Abstract:
A media-detection system and method for identifying a type of data cartridge. According to one embodiment, the media-detection system comprises at least one indicator arm displaceable by at least one surface feature of the data cartridge as the data cartridge is loaded in a cartridge-receiving device. The media-detection system also comprises at least one sensor detecting the displacement of the at least one indicator arm as the data cartridge is loaded, thereby indicating the type of data cartridge in the cartridge-receiving device.

Description:
FIELD OF THE INVENTION  
         [0001]    The invention generally pertains to media-detection systems, and more specifically, to media-detection systems and methods for identifying types of data cartridges.  
         BACKGROUND OF THE INVENTION  
         [0002]    Media storage systems are commonly used to store data cartridges at known locations and to retrieve the desired data cartridges so that data may be written to and/or read from the data cartridges. Such media storage systems are often referred to as autochangers or library storage systems.  
           [0003]    A typical autochanger or media storage system may include one or more different types of cartridge-receiving devices. For example, one type of cartridge-receiving device may comprise an individual cartridge storage location (e.g., for holding a single data cartridge) or a storage rack or “magazine” (e.g., for holding a plurality of data cartridges). Another type of cartridge-receiving device may comprise one or more cartridge read/write devices for reading data from and/or writing data to data cartridges. Yet another type of cartridge-receiving device is a cartridge-engaging assembly or “picker”. The cartridge-engaging assembly is provided for transporting the data cartridges in the media storage system (e.g., between the storage magazines and the read/write device).  
           [0004]    In use, it is often useful to know which type of data cartridge is present in the cartridge-receiving device. For example, if a linear tape open (LTO) data cartridge is being retrieved for a read/write operation, it may be necessary to deliver the data cartridge to a read/write device designed for LTO data cartridges. Alternatively, if a digital linear tape (DLT) or super digital linear tape (SDLT) data cartridge is being retrieved for a read/write operation, it may be necessary to deliver the data cartridge to different read/write devices designed for either the DLT or SDLT data cartridges. Current approaches rely on separation of the different types of data cartridges in separate media storage systems.  
         SUMMARY OF THE INVENTION  
         [0005]    An embodiment of a media-detection system comprises at least one indicator arm displaceable by at least one surface feature of the data cartridge as the data cartridge is loaded in a cartridge-receiving device. At least one sensor detects the displacement of the at least one indicator arm as the data cartridge is loaded, thereby indicating the type of data cartridge in the cartridge-receiving device.  
           [0006]    An embodiment of a method for identifying a type of data cartridge comprises: receiving the data cartridge in the cartridge-receiving device, detecting a state of at least one indicator arm while the data cartridge is being received in the cartridge-receiving device, and determining the type of data cartridge being received in the cartridge-receiving device based on the state of the at least one indicator arm. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]    Illustrative and presently preferred embodiments of the invention are shown in the drawings, in which:  
         [0008]    [0008]FIG. 1 is a plan view of a media storage system as it may be used according to one embodiment of the invention to store and access data cartridges therein;  
         [0009]    [0009]FIG. 2 is a perspective view of one embodiment of a cartridge-engaging assembly that may be used to retrieve and transport data cartridges in the media storage system of FIG. 1, showing one embodiment of the media-detection system for use therewith;  
         [0010]    FIGS.  3 ( a ) through  3 ( c ) are perspective views of (a) linear tape open (LTO), (b) digital linear tape (DLT), and (c) super digital linear tape (SDLT) data cartridges;  
         [0011]    FIGS.  4 ( a ) and  4 ( b ) are perspective views of one embodiment of media-detection system in (a) a raised position, and (b) a lowered position;  
         [0012]    FIGS.  5 ( a ) through FIG. 5( c ) are simplified side-views of the media-detection system shown in FIGS.  4 ( a ) and  4 ( b ) illustrating operation thereof according to one embodiment;  
         [0013]    [0013]FIG. 6 is a perspective view of another embodiment of the media-detection system;  
         [0014]    FIGS.  7 ( a ) through FIG. 7( c ) are simplified cut-away side views of the media-detection system shown in FIG. 6 illustrating operation thereof according to one embodiment; and  
         [0015]    [0015]FIG. 8 is a flow chart illustrating operation of program code according to one embodiment of the invention. 
