This invention relates to automated data storage libraries configured to store data storage cartridges in a plurality of storage slots, and, more particularly, to calibration of at least one location in the library.
Automated data storage libraries are known for providing cost effective storage and retrieval of large quantities of data, typically from data storage cartridges stored in storage slots of the library. The data storage cartridges are typically extracted from the storage slots, placed in the storage slots, and transported within the library by one or more accessors. In order to operate at the highest efficiency, the controller(s) operating the accessor(s) must know the precise location of each cartridge that is being accessed to be extracted and the precise location of the storage slot at which a cartridge is to be placed.
Mechanical tolerances typically exist within a library such that the precise positions of the storage slots and the cartridges they contain may be different from the expected positions. Calibration techniques may employ fiducial marks (also called calibration targets) permanently provided at points within the library to ascertain the difference between where the fiducial is expected to be located and where it is actually located. For example, a fiducial may be located at a corner within a library frame or a bank of storage slots in the frame. This difference is then employed to adjust the expected location of one or more points within the frame or that bank of storage slots. Performing this calibration allows greater tolerances in the design and manufacture of the library and its components.
It may be desirable to provide calibration at additional points within the library, exemplified by the advent of libraries having multi-cartridge deep slot cells, to insure that cartridges are correctly accessed.
Calibration of an automated data storage library having a plurality of storage slots configured to store at least one data storage cartridge, in one embodiment, comprises placing a cartridge-like element having similar external dimensions as a data storage cartridge in one of the plurality of storage slots having a known location, the cartridge having a fiducial mark thereon; sensing the fiducial mark; and calibrating the position of the fiducial mark with respect to the known location of the storage slot.
In one embodiment, the element comprises an exterior shell having similar external dimensions as a data storage cartridge; and a fiducial mark located on the exterior shell comprising at least one contrasting edge defining a specific calibration location on the element.
In a further embodiment, the fiducial mark comprises an energy emitting, energy absorbing and/or energy reflecting mark contrasting with the remainder of the fiducial mark to form the contrasting edge(s).
In another embodiment, the step of sensing the fiducial mark comprises emitting energy towards the element and reading back energy from the fiducial mark.
In a further embodiment, the fiducial mark comprises at least an edge of the element, and the step of sensing the fiducial mark comprises reading the presence of the edge from reflected energy.
In another embodiment, the fiducial mark comprises an energy emitting material, and the step of sensing the fiducial mark comprises reading the energy from the fiducial mark.
In another embodiment, where the automated data storage library comprises at least one accessor configured to selectively extract, place and transport the data storage cartridges with respect to the storage slots; and the placing step and the sensing step are conducted by the accessor(s).
In a further embodiment, the plurality of storage slots comprise both single cartridge storage slots and multi-cartridge deep slot cells arranged in tiers from front to rear; and the step of placing the cartridge comprises placing the cartridge in one of the single cartridge storage slots and the frontmost tier of one of the multi-cartridge deep slot cells.
In another embodiment, the sensor comprises a camera.
In still another embodiment, the sensor comprises a Hall effect detector.
For a fuller understanding of the present invention, reference should be made to the following detailed description taken in conjunction with the accompanying drawings.
a, 10b, 10c and 10d illustrate embodiments of fiducial marks employed with the element of
This invention is described in preferred embodiments in the following description with reference to the Figures, in which like numbers 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 variations may be accomplished in view of these teachings without deviating from the spirit or scope of the invention.
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 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.
As described above, the storage frames 11 may be configured with different components depending upon the intended function. One configuration of storage frame 11 may comprise storage slots 16 and/or multi-cartridge deep slot cells 100, data storage drive(s) 15, and other optional components to store and retrieve data from the data storage cartridges, and another storage frame 11 may comprise storage slots 16 and/or multi-cartridge deep slot cells 100 and no other components.
For a fuller understanding of an automated data storage library having both single cartridge storage slots 16 and multi-cartridge deep slot cells 100, refer to U.S. patent application Ser. No. 12/200,689, filed Aug. 28, 2008, which is incorporated herein for reference.
The first accessor 18 comprises a gripper assembly 20 for gripping one or more data storage cartridges. The gripper assembly may include one or more sensors 22, mounted on the gripper 20, to “read” identifying information about the data storage cartridge and to locate fiducial marks, as will be discussed.
While the automated data storage library 10 is illustrated 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.
The library of
In the exemplary library, first accessor 18 and second accessor 28 move 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 cartridge at the storage slots 16 and multi-cartridge deep slot cells 100, or input/output stations 24, 25, and to mount and demount the data storage cartridge at the data storage drives 15.
