Proximity auditing of storage library cartridge magazines

Embodiments are described for proximity auditing of removable media cartridge magazines in a data storage library. For example, a proximity sensor mounted on a robotic assembly can be used to detect one or more target features of cartridge magazines. In particular, the proximity sensor can look for relatively large structural features of a removable cartridge magazine in a manner that is fast and reliable, and does not rely on precise positioning of the robotic assembly with respect to the magazine. Some implementations can use the proximity sensor in conjunction with further auditing and/or other functions of line camera, and/or other sensors of the robotic assembly. Proximity-based auditing of the magazines can permit storage library systems to initialize faster and with more reliable inventory information.

FIELD

Embodiments relate generally to data storage library systems, and, more particularly, to use of proximity sensors for storage library cartridge magazine detection.

BACKGROUND

Storage library systems are often used by enterprises and the like to efficiently store and retrieve data from storage media. In the case of some storage libraries, the media are data cartridges (e.g., tape cartridges) that are typically stored and indexed within a set of magazines. When particular data is requested, a specialized robotic mechanism finds the appropriate cartridge, removes the cartridge from its magazine, and carries the cartridge to a drive that is designed to receive the cartridge and read its contents. Some storage libraries have multiple drives that can operate concurrently to perform input/output (IO) operations on multiple cartridges.

Operation of the robotic mechanism in the context of a data storage system typically involves a number of different location related tasks. For example, the robotic mechanism may be used for targeting of specific locations within the data storage system, for performing pick and place operations on media cartridges, for reading barcodes and/or other symbols or features, for auditing the existence and/or absence of media cartridges in magazines or drives, etc. Each of these and other operations can be frustrated when location-related errors are introduced into the environment if proper corrective feedback is not provided. For example, errors can easily be introduced into the system from physical jarring or manipulation of components, from compounding of errors inherent in electronic components, etc.

Some such operations can relate to auditing of inventory locations. For example, inventory locations can include media cartridge storing cells provided in a stacked arrangement (in a magazine) for convenient storage of large numbers of media cartridges. Performing a tape audit in a storage library system can involve distinguishing between unlabeled cartridges or magazines (or errors in the detection system) and empty cell or magazine locations. Some conventional systems perform such audits by either having the robotically actuated hand assembly reach into cells or other locations mechanically to sense whether a cartridge or magazine is present, or by using the robot to read barcodes or other labels. Extending the robotically actuated hand assembly into many locations for auditing purposes can add significant delay to the audit time, and reading labels can add cost and error (and often complex calibration processes).

BRIEF SUMMARY

Among other things, systems and methods are described for proximity auditing of removable media cartridge magazines in a data storage library. For example, a proximity sensor mounted on a robotic assembly can be used to detect one or more target features of cartridge magazines. In particular, the proximity sensor can look for relatively large structural features of a removable cartridge magazine in a manner that is fast and reliable and does not rely on precise positioning of the robotic assembly with respect to the magazine. Some implementations can use the proximity sensor in conjunction with further auditing and/or other functions of a line camera and/or other sensors of the robotic assembly. Proximity-based auditing of the magazines can permit storage library systems to initialize faster and with more reliable inventory information.

According to one set of embodiments, a system is provided for auditing removable cartridge magazines in a storage library system. The system includes: a robotic assembly operable to ferry media cartridges in the storage library system; a proximity sensor integrated with the robotic assembly; and a processor. The robotic assembly can move the proximity sensor to search for a structural feature that is present when a corresponding removable cartridge magazine is installed in an installation location of the storage library system. The processor has a proximity sensor input and a cartridge audit output. The cartridge audit output indicates presence of the corresponding removable cartridge magazines in the installation location in response to detection of the structural feature by the proximity sensor.

According to another set of embodiments, a method is provided for auditing removable cartridge magazines in a storage library system. The method includes: moving a proximity sensor to an audit location in the storage library system, the proximity sensor being integrated with a robotic assembly operable to ferry media cartridges in the storage library system and the audit location corresponding to an installation location for a removable cartridge magazine; searching, with the proximity sensor, for a structural feature that is present only when a corresponding removable cartridge magazine is installed in the installation location; and outputting a cartridge presence indication in response to the searching, the cartridge presence indication indicating the corresponding removable cartridge magazine is installed in the installation location when the structural feature is found, and the cartridge presence indication indicating the corresponding removable cartridge magazine is not installed in the installation location when the structural feature is not found.

