Determining cartridge conflicts with deep slot technology

A library includes a frame, a plurality of cartridge slots disposed within the frame and at least one counter configured to determine the presence of cartridges stored within the plurality of cartridge slots without removing the cartridges. The library also includes at least one controller in communication with the counter and configured to count a number of cartridges within the cartridge slots and compare the counted number to a capacity on demand value.

FIELD OF INVENTION

The present invention generally relates to storage libraries. More specifically, the invention relates to storage libraries with removable media.

BACKGROUND OF THE INVENTION

Automated data storage libraries are known for providing cost effective storage and retrieval of large quantities of data. The data in automated data storage libraries is stored on data storage media that are, in turn, stored on storage shelves or the like inside the library in a fashion that renders the media, and its resident data, accessible for physical retrieval. Such media is commonly termed “removable media.” Data storage media may comprise any type of media on which data may be stored and which may serve as removable media, including but not limited to magnetic media (such as magnetic tape or disks), optical media (such as optical tape or disks), electronic media (such as PROM, EEPROM, flash PROM, CompactFlash™, Smartmedia™, Memory Stick™, etc.), or other suitable media. Typically, the data stored in automated data storage libraries is resident on data storage media that is contained within a cartridge and referred to as a data storage media cartridge. An example of a data storage media cartridge that is widely employed in automated data storage libraries for mass data storage is a magnetic tape cartridge.

In addition to data storage media, automated data storage libraries typically contain data storage drives that store data to, and/or retrieve data from, the data storage media. The transport of data storage media between data storage shelves and data storage drives is typically accomplished by one or more robot accessors (hereinafter termed “accessors”). Such accessors have grippers for physically retrieving the selected data storage media from the storage shelves within the automated data storage library and transport such media to the data storage drives by moving in the X and Y directions.

In an effort to increase storage capacity, deep slot technology (or deep cartridge slots) allows for storage slots that contain more than a single cartridge. Such storage libraries allow for higher density, or more cartridges stored per square foot. In ‘deep slot’ libraries, two or more cartridges are arrayed in series so that accessing desired cartridges may require removing cartridges stored in front of the desired cartridge. As used herein, the term “deep slot” refers to a magazine or storage slot including an array of storage slots such that at least two slots are arranged in series such that accessing an interior slot requires traversing at least one exterior slot.

Deep slot technology requires that there be enough free storage space to hold the number of cartridges that can be contained in a deep slot, minus one. This is because the library may have to access the last cartridge in a deep slot, and the cartridges in front of the last cartridge must be moved out of the way. For example, if a library has storage slots that can contain 5 cartridges, then the library will need to be able to place 4 of the 5 cartridges somewhere else, while it accesses the 5th cartridge with a library gripper. This additional required space shall be referred to as “swap space”. Swap space may comprise additional storage slots, I/O slots, drive slots, gripper slots, or any other location that may be used to hold a cartridge while another cartridge is being accessed.

One problem with deep slot technology is inventory. This is because, except for the first cartridge, a bar code reader cannot see the cartridge labels in a deep slot without removal. As a result, the library must remove each cartridge to read the label of the cartridge behind it, and to ensure that there are no more cartridges to read. This can be very time consuming, and an operator may be long gone after replacing a magazine, closing a library door, or powering up a library.

What is needed is a quick method of determining that the minimum required number of storage slots are available as swap space in a deep slot library after a magazine has been placed in the library, after a library door has been closed, or after a library reset or power-on.

Furthermore, capacity on demand systems provide vendors the ability to offer their customers more physical storage capacity than the customer has paid for, while allowing an upgrade to storage capacity without installing new hardware. Such systems allow a customer greater flexibility in managing storage requirements. However, with deep slot technology, such systems run the danger to the vendor that a customer could place more cartridges in a capacity on demand system than the customer has paid for, and it would be difficult for the library to detect.

What is needed is a method of determining if more cartridges have been placed in a deep slot library than have been activated with a capacity on demand solution.

It is therefore a challenge to develop strategies for storing cartridges to overcome these, and other, disadvantages.