     
    
     DETAILED DESCRIPTION  
       [0016]    An embodiment of a media-detection system  10  (FIG. 2) is shown and described herein as it may be used in media storage system  12  (FIG. 1) for identifying types of data cartridges  14  (e.g., FIG. 3( a ) through FIG. 3( c )).  
         [0017]    Briefly, media storage systems  12  are used to store large volumes of computer readable data. The computer readable data is typically stored on multiple data cartridges  14  in the media storage system  12 . One or more storage magazines  16  may be arranged in the media storage system  12 , for example, in the generally U-shaped configuration shown in FIG. 1, although other arrangements are also possible. The media storage system  12  also includes a cartridge-engaging assembly  18  that can be operated to retrieve and transport data cartridges  14  between the storage magazines and read/write device(s)  20 .  
         [0018]    As an illustration of the use of the media storage system  12 , a host computer may issue a request to access one of the data cartridges  14  stored in storage magazine  16  to read and/or write data thereto. In response, a control system  100  causes the cartridge-engaging assembly  18  to move along a positioning rail  22  (i.e., in the directions of arrow  24 ) until the cartridge-engaging assembly  18  is positioned adjacent the requested data cartridge  14  (e.g., at position  26 ). Once positioned, the controller  100  signals the cartridge-engaging assembly  18  to withdraw the data cartridge  14  from the storage magazine  16 . The control system  100  then causes the cartridge-engaging assembly  18  to move along the positioning rail  22  until it is adjacent the read/write device  20  (e.g., at position  26 ′), where the data cartridge  14  is unloaded for a read and/or write operation.  
         [0019]    An exemplary cartridge-engaging assembly  18 , for use with the media storage system  12 , is shown in FIG. 2 with one side removed. The cartridge-engaging assembly  18  may comprise a frame assembly  28  having sidewalls  35  and top and bottom walls  33 . Frame assembly  28  defines a cavity or chamber  30  therein, which is sized to receive a data cartridge  14  (e.g., for carrying it to the read/write device  20 ).  
         [0020]    A cartridge-plunge mechanism  34  is slidably mounted to the frame assembly  28  so that the cartridge-plunge mechanism  34  may be extended and retracted in the directions illustrated by arrows  31 ,  32 , respectively. Cartridge-plunge mechanism  34  may also be provided with a finger assembly  36  configured to engage data cartridges  14 . Movement of the cartridge-engaging assembly  18  may be achieved via actuator system  38  that moves the cartridge-engaging assembly  18  along the U-shaped path defined in the media storage system  12  by the positioning rail  22 .  
         [0021]    The foregoing description of the media storage system  12  and cartridge-engaging assembly  18  is provided in order to better understand one environment in which the invention may be used. However, it should be understood that the invention may be used in any of a wide range of other types of media storage systems, and in conjunction with any of a wide range of cartridge-engaging assemblies now known or that may be developed in the future. Consequently, the invention should not be regarded as being limited to use with the particular media storage system  12  and cartridge-engaging assembly  18  shown and described herein.  
         [0022]    According to the invention, more than one type of storage media may be used at the same time in a “mixed” media storage system  12 . Three different types of data cartridges  14 ,  14 ′, and  14 ″ are shown for purposes of illustration in FIGS.  3 ( a )- 3 ( c ), as they may be used according to the teachings of the invention in media storage system  12 . It is noted that the data cartridges will be generally referred to herein as data cartridges  14  unless reference is being made to one of the particular types of data cartridges shown. It is also noted that the data cartridges  14  are preferably loaded into the cartridge-engaging assembly  18  in the direction generally illustrated by arrow  40 , however, it is understood that the invention is not limited to such a direction.  
         [0023]    [0023]FIG. 3( a ) illustrates an example of an LTO data cartridge  14 . The LTO data cartridge  14  may be characterized as having a generally flat surface  42  extending from the leading edge  41  to about mid-way along the top edge of the LTO data cartridge  14 .  