According to another set of embodiments, another system is provided for auditing removable cartridge magazines in a storage library system. The system includes a processor in communication with a proximity sensor integrated with a robotic assembly operable to ferry media cartridges in the storage library system, and a data store having instructions stored thereon. When executed, the instructions cause the processor to perform steps including: searching, with the proximity sensor, for a structural feature that is present only when a corresponding removable cartridge magazine is installed in an installation location; and outputting a cartridge presence indication in response to the searching, the cartridge presence indication indicating the corresponding removable cartridge magazine is installed in the installation location when the structural feature is found, and the cartridge presence indication indicating the corresponding removable cartridge magazine is not installed in the installation location when the structural feature is not found.

DETAILED DESCRIPTION

In the following description, numerous specific details are set forth to provide a thorough understanding of the present invention. However, one having ordinary skill in the art should recognize that the invention may be practiced without these specific details. In some instances, circuits, structures, and techniques have not been shown in detail to avoid obscuring the present invention.

FIG. 1shows an illustrative storage library system100as a context for various embodiments. The storage library system100can be an automated tape library, such as the SL8500 Modular Library System produced by Oracle Corporation. Embodiments are not intended to be limited to any particular type or implementation of automated tape library system and may apply in context of any suitable storage library system100. Generally, embodiments are directed to auditing presence and/or absence of cartridge magazines in such storage library systems100. Such storage library systems100can include a large number of media cartridges (e.g., storage tapes) that have data stored thereon. The media cartridges are physically maintained within the library's chassis160in cartridge magazines170. For example, the cartridge magazines170can include an array of magazine cells175, each adapted to hold a media cartridge. Some cartridge magazines170can be permanently attached to the library's chassis160, and other cartridge magazines170can be removable from the library's chassis160. For example, some cartridge magazines170can be used by a library operator to import and/or export cartridges (e.g., in hulk) to and/or from the storage library system100.

Such storage library systems100typically also include one or more robotic mechanisms (not shown) that have pick and place mechanisms (e.g., a robotic “hand”). The robotic mechanisms can move throughout the storage library system100(e.g., on rails or other structures) between cartridge magazines170, banks of tape drives in the storage library system100, and/or other locations in the storage library system100. For example, the robotic mechanisms can be used to locate a desired media cartridge in its magazine cell175, remove the media cartridge from the magazine cell175, terry the media cartridge to a media drive (e.g., a tape drive), and place the media cartridge in the media drive for performance of data input/output operations. Typically, such storage library systems100operate under operational requirements, including that the storage library system100continue to function, even when one or more removable cartridge magazines170are not installed. Further, certain operations of the storage library systems100can involve detection and/or knowledge of whether one or more removable cartridge magazines170are present. For example, the storage library systems100can include an auditing or inventory phase of operation, during which a determination is made as to which cartridge magazines170are present or absent, which magazine cells175are full or empty, which media cartridges are present, etc.

Some conventional approaches to detection of cartridge magazines170use a line or barcode scanner. In some cases, cartridge magazines170can include target features that are used to calibrate an X-Y position for accurate positioning of the robot with respect to a particular cartridge magazine170, and a camera (or other suitable device) on the hand is used to look for, and at, those target features. For example, the target features can include a visible pattern, formed by a set of injection-molded tapered raised ribs with a foil pattern heat stamped onto the ribs to form the visible pattern, by an adhesive-backed label with a visible pattern displayed thereon applied to an inside portion of each cell, or by any other suitable manner. In some conventional implementations, an attempt is made first to find a cartridge magazine170by locating its target feature. If the target is not found, there can additionally be a special “No Magazine” barcode label (or other type of special label) attached to the library's chassis160behind where the magazine mounts (e.g., a storage wall130) and the camera can then be used to look for the “No Magazine” barcode label. If the “No Magazine” label is seen by the camera, the storage library system100can log that cartridge magazine170as “not present” (or any suitable designation). Thus, some implementations can use the targeting to determine whether a cartridge magazine170is present, to accurately position the robotic hand with respect to the cartridge magazine170, and/or to audit magazine cells175of the cartridge magazine170(e.g., to determine if a magazine cell175is full or empty, to identify its contents, etc.).

