Abstract:
A tape drive bezel forming a front surface of a tape drive is provided, the bezel comprising a housing, an opening in the housing for receiving a tape cartridge, a plurality of targets or fiducials, each fiducial providing an alignment target for one of a plurality of robotic assemblies to insert or remove a tape cartridge in the opening of the housing, and a plurality of projections extending from the front of the housing forming legs for supporting the tape drive and for protecting the fiducials from handling damage. The plurality of fiducials provided on the bezel are compatible with the plurality of robotic assemblies used by different tape library systems enabling a tape drive fitted with the bezel to be used interchangeably with the different libraries.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates in general to tape drives and in particular to tape drives having bezels which accommodate magnetic tape cartridges. 
   2. Description of the Related Art 
   Magnetic tape cartridges or cassettes are used to house magnetic tape as the medium for recording and storage of information in magnetic tape libraries. Read and write operations of information to and from the tape medium is carried out by insertion of the tape cartridge into a read/write device referred to as a tape drive, tape recorder or tape deck. Tape drives are usually designed as a component of a specific tape library product. Insertion and removal of a tape cartridge into and from a tape drive is usually done by an accessor comprising an automated gripper device through a bezel forming a front face of the tape drive. 
   The bezel, which provides a physical interface between the gripper and the tape drive, is required to have an opening, or window, to accommodate the shape of the tape cartridge and a number of features which interact with the gripper to facilitate the mechanical processes for insertion and removal of the tape cartridge by the gripper. Typically, a required feature on the bezel is a target or fiducial that the gripper senses in order to locate the window in which to insert or from which to remove a tape cartridge. A problem with the present art is that each library product uses fiducials that differ in location, shape, size and reflectivity so that only tape drives having a bezel with the unique fiducials of that library can be used with that library. Another problem is that the fiducials on the bezels forming the front face of the tape drive are susceptible to damage when the tape drive is manually removed from the library. Therefore, there is a need for an improved bezel design that overcomes these problems. 
   SUMMARY OF THE INVENTION 
   In accordance with the principles of the present invention, there is disclosed a tape drive bezel forming a front surface of a tape drive, the bezel comprising a housing, an opening in the housing for receiving a tape cartridge, a plurality of targets or fiducials, each fiducial providing an alignment target for one of a plurality of robotic assemblies to insert or remove a cartridge in the opening of the housing, and a plurality of projections extending from the front of the housing forming legs for supporting the tape drive and for protecting the fiducials from handling damage. The plurality of fiducials provided on the bezel are compatible with the plurality of robotic assemblies used by different tape library systems enabling a tape drive fitted with the bezel to be used interchangeably with the different libraries. 
   An embodiment of the bezel of the present invention comprises a housing for engaging the front of a tape drive, an opening in the housing for receiving a tape cartridge, three fixed targets or fiducials mounted on fiducial support structures, a slot for supporting a removably mounted fourth fiducial, and three integrally formed legs extending from the front surface of the housing. Each fiducial is positioned on the front surface of the housing so that an optically reflective surface provides an alignment target for one of a plurality of robotic assemblies to insert or remove a tape cartridge in the opening. The three legs extend from the front surface of the housing a height greater than the height of the fiducials above the housing surface so that if the housing of the tape drive is in contact with a surface, the legs provide support for the tape drive without the fiducials contacting the surface. 
   The above as well as additional objects, features, and advantages of the present invention will become apparent in the following detailed description. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a fuller understanding of the nature and advantages of the present invention, as well as the preferred mode of use, reference should be made to the following detailed description read in conjunction with the accompanying drawings. In the following drawings, like reference numerals designate like or similar parts throughout the drawings: 
       FIG. 1   a  is a front perspective view of an embodiment of a tape drive bezel according to the present invention; 
       FIG. 1   b  is a perspective view of a removable fiducial for use with the bezel of  FIG. 1   a;    
       FIG. 2  is a perspective view of an exemplary tape cartridge; 
       FIG. 3  is a perspective view of a gripper cage supporting two grippers; 
       FIG. 4  is a front perspective view of a tape drive; 
       FIG. 5  is a simplified diagram of a tape drive system; and 
       FIG. 6  is a front perspective view of a tape library. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1  is front perspective view of an embodiment of a tape drive bezel  100  for a tape drive system. The bezel  100  comprises a housing  101  having a substantially rectangular shape that engages a front surface of a tape drive. The housing  101  has a top edge  102 , a bottom edge  103 , a left edge  104 , a right edge  105  and a window or opening  106  for receiving a tape cartridge  200  shown in  FIG. 2 . The opening  106  is essentially rectangular to accommodate passage of the tape cartridge  200  through the bezel to the tape drive. The longer dimension of the rectangular shaped opening  106  lies parallel to the top edge  102 . The horizontal surface  108  defining the bottom of the opening  106  has two ramps  110  that slope upward from front surface  112  of the housing  101  to guide the bottom surface of the tape cartridge upward into the opening of the slot when the cartridge is inserted into the tape drive by a gripper forming a part of a robotic assembly (actuator) of a tape library system for inserting or removing a tape cartridge. 
