed. In one embodiment, the appliance  100  is a modular rack appliance having a size of five rack mount units (“RMU”), although other form factors can also be used. 
         [0021]    In the example illustrated in  FIG. 1 , the interior components of the appliance  100  include two 12.7 mm or 9.5 mm slim drives housed in separate field-replaceable unit (“FRU”) modules  103 A,  103 B. Each FRU drive can be made compatible according to the Parallel Advanced Technology Attachment/Serial Advanced Technology Attachment (“SATA/PATA”) requirements for interfacing with the appliance  100 . The FRU modules  103 A,  103 B are modules to enable the drive housed therein to be swapped out of the appliance  100  by a customer in the field without the need to power down the appliance to execute the exchange. Features of the FRU modules  103 A,  103 B that enable them to be easily replaceable in the field will be described in greater detail with respect to  FIGS. 4A-8 . 
         [0022]    Referring back to  FIG. 1 , the FRU modules  103 A,  103 B house optical drives that are oriented vertically in the center of a circular disc carousel  104 , also referred to herein as a bowl  104 . The carousel  104  holds, for example, 200 discs in individual slots, and rotates around the FRU modules  103 A,  103 B. The carousel is one means for storing a plurality of optical discs that rotates around the FRU modules  103 A,  103 B. A slot  109  in the front  110  of the appliance  100  provides a means to load/unload discs  105  to/from the carousel. 
         [0023]    The interior components of the appliance  100  also include a disc transfer assembly  101 . Each drive within the FRU modules  103 A,  103 B has a respective side  102 A,  102 B of a disc transfer assembly  101  positioned to transfer individual optical discs  105  from the carousel  104  to the respective drive in the FRU  103 A,  103 B during the disc loading operation, and from the respective drive in the FRU  103 A,  103 B to the carousel  104  in the disc unloading operation. 
         [0024]    Also illustrated among the interior components of the appliance  100  in  FIG. 1  are a pusher arm  106  and a knife assembly  107  that will be described in greater detail with respect to  FIGS. 2A-C  and  3 A-C in Section  2  below.  FIG. 1  also illustrates a latch  108 , that will be described in greater detail with respect to  FIGS. 4A-B  and  6 A-B in Section 3 below. 
       2. Disc Handling 
       [0025]      FIGS. 2A-C  illustrate the disc handling operation of loading a disc  105  into an optical drive  130  of the appliance  100 , in accordance with one embodiment. The carousel  104  rotates around the optical drives in FRUs  103 A,  103 B until the appropriate disc is aligned with the appropriate side  102 A,  102 B of the disc transfer assembly  101 .  FIG. 2A  shows the initial position of the pusher arm  106 , the disc  105 , and the knife  107  relative to the optical drive  130 . In the example shown, the pusher arm  106  operates by sliding back and forth on a track  122  above the arm  106 . In other embodiments, the pusher arm  106  may be articulated in various ways. For example, the pusher arm  106  may have cam action for sliding the disc  105  into the drive. In one embodiment, the pusher arm has a curved contact surface corresponding to the curve of the outer edge of an optical disc  105 . The pusher arm is one means for pushing a disc at least partially into a drive. Referring to  FIG. 2A , the pusher arm  106  is at rest in the position furthest from the optical drive  130 . The disc  105  is resting in the bowl  104 , and the knife  107  is in the lower position in preparation for the transfer of the disc  105  from the bowl  104  to the optical drive  130 . The knife  107  is a tool that, when extended or inserted at least partially in front of the opening in the optical drive  130 , assists a partially loaded disc  105  in completing the loading process and/or prevents unintended disc  105  ejections or loads. The knife may be mounted, for example, above or below the opening in the optical drive to perform these functions. 