However, such a conventional approach can yield errors in some cases, such as when the camera fails to see the target features and then fails to see the “No Magazine” label. It can be difficult (e.g., or expensive, etc.) to implement the camera to reliably read both kinds of targets, as they may be in appreciably different focal planes. For example, the target features may be on a front side of the cartridge magazines170that is relatively close to the camera, while the “No Magazine” label may be on the storage wall130relatively far from the camera (behind where the cartridge magazines170would be if present). Such a combined failure can mean that no cartridge magazine170is present, but the camera failed to successfully find or read the “No Magazine” label; or that a cartridge magazine170is present, but the camera failed to successfully find or read the magazine target features; or a the camera is not functioning properly; etc. For example, some such conventional approaches can make multiple attempts to read the magazine target feature (even though there may be no cartridge magazine170), which can take appreciable amounts of time and can still result in an erroneous result.

Embodiments described herein seek to improve the speed and/or reliability of auditing (e.g., inventory) processes for storage library systems100. As described herein, a proximity sensor mounted on the robot's hand can be used to detect one or more target features of the cartridge magazines170. Some implementations use the proximity sensor to look for the magazine target features before any attempts are made to look for the target features with a line camera, barcode scanner, or the like. As noted above, the camera can typically be optimized to read targets and barcode labels attached to tape cartridges, and the like, so that the “No Magazine” label may be out of its focal plane (e.g., 4 inches farther away from the camera). In contrast, though the robot's proximity sensor may be unable to read any target features, embodiments can use the proximity sensor to detect target features in a more optimized manner, including with more reliability and/or in less time. This can permit the storage library systems100to initialize faster and with more reliable inventory information. In some embodiments, the storage library systems100can be implemented without “No Magazine” labels (or the like), which can reduce cost and/or provide other features.

FIG. 2shows an illustrative portion of a storage library system200having a partial library chassis160and a robotic assembly120, according to various embodiments. The library chassis160houses a storage wall130shown as having a cartridge magazine170with one media cartridge110in a corresponding magazine cell175. As described above, the robotic assembly120can move throughout the storage library system200to perform media cartridge110related tasks, such as pick and place tasks, media cartridge110auditing tasks, cartridge magazine170auditing tasks, etc. For example, the robotic assembly120can move in up, down, left, and right directions, as indicated by arrows inFIG. 2.

Some of the tasks of the robotic assembly120can rely on sensor feedback data from one or more sensors of the robotic assembly120. The illustrated robotic assembly120includes a line camera210and a proximity sensor220. The line camera210can be a barcode scanner, camera, and/or the like mounted on the hand of the robotic assembly120to read barcodes and/or other specialized features. In one implementation, the line camera210on the robotic hand can include an LED board with multiple surface-mounted lights to light up a surface to be read by the line camera210, a charge-coupled device (CCD) chip (e.g., or any photosensitive chip, for example, with a horizontal slit to distinguish light and dark lines on a projected image), a lens and/or other optics to project an image from a pattern to be read by the line camera210onto the CCD chip, and a computational system for controlling the line camera210and processing the image pattern (e.g., deciphering the pattern). An example of an illumination footprint215is shown as an illustrative region over which the line camera210is able to obtain optical information (e.g., imagery). The far edge of the illumination footprint215can correspond to an illustrative focal plane of the line camera210. As shown, the line camera210can be designed with a focal plane corresponding substantially to a distance between the line camera210and features of interest (e.g., an “N” target and/or cartridge barcode, as described below). Notably, the back of the storage wall130(e.g., the region behind where a cartridge magazine170would be) can typically be out of the focal plane of the line camera210.