SUMMARY OF THE INVENTION

One embodiment of the invention provides a library that includes a frame, a plurality of cartridge slots disposed within the frame and at least one counter configured to determine a number of cartridges stored within the plurality of cartridge slots without removing the cartridges from a cartridge slot. The library also includes at least one controller in communication with the counter and configured to count a number of cartridges within the cartridge slots and compare the counted number to a capacity on demand value.

Another embodiment of the present invention is a method for providing data storage that includes determining a capacity on demand value, associated with an allowed storage capacity of a library and counting a number of cartridges within the library, without removing cartridges from the library. The method further includes comparing the counted number of cartridges with the capacity on demand value, issuing an excess storage message based on the comparison, and providing data storage.

Yet another embodiment of the invention provides a method of establishing an inventory of cartridges in a data storage system. The method includes operating a reader to determine at least one metadata associated with each cartridge stored in a library, listing the determined metadata, counting the stored cartridges based on the list without removing cartridges from the library, and determining a capacity on demand value, the capacity on demand value associated with an allowed storage capacity. The method further includes comparing the counted number of cartridges with the capacity on demand value and establishing an inventory based on the metadata.

The foregoing embodiment and other embodiments, objects, and aspects as well as features and advantages of the present invention will become further apparent from the following detailed description of various embodiments of the present invention. The detailed description and drawings are merely illustrative of the present invention, rather than limiting the scope of the present invention being defined by the appended claims and equivalents thereof.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

This invention is described in preferred embodiments in the following description with reference to the Figures, in which like numerals represent the same or similar elements. While this invention is described in terms of the best mode for achieving this invention's objectives, it will be appreciated by those skilled in the art that it is intended to cover alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims.

The invention will be described as embodied in an automated magnetic tape library storage system for use in a data processing environment. Although the invention shown uses magnetic tape cartridges, one skilled in the art will recognize the invention equally applies to optical disk cartridges, magnetic disk cartridges, or other removable storage media and the use of either different types of cartridges or cartridges of the same type having different characteristics. Furthermore the description of an automated magnetic tape storage system is not meant to limit the invention to magnetic tape data processing applications as the invention herein can be applied to any media storage and cartridge handling systems in general.

Turning now to the Figures,FIGS. 1 and 2illustrate an automated data storage library10which stores and retrieves data storage cartridges containing data storage media (not shown) in storage shelves16. It is noted that references to “data storage media” herein refer to data storage cartridges, and for purposes herein the two terms are used synonymously. An example of an automated data storage library which may implement the present invention, and has a configuration as depicted inFIGS. 1 and 2, is the IBM TS3500 tape library. The library ofFIG. 1comprises a left hand service bay13, one or more storage frames11, and right hand service bay14. As will be discussed, a frame may comprise an expansion component of the library. Frames may be added or removed to expand or reduce the size and/or functionality of the library. Frames may comprise additional storage shelves, drives, import/export stations, accessors, operator panels, etc.

FIG. 2shows an example of a storage frame11, which is the base frame of the library10and is contemplated to be the minimum configuration of the library. In this minimum configuration library10comprises storage frame11and there is only a single accessor (i.e., there are no redundant accessors) and there is no service bay. The library10is arranged for accessing data storage media in response to commands from at least one external host system (not shown), and comprises a plurality of storage shelves16, on front wall17and rear wall19for storing data storage cartridges that contain data storage media; at least one data storage drive15for reading and/or writing data with respect to the data storage media; and a first accessor18for transporting the data storage media between the plurality of storage shelves16and the data storage drive(s)15. The data storage drives15may be optical disk drives or magnetic tape drives, or other types of data storage drives as are used to read and/or write data with respect to the data storage media. The storage frame11may optionally comprise an operator panel23or other user interface, such as a web-based interface, which allows a user to interact with the library. The storage frame11may optionally comprise an upper I/O station24and/or a lower I/O station25, which allows data storage media to be inserted into the library and/or removed from the library without disrupting library operation. The library10may comprise one or more storage frames11, each having storage shelves16accessible by first accessor18.

As described above, the storage frames11may be configured with different components depending upon the intended function. One configuration of storage frame11may comprise storage shelves16, data storage drive(s)15, and other optional components to store and retrieve data from the data storage cartridges. The first accessor18comprises a gripper assembly20for gripping one or more data storage media and may include a bar code scanner22or other reading system, such as a cartridge memory reader or similar system, mounted on the gripper20, to “read” identifying information about the data storage media.

