Abstract:
A data library supporting a plurality of data cartridges, at least one filter cartridge, and a picker/placer mechanism that is capable of manipulating both types of cartridges. The filter cartridge prevents airborne particulates from contaminating the data library. The cartridge design allows the picker/placer to be used to insert or remove a filter for cleaning or replacement, thereby obviating the need for shutting down the library for filter maintenance.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The device of the present invention relates to an air filtering system for a data storage device. More specifically, the invention relates to a system for controlling dust and contamination within a robotically operated data storage library.  
           [0002]    As is easily appreciated by most members of today&#39;s society, information and data affect virtually all aspects of life. Computer systems are used to manage and use this data for all types of different reasons. Naturally, the storage and retrieval of data is a critical part of making these systems work.  
           [0003]    It is well understood that data storage can be accomplished using several mechanisms, including hard drives, tape media, optical disks, magnetic media, removable storage cards, etc. Since the launch in 1982 of the audio CD, optical disks have become a very popular storage media due to their durability, random access features, and the high capacities that can be achieved on a single removable disk. The computerization of businesses has steadily increased the amount of data that is processed. As more data is processed, the amount of data which must be stored increases as well. To meet the need of this ever increasing amount of data, cost-effective data storage is desired. To remain competitive and to meet the needs for storage, increasing the disk capacity is a paramount development goal for optical drive products. (See, P. Asthana, B. I. Finkelstein, and A. A. Fennema, “Rewritable optical disk drive technology,” IBM Journal of Research and Development, Vol. 40, No. 5 (1996))  
           [0004]    As disks are engineered to provide greater capacity, dust and other contaminants are more problematic. One method of increasing an optical disk&#39;s capacity is by using a stronger object lens, which must be placed closer to the optical media. Dust becomes a more pressing problem in these situations because a dust particle now interferes with a greater portion of the focused laser beam. If enough of the laser beam is obstructed, data may be inaccessible. Thus, while optical disks were once lauded for their durability and ability to resist small amounts of contaminates, the super capacity drives now on the market are less resistant to the deleterious effects of contamination. As a result, contamination must either be prevented from reaching the disk or cleaning of the disk is required once it is contaminated.  
           [0005]    There have been various attempts to deal with disk contamination. One common method has been to package the disk within a disk cartridge. Disk cartridges include a door assembly which is opened by the disk drive so that the disk within the cartridge can be accessed. Of course, as soon as the door assembly is opened, the disk is exposed to airborne dust. Thus, additional measures are desired to ensure that the surrounding atmosphere is free of dust when the disk door is open.  
           [0006]    One solution to the aforementioned need for increased data storage is the data storage library. Understandably, data storage libraries have become increasingly complex as the demand for storage capacity increases. Storage libraries are traditionally designed to accommodate large organizations and include mechanized picker/placers used to retrieve disk cartridges automatically as they are summoned by a computer system. The cartridges are then transported to an open storage drive so they can be easily read or written to. In order to maintain the maximum efficiency of the optical storage devices used, and to avoid the problems outlined above, these libraries must be kept free from dust and other airborne contaminants. Air quality controls will help to minimize mechanical problems and avoid comprising the data stored on the disks.  
           [0007]    In order to maintain a high level of air quality, some existing libraries are equipped with air filtration systems. These filtration systems include ducts to direct air flow, fans, and filter elements. Like all filtration systems, the filters must be periodically removed and cleaned. This becomes problematic in highly used data storage libraries because the library must be temporarily shut down while it is manually opened in order to access the filters. This can disrupt operation of the data storage system and cause undesired delays. Further, the periodic opening and closing of the library cabinet exposes the interior to additional levels of dust.  
           [0008]    One approach to the problems created by opening the library cabinet or shutting the library down, is to utilize an external filter along with an internal fan to draw air into the cabinet through the filter. However, this solution presents certain problems. First, after the filter is removed, a relatively large passageway directly to the interior of the library remains through which a significant amount of airborne contaminates are allowed to pass. If the library remains operational, and the fan remains on, this problem is exacerbated by increased airflow. Second, it is foreseeable that the filter may get jostled during removal, causing a build up of dust to become agitated and dislodged from the filter into the air, thus potentially emitting a cloud of dust into the cabinet interior. Third, outside filters do not lend themselves to automated management systems without some form of human interaction. Though a timer can be implemented that reminds a user to change the filter, the user is still required to manually change the filter and reset the timer. Fourth, the level of desired cleanliness inside a data library calls for a filter capable of filtering fine particles. Filters having a low enough micron rating to accomplish such filtering would get clogged quickly if mounted on the outside of the library cabinet.  