Embodiments of the proximity sensor220can include an optical source and an optical sink arranged in an optical relationship with one another. For example, the optical sink can be mounted to the robotic assembly120above the optical source, and both can be focused and/or pointed in such a way that the optical sink can sense optical signals originating from the optical source and reflecting off a surface. An illustrative optical path225shows how a transmitted optical signal could reflect off an object and back to an optical sink of the proximity sensor220if a proximate object were present. A threshold optical response magnitude can be selected so that reflected optical signals exceeding the magnitude correspond to objects within a certain distance of the optical source and/or optical sink. For example, by sensing a reflected optical signal having a magnitude exceeding the threshold, the proximity sensor220can determine the presence of an object “in proximity” to the proximity sensor220. In some conventional libraries, such a proximity detector can detect presence of a media cartridge110. Embodiments described herein use the proximity sensor220to detect particular features of cartridge magazines170, for example, for use in cartridge magazine auditing. Embodiments of the proximity sensor220can sense optical signals reflected directly by the desired features of the cartridge magazines170when present, so that there is a clearly discernable difference in optical response between presence or absence of such a feature in proximity to the proximity sensor220. For example, presence of the feature can cause an optical signal from the optical source to reflect back to the optical sink to a sufficient degree to manifest an optical response exceeding the threshold optical response magnitude; while absence of the feature can cause the optical signal from the optical source to fail to reflect back to the optical sink at all, or at least to reflect back poorly, so as to manifest an optical response falling below the threshold optical response magnitude. Some implementations of the proximity sensor220can be positioned, angled, optically filtered, optically masked, focused, electrically and/or optically tuned, and/or otherwise configured to manifest the desired threshold response to the desired target features.

Though not explicitly shown, embodiments include one or more components and/or processors (e.g., in the proximity sensor220, in the robotic assembly120, in the storage library system200, etc.) to determine whether the optical response of the proximity sensor220exceeds the threshold optical response magnitude. In some embodiments, there can be a large variation in intensity of the transmitted optical signals from the optical source (e.g., one or more LEDs). For example, the optical signal intensities can vary as much as −50%/+100%, and the received reflections can vary in intensity by corresponding amounts. In such embodiments, detection can be unreliable when comparing the widely varying intensities to a fixed threshold. Accordingly, some implementations use a varying (e.g., dynamic) threshold optical response magnitude. For example, the processor(s) can be used to compare the optical signal received by the optical sink of the proximity sensor220with a reference signal, and the reference signal can be configured dynamically to respond to the variations in optical intensity. For example, reference signal intensity can be proportional to the optical signal intensity.

FIG. 3shows a simplified block diagram300that includes an illustrative robotic assembly120, according to various embodiments. The robotic assembly120has a number of functional blocks, including one or more line cameras210, one or more proximity sensors220, one or more on-board processors310, a decoder module320, a driver module330, and one or more data stores340. In some embodiments, the robotic assembly120is in communication with one or more off-board processors360. For example, the on-board processor(s)310can include dedicated and/or general-purpose processing circuitry integrated with the robotic assembly120to assist with performing its functions; and the off-board processors360can include the main and/or other processors of the storage library system, or any other controller external to the robotic assembly120. In some implementations, some or all of the processing functionality is removed from the robotic assembly120(i.e., performed by the off-board processors360. For example, functionality of one of more component blocks shown inFIG. 3can be implemented as instructions (e.g., software, firmware, etc.) that cause one or more processors of the data storage system, when executed, to implement such functions.

Embodiments of the robotic assembly120can be used effectively as a carriage for the line camera(s)210and/or proximity sensor(s)220. For example, movement of the robotic assembly120can be directed by the driver module330and can be used to effectively move and/or point the line camera(s)210and/or proximity sensor(s)220at desired locations. As described above, the proximity sensor220can be pointed, so that a transmitted optical signal (e.g., an LED light) can reflect off an object in particular proximity to the sensor and can be received by the proximity sensor220at a signal level indicating presence or absence of the proximate object. In alternative implementations, determination of presence or absence of a proximate object can involve detecting and/or analyzing characteristics of the received signal, such as the timing, wavelength, etc. of the reflected signal. Accordingly, features of the proximity sensor(s)220can be directed by the on-board processors310and/or off-board processors360, and/or can be impacted by data maintained in the data store(s)340.

