Abstract:
An apparatus includes: a media; a head over the media; a read channel, coupled to the head, configured to extract data from the media; control circuitry, coupled to the read channel, configured to execute a read command; and wherein the read channel is further configured to: generate, based on extracting the data from the media, a data condition indicator, and provide, for use by the control circuitry, the data and the data condition indicator.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Patent Application Ser. No. 62/028,761 filed Jul. 24, 2014, and the subject matter thereof is incorporated herein by reference thereto. 
    
    
     TECHNICAL FIELD 
     An embodiment relates generally to an electronic system, and more particularly to a system for media scan. 
     BACKGROUND 
     Modern consumer and industrial electronic devices require storage of information, such as digital photographs, electronic mail, calendar, or contacts. These devices can be electronic systems, such as notebook computers, desktop computers, servers, televisions, and projectors, and are providing increasing levels of functionality to support modern life. Preserving the user data stored in the storage devices is of the utmost importance. 
     As recording technologies advance in hard disk drives, the Tracks-Per-Inch (TPI) has increased. This has become increasingly challenging to maintain the writer element over the center of the track as the tracks have become closer together. Manufacturing processes have recorded a per track position reference for the entire media. The per track position reference can be susceptible to transient media flaws caused by debris on the media surface. When the per track position reference is recorded in the presence of transient debris, the tracks can be susceptible to unreliable data read back due to mis-positioning of the per track position reference. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1A, 1B, and 1C  show an operational diagram of an electronic system with media scan according to one of the embodiments. 
         FIG. 2  shows a servo control system, of the electronic system  100 , for generating a position error signal (PES), in accordance with an embodiment. 
         FIG. 3  is a functional block diagram of an HDI detection engine, for manufacturing media scan, in an embodiment. 
         FIG. 4  provides an exemplary PES waveform of one of the embodiments of a HDI detection engine. 
         FIG. 5  provides an exemplary HDI scan waveform of one of the embodiments of the HDI detection engine. 
         FIG. 6  shows a media map as recorded by the HDI detection engine in an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Storage systems can include storage devices, such as hard disk drives (HDD), solid state drives (SSD), hybrid drives, and optical storage devices. During the manufacturing processes, the foundation is laid for the performance and data reliability of the storage systems. The management of the media is a key piece the functional preparation of the end product. Debris or damage to the media should be detected and blocked from use in order to preserve data reliability and prevent subsequent damage to the head. 
     While the manufacturing scan activity has been extremely beneficial, it nevertheless has not yet been able to accommodate the transient nature of debris or media damage caused by head-disk interaction (HDI). HDDs have demonstrated that over 60% of failed drives are caused by head wear, as a result of excessive usage, damage from debris, and head-disk interaction caused by rapid changes in flying height due to damaged areas. As a result, the detection and avoidance of these areas of debris and media damage can extend the life and performance of the storage system. 
     A need still remains for an electronic system as various embodiments with media scan mechanism for providing reliable data while not prematurely wear-out the head or spreading debris across additional areas of the media. In view of the ever-increasing commercial competitive pressures, along with growing consumer expectations and the diminishing opportunities for meaningful product differentiation in the marketplace, it is increasingly critical that answers be found to these problems. Additionally, the need to reduce costs, improve efficiencies and performance, and meet competitive pressures adds an even greater urgency to the critical necessity for finding answers to these problems. 
     Solutions to these problems have been long sought but prior developments have not taught or suggested any solutions and, thus, solutions to these problems have long eluded those skilled in the art. 
     Certain embodiments have other steps or elements in addition to or in place of those mentioned above. The steps or elements will become apparent to those skilled in the art from a reading of the following detailed description when taken with reference to the accompanying drawings. 
     The following embodiments are described in sufficient detail to enable those skilled in the art to make and use the various embodiments. It is to be understood that other embodiments would be evident based on the present disclosure, and that system, process, or mechanical changes can be made without departing from the scope of an embodiment. 
     In the following description, numerous specific details are given to provide a thorough understanding of the various embodiments. However, it will be apparent that the various embodiments can be practiced without these specific details. In order to avoid obscuring an embodiment, some well-known circuits, system configurations, and process steps are not disclosed in detail. 
     The drawings showing embodiments of the system are semi-diagrammatic, and not to scale and, particularly, some of the dimensions are for the clarity of presentation and are shown exaggerated in the drawing figures. Similarly, although the views in the drawings for ease of description generally show similar orientations, this depiction in the figures is arbitrary for the most part. Generally, the various embodiments can be operated in any orientation. 