         [0024]    [0024]FIG. 3( b ) illustrates an example of a DLT data cartridge  14 ′. The DLT data cartridge  14 ′ may be characterized as having a generally flat surface  44  extending from the leading edge  41 ′ for about 1 inch along the top edge of the DLT data cartridge  14 ′, and then a depression  45  formed in the top edge of the DLT data cartridge  14 ′.  
         [0025]    [0025]FIG. 3( c ) illustrates an example of an SDLT data cartridge  14 ″. The SDLT data cartridge  14 ′ may be characterized as having a generally flat surface  47  extending from the leading edge  41 ″ for about 1 inch along the top edge of the SDLT data cartridge  14 ″, and then a depression  48  formed in the top edge of the DLT data cartridge  14 ′. In addition, the SDLT data cartridge  14 ″ is characterized by a tab  49  formed in or otherwise provided in the depression  48  and spaced about 1.5 inches from the leading edge  41 ″ of the data cartridge  14 ″.  
         [0026]    While the invention is shown and described herein as it could be used to store and retrieve LTO, DLT, and SDLT data cartridges ( 14 ,  14 ′, and  14 ″) having standard sizes and configurations, the invention is not limited to any particular type or style of data cartridge. Consequently, the present invention should not be regarded as limited to use with LTO, DLT, and SDLT data cartridges. Suitable modifications can be readily made by one skilled in the art after having become familiar with the teachings of the present invention so that it can be used to detect other types of data cartridges based on surface features unique to those types of data cartridges.  
         [0027]    In order to determine the type of data cartridge  14  present in the cartridge-engaging assembly  18 , the cartridge-engaging assembly  18  may be provided with media-detection system  10  (FIG. 2), which is shown in more detail by itself in FIGS.  4 ( a ) and  4 ( b ).  
         [0028]    Media-detection system  10  is shown according to one embodiment in FIG. 2 mounted in chamber  30  of the cartridge-engaging assembly  18 . Preferably, media-detection system  10  is pivotally mounted to the cartridge-engaging assembly  18 . For example, media-detection system  10  may comprise an indicator arm  50  mounted to a rod member  58 , as shown in FIGS.  4 ( a ) and  4 ( b ). The rod member  58  may have pins  55  on each end thereof which may be inserted into an opening formed on each side of chamber  30  (e.g., in sidewalls  35 ). Accordingly, the indicator arm  50  may be pivoted about axis  54  in downward direction illustrated by arrow  56  and in upward direction illustrated by arrow  57 .  
         [0029]    An embodiment of indicator arm  50  is shown in FIG. 4( a ) having an indicator portion  51 , head portion  52 , and end portion  53 . When data cartridge  14  is received in chamber  30  of the cartridge-engaging assembly  18 , head portion  52  contacts the leading edge  41  of the data cartridge  14 , displacing the indicator arm  50  as indicator portion  41  travels over one or more surface features of the data cartridge  14  (e.g., surface  42 ,  44 ,  47 , depression  45 ,  48 , and tab  49 ). Preferably, the indicator arm  50  is resiliently biased downward (e.g., by spring member  101  or other suitable means) in position  71  (FIG. 4( b )) and moves upward to the raised position  70  (FIG. 4( a )) as raised surface features on the top surface of data cartridges  14  (e.g., “lip”  44  in FIG. 3( b )) are encountered.  
         [0030]    Of course indicator arm  50  is not limited to any particular design. For example, head portion  51  may be provided with a roller or bearing member mounted to the head portion  52  to engage data cartridge  14  as data cartridge  14  is received in chamber  30 . Likewise, indicator arm  50  may be mounted in any suitable manner and is not limited to that described herein. The particular design and mounting of indicator arm  50  will depend upon various design considerations, such as, but not limited to, the desired resiliency, durability, and cost of manufacture.  
         [0031]    Media-detection system  10  may also comprise a flag  60  mounted to indicator arm  50  and operatively associated with sensor  62 . Flag  60  is movable into and out of the detection range of sensor  62  when the indicator arm  50  pivots about axis  54 , indicating the displacement of the indicator arm  50  to the sensor  62 . For example, in FIG. 4( a ), the indicator arm  50  is shown in a raised position  70 , wherein the flag is in range of the sensor  62  (e.g., blocking an optical path). In FIG. 4( b ), the indicator arm  50  is shown in a lowered position  71 , wherein the flag is out of range of the sensor  62  (e.g., the optical path is not blocked).  