As described herein, embodiments can use the proximity sensor220for a threshold detection of presence and/or absence of a cartridge magazine170. Such detection can involve the proximity sensor220determining whether a relatively coarse (e.g., large) magazine target feature is in proximity to the proximity sensor220, for example, without concern for decoding or otherwise interpreting the detected feature. The detection with the proximity sensor220can be used in conjunction with detection (e.g., and/or decoding, etc.) by the line camera210. In some embodiments, the proximity sensor220is used to quickly determine whether a cartridge magazine170is present in an audit location of a storage wall130. If the cartridge magazine170appears to be present, the line camera210can be used to look for the “N” target420and/or other targeting features. The further detection by the line camera210can facilitate orientation of the robotic assembly120with respect to the detected cartridge magazine170, etc. In some implementations, optical information received by the line camera210can be decoded by decoder module320. For example, the decoder module320can receive contrast data, topographic data, imagery, etc. from the line camera210and can decode the data to obtain information about the detected target feature (e.g., to identify an edge of a geometric feature, to decode a barcode, to find and/or decode a particular symbol, etc.). In some alternative embodiments, the proximity sensor220is used to audit cartridge magazines170only in response to a particular result of conventional auditing by a line camera210. For example, in the event that auditing by the line camera210is inconclusive (e.g., no “N” target420of a cartridge magazine170is detected, but a “No Magazine” label410is also not seen), the proximity sensor220can be used (e.g., rather than iterating multiple times with the line camera210).

In some embodiments, as described above, the processor (e.g., the on-board processors310and/or off-board processors360) is in communication with the proximity sensor(s)220integrated with the robotic assembly120. The data store(s)340can include instructions stored thereon, which, when executed, cause the processor to perform steps. The steps can include: searching, with the proximity sensor(s)220, for a structural feature that is present only when a corresponding removable cartridge magazines170is installed in an installation location (e.g., of a storage wall130); and outputting a cartridge presence indication in response to the searching. The cartridge presence indication can indicate that the corresponding removable cartridge magazine170is installed in the installation location when the structural feature is found, and the cartridge presence indication can indicate that the corresponding removable cartridge magazine is not installed in the installation location when the structural feature is not found. In some such embodiments, the steps further include moving the proximity sensor(s)220to an audit location prior to the searching (e.g., the audit location corresponds to the installation location for the removable cartridge magazine170). Some embodiments are implemented so that the searching steps include transmitting an optical signal from an optical source of the proximity sensor(s)220, and detecting receipt of the optical signal by an optical sink of the proximity sensor(s)220after reflection of the optical signal off an object (e.g., the structural feature) in proximity to the proximity sensor(s)220. For example, such searching can include determining whether the optical signal is received by the optical sink at a magnitude exceeding a threshold level, where the threshold level can be set so that the magnitude of the received optical signal exceeds the threshold level only when the structural feature is present within a predefined distance range from the proximity sensor(s)220. In some embodiments, the steps can further cause the processor to direct the line camera210to optically profile a target feature (e.g., the “N” target420) of the structural feature in response to the cartridge presence indication indicating the corresponding removable cartridge magazine170is installed in the installation location. For example, the optical profiling can involve imaging and/or otherwise obtaining sufficient optical information to recognize and/or decode the target feature.

FIG. 4shows another partial storage library system400having an illustrative storage wall130, according to various embodiments. As shown, the storage wall130has space for three cartridge magazines170, and each cartridge magazine170has twelve magazine cells175for holding media cartridges110. Some conventional storage library systems400include multiple types of targeting features that can have different uses. In the illustrative storage wall130, each location for a cartridge magazine170can include a “No Magazine” label410. The “No Magazine” label410can be affixed to the storage wall130so that it is visible to one or more sensors of the robotic assembly120when no cartridge magazine170is present in that location, and so that it is hidden behind a cartridge magazine170when a cartridge magazine170is present in the location. Some storage library systems400also include an “N” target420, or the like, on each cartridge magazine170. For example, the “N” target420can be a plastic target integrated into each cartridge magazine170and shaped with features (e.g., precise straight and angled lines substantially arranged in an ‘N’ shape) that can facilitate precise positioning of the robotic assembly120with respect to the cartridge magazine170. Some storage library systems400can also include cartridge barcode labels430and/or other targeting features.