         [0026]      FIG. 2B  illustrates the position of the pusher arm  106 , the disc  105 , and the knife  107  in the middle of the loading operation. In this example, the pusher arm  106  moves laterally along the track  122  with enough force to roll or slide the disc  105  from the bowl  104  partially into the optical drive  130 . In one embodiment, the components of the disc transfer assembly  101 , including the pusher arm  106 , only contact the trailing edge of the disc  105  to avoid damage to the data stored on the disc  105 . During the loading procedure, the knife  107  remains in the lower position, and does not block the access of the disc  105  to the optical drive  130 . 
         [0027]      FIG. 2C  illustrates the position of the pusher arm  106 , the disc  105  and the knife  107  at the conclusion of the loading operation. The pusher arm  106  retracts along the track  122  to the position furthest from the optical drive  130 . The knife  107  moves from an inactive position to an active position, in this case, a raised position. The knife  107  can be moved from an inactive position to an active position by any mechanism known to those of skill in the mechanical arts, such as a screw. 
         [0028]    The active position of the knife  107  has two main benefits. First, the raising of the knife  107  causes the leading edge of the knife  107  to exert a lateral force on the curved outside edge of the disc  105  to push the disc  105  further into the optical drive  130  if needed to activate the internal mechanism of the optical drive  130  that draws in a disc  105 . The knife  107  makes contact, if any, with an outside edge of the disc  105  to prevent any damage to the data-carrying portions of the disc  105 . Second, in the active position, the knife  107  acts as a lock that prevents an undesired unloading of the disc  105  from the drive  130  when the bowl  104  is not in the correct position to receive the disc  105 . The knife  107  in the active position also blocks an attempted loading of a second disc  105  into the same drive  130  when the drive  130  is already occupied by a disc  105 . In one embodiment, the knife  107  is a tool having a relatively long flat blade that is used to nudge a disc  105  further into the optical drive  130  if needed and perform the blocking function to prevent undesired unloading or attempting loading of a second disc, as described above. The knife need not have a sharp or cutting edge. The knife is one means for exerting the lateral force to push the disc further into the optical drive and partially block the opening to the optical drive  130 , but other mechanisms are also possible. 
         [0029]      FIGS. 3A-C  illustrate unloading a disc  105  from an optical drive  130  of a data storage appliance  100 , in accordance with one embodiment. The carousel  104  rotates around the optical drives in FRUs  103 A,  103 B until the appropriate slot for storage of the disc  105  in the carousel  104  is aligned with the appropriate side  102 A,  102 B of the disc transfer assembly  101 .  FIG. 3A  shows the initial position of the pusher arm  106 , the disc  105 , and the knife  107  relative to the optical drive. The pusher arm  106  is in the position furthest from the optical drive  130 . In the example shown, the knife  107  moves to the lower, inactive position in preparation for the disc  105  unloading from the optical drive  130  and returns to the top, active position after the disc  105  has been ejected to ensure the disc  105  completes the move back to the carousel  104 . 
         [0030]      FIG. 3B  illustrates the position of the pusher arm  106 , the disc  105 , and the knife  107  in the middle of the unloading operation. In this example, the pusher arm  106  moves laterally along track  122  into position to catch the disc  105  that is being ejected from the optical drive  130 . In some embodiments, the disc transfer assembly  101  is funnel-shaped at the bottom, which allows for smooth disc handling. In this way, the optical disc  105  is controlled as it is expelled from the drive  130 , which helps prevent the disc  105  from crashing into adjacent discs in the bowl  104  and from failing to be stored in the proper slot in the bowl  104 . 
         [0031]      FIG. 3C  illustrates the position of the pusher arm  106 , the disc  105 , and the knife  107  at the conclusion of the unloading operation. The pusher arm  106  retracts along track  122  to the position furthest from the optical drive  130 . At the same time, the knife  107  raises, which pushes the disc  105  away from the optical drive  130  and further into the bowl  104 . At the conclusion of the unloading operation, the disc  105  is once again at rest in a slot in the bowl  104 . The knife  107  remains in the raised position to prevent the undesired loading of a disc  105 . 