FIG. 3illustrates an embodiment of an automated data storage library10ofFIGS. 1 and 2, which employs a distributed system of modules with a plurality of processor nodes. An example of an automated data storage library which may implement the distributed system depicted in the block diagram ofFIG. 3, and which implement the present invention, is the IBM TS3500 tape library. For a fuller understanding of a distributed control system incorporated in an automated data storage library, refer to U.S. Pat. No. 6,356,803, which is entitled “Automated Data Storage Library Distributed Control System,” which is incorporated herein for reference.

While the automated data storage library10has been described as employing a distributed control system, the present invention may be implemented in automated data storage libraries regardless of control configuration, such as, but not limited to, an automated data storage library having one or more library controllers that are not distributed, as that term is defined in U.S. Pat. No. 6,356,803. The library ofFIG. 3comprises one or more storage frames11, a left hand service bay13and a right hand service bay14. The left hand service bay13is shown with a first accessor18. As discussed above, the first accessor18comprises a gripper assembly20and may include a reading system22to “read” identifying information about the data storage media. The right hand service bay14is shown with a second accessor28. The second accessor28comprises a gripper assembly30and may include a reading system32to “read” identifying information about the data storage media. In the event of a failure or other unavailability of the first accessor18, or its gripper20, etc., the second accessor28may perform some or all of the functions of the first accessor18. The two accessors18,28may share one or more mechanical paths or they may comprise completely independent mechanical paths. In one example, the accessors18,28may have a common horizontal rail with independent vertical rails. The first accessor18and the second accessor28are described as first and second for descriptive purposes only and this description is not meant to limit either accessor to an association with either the left hand service bay13, or the right hand service bay14.

In the exemplary library, first accessor18and second accessor28move their grippers in at least two directions, called the horizontal “X” direction and vertical “Y” direction, to retrieve and grip, or to deliver and release the data storage media at the storage shelves16and to load and unload the data storage media at the data storage drives15.

The exemplary library10receives commands from one or more host systems40,41or42. The host systems, such as host servers, communicate with the library directly, e.g., on path80, through one or more control ports (not shown), or through one or more data storage drives15on paths81,82, providing commands to access particular data storage media and move the media, for example, between the storage shelves16and the data storage drives15. The commands are typically logical commands identifying the media and/or logical locations for accessing the media. The terms “commands” and “work requests” are used interchangeably herein to refer to such communications from the host system40,41or42to the library10as are intended to result in accessing particular data storage media within the library10.

The exemplary library is controlled by a distributed control system receiving the logical commands from hosts, determining the required actions, and converting the actions to physical movements of first accessor18and/or second accessor28.

In the exemplary library, the distributed control system comprises a plurality of processor nodes, each having one or more processors. In one example of a distributed control system, a communication processor node50may be located in a storage frame11. The communication processor node provides a communication link for receiving the host commands, either directly or through the drives15, via at least one external interface, e.g., coupled to line80.

The communication processor node50may additionally provide a communication link70for communicating with the data storage drives15. The communication processor node50may be located in the frame11, close to the data storage drives15. Additionally, in an example of a distributed processor system, one or more additional work processor nodes are provided, which may comprise, e.g., a work processor node52that may be located at first accessor18, and that is coupled to the communication processor node50via a network60,157. Each work processor node may respond to received commands that are broadcast to the work processor nodes from any communication processor node, and the work processor nodes may also direct the operation of the accessors, providing move commands. An XY processor node55may be provided and may be located at an XY system of first accessor18. The XY processor node55is coupled to the network60,157, and is responsive to the move commands, operating the XY system to position the gripper20.

Also, an operator panel processor node59may be provided at the optional operator panel23for providing an interface for communicating between the operator panel and the communication processor node50, the work processor nodes52,252, and the XY processor nodes55,255.