   A novel feature of the bezel  100  of the present invention is the provision of a plurality of targets or fiducials for providing alignment targets for a robotic assembly during loading and unloading operations of a tape cartridge to and from a tape drive. In the embodiment shown in  FIG. 1   a , four fiducials are provided to enable use of the tape drive with a plurality of different tape library products. 
   A first fiducial support  114  having a truncated pyramidal shape protruding from the front surface  112  of the bezel provides a supporting structure for a first fiducial  116  for use with a first tape library. The first fiducial  116  is fixed on the flat protruding surface  113  parallel to the front surface of the bezel and provides a target surface which is sensed by a positioning sensor on the tape cartridge loading gripper for positioning of the gripper with respect to the bezel  100  during or prior to the operation of loading or unloading a tape cartridge from a first library into the tape drive. 
   A second fiducial support  118  having an L-shape protruding from the front surface  112  provides support for a second fiducial  119  for use with a second tape library. The second fiducial  119  comprises a horizontal fiducial element  120  and a vertical fiducial element  122 . A vertical leg  123  of the L-shaped second support is located at and parallel to the right edge  105  of the bezel and a horizontal leg  121  of the L-shaped support is located a short distance below and parallel to the top edge  102  of the bezel. The L-shaped second support has a flat surface  124  protruding from and parallel to the front surface  112  of the bezel. The horizontal fiducial element  120  having a rectangular shape is fixed to the horizontal leg  121  and the vertical fiducial element  122  having a rectangular shape is fixed to the vertical leg  123 . The horizontal and vertical fiducial elements provide alignment targets for sensing by a positioning sensor or sensors on a tape cartridge loading gripper of a tape library system for positioning of the gripper with respect to the bezel  100  during the operation of loading or unloading a tape cartridge from a second library into the tape drive. 
   A third fiducial  140  for use with a third tape library is located near the upper left corner of the housing  101 . The third target comprises a reflective element recessed from the surface  112  that is inserted in an receiving opening  142  formed in the housing. The reflective element of the third fiducial  140  provides an alignment target for sensing by a positioning sensor on a tape cartridge loading gripper of a tape library system for positioning the gripper with respect to the bezel  100  during the operation of loading or unloading a tape cartridge from a third tape library into the tape drive. 
   The housing  100  includes a slide guide or receiving slot  134  having upper and lower grooves  136  and  138 , respectively, for holding a barcode label (not shown). A barcode scanner on the gripper reads identification information for a particular tape library system from the barcode label. Alternatively, the slot  134  may be used to support a fourth fiducial  150  shown in  FIG. 1   b  for use with a fourth tape library. The fourth fiducial  150  is a generally rectangular shaped structure having a front surface  152  and a rear edge  154 . Rails  156  formed along the upper and lower edges of the rear edge  154  fit in a sliding relationship into the upper and lower grooves  136  and  138  of slot  134  to position the fourth fiducial  150  on the housing. A reflective surface element  158  fixed on the front surface  154  provides an alignment target for sensing by a positioning sensor on a tape cartridge loading gripper of a tape library system for positioning the gripper with respect to the bezel  100  during the operation of loading or unloading a tape cartridge from a fourth tape library into the tape drive. Fourth fiducial  150  is easily installed or removed as needed for use of the tape drive having the universal bezel  100  with a compatible tape library. 
   For use with a gripper having a light source and an optical sensor device for detecting the fiducials used for positionally locating the gripper with respect to the bezel, the fiducials have reflective surfaces for reflection of light emitted by a light emitting diode (LED), a laser or other suitable source of a well-defined light beam. The fiducials are fixed to the fiducial supporting structures so as to provide well-defined references for positional location of features on the bezel by the sensor system on the gripper forming part of a robotic assembly on the actuator of a library system. Alternatively, fiducials may be used that are compatible with other sensor devices including, but not limited to, capacitive, electrostatic, magnetic, radio-frequency, acoustic and thermal sensors. 