As described above, the storage library system400can include a robotic assembly120with a line camera210. The line camera210is conventionally used to read and interpret labels, such as the “No Magazine” labels410(shown as a barcode), the “N” targets420, the cartridge barcode labels430, etc. The line camera210is typically used for such tasks because the optical information it receives can be decoded for interpreting barcode data, for precision locating of the robotic assembly120, etc. However, as noted above, the line camera210can typically be optimized for a particular focal plane (it may be too expensive or otherwise impractical or undesirable to design the camera with multiple or adjustable focal planes), so that the line camera210may not be capable of reliably reading targeting features (e.g., barcodes) in multiple focal planes. For example, the line camera210can be optimized to read cartridge barcode labels430and “N” targets420, both of which may be appreciably closer than the “No Magazine” labels410on the a storage wall130(e.g., four inches closer to the line camera210). Accordingly, the “No Magazine” label410may be out of the focal plane of the line camera210and may not be reliably read in some cases. For example, in operation, the line camera210can be used conventionally to determine whether a cartridge magazine170is present by looking for the “N” target420. If the “N” target420is not found, the line camera210can look for the “No Magazine” label410. However, poor focus and/or other line camera210issues can cause a false response. For example, features of the “No Magazine” label410can be misinterpreted as features of the “N” target420, neither the “N” target420nor the “No Magazine” label410can be detected, etc. In these and other cases, it can be uncertain whether there is or is not, in fact, a cartridge magazine170; or if, alternatively, there is a problem with the line camera210and/or its data. Some conventional approaches attempt to find the cartridge magazine170multiple times, seeking to mitigate false results. However, such approaches can still yield false results if there is an issue with the line camera210, and/or can cause auditing of cartridge magazines170to take an undesirably long time.

While the line camera210can enable performance of tasks by detecting and interpreting target features, the proximity sensor220of the robotic assembly120can typically only determine whether there is something in proximity thereto. For example, the proximity sensor220is typically used to detect whether a magazine cell175is occupied or empty in response to detecting whether something or nothing is in a particular magazine cell175location, respectively. However, such a detection typically still relies on the line camera210, for example, to have previously oriented the robotic assembly120(and thereby the proximity sensor220) to the cartridge magazine170. Thus, because of the inability of the proximity sensor220to read and interpret target features like the “N” target420, and the resulting inability of the proximity sensor220to precisely orient the robotic assembly120to a cartridge magazine170, the proximity sensor220has not conventionally been used to audit cartridge magazines170. As described herein, embodiments use the proximity sensor220in the auditing of cartridge magazines170, at least to provide a threshold determination of whether a cartridge magazine170is present. Some embodiments can be implemented without “No Magazine” labels410. For example, the auditing can be performed by the proximity sensor220, after which the line camera210can be used to locate the “N” target420(or other suitable feature) for orienting the robotic assembly120and/or enabling other tasks.

FIG. 5shows an illustrative portion of a storage library system500, such as the one shown inFIG. 2. In particular, the proximity sensor220of the robotic assembly120is shown positioned to detect presence of a cartridge structural feature. For example, the cartridge magazines170can have a structural feature at one or both ends that can include the “N” target420. As shown, the structural feature is relatively large (e.g., relatively thick and wide) and can appreciably protrude from surrounding structure. Such a feature can easily be detected by a proximity sensor220without precise location of the robotic assembly120. This can be in contrast to thin structural edges and/or other relatively small features, which may easily be missed by the proximity sensor220when the robotic assembly120is slightly misaligned with respect to the cartridge magazines170and/or the storage wall130.

As described above, having made a preliminary determination with the proximity sensor220that a cartridge magazine170is present, the line camera210can be used to acquire additional optical information. The additional optical information can be used, for example, precisely to orient (e.g., position, align, etc.) the robotic assembly120, to recognize the “N” target420, to read and decode one or more cartridge barcode labels430, etc. For the sake of added clarity,FIG. 6shows an illustrative portion of a storage library system600, such as the one shown inFIG. 2, with the line camera210of the robotic assembly120positioned to detect presence of the “N” target420.