           [0009]    There is thus a need for a filtration system for a data storage library which can be maintained without shutting down the operation of the library. Such a system can be managed by the library controller to insure the most optimum operating conditions.  
           [0010]    There is also a need for a system that can control dust within a library while minimizing exposure to the outside atmosphere;  
           [0011]    There is a further need for a filtration system that can be tracked and maintained automatically. Such a system must also be capable of easy incorporation into a data storage library.  
         BRIEF SUMMARY OF THE INVENTION  
         [0012]    The present invention addresses the aforementioned needs by providing a filtering system which utilizes a transportable filter cartridge designed for a data library. The cartridge includes several of the external features and dimensions that are found on the media cartridges used in the library. These similar features allow the robotic arm, or picker/placer mechanism of the library to be used to change the filters when replacement or cleaning is necessary. This design obviates a need for the library to be shut down and opened in order to replace or clean filters.  
           [0013]    The present invention also manages air flow into the cabinet of a library system to control the interior environment. This includes the controlled operation of fans and necessary ducts to direct air in a desired manner. In order to control dust, mechanisms are required to direct air through a filter element which is contained in the filter cartridge.  
           [0014]    One aspect of the present invention is a filter cartridge which includes a shutter door that covers the filter portion or element. The shutter door opens as the cartridge is placed in the operative filter slot of the data library, thereby allowing air to flow through the filter. However, when the filter cartridge is removed for cleaning or replacement, the shutter door closes, thereby preventing dirt trapped by the filter from contaminating the data library.  
           [0015]    Another aspect of the present invention is a system or mechanism for preventing the insertion of the filter cartridge into a media drive and for preventing the insertion of a media cartridge into an operative filter cartridge slot within the library. The operative filter cartridge slot is configured to appropriately position the filter cartridge in the ducting so that air is directed through the filter element. The need for misinsertion mechanisms is obvious considering the drastic differences between the cartridges involved (i.e., filter cartridge and data cartridge). Preferably this misinsertion mechanism is a keying feature that includes a physical attribute of the cartridge housing that corresponds with a physical attribute of the appropriate slot. Importantly, the attribute of the filter cartridge housing does not interfere with the ability of the picker/placer mechanism to insert and remove the filter cartridge housing. Alternatively, this could include a marking device, readable by the picker/placer mechanism, that identifies the filter cartridge and prevents the picker/placer mechanism from placing the filter cartridge in a media drive. Additionally, the picker/placer mechanism is constructed and arranged to require the presence of such a marking on a cartridge before it places the cartridge in a filter cartridge slot. This also prevents the picker/placer mechanism from placing the media cartridge in a filter cartridge slot.  
           [0016]    Another aspect of the cartridge is a marking system that facilitates an ability of the data library to maintain an inventory of the filter cartridges. The inventory preferably includes a time tracking feature that allows the library to maintain a history on the duration of service of each filter cartridge, so that replacement and cleaning may be scheduled accordingly. Further, filter cartridges can be automatically changed/replaced by the control systems within the library. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]    [0017]FIG. 1 is a perspective view of a data cartridge of the prior art;  
         [0018]    [0018]FIG. 2 is a perspective view of a data library of the present invention;  
         [0019]    [0019]FIG. 3 is a perspective view of a filter cartridge of the present invention; and,  
         [0020]    [0020]FIG. 4 is a plan view of a preferred bin embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0021]    An example of a data cartridge  101  is shown in FIG. 1. Data cartridge  101  includes a housing  102  and a slideable, spring loaded shutter door  103  that, when opened, uncovers an access window  104  to a computer readable disk  105 . The housing  102 , in addition to defining the window  104 , includes notches  106  for allowing a picker/placer mechanism to grab and manipulate the data cartridge  101 . In FIG. 1, this includes a pair of opposed notches  106  near the outer edge  107  of the data cartridge  101 , but may be any suitable notch, ridge, protuberance, indentation, or the like. The housing also includes a plurality of flag holes  108  near the outer edge  107 . These flag holes  108  are detectable by the library slot into which the data cartridge  101  is placed, by the picker/placer that is used to manipulate the data cartridge  101 , or both. Various meanings may be associated with these flag holes  108  such as, write protected, head cleaning disk, maximum memory capacities, or any important characteristic of the cartridge that should be identified by either the slot or the picker/placer mechanism. Alternatively, these flag holes may interact with structures within the media drive in order to accommodate operation.  