     Referring now to  FIGS. 1A, 1B, and 1C , therein are shown an operational diagram of an electronic system  100  according to an embodiment. The electronic system  100  can represent an apparatus for one of the various embodiments. Various embodiments can include the embodiment depicted in  FIGS. 1A, 1B, and 1C  which by way of an example is shown as a hard disk drive although it is understood that the electronic system  100  can be a tape drive, a solid-state hybrid disk drive, or other magnetic media-based storage device. Further for example, the electronic system  100  can represent a desktop computer, a notebook computer, a server, a tablet, a television, a household appliance, or other electronic systems utilizing magnetic media storage. 
     The electronic system  100  including a head  102  actuated over a media  104 . The head  102  can be mounted to a flex arm  118  attached to an actuator arm  122 . The head  102  ( FIG. 1B ) can optionally include a laser  106  for heating the media  104  during part of a write process (e.g., the head is part of an Energy-Assisted Magnetic Recording (EAMR) drive). A flying height  108  can be adjusted (e.g., by use of a heater element in the head not shown in  FIG. 1B ) while writing data to the media  104  or as an error recovery process during reading from the media  104 . Also in an embodiment of  FIG. 1B , the head  102  comprises a write element  110  (e.g., an inductive coil) and a read element  112  (e.g., a magnetoresistive read element). 
     The media  104  is a structure for storing information on data tracks  124 . For example, the media  104  can be made of an aluminum alloy, ceramic/glass, or a similar non-magnetic material. The top and bottom surfaces of the media  104  can be covered with magnetic material deposited on one or both sides of the media  104  to form a coating layer capable of magnetization. As an example, the media  104  can be a disk platter for one embodiment of the electronic system  100  as a rotating storage system, such as a hard disk drive (HDD). As a further example, the media  104  can be a linear magnetic strip for one embodiment of the electronic system  100  as a linear storage system, such as a tape drive. 
     The laser  106 , as an example, can be a laser diode or other solid-state based lasers. In addition, embodiments can employ any suitable techniques for focusing the laser  106  on the media  104 , such as a suitable waveguide, magnifying lens, or other suitable optics. The laser  106  is increased to a write power in order to heat the disk, thereby decreasing the coercivity of the media  104  so that the data is written more reliably on the data tracks  124 . 
     The spindle motor  116  can rotate the media  104 , about a center of the media  104 , at constant or varying speed  107 . For illustrative purposes, the spindle motor  116  is described as a motor for a rotation, although it is understood that the spindle motor  116  can be other actuating motors for a tape drive, as an example. 
     As examples, a head actuation motor (HAM)  130  can be a voice coil motor assembly, a stepper motor assembly, or a combination thereof. The head actuation motor (HAM)  130  can generate a torque or force for positioning the head  102 . The HAM  130  can operate in conjunction with a piezoelectric control on the head  102 . 
     A tapered end of the flex arm  118  can support the head  102 . The flex arm  118  can be mounted to the actuator arm  122 , which is pivoted around a bearing assembly  126  by the torque generated by the head actuation motor  130 . The head  102  can include a single instance of the write element  110  and a single instance of the read element  112  that is narrower than the write element  110 . The head  102  can fly over the media  104  at a dynamically adjustable span of the flying height  108 , which represents a vertical displacement between the head  102  and the media  104 . The head  102  can be positioned by the flex arm  118  and the actuator arm  122  and can have the flying height  108  adjusted by control circuitry  138 . 
     The head  102  can be positioned over the media  104  along an arc shaped path between an inner diameter of the media  104  and outer diameter of the media  104 . For illustrative purposes, the actuator arm  122  and the head actuation motor  130  are configured for rotary movement of the head  102 . The actuator arm  122  and the head actuation motor  130  can be configured to have a different movement. For example, the actuator arm  122  and the head actuation motor  130  could be configured to have a linear movement resulting in the head  102  traveling along a radius of the media  104 . 
     The head  102  can be positioned over the media  104  to create magnetic transitions in the media  104  or detect magnetic transitions from the data tracks  124  recorded in the coating layer that can be used to represent written data or read data, respectively. The position of the head  102  and the speed  107  of the media  104  can be controlled by the control circuitry  138 . Examples of the control circuitry  138  can include a processor, an application specific integrated circuit (ASIC) an embedded processor, a microprocessor, a hardware control logic, a hardware finite state machine (FSM), a digital signal processor (DSP), digital circuitry, analog circuitry, optical circuitry, or a combination thereof. The control circuitry  138  can also include memory devices, such as a volatile memory, a nonvolatile memory, or a combination thereof. For example, the nonvolatile storage can be non-volatile random access memory (NVRAM) or Flash memory and a volatile storage can be static random access memory (SRAM) or dynamic random access memory (DRAM). 