       3. Field-Replaceable Units 
       [0032]      FIGS. 4A-B  are views of an example of a field-replaceable unit (“FRU”)  103  for housing a standard optical slim drive  130 , in accordance with one embodiment.  FIG. 4A  illustrates one side of the FRU housing  440 , and  FIG. 5B  illustrates the opposite side. The proper functioning and reliability of the media library appliance  100  relies on the accurate alignment of the FRUs  130  with respect to the remainder of the appliance  100  when the FRU  103  is replaced by a customer in the field, from time to time. Thus, the FRU  103  comprises a molded frame with various features that allow accurate registration of the optical drive  130  within the appliance  100  upon replacement. In this example, the alignment grooves  441  and the alignment tabs  442  assist in properly registering the FRU registering plane  443  to a matching reference plane inside the appliance  100 . In addition, spring tabs  445  shown on the reverse side of the FRU housing  440  in  FIG. 4B  are used to accurately position the FRU  103  in relation to a funnel of the carousel  104  of the appliance  100 , which allows for smooth disc transfers into and out of the optical drive  130  within the FRU  103 . These keying features ensure a 3-axis alignment that properly positions the FRU  103  inside the appliance  100 . 
         [0033]      FIG. 4A  also illustrates an optical drive PCBA  444 . In one embodiment, the optical drive printed circuit board assembly (“PCBA”)  144  is positioned along the side of the drive  103  (oriented vertically) for easy access. 
         [0034]      FIGS. 4A-B  also illustrates elements of the latch  108  of the FRU  103  in more detail. In one embodiment, the latch  108  comprises a latch release button window  448  and latch locking windows  449 . The latch release button window  448  is an opening through which a user can reach to depress a latch button (shown in  FIGS. 6A-B ) to release latch locking tabs (also shown in  FIGS. 6A-B ). By releasing the latch locking tabs, the latch disengages from the latch locking windows  449  of the FRU  103 . Thus, the FRU  103  can be lifted out of the appliance  100  using the handle  409 . 
         [0035]      FIGS. 5A-B  are views of another example of a FRU  103 , in accordance with one embodiment.  FIG. 5A  shows one side of the FRU housing  440 , and  FIG. 5B  shows the other side.  FIGS. 5A-B  show one alternative for the placement of the various alignment features of the FRU  103 , but many variations are also possible. Alternative designs may include more or fewer tabs, ribs, grooves, “snap-in” features, or any combination of these or other alignment features known to those of skill in the art for providing 3-axis alignment of the FRU  103 . In the example illustrated in  FIGS. 5A-B , four alignment tabs with positive “snap-in” features  542  are placed on one side of the housing  440  along the registering plane  543  that mate with corresponding features in the appliance  110 . On the other side of the housing  440 , four spaced ribs  541  are used for alignment to ensure a snug fit between the appliance  110  and registering plane  543 . 
         [0036]      FIGS. 5A-B  also illustrates elements of an alternate latch  108  of a FRU  103  in more detail. In this embodiment, the latch  108  comprises a button-latch  508  which locks the FRU  103  into a corresponding slot in the sheet metal assembly the appliance  100 . By pressing the button-latch, the lock in to the slot is released, and FRU  103  can be lifted out of the appliance  100  using the handle  509 . 
         [0037]      FIGS. 6A-B  are views of an example of a FRU  103  of  FIGS. 4A-B  positioned for insertion in the appliance  100 , in accordance with one embodiment. These views illustrate one example of the alignment of a groove  441  on a FRU  103  and the corresponding alignment pin  661  that fit together when the FRU  103  is inserted. Likewise, the alignment tabs  442  on the FRU  103  fit together with the corresponding alignment slots  662  in the hardware surrounding the FRU  103 . As described above, many alternatives are also possible. As shown in  FIGS. 6A-B , the FRU  103  slides vertically into and out of the appliance  100 . 