A network, for example comprising a common bus60, is provided, coupling the various processor nodes. The network may comprise a robust wiring network, such as the commercially available CAN (Controller Area Network) bus system, which is a multi-drop network, having a standard access protocol and wiring standards, for example, as defined by CiA, the CAN in Automation Association, Am Weich Selgarten 26, D-91058 Erlangen, Germany. Other networks, such as Ethernet, or a wireless network system, such as RF or infrared, may be employed in the library as is known to those of skill in the art. In addition, multiple independent networks may also be used to couple the various processor nodes.

The communication processor node50is coupled to each of the data storage drives15of a storage frame11, via lines70, communicating with the drives and with host systems40,41and42. Alternatively, the host systems may be directly coupled to the communication processor node50, at input80for example, or to control port devices (not shown) which connect the library to the host system(s) with a library interface similar to the drive/library interface. As is known to those of skill in the art, various communication arrangements may be employed for communication with the hosts and with the data storage drives. In the example ofFIG. 3, host connections80and81are SCSI busses. Bus82comprises an example of a Fibre Channel bus which is a high speed serial data interface, allowing transmission over greater distances than the SCSI bus systems.

The data storage drives15may be in close proximity to the communication processor node50, and may employ a short distance communication scheme, such as SCSI, or a serial connection, such as RS-422. The data storage drives15are thus individually coupled to the communication processor node50by means of lines70. Alternatively, the data storage drives15may be coupled to the communication processor node50through one or more networks, such as a common bus network.

Additional storage frames11may be provided and each is coupled to the adjacent storage frame. Any of the storage frames11may comprise communication processor nodes50, storage shelves16, data storage drives15, and networks60.

Further, as described above, the automated data storage library10may comprise a plurality of accessors. A second accessor28, for example, is shown in a right hand service bay14ofFIG. 3. The second accessor28may comprise a gripper30for accessing the data storage media, and an XY system255for moving the second accessor28. The second accessor28may run on the same horizontal mechanical path as first accessor18, or on an adjacent path. The exemplary control system additionally comprises an extension network200forming a network coupled to network60of the storage frame(s)11and to the network157of left hand service bay13.

InFIG. 3and the accompanying description, the first and second accessors are associated with the left hand service bay13and the right hand service bay14respectively. This is for illustrative purposes and there may not be an actual association. In addition, network157may not be associated with the left hand service bay13and network200may not be associated with the right hand service bay14. Depending on the design of the library, it may not be necessary to have a left hand service bay13and/or a right hand service bay14.

An automated data storage library10typically comprises one or more controllers to direct the operation of the automated data storage library. Host computers and data storage drives typically comprise similar controllers. A controller may take many different forms and may comprise, for example but not limited to, an embedded system, a distributed control system, a personal computer, or a workstation. Essentially, the term “controller” as used herein is intended in its broadest sense as a device that contains at least one processor, as such term is defined herein.FIG. 4shows a typical controller400with a processor402, RAM (Random Access Memory)403, nonvolatile memory404, device specific circuits401, and I/O interface405. Alternatively, the RAM403and/or nonvolatile memory404may be contained in the processor402as could the device specific circuits401and I/O interface405. The processor402may comprise, for example, an off-the-shelf microprocessor, custom processor, FPGA (Field Programmable Gate Array), ASIC (Application Specific Integrated Circuit), discrete logic, or the like. The RAM (Random Access Memory)403is typically used to hold variable data, stack data, executable instructions, and the like. The nonvolatile memory404may comprise any type of nonvolatile memory such as, but not limited to, EEPROM (Electrically Erasable Programmable Read Only Memory), flash PROM (Programmable Read Only Memory), battery backup RAM, and hard disk drives. The nonvolatile memory404is typically used to hold the executable firmware and any nonvolatile data. The I/O interface405comprises a communication interface that allows the processor402to communicate with devices external to the controller. Examples may comprise, but are not limited to, serial interfaces such as RS-232, USB (Universal Serial Bus), SCSI (Small Computer Systems Interface), SAS (Serial Attached SCSI), Fibre Channel, or Ethernet. The device specific circuits401provide additional hardware to enable the controller400to perform unique functions such as, but not limited to, motor control of a cartridge gripper. The device specific circuits401may comprise electronics that provide, by way of example but not limitation, Pulse Width Modulation (PWM) control, Analog to Digital Conversion (ADC), Digital to Analog Conversion (DAC), etc. In addition, all or part of the device specific circuits401may reside outside the controller400.