     A system interface  140  can couple the control circuitry  138  to a host electronics (not shown). The system interface  140  can transfer interface tasks  142  between the host electronics and the control circuitry  138 . The interface tasks  142  can be encoded or decoded by the control circuitry  138  in preparation for transfer to or from the media  104 . 
     The control circuitry  138  can be configured to control the spindle motor  116  for adjusting the speed  107  of the media  104 . The control circuitry  138  can be configured to cause the head  102  to move relative to the media  104 , or vice versa. The control circuitry  138  can be configured to control the speed  107  of the media  104  and the position of the head  102  by reading servo sectors  114  strategically placed on the media  104 . The servo sectors  114  can be recorded on the media  104  during a manufacturing process. The control circuitry  138  can also be configured to scan the media  104  in order to detect the location of debris on the media  104  that can be caused by head-disk interaction. 
     In an embodiment, the electronic system  100  further comprises control circuitry  138  configured to execute the flow diagrams of  FIG. 1C . As an example, actions  144  to  150  can represent the flow diagram where an embodiment is employing a data management mechanism for maintaining data integrity. 
     In an action  144 , the head  102  is flown over the media  104  during execution by the electronic system  100 , such as a manufacturing test fixture, a hard disk drive, a tape drive, or a hybrid drive. 
     In an action  146 , the control circuitry can be configured to control a head actuation motor for positioning the head over the media. The control circuitry  138  can detect the actual position of the head relative to the intended position of the head by reading the servo sectors and monitoring a position error signal (PES). 
     In an action  148 , the control circuitry can be configured to detect a head-disk interaction based at least in part on a position error signal (PES) of the head. It is understood that an instantaneous increase in the PES can indicate debris or media damage. The locations of the PES anomaly can be stored for further analysis. 
     In an action  150 , the control circuitry can be configured to generate a media map of locations in the media having the PES based at least in part on the detected HDI. The media map can include the location and approximate size of the damaged area on the media. The media map can be used in the allocation of spare tracks and sectors and to establish keep-out areas reserved from use during normal user operations. 
     It has been discovered that an embodiment of the electronic system  100  can improve manufacturing yield. The electronic system  100  can provide a manufacturing mechanism that verifies the condition of the media  104  prior to recording the reference track location for user operation. Embodiments can allow the manufacturing process to identify and reserve damaged areas of the media  104  while generating the media map, which can be utilized in the normal operation of the electronic system  100  to avoid known media damage locations. 
     Referring now to  FIG. 2 , therein is shown a servo control system  201 , of the electronic system  100 , for generating a position error signal (PES)  210 , in accordance with an embodiment. The servo control system  201  controls the head actuation motor  130  in order to position the head assembly  102  radially over the media  104 . A read/write channel  202  demodulates the read signal  128  from the servo sectors  114  into an estimated position  204  for the head assembly  102  relative to the data track  124  of  FIG. 1A  on the media  104 . The estimated position  204  is applied to a first adder  206  for subtracting a reference position  208  in order to generate the PES  210 . 
     A magnitude of the PES  210  can be monitored by the control circuitry  138  for generating the HAM control signal  120  to prevent large tracking errors normally observed when debris is present on the media  104 . The control circuitry  138  can also record the location of severe occurrences of the PES  210  based on thresholds established for the detection of the head-disk interaction. 
     It has been discovered that the debris caused by the head-disk interaction (HDI) can modify the reference position  208  during the manufacturing process. If the modification of the reference position  208  is not addressed during the manufacturing process, long term data reliability problems can occur. Embodiments of the electronic system  100  of  FIG. 1A  can allow detection of the debris caused by the head-disk interaction (HDI) in order to allow the manufacturing process the criteria to disqualify the damaged data tracks  124 . 