         [0038]    When the FRU  103  is in the appliance  100 , a latch release button  668  extends partially through the opening in the handle  409 , thus forming a locking mechanism. In order to release the FRU  103  from the appliance  100 , a person depresses the latch release button using one or more fingers extending through the opening in the handle  409 . Then, the person can lift the FRU  103  out of appliance  100  with the same one or more fingers that depressed the latch release button  668 . These features of the invention allow for a single finger removal of the FRU  103  that has been latched into the appliance  100 . 
         [0039]      FIG. 7A  illustrates the alignment of two FRUs  103 A,  103 B positioned for insertion in the appliance  100 , in accordance with one embodiment. Note that in this embodiment, the FRUs  103 A,  103 B reside back to back within the appliance  100 , as illustrated in  FIG. 7B . This arrangement of optical drives has the benefit of keeping the footprint of the appliance  100  relatively small. 
         [0040]    Also shown in  FIG. 7A  are various alignment features, including tabs, slots, and holes, on the appliance  100  that correspond to various alignment features present on the FRU  103 A,  103 B. First, lead-in chamfers  770  guide the insertion of the FRU  103 A,  103 B into the compartment within the appliance  100 . The alignment tabs with positive “snap-in” features  542  on the FRU  103 B, snap into the corresponding holes  772  on the appliance  100 . The slots or holes  772  may have lead-in chamfers  771  for assisting with the engagement of the alignment tabs  542  to the corresponding holes  772 . In addition, guiding tabs  774  assist in the removal of the FRU by pressing inward on the positive “snap-in” features  542  of the FRU  103 A,  103 B to assist the features  542  with exiting the corresponding holes  772  as the FRU is lifted upward. The button-latch  508  on the FRU  103 A,  103 B has a corresponding locking slot  778  on the appliance  100 . The button-latch  08  protrudes through the slot to lock the FRU  103 A,  103 B in place. A divider  777 A separate the two FRUs  103 A,  103 B. A lower ramp  777 B of the divider  777 A guides a FRU  103 A,  103 B into place by pushing the FRU  103 A,  103 B away from the divider  777 A at the bottom of the registering plane  543 . The alignment ribs  541  push the FRU  103 A,  103 B away from the divider  777 A at the top of the registering plane  532 . 
         [0041]      FIG. 8  illustrates an optional feature of the disc transfer assembly  101 , in accordance with one embodiment of the invention. In one embodiment, the pusher arm  106  corresponding to a functional FRU  103  can be positioned as shown in  FIG. 8  to block access to the latch release button  668  to prevent accidental removal of a functional FRU  103 . As an additional or alternative signal to the user, a green LED or other signaling mechanism associated with the functional FRU  103  may also be used to indicate which of the two optical drive FRUs is functioning properly. In contrast, the pusher arm  106  of the failed FRU  103  is not positioned to block access to the latch release button  668  for the FRU  103 , and the failed FRU  103  may also be marked by a red LED or other signaling mechanism associated with the failed FRU  103 . Thus, this optional feature provides a mechanism for preventing a user from accidentally replacing the wrong FRU  103 . 
         [0042]    The above description is included to illustrate the operation of the embodiments and is not meant to limit the scope of the invention. From the above discussion, many variations will be apparent to one skilled in the relevant art that would yet be encompassed by the spirit and scope of the invention. Those of skill in the art will also appreciate that the invention may be practiced in other embodiments. First, the particular naming of the components, capitalization of terms, the attributes, or any other programming or structural aspect is not mandatory or significant, and the mechanisms that implement the invention or its features may have different names, formats, or protocols. Also, the particular division of functionality between the various system components described herein is merely exemplary, and not mandatory; functions performed by a single system component may instead be performed by multiple components, and functions performed by multiple components may instead performed by a single component. 
         [0043]    Finally, it should be noted that the language used in the specification has been principally selected for readability and instructional purposes, and may not have been selected to delineate or circumscribe the inventive subject matter. Accordingly, the disclosure of the present invention is intended to be illustrative, but not limiting, of the scope of the invention.