PATENT DOCUMENT

Publication Number: US-8482876-B2
Application Number: US-201213358288-A
Country: US
Kind Code: B2

Title: Method and device for hard drive shock event detection

Abstract:
A method and system for sensing the current applied to the motor of a data storage device and determining whether a shock event has occurred by processing the sensed current levels.

Claims:
What is claimed is: 
     
       1. A system comprising:
 a spindle motor that rotates a computer readable medium; 
 a driver that provides a drive current to the spindle motor for driving the spindle motor to rotate the computer readable medium; 
 a sensor that:
 receives the drive current for driving the spindle motor from the driver; and 
 provides an output signal based on the received drive current; and 
 
 a processor that processes the output signal for detecting a shock event. 
 
     
     
       2. The system of  claim 1 , wherein the driver provides the drive current to the spindle motor for rotating the spindle motor. 
     
     
       3. The system of  claim 2 , wherein rotation of the spindle motor rotates the computer readable medium. 
     
     
       4. The system of  claim 1 , wherein the sensor monitors the received drive current, and wherein the sensor provides the output signal based on the monitored drive current. 
     
     
       5. The system of  claim 1 , wherein the processor processes the output signal by determining whether the output signal is one of equal to and greater than a threshold level corresponding to the shock event. 
     
     
       6. The system of  claim 1 , further comprising a data store that stores a library of known threshold levels, wherein each threshold level of the known threshold levels corresponds to a respective shock event of a known intensity, and an intensity of the detected shock event is determined by comparing the output signal to one or more of the known threshold levels. 
     
     
       7. The system of  claim 1 , wherein the sensor receives the drive current from the driver over a first period of time and provides the output signal as a plurality of output signals over a second period of time. 
     
     
       8. The system of  claim 7 , wherein the processor processes the plurality of output signals for detecting the shock event. 
     
     
       9. The system of  claim 8 , wherein the processor determines a change in a level between at least two of the plurality of output signals for detecting the shock event. 
     
     
       10. The system of  claim 9 , wherein the processor detects the shock event by determining whether the change in the level is one of equal to and greater than a threshold level corresponding to the shock event. 
     
     
       11. A method comprising:
 providing a drive current from a driver; 
 receiving the drive current from the driver at a spindle motor 
 driving the spindle motor to rotate a computer readable medium using the drive current received at the spindle motor; 
 receiving the drive current from the driver at a sensor; 
 generating an output signal with the sensor based on the drive current received at the sensor; 
 receiving the output signal from the sensor at a processor; 
 processing the received output signal with the processor; and 
 detecting a shock event based on the processing. 
 
     
     
       12. The method of  claim 11 , wherein the driving the spindle motor comprises rotating the spindle motor, and wherein the rotating the spindle motor rotates the computer readable medium coupled to the spindle motor. 
     
     
       13. The method of  claim 11 , wherein the processing comprises comparing the received output signal with at least one value of a plurality of values stored in a table that is accessible by the processor. 
     
     
       14. The method of  claim 13 , wherein each value of the plurality of values is associated with a known shock intensity, and an intensity of the detected shock event is determined by comparing the received output signal with at least one value of the plurality of values. 
     
     
       15. The method of  claim 13 , wherein the table is associated with a characteristic of the spindle motor. 
     
     
       16. The method of  claim 11 , wherein the receiving the drive current from the driver at the sensor comprises receiving the drive current from the driver at the sensor over a first period of time, and wherein the generating the output signal comprises generating a plurality of output signals with the sensor over a second period of time based on the drive current received at the sensor over the first period of time. 
     
     
       17. The method of  claim 16 , wherein:
 the receiving the output signal from the sensor at the processor comprises receiving the plurality of output signals; and 
 the processing the received output signal with the processor comprises processing the plurality of received output signals with the processor. 
 
     
     
       18. The method of  claim 17 , wherein the processing comprises determining a change in a level between at least two of the plurality of received output signals. 
     
     
       19. The method of  claim 18 , wherein the detecting the shock event comprises determining whether the change in the level is one of equal to and greater than a threshold level corresponding to the shock event. 
     