     Referring now to  FIG. 3 , therein is shown a functional block diagram of an HDI detection engine  301 , for manufacturing media scan, in an embodiment. The functional block diagram of the HDI detection engine  301  may be implemented in the control circuitry  138 . In an embodiment, the HDI detection engine  301  can include a number of components/modules as shown. Those skilled in the art will recognize that some components/modules may be combined into fewer components/modules or implemented as more components/modules while achieving the same results. As shown, the HDI detection engine  301  can include a PES input  302  to a band-pass filter  304 , such as an 8 th  order infinite impulse response (IIR) filter. The PES input  302  may be generated by controlling the head actuation motor for positioning the head over the media and processing read signals from the head as it flies over parts of the media. The band-pass filter  304  can receive the PES  210  in a raw state and pass only an HDI band  306 , which can contains a particular frequency range which is determined by the HDI sensitive suspension mode of the flex arm  118  of  FIG. 1A . By way of an example, the HDI band  306  can be in the range 17.5 to 21.5 kHz. It is understood that other frequency ranges are possible and that adjustments of the parameters of the band-pass filter  304  can change to a different frequency range. 
     The HDI band  306  can be an input to an amplitude detector  308 , such as a first order low-pass filter, for performing a full-wave rectification of the HDI band  306 . The amplitude detector  308  can produce the PES amplitude  310 . A peak detector  312  can monitor the PES amplitude  310  for detecting a PES peak  313 . 
     A wedge counter  314  can be coupled to the peak detector  312  for monitoring the wedge number of the servo sectors  114  of  FIG. 1A . The peak detector  312  can also be coupled to an HDI threshold checker  316 . The HDI threshold checker  316  can perform a hard threshold check  318  to determine if the PES peak  313  exceeds a hard HDI threshold  318 , a soft HDI threshold  320 , or a combination thereof. 
     The activation of the hard HDI threshold  318  or the soft HDI threshold  320  can cause the current sector number output of the wedge counter  314  to be written to a memory log  322  for further processing as a potential problem location or transient error. The hard HDI threshold  318  and the soft HDI threshold  320  can be adjusted by the control circuitry  138  of  FIG. 1A . The hard HDI threshold  318  can be a level at which the detection of the PES peak  313  indicates that a solid repeatedly detectable error has been found that can be caused by an HDI media damage. The soft HDI threshold  320  can be a level at which the detection of the PES peak  313  indicates that a transient and possibly moveable error exists on the media  104  of  FIG. 1A , which could be caused by debris in the data tracks  124 . The presence of the debris in the data tracks  124  can indicate the presence of the HDI damage in a nearby one of the data tracks  124 . The detection of the PES peak  313  over the soft HDI threshold  320  but not over the hard HDI threshold  318  can indicate a transient or temporary error in the data tracks  124 . In some cases any debris that can cause the soft HDI threshold  320  to be activated might be swept from the media  104  in subsequent scan attempts. The memory log  322  can be stored in a volatile or non-volatile memory device, a communications port for manufacturing interface, a reserved area of the media  104 , or a combination thereof. 
     The output of the hard HDI threshold  318  can activate a retry counter module  324 . The retry counter module  324  can be coupled to a scan window generator  326 . The scan window generator  326  can limit the samples of the PES  210  to a fixed number of the servo sectors  114 . The effect of the HDI is localized to the area around the point of contact between the head  102  of  FIG. 1B  and the media  104  of  FIG. 1B . By limiting the analysis to a given number of the servo sectors  114 , a detailed location of the HDI can be identified. 
     The retry counter module  324  can hold the scan window generator  326  from altering the sampling window of the PES input  302 . The retry counter module  324  can be configured to halt the progression of the scan window generator  326  until a terminal retry count is reached or the hard HDI threshold  318  is not detected on one of the retries. If the retry counter module  324  is initiated by the detection of the hard HDI threshold  318 , but it is not asserted on a subsequent retry, the content of the wedge counter  314  remains in the memory log  322  as a transient error. If the hard HDI threshold  318  is asserted on each of the scans until the terminal count is detected, the wedge location output of the wedge counter  314  is written to a map-out memory  328 . The map-out memory  328  can be a volatile or non-volatile memory device, a communications port for manufacturing interface, a reserved area of the media, or a combination thereof. The contents of the map-out memory  328  can be collected throughout the manufacturing process and the associated data tracks  124  of  FIG. 1A  are deallocated from the user capacity. The deallocation of the data tracks  124  can help prevent the spread of the debris and additional media damage caused by the head-disk interaction. 
     A track counter module  330  can keep a tally of the number of the data tracks  124  of  FIG. 1A  that have been scanned on the media  104 . The track counter module  330  can be conditioned to halt the scan window generator  326  when a terminal track count is achieved. The track counter module  330  can also initialize the scan window generator  326  when a new track scan is initiated. 