   Another novel feature of the bezel  100  of the present invention is the provision of a plurality of supports or legs for providing stable support and protection of the tape drive deck when it is manually removed from a tape library. The legs allow the tape drive to be set down and supported on the bezel face without risk of damage to the fiducials and other features on the front surface  112  of the housing  101 . In the embodiment shown in  FIG. 1   a , three legs provide a stable three point support for the tape drive. A first leg  126  extends from the front surface  112  of the housing  101  at the left edge  104 . A second leg  128  extends from the surface  112  at the right end of the bottom edge  103 . A third leg  130  extends from the surface  112  at the right end of the top edge  102 . The legs  126 ,  128  and  130  are preferably all formed as integral molded parts of the housing  101  and they all extend an equal distance d  131  away from the surface  112 . Ribs  132  may be provided on the legs to provide greater strength and rigidity. Alternatively, one or more of the plurality of legs may be separate support elements fixed to the housing by suitable attachment means including, but not limited to, adhesives, bolts, screws and rivets. The distance d that the legs extend away from surface  112  is chosen to be larger than the largest distance that any one of the reflective surfaces of fiducials  116 ,  119 ,  140  and  150  protrudes from surface  112 . By choosing d to be larger than the distance of any of the fiducial surfaces from the housing front surface  112 , the legs  126 ,  128  and  130  serve to protect the fiducials from damage when the tape drive is manually removed from a tape library system and set on the bezel end on a floor or other supporting surface. 
   Housing  101  is preferably made of polycarbonate material and is formed by a molding process well known to the art. Bezel  100  is fixed on a front surface of a tape drive by screws, bolts or clamps using attachment tabs  144  formed as integral parts of the molded housing  101 . 
     FIG. 3  is a perspective view of a gripper cage  300  forming part of a robotic assembly for handling tape cartridges in a tape library system using the bezel  100  of the present invention. The gripper cage  300  supports two grippers  302 ,  304  each operatively associated with a sensor  306 . Sensor  306  usually comprises an LED source and a light detector or camera for sensing the position of one of the fiducials  116 ,  119 ,  140  and  150  of the bezel  100 . Sensor  306  may be positioned differently with respect to the grippers  302  and  304  for different library systems. A different one of the fiducials  116 ,  119 ,  140  and  150  may be sensed by the sensor  306  for a different library system using bezel  100  in accordance with the present invention. Using the appropriate fiducial for the gripper of the library system being used, the sensor on this gripper locates the drive and then locates the cartridge from calibrated mathematical relationships. The bezel  100  must be designed so that the mechanisms of the gripper do not interfere with the bezel and vice versa. 
   A tape drive  400  incorporating the tape drive bezel  100  of the present invention is described with reference to  FIGS. 4 and 5 . The tape drive  400  has a generally rectangular shape housing a magnetic tape drive system  500 . The tape drive  400  has a front end  402  on which bezel  100  is mounted. 
     FIG. 5  is a simplified diagram of an embodiment of a magnetic tape drive system  500  for writing and reading information to and from magnetic media in a magnetic tape cartridge. A tape drive control unit  502  provides a motor control signal to rotate tape reels  504  and move magnetic tape  506  across the read/write transducer head  501 . Read/write channel  508  transmits read/write signals between the read/write transducer  501  and the control unit  502 . The data is communicated through I/O channel  510  with host  512 . Lateral positioning of the transducer  501  with respect to the tape  506  is accomplished by coarse and fine positioning actuators  514 . The lateral repositioning by a coarse actuator is required to access the various tracks of the tape  506  with the transducer  501 . A servo system and fine actuator may be employed for accurate lateral repositioning of the transducer  501 . An exemplary servo system includes a servo detector  516  to detect both the track that the head is currently on and whether the head is off center. Control unit  502  indicates the track address of a desired new track to position error detection controller  518  for repositioning the head. Servo detector  516  indicates the current track to position error detection controller  518 , and the controller provides a servo position error signal to the coarse actuator of positioning actuators  514  which repositions the transducer  501  to the new track. The servo system also provides track following signals to the fine actuator of positioning actuators  514  so that the tracks on tape  506  may be closely spaced. 
     FIG. 6  shows front perspective view of an exemplary automated tape library  600  using a tape drive  614  incorporating the bezel  100  of the present invention. Tape library  600  comprises a frame  602  containing an operator panel  604 , an I/O  606 , an accessor  608 , tape cartridge storage slots  610 , a gripper cage  612  and a plurality of tape drives  614 . Accessor  608  moves vertically and horizontally on Y-rail  616  and X-rail  618 , respectively, to provide access to tape cartridge slots  610  and tape drives  614  by grippers mounted on the gripper cage  612 . The frame  602  is designed to hold up to 12 tape drive  614  (four are shown in  FIG. 6 ). A tape drive library may consist of an assembly of a plurality of frames  602 . 
   While the present invention has been particularly shown and described with reference to the preferred embodiments, it will be understood by those skilled in the art that various changes in form and detail may be made without departing from the spirit, scope and teaching of the invention. Accordingly, the disclosed invention is to be considered merely as illustrative and limited only as specified in the appended claims.