While the automated data storage library10is described as employing a distributed control system, the present invention may be implemented in various automated data storage libraries regardless of control configuration, such as, but not limited to, an automated data storage library having one or more library controllers that are not distributed. A library controller may comprise one or more dedicated controllers of a prior art library. For example, there may be a primary controller and a backup controller. In addition, a library controller may comprise one or more processor nodes of a distributed control system. For example, communication processor node50(FIG. 3) may comprise the library controller while the other processor nodes (if present) may assist the library controller and/or may provide backup or redundant functionality. In another example, communication processor node50and work processor node52may work cooperatively to comprise the library controller while the other processor nodes (if present) may assist the library controller and/or may provide backup or redundant functionality. Still further, all of the processor nodes may comprise the library controller. Herein, library controller may comprise a single processor or controller or it may comprise multiple processors or controllers.

FIG. 5illustrates an embodiment of the front501and rear502of a data storage drive15. In the example ofFIG. 5, the data storage drive15comprises a hot-swap drive canister. This is only an example and is not meant to limit the invention to hot-swap drive canisters. In fact, any configuration of data storage drive may be used whether or not it comprises a hot-swap canister.

FIG. 6illustrates an embodiment of a data storage cartridge600with a cartridge memory610shown in a cutaway portion of the Figure. This is only an example and is not meant to limit the invention to cartridge memories. In fact, any configuration of data storage cartridge may be used whether or not it comprises a cartridge memory.

FIG. 7Aillustrates a perspective view of one embodiment of a storage frame700, in accordance with one aspect of the invention. Frame700includes the elements of frame11ofFIG. 2, with an additional counter715. Counter715is configured to determine the presence of cartridges stored within one or more deep cartridge slots, and in communication with a controller configured to count the number of cartridges and compare the counted number with a limit value. The limit value may include a predetermined capacity on demand value and/or a predetermined maximum value that allows the library to maintain a swap space. It may be desired to have more than the minimum required swap space to improve overall library performance. For example, there may be a swap space in each storage frame11, one at each end of the library, one at the top and one at the bottom of each frame, etc. The counter715can be any appropriate device or combination of devices. In one embodiment, counter715includes an RFID reader, configured to interact with RFID tags implanted within each cartridge. In another embodiment, counter715includes a cartridge memory reader, configured to interact with the cartridge memory610of cartridge600. In one embodiment, the counter715is positioned on the gripper20so the library can move the counter715to various locations within the library. In another embodiment, the counter715is located at a fixed location within the library. In another embodiment, there are a plurality of counters715located within the library10. In one such embodiment, each of the plurality of counters715is in communication with a central controller (not shown), via a wired or wireless network for example, for maintaining a central count. In one embodiment, counter715includes one or more slot sensors. A slot sensor is a device that can tell the presence or absence of cartridges in a deep slot. The slot sensor may comprise an infrared emitter/detector, a hall effect sensor, or any other sensor for detecting the presence of objects as is known to those of skill in the art.

FIG. 7Billustrates a perspective view of one embodiment of a magazine100in accordance with one aspect of the invention. Magazine100includes a housing110defining an interior space115. A plurality of storage slots120is disposed within the housing. Storage slots120are, in one embodiment, configured for holding a plurality of cartridges130.

Additionally, in one embodiment, magazine100further includes at least one cartridge blocker150. In such embodiments, the cartridge blocker150includes an external portion155outside of the interior space115and an internal portion165within the interior space115. The cartridge blocker150alternates between an open position and a closed position, wherein the open position provides access to at least one of the storage slots120, and wherein the closed position substantially prevents access to at least one of the storage slots120. In one embodiment, the cartridge blocker is biased with a biasing member, such as a spring, toward the open position. In one embodiment, the cartridge blocker is biased with a biasing member, such as a spring, toward the closed position. In other embodiments, the cartridge blocker150is positioned with a locking member, such as a protrusion. In this example, the storage slots from top to bottom are considered to be in parallel. The storage slots from front to back, in one particular row, are considered to be in series. In one embodiment, storage slots that are arranged in series do not have a permanent physical barrier between them. In another embodiment, storage slots that are arranged in parallel have a physical barrier between adjacent storage slots. The physical barrier is used to prevent a cartridge from inadvertently passing from one slot to another slot. In one embodiment, the physical barrier can be moved or removed. In another embodiment, the physical barrier is maintained by a spring. In another embodiment, the physical barrier is maintained by a blocker. In another embodiment the physical barrier is fixed.