     It has been discovered that the control circuitry  138  can configure the HDI detection engine  301  to adjust the levels of the hard HDI threshold  318 , the soft HDI threshold  320 , the retry counter module  324 , and the parameters of the band-pass filter  304 . The control circuitry  138  can also assign the location and attributes of the memory log  322  and the map-out memory  328 . The adjustments allow the embodiments to be adapted for different mechanical structures of the head  102  and the flex arm  118 . The control circuitry  138  can adjust the configuration in order to adapt to changes in the flying height  108  of  FIG. 1B  that might be required in different embodiments. 
     Referring now to  FIG. 4 , therein is shown an exemplary PES waveform  401  of one of the embodiments of a HDI detection engine in an embodiment. The exemplary PES waveform  401  depicts wedge numbers  402  along the horizontal axis and the PES input  302  along the vertical axis. An example of an HDI scan window  404  is shown sampling between wedge number  20  and wedge number  45  as an area of suspected HDI. 
     The PES input  302  can have a positive or negative sign indicating the direction of the position error relative to the center of the data track  124  of  FIG. 1A . If the head  102  of  FIG. 1A  is positioned on a data track  124  with debris or damage to the media  104  of  FIG. 1A , the magnitude of the PES input  302  can exceed the hard HDI threshold  318  of  FIG. 3  or the soft HDI threshold  320  of  FIG. 3 . 
     The width of the HDI scan window  404  can be adjusted by the control circuitry  138  of  FIG. 1A  in order to verify the detection of the debris of media damage. As the scan window generator  326  increments across the wedge numbers  402 , the width of the HDI scan window  404  can be adjusted in order to refine the identification of the location of the damage to the media  104 . The HDI scan window  404  is shown between wedges  20  and  45  as an example only and the width of the HDI scan window  404  can differ. It is understood that the configuration of the HDI scan window  404  can be supported by an analysis algorithm that can dynamically adjust the width of the HDI scan window  404 . 
     The HDI scan window  404  can incrementally move across the wedge numbers  402  of the data track  124  under analysis. If none of the PES input  302  exceeds the hard HDI threshold  318  or the soft HDI threshold  320 , the HDI scan window  404  will reset to the beginning of the wedge numbers  402  as the track counter module  330  of  FIG. 3  increments to the beginning of the next instance of the data track  124 . 
     It has been discovered that the HDI scan window  404  can be adjusted dynamically to further identify the location of any debris or damage to the media  104 . Each of the wedge numbers  402  that is identified as having exceeded the hard HDI threshold  318  or the soft HDI threshold  320  can be saved in the memory log  322  of  FIG. 3  or the map-out memory  328  of  FIG. 3  for later configuration of the available instances of the data tracks  124  on the media  104 . 
     Referring now to  FIG. 5 , therein is shown an exemplary HDI scan waveform  501  of one of the embodiments of the HDI detection engine  301  in an embodiment. The HDI scan waveform  501  depicts the wedge numbers  402  on the horizontal axis and the PES amplitude  310  on the vertical axis. 
     An HDI location  502  can be identified when the PES amplitude  310  exceeds the hard HDI threshold  318 . The verification of the HDI location  502  can include multiple retries of the sampling of the HDI scan window  404  of  FIG. 4 . When all of the retries identify the wedge numbers  402  included in the HDI scan window  404  exceed the hard HDI threshold  318 , the range of the wedge numbers included in the HDI scan window can be listed in the map-out memory  328  of  FIG. 3 . Any of the data tracks  124  of  FIG. 1A  having the HDI location  502  can be avoided in the final configuration of the user capacity in order to prevent the spread of the debris or creating additional damage to the media  104 . 
     It is understood that the values indicated for the hard HDI threshold  318  or the soft HDI threshold  320  is an example only and other values can be used as appropriate to the electronic system  100  of  FIG. 1A . Any instance of the PES amplitude  310  exceeding only the soft HDI threshold  320  can be listed to the memory log  322  of  FIG. 3  as a suspected HDI location (not shown), which might not be included in the user capacity provided by the manufacturing process. In contrast any instance of the PES amplitude  310  exceeding only the hard HDI threshold  318  is detected as a permanent area of damage that can be removed from the user capacity provided by the manufacturing process. 
     Referring now to  FIG. 6 , therein is shown a media map  601  as recorded by the HDI detection engine  301  in an embodiment. The media map  601  depicts a media extent  602  indicating the outer range of the media  104  of  FIG. 1A . The media extent  602  can represent the data track  124  of  FIG. 1A  that is closest to the outer diameter of the media  104 . 