         [0032]    Other embodiments are also contemplated as being within the scope of the invention. For example, more than one optical path may be used to more finely detect displacement of indicator arm  50 . In another embodiment, the flag may be in range of the sensor  62  (e.g., blocking an optical path) when the indicator arm  50  is in a lowered position and the flag may be out of range of the sensor  60  (e.g., the optical path is not blocked) when the indicator arm  50  is in a raised position. In any event, the displacement or state of the indicator arm  50  may be used to determine the type of data cartridge  14  received in chamber  30 , as will be explained in more detail below.  
         [0033]    Sensor  62  may be mounted to one of the sidewalls  35  of the cartridge-engaging assembly  18  in such a manner that flag  60  is movable into and out of the detection range of the sensor  62  when indicator arm  50  rotates in the directions of arrows  56  and  57 . It is noted, however, that sensor  62  may be mounted to cartridge-engaging assembly  18  in any suitable manner. Indeed, sensor  62  need not be mounted to one of the sidewalls  35  of cartridge-engaging assembly  18  and can instead be mounted to the top wall  33 .  
         [0034]    Any suitable sensor  62  may be used to determine the position of flag  60 . Generally, sensor  62  may comprise a signal emitter and a signal detector. The sensor  62  determines the position of the flag  60  based on signals it receives. It is also noted that any suitable flag  60  may be used with sensor  62  according to the teachings of the invention.  
         [0035]    In one embodiment, sensor  62  may comprise one or more light emitting diodes (LEDs) or other suitable light source and one or more photo-detectors positioned opposite the light source. The flag  60  may be manufactured from an opaque material and assembled so that it moves between the light source and photo-detector(s). The flag  60  may thus block all or a portion of the optical path between the light source and the photo-detector. Accordingly, sensor  62  is used to detect the position of flag  60 .  
         [0036]    In another embodiment, the sensor  62  may comprise a mechanical limit switch that can be “thrown” or otherwise activated by movement of flag  60 . Yet other embodiments are also contemplated as being within the scope of the invention.  
         [0037]    Operation of media detection system  10  according to one embodiment of the invention is illustrated in FIG. 5( a ) through FIG. 5( c ). In FIG. 5( a ), LTO data cartridge  14  is shown as it may be loaded into the cartridge-engaging assembly  18  (illustrated by arrow  40 ). Indicator arm  50  is initially biased in lower position  71 , and the flag  60  is out of range of the sensor  62  (e.g., in a “LOW” state). As LTO data cartridge  14  is loaded into chamber  30 , indicator arm  50  comes into contact with the leading edge  41  of data cartridge  14 , whereupon indicator arm  50  is displaced and moves upward toward raised position  70 . In this position, the flag  60  is in range of sensor  62  (e.g., in a “HIGH” state), where it remains during loading of the LTO data cartridge  14 . Accordingly, in this example, an LTO-type data cartridge  14  is present in chamber  30  when sensor  62  detects a “LOW” state, followed by a “HIGH” state during the loading operation.  
         [0038]    In FIG. 5( b ), DLT data cartridge  14 ′ is shown as it may be loaded into the cartridge-engaging assembly  18  (illustrated by arrow  40 ). When chamber  30  is empty, indicator arm  50  is initially biased in lower position  71  and flag  60  is out of range of the sensor  62  (e.g., in a “LOW” state). As DLT data cartridge  14 ′ is loaded into chamber  30 , indicator arm  50  comes into contact with the leading edge  41 ′ of DLT data cartridge  14 ′, displacing indicator arm  50  so that it moves into raised position  70 . When the indicator arm  50  is in the raised position  70 , flag  60  is in range of the sensor  62  (e.g., in a “HIGH” state). As the DLT data cartridge  14 ′ is loaded, the indicator arm  50  moves into depression  45  formed in the top surface of DLT data cartridge  14 ′ (e.g., position  71 ), and flag  60  moves out of range of sensor  62  (e.g., returning to a “LOW” state). Accordingly, in this example the states “LOW”, “HIGH”, and then “LOW” detected during the loading operation correspond to the DLT-type data cartridge  14 .  