FIG. 8illustrates one embodiment of a method800for providing data storage, in accordance with one aspect of the invention. Method800begins at step810by determining a capacity limit value associated with an allowed storage capacity. The capacity limit value is a predetermined number indicative of the allowed storage capacity. The actual value may be stored in nonvolatile memory so that it can be configured, changed, and retained. In one embodiment, a storage system includes more storage capacity than a user is licensed, or authorized to use. The amount of storage authorized for use by the user is the capacity of the storage system, while the excess is termed excess storage capacity or capacity on demand. A number of cartridges is counted at step820. The count can be made using any appropriate device, such as a RFID device, a cartridge memory reader, slot sensors, etc. The counted number of cartridges is compared, such as with a processor, the library controller, ASIC, FPGA, discreet circuits, or other comparator, with the capacity limit value at step830. In one embodiment, the comparison is made by library firmware. Based on the comparison, an excess storage message is issued at step840. In one embodiment, the excess storage message is issued when the counted number of cartridges is greater than the capacity limit value. In another embodiment, the excess storage message is issued when the counted number of cartridges is greater than or equal to the capacity limit value. In one embodiment, the excess storage message is issued when the counted number of cartridges is within a predetermined difference of the capacity limit value. For example, if the comparison illustrates that the capacity limit value is less than 10% over the counted number of cartridges, an excess storage message can be issued so that the user becomes aware that their storage utilization is approaching a limit. The excess storage message can by any alert, such as a tone, indicator light, email, SMS (Short Message Service), SNMP (Simple Network Management Protocol) trap or notification, operator panel message, suspension of library access to certain cartridges or storage slots, reduced library functionality, or other form of message, notification, alert, or restriction. In one embodiment, the excess storage message traverses a network. In one embodiment, the excess storage message is posted to the user interface of the library. Reduced library functionality may comprise the inability to access certain library functions or capabilities. Data storage is then provided at step850. Providing data storage refers to the library being ready to accept host commands.

In one embodiment, an RFID device and/or cartridge memory (CM) device monitors the insertion and withdrawal of cartridges and/or magazines from the library and keeps a running tally of the number of cartridges within the library to compare to the capacity on demand value. The RFID/CM device can be placed at any appropriate location to interact with cartridges entering and exiting the library. In one embodiment, the RFID/CM device is positioned near an entrance to the library, such as on front wall17(FIG. 2). In another embodiment, the RFID/CM device is positioned on the gripper20. In another embodiment, the RFID/CM device is placed in or around the I/O station24,25. Still further, the RFID/CM device is positioned in each deep slot, around each group of deep slots, or in a location that can monitor or interact with all of the deep slots at once.

FIG. 9illustrates one embodiment of additional method steps900, in accordance with one aspect of the invention. In one embodiment, method900is implemented following execution of method800. Method900begins at910by receiving an increase capacity message. The increase capacity message is a command to increase the capacity on demand value. In other words, the increase capacity message allows a user to take advantage of storage that is present but is not licensed or authorized to be used. In one embodiment, the increase capacity message is received from a vendor over a network in response to receipt of additional consideration. Additional consideration may comprise a credit card, a purchase order, a license key, etc. A vendor may comprise the manufacturer of the storage system, the company that sold the storage system, a company responsible for selling upgrades or features for the storage system, etc. In one embodiment, the increase capacity message is received directly at the library via a user interface. The increase capacity message includes an instruction indicative of the increment to increase the capacity limit value, and thereby providing capacity on demand. Based on receiving the increase capacity message, the capacity limit value is incremented at step920, and the incremented capacity limit value may be compared to the counted number of cartridges at step930. In one embodiment, if the counted number of cartridges remains greater than the incremented capacity limit value, an additional excess storage message is issued. In one embodiment, if the counted number of cartridges remains greater than or equal to the incremented capacity limit value, an additional excess storage message is issued. In yet another embodiment, if the counted number of cartridges remains within a predetermined margin (such as 5% or 10%) of the incremented capacity limit value, an additional excess storage message is issued.