The exemplary library 10 receives commands from one or more host systems 40, 41 or 42. The host systems, such as host servers, communicate with the library directly, e.g., on path 80, through one or more control ports (not shown), or through one or more data storage drives 15 on paths 81, 82, providing commands to access particular data storage cartridges and move the cartridges, for example, between the storage slots 16 and the data storage drives 15. The commands are typically logical commands identifying the cartridges or cartridge 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 system 40, 41 or 42 to the library 10 as are intended to result in accessing particular data storage media within the library 10.
The exemplary library is controlled by a library controller, which in one embodiment comprises a distributed control system receiving the logical commands from hosts, determining the required actions, and converting the actions to physical movements of and actions by first accessor 18 and/or second accessor 28.
In the exemplary library, the distributed control system comprises a plurality of processor nodes, each having one or more computer processors. In one example of a distributed control system, a communication processor node 50 may be located in a storage frame 11. The communication processor node provides a communication link for receiving the host commands, either directly or through the drives 15, via at least one external interface, e.g., coupled to line 80.
The communication processor node 50 may additionally provide a communication link 70 for communicating with the data storage drives 15. The communication processor node 50 may be located in the frame 11, close to the data storage drives 15. 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 node 52 that may be located at first accessor 18, and that is coupled to the communication processor node 50 via a network 60, 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 node 55 may be provided and may be located at an XY system of first accessor 18. The XY processor node 55 is coupled to the network 60, 157, and is responsive to the move commands, operating the XY system to position the gripper 20.
Also, an operator panel processor node 59 may be provided at the optional operator panel 23 for providing an interface for communicating between the operator panel and the communication processor node 50, the work processor nodes 52, 252, and the XY processor nodes 55, 255.
A network, for example comprising a common bus 60, 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 node 50 is coupled to each of the data storage drives 15 of a storage frame 11, via lines 70, communicating with the drives and with host systems 40, 41 and 42. Alternatively, the host systems may be directly coupled to the communication processor node 50, at input 80 for 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 of
The data storage drives 15 may be in close proximity to the communication processor node 50, and may employ a short distance communication scheme, such as SCSI, or a serial connection, such as RS-422. The data storage drives 15 are thus individually coupled to the communication processor node 50 by means of lines 70. Alternatively, the data storage drives 15 may be coupled to the communication processor node 50 through one or more networks, such as a common bus network.
Additional storage frames 11 may be provided and each is coupled to the adjacent storage frame. Any of the storage frames 11 may comprise communication processor nodes 50, storage slots 16, multi-cartridge storage cells 100, data storage drives 15, and networks 60.
Further, as described above, the automated data storage library 10 may comprise a plurality of accessors. A second accessor 28, for example, is shown in a right hand service bay 14 of
In
An automated data storage library 10 typically 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 library 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 “library controller” as used herein is intended in its broadest sense as a device that contains at least one computer processor, as such term is defined herein.
While the automated data storage library 10 is 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 node 50 (
The element 610 may comprise a cartridge memory 619 shown in a partial outline portion of the Figure. The cartridge memory may be readable by the accessor or another component of the library. A cartridge label (see label 654 of
Alternatively, the multi-cartridge deep slot cell 100 is built into the frame of the automated data storage library.
A retaining gate cartridge blocking mechanism (not shown) retains the data storage cartridges in the multi-cartridge deep slot cell 100. The retaining gate can be activated by an accessor of an automated tape library, and allows insertion of cartridges into the multi-cartridge deep slot cell. The retaining gate allows for positive cartridge retention against the pressure of biasing spring 152, and ensures that one or more data storage cartridges do not get pushed out of the front of the multi-cartridge deep slot cell 100 simultaneously while allowing the pushing mechanism of the multi-cartridge deep slot cell 100 to always push the data storage cartridge(s) to the opening in a multi-cartridge deep slot cell 100. The accessor opens the retaining gate to gain access to the data storage cartridge in the frontmost tier and, upon its extraction, the biasing spring 152 moves the cartridge(s) behind the extracted cartridge forward, promoting the cartridge(s) by one tier.
For a fuller understanding of the multi-cartridge deep slot cell and retaining gate, refer to U.S. patent application Ser. No. 11/674,904, which is entitled “Retaining Gate for Deep Storage Slot Retention of Storage Cartridges”, which is incorporated herein for reference.
Access to a storage slot may include the ability to remove a cartridge from a storage slot, the ability to place a cartridge into a storage slot, or combinations thereof.