         [0039]    In FIG. 5( c ), SDLT data cartridge  14 ″ is shown as it may be loaded into the cartridge-engaging assembly  18  (illustrated by arrow  40 ). Again, when chamber  30  is empty, indicator arm  50  is initially biased in lower position  71  and flag  60  is out of range of the sensor  62  (e.g., in a “LOW” state). As SDLT data cartridge  14 ″ is loaded into chamber  30 , indicator arm  50  comes into contact with the leading edge  41 ″ of SDLT data cartridge  14 ″ and displaces indicator arm  50 . Indicator arm  50  moves into raised position  70 , wherein flag  60  is in range of the sensor  62  (e.g., in a “HIGH” state). As the SDLT data cartridge  14 ″ is loaded into chamber  30 , the indicator arm  50  moves into depression  48  formed in the top surface of SDLT data cartridge  14  (e.g., position  71 ). The flag  60  moves out of range of the sensor  62  and returns to a “LOW” state. The SDLT data cartridge  14 ″ has a tab  49  in depression  48 . When indicator arm  50  comes into contact with tab  49 , it once again returns to the raised position  70  and flag  60  moves into range of the sensor  62  (e.g., in a “HIGH” state). Accordingly, in this example the states “LOW”, “HIGH”, “LOW”, and then “HIGH” detected during the loading operation correspond to the SDLT-type data cartridge  14 ″.  
         [0040]    A control system  100  (e.g., comprising computer-readable program code stored on computer-readable storage media) may be operatively associated with media-detection system  10 . The control system  100  receives the signal detected by sensor  62  and determines the type of data cartridge  14  received in the cartridge-engaging assembly  18  (e.g., using a “look-up” table). For example, the control system interprets the detected states “LOW” and then “HIGH” during the loading operation as an LTO-type data cartridge  14 ; “LOW”, “HIGH”, then “LOW” again during the loading operation as a DLT-type data cartridge  14 ′ ; and “LOW”, “HIGH”, “LOW”, and then “HIGH” again during the loading operation as an SDLT-type data cartridge  14 ″. Accordingly, the control system can determine, track and manage (e.g., deliver the data cartridges to appropriate read/write devices) different or mixed media types in the same media storage system  12 .  
         [0041]    According to another embodiment, the media-detection system  10  may be operated wherein the state of the indicator arm  50  is determined with respect to distance. The control system may poll sensor  62  when the data cartridge  14  is at one or more predetermined positions in chamber  30 . For example, the control system may poll sensor  62  when the data cartridge  14  is loaded about 1 inch, again at about 1.5 inches, and again at 2 inches. The state of the indicator arm  50  at each of the predetermined distances may be used to determine the type of data cartridge  14  loaded into chamber  30 . The position of the data cartridge  14  can be readily determined (e.g., based on the position of the cartridge-plunge mechanism  34 ) using, for example, optical, electrical, and/or mechanical position sensors that are readily available, or others which may become available, for use with the cartridge-engaging assembly  18 .  
         [0042]    Although the above illustration is discussed in regard to two states (i.e., “HIGH” and “LOW”), as illustrated in FIG. 5( a ) through FIG. 5( c ). Suitable modifications to the media-detection system  10  can readily be made by one skilled in the art after having become familiar with the teachings of the invention. For example, the sensor  62  may also detect “MEDIUM”, “VERY LOW”, and/or “VERY HIGH” states.  
         [0043]    Another embodiment of media-detection system  110  is shown in FIG. 6. It is noted that one-hundred and two-hundred series reference numbers are used to refer to like elements.  