     
       20. Non-transitory computer-readable media for controlling an electronic device, comprising computer-readable code recorded thereon for:
 providing a drive current from a driver to a spindle motor that rotates a storage disk; 
 receiving the drive current from the driver with a sensor; 
 providing an output signal based on the received drive current from the sensor to a processor; 
 processing the output signal with the processor; and 
 detecting a shock event based on the processing.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 12/217,256 filed Jul. 2, 2008, issued as U.S. Pat. No. 8,107,183 on Jan. 31, 2012, which is hereby incorporated by reference in its entirety. 
    
    
     BACKGROUND 
     This invention relates to the detection of a shock event associated with a hard drive of a computing device. 
     Traditional computing devices include non-volatile data storage media. One type of non-volatile media is a hard drive that provides relatively high capacity and long term storage of data. The data may include media files (e.g., songs, video, and pictures), software programs, electronic information, and electronic data or files. Existing hard drives include a one or more data disks where data is magnetically stored. Typically, an armature is moved adjacent to the surface of a disk to read or write data from or to the disk respectively while the disk rotates at a particular speed. 
     Hard drives can be susceptible to mechanical failure or damage due to a physical shock or vibration. Thus, certain hard drives utilize sensors that detect the physical orientation, surrounding environment, or movement of the hard drive and, thereby, detect the occurrence a shock event. One such sensor is an acceleration sensor. One problem with existing shock sensing mechanisms is that additional components, such as an acceleration sensor, are required to enable shock detection based on surrounding environmental conditions. The additional components can add cost, use limited circuit board space, and increase hard drive circuitry size. Accordingly, there is a need to detect hard drive shock events in a more efficient, less obtrusive, and less costly manner. 
     SUMMARY 
     The invention, in various embodiments, addresses deficiencies in the prior art by providing systems, methods and devices that enable the detection of a shock event in a less complex and costly manner without the need for sensing surrounding environmental conditions. 
     In one aspect, a data storage device includes a computer readable medium, a motor that rotates the computer readable medium, a current source (e.g., motor driver circuit) that drives the motor using a motor current, a current sensor that detects the motor current and outputs a current level signal, and a processor, in communication with the current sensor, that processes the current level signal to determine whether a shock event has occurred. 
     In one configuration, the processing by the processor includes determining whether the current level signal is equal to or greater than a threshold level corresponding to a shock event. In certain configurations, the storage device includes a data store that stores a library of known threshold levels where each threshold level corresponds to a shock event of a known intensity. 
     In one feature, shock event intensity is determined by comparing the current level signal to the library of known threshold levels. In another feature, shock event intensity is determined by algorithmically estimating the shock event intensity based on a defined best fit function of the current level signal versus shock event intensity. The function may include at least one of a linear function and a non-linear function. The function may be determined, at least in part, by empirically testing the device over a range of shock event intensities to determine a corresponding range of current level signals (or corresponding changes in current level signals). One approach to measuring shock intensity is to measure gravitational acceleration G applied to a device. The intensity may also include a duration of an applied gravitational acceleration G. One particular shock intensity may be, for example, 70 Gs over a 40 msec period. 
     In another configuration, the sensor detects the motor current over a period of time and outputs a plurality of current level signals over a period of time. Thus, the processing may include processing the plurality of current level signals. The processing may include determining a change in the current level between at least two of the plurality of current level signals. The processing may also include determining whether a shock event occurred by determining whether the change in the current level is equal to or greater than a threshold level corresponding to a shock event. 
     In a further configuration, the processing includes generating a datagram (e.g., plot) of the plurality of current signals over a period of time. Again, the storage device may include a data store for storing a library of known datagrams where each datagram may correspond to a shock event of at least one of a known intensity and duration. The processing may include comparing a generated datagram with the library of known datagrams to identify the shock event. The storage device may be a hard disk drive. The current level signal may be at least one of a current, voltage, information bits, and data packet. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objects and advantages of the present invention will be apparent upon consideration of the following detailed description, taken in conjunction with accompanying drawings, in which like reference characters refer to like parts throughout, and in which: 
         FIG. 1  is a perspective view of a configuration of a hard disk drive  100  according to an illustrative embodiment of the invention; 
         FIG. 2  is an exploded perspective view of a configuration of the hard disk drive  100  according to an illustrative embodiment of the invention; 
         FIG. 3  shows a simplified functional block diagram of a computer system according to an illustrative embodiment of the invention; 
         FIG. 4A  shows a diagram of a storage device according to an illustrative embodiment of the invention; 
         FIG. 4B  shows a simplified diagram of an exemplary current sensor according to an illustrative embodiment of the invention; 
         FIG. 5  is a perspective view of a media device according to an illustrative embodiment of the invention; 
         FIG. 6  is a perspective view of a personal computer system according to an illustrative embodiment of the invention; and 
         FIG. 7  is a flow diagram of a process for detecting a shock event according to an illustrative embodiment of the invention. 
     