FIG. 7shows a flow diagram of an illustrative method700for auditing removable cartridge magazines in a storage library system, according to various embodiments. Some embodiments of the method700can operate in context of the systems described above with reference toFIGS. 1-6. Embodiments of the method700can begin at stage704by moving a proximity sensor to an audit location in the storage library system. The audit location can correspond to an installation location for a removable cartridge magazine (e.g., one of multiple locations in a storage wall). As described above, the proximity sensor can be integrated with a robotic assembly operable to ferry media cartridges in the storage library system.

At stage708, embodiments can search, with the proximity sensor, for a structural feature that is present only when a corresponding removable cartridge magazine is installed in the installation location. For example, as described above, the structural feature can be integrated into the cartridge magazine (e.g., as a wall, or the like). In some implementations, searching for the structural feature can include transmitting an optical signal from an optical source of the proximity sensor and detecting receipt of the optical signal by an optical sink of the proximity sensor after reflection of the optical signal off an object in proximity to the proximity sensor. In some such instances, the searching further includes determining whether the optical signal is received by the optical sink at a magnitude exceeding a threshold level. For example, the threshold level can be set so that the magnitude of the received optical signal exceeds the threshold level only when the structural feature is present within a predefined distance range from the proximity sensor.

At stage712, embodiments can output a cartridge presence indication in response to the searching at stage708. The cartridge presence indication can indicate that the corresponding removable cartridge magazine is installed in the installation location when the structural feature is found; and the cartridge presence indication can indicate that the corresponding removable cartridge magazine is not installed in the installation location when the structural feature is not found. Some embodiments can perform further auditing related tasks in response to detecting presence of the cartridge magazine by the proximity sensor. For example, at stage716, embodiments can optically profile (e.g., with a line camera integrated with the robotic assembly) a target feature (e.g., an “N” target) of the structural feature in response to the cartridge presence indication indicating the corresponding removable cartridge magazine is installed in the installation location.

The methods disclosed herein comprise one or more actions for achieving the described method. The method and/or actions may be interchanged with one another without departing from the scope of the claims. In other words, unless a specific order of actions is specified, the order and/or use of specific actions may be modified without departing from the scope of the claims.

The various operations of methods and functions of certain system components described above may be performed by any suitable means capable of performing the corresponding functions. The means may include various hardware and/or software component(s) and/or module(s), including, but not limited to a circuit, an application specific integrated circuit (ASIC), or processor. For example, logical blocks, modules, and circuits described may be implemented or performed with a general purpose processor, a digital signal processor (DSP), an ASIC, a field programmable gate array signal (FPGA), or other programmable logic device (PLD), discrete gate, or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any commercially available processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

The steps of a method or algorithm or other functionality described in connection with the present disclosure, may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in any form of tangible storage medium. Some examples of storage media that may be used include random access memory (RAM), read only memory (ROM), flash memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM and so forth. A storage medium may be coupled to a processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. A software module may be a single instruction, or many instructions, and may be distributed over several different code segments, among different programs, and across multiple storage media. Thus, a computer program product may perform operations presented herein. For example, such a computer program product may be a computer readable tangible medium having instructions tangibly stored (and/or encoded) thereon, the instructions being executable by one or more processors to perform the operations described herein. The computer program product may include packaging material. Software or instructions may also be transmitted over a transmission medium. For example, software may be transmitted from a website, server, or other remote source using a transmission medium such as a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technology such as infrared, radio, or microwave.

Other examples and implementations are within the scope and spirit of the disclosure and appended claims. For example, features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations. Also, as used herein, including in the claims, “or” as used in a list of items prefaced by at least one of indicates a disjunctive list such that, for example, a list of “at least one of A, B. or C” means A or B or C or AB or AC or BC or ABC (i.e., A and B and C). Further, the term “exemplary” does not mean that the described example is preferred or better than other examples.

Various changes, substitutions, and alterations to the techniques described herein can be made without departing from the technology of the teachings as defined by the appended claims. Moreover, the scope of the disclosure and claims is not limited to the particular aspects of the process, machine, manufacture, composition of matter, means, methods, and actions described above. Processes, machines, manufacture, compositions of matter, means, methods, or actions, presently existing or later to be developed, that perform substantially the same function or achieve substantially the same result as the corresponding aspects described herein may be utilized. Accordingly, the appended claims include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or actions.