         [0022]    [0022]FIG. 2 shows an example of a data library  100 , in which the data cartridge  101  may be used and stored. The library  100  includes a picker/placer  110  that is positionable for accessing data cartridges  101 . At least two cartridge grippers  124  allow the picker/placer  110  to grab and manipulate the data cartridges  101 . More specifically, the grippers  124  allow the picker/placer  110  to remove or insert data cartridges  101  from or to the plurality of data cartridge slots  112  formed in a column  116  of the library  100 . A library  100  may have more than one column  116  of slots. An access door  114 , allows an operator to introduce cartridges to the library or remove them therefrom. A similar data library  100  is described in detail in U.S. Pat. No. 5,602,821, incorporated by reference herein in its entirety.  
         [0023]    Referring now to FIG. 3, there is shown a preferred filter cartridge  20  of the present invention. Filter cartridge  20  generally includes a housing  22 , a filter  24  contained within a window  25  defined by the housing  22 , and, preferably a shutter door  26 . The housing  22  is constructed and arranged to be similar to the housing  22  of data cartridge  101 , shown in FIG. 1. Most importantly, the housing  22  includes an outer edge  28  and a notch  30  for allowing a picker/placer mechanism  110  to grab and manipulate filter cartridge  20 . The notches  30  of the preferred embodiment shown in FIG. 3 is a pair of opposed notches  30 , but may be suited, as explained above, to the particular picker/placer mechanism  110  used by the library  100 . Thus, for purposes of the present invention, the specific mechanism for allowing a picker/placer mechanism  110  to grab and manipulate filter cartridge  20  is only important to the extent that a given picker/placer  110  may be used to grab and manipulate both the data cartridges  101  and the filter cartridges  20 , used in a particular data library  100 .  
         [0024]    As introduced above, preferably, the filter cartridge  20  also includes a mechanism to cover the filter  24  whenever the filter cartridge  20  is not installed in an operative filter slot  42  (see, FIG. 4, discussed below) of the library  100 . The shutter door  26  is a preferred mechanism and is shown in FIG. 3 in the open position, whereby the filter  24  is exposed. The shutter door  26  is moveable, and preferably spring biased towards a closed position (not shown) whereby the filter  24  is covered.  
         [0025]    Notably, the shutter door  26  of the filter cartridge  20  moves in a direction that is perpendicular to the outer edge  28  of the filter cartridge  20 , whereas the shutter door  103  of the data cartridge  101  moves in a direction that is parallel to the outer edge  7  of the data cartridge  101 . The filter cartridge  20  is constructed and arranged to maximize the size of the filter  24  that is usable when the filter cartridge  20  is inserted into an operative filter slot  42  in the library  100 . A bigger filter  24  provides less resistance to air flow and can collect a greater quantity of contaminants before it needs to be replaced. Providing a shutter door  26  that opens by moving toward the outside edge  28  of the filter cartridge  20  to expose the filter  24 , permits a greater exposed filter area. Conversely, the necessary exposed portion of the disk  105  that spins within the data cartridge  101  is relatively small and necessarily radial. Thus, in a data cartridge  101  a thin window  104  that extends to the center of the disk  105 , is optimal. Such a window  104  is only as large as necessary, thus minimizing the exposure of the disk  105  to potential contaminants.  
         [0026]    The design of filter cartridge shutter door  26  also provides a mechanism for preventing the accidental insertion of a data cartridge  20  into a operative filter slot  42 . The cartridge housing  22  defines a groove  32  on either side  34  of the filter cartridge  20 . The shutter door  26  includes a pair of overhangs  36  that extend over the sides  34  of the filter cartridge  20 . The overhangs  36  each include a tab  38  that travels within the groove  32 .  
         [0027]    Referring to FIGS. 3 and 4, the groove  32 /tab  38  arrangement serves multiple functions. The arrangement controls the travel of the shutter door  26  and holds the shutter door  26  onto the housing  102 . FIG. 4 shows a preferred storage bin  60  of the present invention. Storage bin  60 , in addition to having data cartridge slots  112  and data cartridge drives  118 , has filter cartridge slots  62 . The filter cartridge slots  62  differ from the data cartridge slots  112  due to a tongue  64 . The tongues  64  interact with grooves  32  of housing  22  to allow only filter cartridges to be placed therein. The initial portion of groove  32  will surround tongue  64  when filter cartridge  20  is inserted into filter cartridge slot  62 . Shutter  26  is not opened however, when placed in these filter cartridge slots  62 . The tongue  64  also prevents the insertion of a data cartridge  101 , which does not have a side groove.  