In this example, the storage slots from top to bottom are considered to be in parallel and comprise the same tier. The storage slots from front to back, in one particular row, are considered to be in series and comprise sequential tiers.
Storage slots 120 are, in one embodiment, configured for storing up to a plurality of data storage cartridges 600, arranged in sequential order of tiers 621, 622, 623, 624 and 625 from front to rear. Herein, the frontmost tier 621 is also called “tier 1”, the next tier 622 is called “tier 2”, etc., and the last tier 625 is also called the “rearmost” tier.
Referring to
The combination of deep slots, springs or biasing mechanisms, and gates of a multi-cartridge deep slot cell, or the combination of an assembly of storage slots may cause cartridges to be presented to the library accessor in unexpected ways, limiting the reliability of the calibration of a frame or bank of storage slots.
In one embodiment, the gripper assembly 20 comprises a calibration sensor 22 of
a, 10b, 10c and 10d illustrate several alternative embodiments of fiducial marks 615 employed with the element 610 of
The fiducial mark comprises an energy emitting, energy absorbing and/or energy reflecting mark contrasting with the remainder of the fiducial mark to form the contrasting edge(s). Examples include magnetic marks, molded marks, imprinted or printed marks, or any other material or form capable of formation of marks having contrasting edges.
Referring to
In a further embodiment, the fiducial mark comprises at least an edge of the element, and the step of sensing the fiducial mark comprises reading the presence of the edge from reflected energy. As discussed above with respect to
Referring to
In step 700, the controller may extract the element 610 having similar external dimensions as a data storage cartridge and having a fiducial mark thereon from the input/output station 24, and at least one controller will direct the accessor to transport the element to a specific multi-cartridge deep slot cell 100, and place the element, for example having a fiducial mark 615, in storage slot at the frontmost tier of the specific multi-cartridge deep slot cell, the storage slot having a known location from which a calibration may be made, as shown in
In step 705, the calibration sensor 22, 32 is positioned to sense a fiducial mark at the known location of the desired storage slot. In step 710, the sensor senses the fiducial mark of the element 610 and the precise location of the contrasting edge(s) of the fiducial mark is determined as discussed above.
In step 715, the difference between the expected position of the contrasting edge(s) at the known position of the storage slot and the sensed precise location is determined, for example, by logic or firmware, for example, at the controller 52, 252, and employed to calibrate the position of the fiducial mark with respect to the previously known location of the storage slot. In step 720, the positioning characteristics of the accessor are adjusted in accordance with the calibration. Additionally, the “known location” of the storage slot may be adjusted to conform to the newly sensed reality.
Step 725 determines whether the calibration of the library is complete, which may comprise the calibration of a number of elements 610 throughout the library, or alternatively, may comprise a single or limited number of elements at one or more specific locations. If the calibration is complete, the process ends at step 730. If the calibration is incomplete, the process returns to step 700 to place an element 610 at a storage slot having a known location, or to move the accessor to the known location at which an element 610 is located, and to repeat the process for that element.
In this manner, a reliable calibration of one or more storage slots at a specific location or throughout the automated data storage library is accomplished.
The invention can take the form of an entirely hardware embodiment, or an embodiment comprising hardware processing software elements. In a preferred embodiment, the invention is implemented in microcode of one or more controllers of
Furthermore, the invention can take the form of a computer program product accessible from a computer usable or computer readable storage medium providing program code for use by or in connection with one or more controllers. For the purposes of this description, a computer usable or computer readable storage medium can be any apparatus that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device.
The storage medium can be an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system (or apparatus or device) or a propagation medium. Examples of a computer readable medium include a semiconductor or solid state memory, magnetic tape, a removable computer diskette, and random access memory (RAM), a read-only memory (ROM), a rigid magnetic disk and an optical disk. Current examples of optical disks include compact disk-read only memory (CD-ROM), compact disk-read/write (CD-R/W) and DVD.
Those of skill in the art will understand that changes may be made with respect to the methods discussed above, including changes to the ordering of the steps. Further, those of skill in the art will understand that differing specific component arrangements may be employed than those illustrated herein.
While the preferred embodiments of the present invention have been illustrated in detail, it should be apparent that modifications and adaptations to those embodiments may occur to one skilled in the art without departing from the scope of the present invention as set forth in the following claims.
Commonly assigned U.S. Patent Application Publication No. 2005/0261850, filed May 24, 2004 is incorporated for its showing of a calibration system for an automated data storage library; and commonly assigned U.S. patent application Ser. No. 12/200,689, filed Aug. 28, 2008, is incorporated for its showing of an automated data storage library having both multi-cartridge deep slot cells and single cartridge storage slots.