         [0044]    Media-detection system  110  may comprise two indicator arms  150 ,  250 . Although not shown, media-detection system  110  may also have pins  55  and be mounted in chamber  30  of the cartridge-engaging assembly  18  similarly to that described for media-detection system  10 . Preferably, media-detection system  110  is mounted so that each indicator arm  150 ,  250  is pivotable about axis  154 ,  254 , respectively. Also preferably, indicator arms  150 ,  250  are resiliently biased (e.g., by a spring member) downward toward a lower position  171 ,  271  (see FIG. 7( b )). Accordingly, when data cartridges  114  are received in, or removed from chamber  30  of the cartridge-engaging assembly  18 , the indicator arms  150 ,  250  are displaced by surface features of the data cartridge  114  (e.g., surface  142 , depression  145 ,  148 , and tab  149  in FIGS.  7 ( a )- 7 ( b )).  
         [0045]    Media-detection system  10  may also comprise flags  160 ,  260  mounted to respective indicator arms  150 ,  250  and operatively associated with respective sensors  162 ,  262 . Accordingly, flags  160 ,  260  move into and out of the detection range of respective sensors  162 ,  262 , indicating the displacement of each of the indicator arms  150 ,  250 . The displacement or state of the indicator arms  150 ,  250  may be used to determine the type of data cartridge  14  received in chamber  30 .  
         [0046]    The media-detection system  110  may be operated according to one embodiment of the invention as follows as illustrated in FIGS.  7 ( a ) through  7 ( c ) and in the flow chart of FIG. 8. The data cartridge is received in the cartridge-engaging assembly  18  in step  300 . As the data cartridge  14  is received, the state of the indicator arm(s)  50  is determined in step  310 . Based on the state of the indicator arm(s)  50 , the type of data cartridge  14  is determined in step  320 .  
         [0047]    As an illustration, FIG. 7( a ) shows an LTO data cartridge  14  fully-loaded in chamber  30  after being receiving in the cartridge-engaging assembly  18 . During loading, indicator arms  150 ,  250  are raised on surface  142  of the LTO data cartridge  114  to positions  170 ,  270 , respectively. Both flags  160 ,  260  remain within range of the respective sensors  162 ,  262  (e.g., each are in a “HIGH” state) during loading. Accordingly, in this example the states “HIGH” and “HIGH” for each indicator arm  150 ,  250  during loading of the data cartridge correspond to the LTO-type data cartridge  14 .  
         [0048]    In FIG. 7( b ), DLT data cartridge  114 ′ is shown fully-loaded in chamber  30  after being received in the cartridge-engaging assembly  18 . Indicator arms  150 ,  250  go from a raised position into depression  145  formed on the top surface of DLT data cartridge  114 ′ (i.e., lowered positions  171 ,  271 , respectively). After going from a “HIGH” state initially, both flags  160 ,  260  remain out of range of the respective sensors  162 ,  262  (e.g., each are in a “LOW” state) during loading. Accordingly, in this example the states “HIGH” and “HIGH” followed by “LOW” and “LOW” for each indicator arm  150 ,  250  as the data cartridge is loaded correspond to the DLT-type data cartridge  114 ′.  
         [0049]    In FIG. 7( c ), SDLT data cartridge  114 ″ is shown fully-loaded in chamber  30  of the cartridge-engaging assembly  18 . One of the indicator arms  150  goes from a raised position into depression  148  formed on the top surface of SDLT data cartridge  114 ″ (i.e., lowered position  171 ) during loading. The other indicator arm  250  goes from a raised position into depression  148  and then back to a raised position (i.e., on tab  149  in upper position  270 ). Flag  160  goes from a “HIGH” state to a “LOW” state during loading, while flag  260  goes from a “HIGH” state to a “LOW” state and again to a “HIGH” state. Accordingly, in this example the states during loading of the data cartridge correspond to the SDLT-type data cartridge  114 ″.  
         [0050]    Additional indicator arms may be used in another embodiment to detect other surface features of the data cartridges. Also, for example, the indicator arm(s) may be mounted in other suitable locations to detect other surface features of the data cartridges.  
         [0051]    It is also to be understood that media-detection system  10  may be used with any cartridge-receiving device, and is not limited to use with cartridge-engaging assembly  18 . For example, media detection system  10  may be used to determine the type of data cartridge  14  in storage magazine(s)  16  and/or read/write device  20 .