FIG. 10illustrates one embodiment of additional method steps1000, in accordance with one aspect of the invention. In one embodiment, method1000is implemented following execution of method800. In one embodiment, method1000is implemented as step820of method800. Method1000begins at step1010by determining metadata for each cartridge within a library. The metadata can be determined with use of an appropriate device, such as an RFID reader, cartridge memory (CM) reader, etc. At step1020, the determined metadata is listed, and at step1030, the cartridges in the library are counted by referencing the list of determined metadata. Listing the metadata may comprise storing the metadata in volatile or nonvolatile memory such as RAM, EEPROM, flash PROM, CompactFlash, Secure Digital Media, hard disk drives, etc. In one embodiment, a database is created in steps1010and1020such that each cartridge is assigned a particular row or column in the database, and at step1030, method1000determines the number of cartridges in the library as the number of rows or columns within the database. In one embodiment, the actual content of the metadata is not considered, and the metadata is only used, in the methods disclosed herein, to count the number of cartridges instead of cataloging their contents. In another embodiment, the metadata is used to identify particular cartridges that caused the excess storage message. For example, the cartridges occupying a fixed swap space, cartridges in excess of the capacity on demand value, cartridges in physical locations that have not been activated for capacity on demand, etc.

FIG. 11illustrates one embodiment of a method1100to perform an inventory of cartridges in a data storage system, in accordance with another aspect of the invention. Method1100begins at step1110by operating a reader to determine metadata associated with each cartridge stored in a library. The reader can be any appropriate device, such as an RFID device, a cartridge memory reader, etc. The determined metadata is listed at step1120, and at step1130, the cartridges are counted based on the list. In one embodiment, a database is created in steps1110and1120such that each cartridge is assigned a particular row or column in the database, and at step1130, method1100determines the number of cartridges in the library as the number of rows or columns within the database.

At step1140, a capacity limit value is determined, and at step1150, the determined number of cartridges is compared with the capacity limit value associated with a physical storage capacity. The physical storage capacity is indicative of the absolute number of cartridges that may be positioned within a library even if a user has not fully licensed that number of cartridges for storage. An inventory of cartridges is then established, at step1160, based on the comparison. In one embodiment, an excess storage message is issued based on a determination that the number of cartridges is greater than the capacity limit value. In one embodiment, an excess storage message is issued based on a determination that the number of cartridges is greater than or equal to the limit value. In one embodiment, an excess storage message is issued based on a determination that the number of cartridges is less than the limit value, but within a predetermined range of the limit value, such as 5% or 10%.

In each of the methods described herein, a determination of sufficient deep slots can be further made, based on the comparison of the counted number of cartridges and the capacity limit value. In addition, as noted in the background, ensuring sufficient deep slot inventory is needed to ensure that the gripper has a swap space (a place to put any cartridges that must be moved to access deeper cartridges). Thus each method disclosed herein can further include an additional step, or alternatively describe another method, wherein the method determines a sufficient deep slot inventory based on the comparison. Further, error or warning messages can then be issued based on the determination of sufficient deep slot inventory for swap space, if there is insufficient deep slot inventory available.

While the figures and description of this invention have discussed the magazine in particular detail, it should be noted that other variations of the magazine may be employed without deviating from the scope of this invention. Indeed, the magazine may comprise any array of cartridge slots (x slots high, y slots across, z slots deep) in any orientation. For example, the magazine may comprise a 1, 5, 2 array where the magazine is 1 slot high, 5 slots wide, and 2 slots deep. In the example ofFIG. 7B, the magazine array is arranged as 4, 1, 5. In addition, there is no requirement for the use of magazines. This invention applies to any deep slot structure, whether based on magazines or not.

While the embodiments of the present invention disclosed herein are presently considered to be preferred embodiments, various changes and modifications can be made without departing from the spirit and scope of the present invention. The scope of the invention is indicated in the appended claims, and all changes that come within the meaning and range of equivalents are intended to be embraced therein.