Abstract:
A data storage device may be destroyed by suspending a transducing head above a data storage medium prior to inducing contact of the transducing head with a first layer of the data storage medium in response to a signal from a controller. Deflection of the transducing head can then be increased to penetrate to a destroy depth in a second layer of the data storage medium that is maintained while the data storage medium spins. The controller may then issue at least one data read command to access data from the data storage medium and when a data read error is received, the data storage medium and transducing head can be verified as destroyed and incapable of accessing data previously written to the data storage medium.

Description:
RELATED APPLICATION 
     The present application makes a claim of domestic priority under 35 U.S.C. 119(e) to U.S. Provisional Application No. 62/430,619 filed Dec. 6, 2016, the contents of which are hereby incorporated by reference. 
    
    
     SUMMARY 
     A data storage device may be destroyed, in accordance with some embodiments, by suspending a transducing head above a data storage medium prior to inducing contact of the transducing head with a first layer of the data storage medium in response to a signal from a controller. Deflection of the transducing head is then increased to penetrate to a destroy depth in a second layer of the data storage medium. The destroy depth is maintained while the data storage medium spins and the controller issues at least one data read command to access data from the data storage medium. When a data read error is received, the data storage medium and transducing head is verified as destroyed and incapable of accessing data previously written to the data storage medium. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block representation of an example portion of a data storage system configured and operated in accordance with some embodiments. 
         FIG. 2  shows a cross-sectional block representation of a portion of an example data storage device capable of being utilized in the data storage system of  FIG. 1 . 
         FIG. 3  displays a block representation of a portion of an example data storage device operated as part of the data storage system of  FIG. 1 . 
         FIG. 4  represents a portion of an example data storage device constructed and operated in accordance with some embodiments. 
         FIG. 5  illustrates a block representation of a portion of an example data storage device that can employ various embodiments of the present disclosure. 
         FIG. 6  is a top view line representation of a portion of an example data storage device employed in the data storage system of  FIG. 1 . 
         FIG. 7  provides a flowchart for an example data storage device destruction routine that may be executed by the data storage system of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     Data is being generated, transferred, and stored in greater volumes and with greater speed than ever before. The proliferation of fast data processing and large data storage capacities has allowed greater amounts of user-unique, personal data to be intentionally, or unintentionally stored in local and remote data storage devices. The trend of remotely storing large amounts of data, such as with cloud computing, further proliferates the dissemination of personal data, which may be confidential and highly sensitive. 
     Increased amounts of available data storage capacity can correspond with large numbers of separate data storage devices that are collectively packaged. In the event a local, or remote, data storage device is to be retired, due to either degraded performance or failure, personal data may remain on the device and can be accessed by others. Hence, various embodiments are directed to a data storage device that can self-destruct to a degree where no previously stored data can be detected or recovered. 
       FIG. 1  illustrates a block representation of an example data storage system  100  that can utilize one or more data storage devices  102  in a local, or remote, structure. It is contemplated that the data storage device  102  can be any type, size, capacity, and speed, as facilitated by a local controller  104 , magnetic data storage medium  106 , and transducing head  108 . The controller  104  can direct data access operations of data writer  110  and data reader  112  portions of the transducing head  108  as well as operation of a suspension  114 , which can have a head-gimbal assembly (HGA) and actuating means. 
     Any number of data storage devices  102  can be interconnected locally or with one or more remote hosts  116 . A remote host  116 , such as a node, processor, or memory, can complement the local controller  104  or autonomously conduct operations of the data storage device  102  via a wired or wireless network  118 . The data storage system  100  can be autonomous or operate in concert with other data storage devices, servers, and systems to provide a data capacity, such as in a cloud computing environment. 
       FIG. 2  is a cross-sectional block representation of a portion of a data storage device  120  that may be employed in the data storage system  100  of  FIG. 1 . The data storage device  120  utilizes a suspension  114  to position the transducing head  108  on an air bearing  122  over selected data bits  124  stored in data tracks  126  on the data storage medium  106 . The suspension  114  can involve a load beam  128  and HGA  130  that allow the data writer  110  and reader  112  to magnetically access one or more data bits  124 . 
     While the suspension  114  can generally position the transducing head  108  above the data storage medium  106 , reduced air bearing  122  sizes and an imperfect top data storage medium surface can degrade the air bearing  122  and data access performance. Hence, the transducing head  108  can be articulated along the X-Z plane by a heater  132  that is directed by the controller  104  and powered by a preamp  134 . That is, an actuating means of the suspension  114  can control X-Y plane movement, as shown by arrow  136 , and a heater  132  can control X-Z plane movement, as shown by arrow  138 . 