     The HDI location  502  can be a single occurrence of the debris or damage to one of the data tracks  124  on the media  104  or it can be an HDI cluster  604  of such occurrences that can span multiple of the data tracks  124 . The occurrence of the HDI cluster  604  can present a risk to long term reliability if the damaged area of the data tracks  124 , within the HDI cluster  604 , are accessed. The debris that can be generated by the HDI cluster  604  can be spread by attempted use of the damaged area of the data tracks  124 . An embodiment of the HDI detection engine  301  of  FIG. 3  can provide the necessary information to avoid the HDI cluster  604  during user operations and thereby extend the usable life of the electronic system  100  of  FIG. 1A . 
     A suspected HDI  606  can be identified when the PES amplitude  310  of  FIG. 3  exceeds the soft HDI threshold  320  of  FIG. 3  but does not exceed the hard HDI threshold  318  of  FIG. 3 . The identification of the soft HDI  606  can be useful in avoiding potentially damaged areas of the media  104  and preventing long term data reliability risk. 
     It is understood that the embodiment of the media map  601  can be different. It could be captured in an associated list, table, or other graphical form. The media map  601  can be maintained in the manufacturing process, stored in a reserved area of the media  104 , or a combination thereof. The media map  601  can form the basis of a spare track and sector strategy operable by the user in the execution of normal field operation. 
     Any suitable control circuitry may be employed to implement the flow diagrams in the above embodiments, such as any suitable integrated circuit or circuits. For example, the control circuitry may be implemented within a read channel integrated circuit, or in a component separate from the read channel, such as a disk controller, or certain operations described above may be performed by a read channel and others by a disk controller. In one embodiment, the read channel and disk controller are implemented as separate integrated circuits, and in an alternative embodiment they are fabricated into a single integrated circuit or system on a chip (SOC). In addition, the control circuitry may include a suitable preamp circuit implemented as a separate integrated circuit, integrated into the read channel or disk controller circuit, or integrated into a SOC. In addition, any of the above described modules and components may be implemented in firmware, software, hardware, or any combination thereof. 
     In one embodiment, the control circuitry comprises a microprocessor executing instructions, the instructions being operable to cause the microprocessor to perform the flow diagrams described herein. The instructions may be stored in any computer-readable medium. In one embodiment, they may be stored on a non-volatile semiconductor memory external to the microprocessor, or integrated with the microprocessor in a SOC. In another embodiment, the instructions are stored on the disk and read into a volatile semiconductor memory when the disk drive is powered on. In yet another embodiment, the control circuitry comprises suitable logic circuitry, such as state machine circuitry. 
     The various features and processes described above may be used independently of one another, or may be combined in various ways. All possible combinations and subcombinations are intended to fall within the scope of this disclosure. In addition, certain method, event or process blocks may be omitted in some implementations. The methods and processes described herein are also not limited to any particular sequence, and the blocks or states relating thereto can be performed in other sequences that are appropriate. For example, described tasks or events may be performed in an order other than that specifically disclosed, or multiple may be combined in a single block or state. The example tasks or events may be performed in serial, in parallel, or in some other manner. Tasks or events may be added to or removed from the disclosed example embodiments. The example systems and components described herein may be configured differently than described. For example, elements may be added to, removed from, or rearranged compared to the disclosed example embodiments. 
     While certain example embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions disclosed herein. Thus, nothing in the foregoing description is intended to imply that any particular feature, characteristic, step, module, or block is necessary or indispensable. Indeed, the novel methods and systems described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the methods and systems described herein may be made without departing from the spirit of the embodiments disclosed herein. 
     The resulting method, process, apparatus, device, product, and/or system is straightforward, cost-effective, uncomplicated, highly versatile, accurate, sensitive, and effective, and can be implemented by adapting known components for ready, efficient, and economical manufacturing, application, and utilization. Another important aspect of various embodiments is that they valuably supports and services the historical trend of reducing costs, simplifying systems, and increasing performance. 
     These and other valuable aspects of the various embodiments consequently further the state of the technology to at least the next level. 
     While the various embodiments have been described in conjunction with a specific best mode, it is to be understood that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the aforegoing description. Accordingly, the embodiments are intended to embrace all such alternatives, modifications, and variations that fall within the scope of the included claims. All matters set forth herein or shown in the accompanying drawings are to be interpreted in an illustrative and non-limiting sense.