         [0028]    The existence and configuration of filter cartridge slots  62  allow only filter cartridge  20  to be housed therein. This provides a mechanical method of tracking the location of both filter cartridge  20  and data cartridges  101  within one library. It should be noted that the filter cartridges  20  could be stored in data cartridge slots  112 , so long as their position is tracked. Thus, filter cartridge slots  62  may not be necessary as filter cartridges  20  would be tracked differently.  
         [0029]    Also shown in FIG. 4 is a filtration system  140  which includes the necessary ducts to direct air from outside the cabinet, through filter  24 , and into the cabinet via vent  142 . Filtration system  140  also has an operative filter slot  144  configured to receive filter cartridge  20 . As can be seen, this operative filter slot  144  includes tongues  64  to interact and appropriately open shutter door  26 .  
         [0030]    Additional measures may also be used to prevent the insertion of a data disk  101  into a filter slot  62  and vice versa. For example, a flag hole  40  may be used to alert the picker/placer  110  that the cartridge  20  is a filter cartridge  20 . In FIG. 1, the positions of the flag holes  108  of the data cartridge  101  are shown in phantom lines to indicate that the flag hole  40  of the filter cartridge  20  is offset from the flag holes  108  of the data cartridge  101 .  
         [0031]    The flag hole  40  may also be used as a tracking and maintenance tool. Again, when the picker/placer  110  detects the flag hole  40 , the picker/placer controller, usually a computer (not shown), ensures that the data cartridge  101  is not placed in a filter slot  62  or operative filter slot  144  of the library  100 . Additionally, the computer controlling the picker/placer, makes a data entry as to the time of placement and the library slot address into which the filter cartridge  20  was placed. Thus, the computer is able to maintain a log of how long each filter cartridge  20  has been in service without replacement or cleaning. Thus, the flag hole  40  may be used to trigger a maintenance schedule.  
         [0032]    Alternatively, another flag, such as a bar code (not shown), or the like may be used to effect preventing a misplaced cartridge and maintenance scheduling. Preferably, for purposes of preventing a misplaced cartridge, however, the flag is detectable by the picker/placer  110 .  
         [0033]    In one embodiment, shown in FIG. 3, the housing  102  is symmetric such that the filter cartridge  20  may be placed in a filter slot  62  of the library  100  in two orientations, so long as the outside edge  28  remains at least partially outside the slot  62 . This feature prevents time consuming loading errors.  
         [0034]    In a second embodiment, not shown, the housing  102  is asymmetric such that the filter cartridge  20  may be loaded in only one orientation into a filter slot  62  of the library  100 . This prevents the reintroduction of residual dirt, still present after an ineffective filter cleaning attempt, into the library  100 , such as would be the case if this dirt was placed on the leeward side of the filter  24  when the ineffectively cleaned filter  24  is placed back into the library  100 .  
         [0035]    While the preferred embodiment shown in the Figures above illustrate the use of a data cartridge  101  containing a disk  105 , it us understood that the present invention is adaptable to other types of libraries. For example, a library that makes use of a data cartridge that houses storage tape could also utilize appropriately configured filter cartridges, Further, a library that utilizes raw media (e.g. CD&#39;s or DVD&#39;s) could also include appropriately configured filter cartridges that are transportable by the picker/placer mechanism.  
         [0036]    In another aspect of the present invention, controls are put in place to insure that the cabinet interior is never exposed to the outside environment. According to this feature of the present invention, a damper is provided in the air flow ductwork to block air flow at appropriate time. This damper would be opened when a filter cartridge is mounted in a appropriate position. This is accomplished by having the cartridge interact with a damper switch. Alternatively, the library controller can coordinate the operation of the damper when filter cartridges are changed. Further, control of the fan can also be included to create a comprehensive air flow control system.  
         [0037]    It is contemplated that features disclosed in this application can be mixed and matched to suit particular circumstances. Various other modifications and changes will be apparent to those of ordinary skill in the art without departing from the spirit and scope of the present invention. Accordingly, reference should be made to the claims to determine the scope of the present invention.