     For most data access operations, the air bearing  122  is maintained at a particular separation distance, which may be as small as a few nanometers, by the suspension  114  and heater  132 . The transducing head  108  may also have one or more sensors dedicated to measuring fly height, such as a dual ended temperature coefficient of resistance (DETCR) sensor  140 . The DETCR sensor  140  can be utilized during fly height calibration and afterwards to detect thermal asperity (contact) events between the head  108  and storage medium  106 . As shown, the DETCR sensor  140  can have a greater relative size compared to the writer  110 , reader  112 , and heater  132 . 
     It is contemplated that the suspension  114 , DETCR  140 , and heater  132  can be used to maintain contact between the transducing head  108  and a top surface of the data storage medium  106 . However, conducting data access operations while the transducing head  108  contacts the data storage medium  106  can be plagued by structural and operational variability, particularly in high data density environments where the medium is spinning at 5000 rpm or more. Hence, contact between the transducing head  108  and data storage medium  106  is generally discouraged with the heater&#39;s main function being the prevention of head-medium contact. 
       FIG. 3  displays a block representation of a portion of a data storage device  150  where a transducing head  108  contacts a protective top layer  152  of the data storage medium  106 . It is noted that contact between the transducing head  108  and medium  106  can occur in a variety of manners, such as a leading edge, trailing edge, or any portion of an air bearing surface (ABS) engaging the protective layer  152 . 
     The controller  104  can employ any number of sensors, such as acoustic, vibration, and/or resistance sensors, to detect the head-medium contact. The controller  104  can, in some embodiments, can detect, or compute, the severity of the head-medium contact, which can be characterized as the depth  154  from the ABS of the medium  106 . Therefore, the controller  104  is able to distinguish that the transducing head  108  is in the protective layer  152  or in an underlying recording layer  156 . 
     While normal data storage device  150  operation would move the transducing head  108  to reduce and mitigate the damage done by the head-medium contact, such as through the creation of debris and hampered performance of the data writer  110  and/or reader  112 , various embodiments respond to detected head-medium contact with the protective top layer  152  by exacerbating head movement into the medium  106 . 
       FIG. 4  is a side view block representation of a portion of a data storage device  160  that expressly sends the transducing head  108  into the recording layer  146  of the data storage medium  106  to create as much debris  162  and damage to the device  160  as possible. While not limiting, the penetration of the transducing head  108  into the recording layer  146  can be facilitated by increasing the signal to the heater  132  compared to the signal associated with the protective layer depth of  FIG. 3 . It is contemplated that the heater signal is maxed to ensure that the transducing head  108  is gouging the data storage medium  106  with as much force as possible. 
     As a result of the induced head-medium contact, a trench  164  is created that is physically void of magnetic recording layer  146  material. Hence, the physical impact, and resultant heat, physically eliminates any data bits, and magnetic bit grains, in the path of the head  108 . While physical damage to the recording layer  146  is useful, the trauma associated with continuous, sporadic, and/or random contact with the recording layer  146  causes the transducing head to malfunction. For instance, the heat of physical contact with the recording layer  146  can melt electrical traces, remove magnetically sensitive portions of a data reader  112 , and disturb the shape of data writer components so that no data access operations can be conducted. Accordingly, the head-medium contact shown in  FIG. 4  causes both the transducing head  108  and data storage medium  106  to become inoperable, which protects any confidential data that may remain stored in the data storage medium  106 . 
     With the creation of debris  162  via the head-medium contact, an entire data storage device can be rendered inoperable (destroyed).  FIG. 5  represents a portion of an example data storage device  170  that has a plurality of data storage media  106  vertically stacked to spin about a common spindle  172 . It is noted that each data storage medium  106  is accessed by multiple transducing heads  108  that are separately controlled by respective suspensions  114 . 
     Through the creation of debris  162  from head-medium contact on as few as one recording surface  174 , the operation of all heads  108  and media  106  can be degraded to the point of being inoperable. That is, debris  162  contaminates every recording surface  174  of the data storage device  170  and eventually causes transducing head  108  damage and failure. Hence, a data storage device  170  can be destroyed by crashing less than all the transducing head  108  present in the device  170 . 
     In some embodiments, all the transducing heads  108  of the data storage device  170  are concurrently or consecutively crashed into the recording layers of the respective data storage media  106  to ensure no data access component of the data storage device  170  is operable. Such physical destruction can result in the production of debris  176  that are pieces of the transducing head  108 , reader  112 , writer  110 , heater  132 , DETCR  140 , and media  106 . While movement of the media  106  by the spindle  172  can disseminate debris throughout the device  170 , portions of the drive  170  may be configured to promote debris  176  dispersion, such as curvilinear interior device surfaces, magnets, and active mechanisms, like a fan. 
     It is contemplated that one or more transducing heads  108  are crashed into an adjacent data storage medium  106  while the medium is stationary. However, various embodiments simultaneously control motion of the data storage media  106  via the spindle  172  while the head(s)  108  gouge into the recording layer  146  in order to effect the maximum damage to the data storage device  170 . The top view line representation of an example data storage device  190  illustrates how a transducing head  108  can produce tracks  192  in the recording surface  174  of a data storage medium  106 . 
     While a single track  192  can be used to render the data storage device  190  inoperable, some embodiments strategically create multiple tracks  192  that each continuously extend into the recording layer of the recording surface  174 . With multiple tracks  192 , a controller  104  can produce different, or similar, track  192 , shapes, sizes, and depths by manipulating the head heater  132  as well as the spindle  172 . For example, a controller  104  may designate different tracks  192  to be different lengths  194  and/or depths into the recording layer  146 , as executed by the controller  104  issuing specific seek operations with the suspension  114  actuator while the medium  106  spins. 
     The ability to control the configuration of a track  192  allows for the controller  104  to produce partial or complete circles  196 , or ellipses, that follow one or more data tracks, as designated by non-user data stored in the medium  106 . A single track  192  may also follow a single data track or cross multiple different data tracks. As such, a controller  104  can orchestrate a pattern of separate tracks  192  that is asymmetrical or symmetrical radially, laterally across the X axis, or vertically across the Y axis. The use of multiple intersecting tracks  192  can ensure some regions of the recording surface  174  are destroyed, such as designated cache regions or physical block addresses assigned with personal and/or confidential data. The use of multiple tracks  192 , and or multiple passes along the same track  192  path, may further ensure the transducing head  108  penetrates into the recording layer  108  to the designated depth. 
     In a non-limiting example, the controller  104  performs at least one seek operation with the transducing head  108  that continuously extends from the ID to the OD while the medium  106  spins at a uniform speed, such as 5400 rpm. It is contemplated that the medium  106  spin velocity varies while a track  192  is being created and/or between the creation of tracks  192 , which can produce different track  192  shapes and cross-sectional profiles that can produce more, or less, debris  162 . 
       FIG. 7  provides an example device destruction routine  200  that can be carried out in accordance with various embodiments. At least one data access operation is carried out in step  202 , such as writing data to or reading data from a recording layer of a data storage medium. It is to be understood that step  202  is to be executed with a functioning data storage device that has been manufactured, tested, and employed by an end-user, such as a customer, that has previously stored user data to the data storage medium. 
     At some time after step  202 , a host issues a device destroy command that is received by a local controller in step  204  and triggers a first head heater signal to be supplied a heater in step  206  while the transducing head is positioned over a predetermined portion of the data storage medium, such as the ID or OD. It is noted that an additional step may be incorporated into routine  200  that specifically actuates the transducing head to a destroy position relative to the underlying recording surface. The first head heater signal causes the transducing head to come into contact with the protective top layer of the data storage medium that is detected in step  208 , which may occur by monitoring the position error signal of the head relative to servo data stored on the medium. 
     With the transducing head contacting the protective top layer, the controller may increase the head heater signal to a second signal strength in step  210  and/or alter the rate at which the data storage medium spins, as illustrated by optional, segmented step  212 . That is, the controller can conduct steps  210  and  212  independently, concurrently, or consecutively, to produce a gouge track ( 192 ) configuration where the transducing head continuously penetrates the recording layer of the data storage medium. For clarity, step  210  can maintain the first head heater signal or increase the signal to ensure the head penetrates through the top protective layer to the underlying recording layer. 
     Penetration of the head into the medium&#39;s recording layer is detected in step  214 , such as by sensing head deflection, head temperature, or spindle resistance. Reaching the prescribed medium depth prompts step  216  to perform at least one seek operation in accordance with the predetermined gouge track configuration, such as from the ID to the OD, or vice-versa. It is noted that step  216  can involve generating multiple different gouge tracks that may intersect, or not. 
     The execution of a gouge track pattern on the data storage medium may be accompanied by the dissemination of debris via a debris promoter. Next, step  222  issues at least one data read command. Such read command can be conducted at one or more regions of the data storage medium continuously, or periodically, to confirm the transducing head and/or the data storage medium is inoperable. In some embodiments, the back electromotive force (EMF) of the actuating suspension can be employed in step  218  to further apply pressure from the transducing head onto the data storage medium. The use of back EMF can allow step  218  to maintain, or increase, physical head-media contact even when all data readers are destroyed and return errors during step  218 . 
     Decision  220  utilizes the read commands of step  218  to verify that the gouge tracks and/or debris resulting from the gouge tracks have rendered the data storage device inoperable. Decision  220  may perform read and/or write commands to non-gouged recording surfaces in a data storage device to provide a comprehensive conclusion that the data storage device is not capable of data storage or retrieval. A determination in decision  220  that at least a part of the data storage device is operable advances routine  200  back to step  214  so that further gouge tracks and debris can be generated. 
     However, if decision  220  determines the device is effectively dead, the local controller issues a device destroyed command in step  222  along with purging any data from local cache, such as volatile and/or non-volatile cache memories located in the data storage device. With step  222  issuing the destroyed command to a host, the data storage device is rendered useless and can be safely removed from service without concern for the previously stored data being retrieved.