    
    
     DESCRIPTION 
       FIG. 1  is a perspective view of a configuration of a hard disk drive  100  according to an illustrative embodiment of the invention. In  FIG. 1 , a magnetic disk  101  includes a nonvolatile storage disk that stores data by magnetizing a magnetic layer. The magnetic disk  101  may include an aluminum substrate or a glass substrate. The drive  100  may include a box-shaped base  102  having an opening in its upper part that accommodates components of the hard disk drive  100 . In certain embodiments, the base  102  is formed by pressing a magnetic material such as steel. Steel, magnetic stainless steel, or the like, may be used as the magnetic material. By use of a gasket (not shown) such as fluorine rubber, the base  102  may be secured to a cover (not shown) for closing the upper opening of the base  102  to form a disk enclosure. With the components of the hard disk drive  100  sealed, the disk enclosure can accommodate the components. 
     In one embodiment, a spindle motor  103  is secured to the base  102 . A hub  104  may be provided on the spindle motor  103 . An actuator  106  may include a head  105  by which data is written to, and/or read from, the magnetic disk  101 . The data may be input/output from/to a host computer system in communication with the drive  100 . In one embodiment, the head  105  includes a write element for converting an electrical (data) signal into a magnetic field according to data to be stored in the magnetic disk  101 . The head  105  may include a read element for converting a magnetic field received from the magnetic disk  101  into an electrical signal. The head  105  may also include a slider on which the write element and/or the read element are formed. 
     In certain embodiments, the actuator  106  supports the head  105 . The actuator  106  may be configured to enable the actuator  106  to pivotally move about a pivoting shaft  107 . The actuator  106  may include an actuator arm  108  and a voice coil motor (VCM)  109 . The drive  100  may include a ramp mechanism  115  that retracts the head  105  from the magnetic disk  101  when the rotation of the magnetic disk  101  stops. The actuator  106  may include a tab  116  located at the tip of the actuator  106 . 
     By use of a top clamp  201 , the magnetic disk  101  may be secured to the hub  104  of the spindle motor  103 , which may be secured to the bottom surface of the base  102 . The magnetic disk  101  may be driven and rotated by the spindle motor  103  at a given rotational speed. When the hard disk drive  100  is not operated, the magnetic disk  101  can stand still. In response to a driving signal supplied from a controller (not shown) to a flat coil, the VCM  109  can pivotally move the actuator arm  108  about the pivot shaft  107  and, thereby, move the head  105  to a position above the magnetic disk  101  or to the outside of the magnetic disk  101 . 
     A circuit board (not shown) may be mounted to the outside (under surface) of the base  102  or some other surface of the drive  100 . The circuit board may include a rectangular shape that covers a portion of the outside of the base  102 . The circuit board may provide electrical power for driving a motor such as the spindle motor  103 . The circuit board may provide power to a coil used for the VCM  109 , provide electrical signaling for reading of the head  105 , and/or all electrical signaling and power to enable operation of the drive  100 . In one embodiment, the circuit board includes a Flexible Printed Circuit (FPC). 
     In certain embodiments, the actuator  106  moves the head  105  to a position above a data area of the magnetic disk  101  that is rotating to enable the reading/writing of data from/to the magnetic disk  101 . The actuator  106  may pivotally move to cause the head  105  to move in a radial direction on the surface of the magnetic disk  101 , permitting the head  105  to access a desired track of the disk  101 . By balancing the pressure produced by air viscosity between the rotating magnetic disk  101  and an Air Bearing Surface (ABS) of a slider facing the magnetic disk  101 , the head  105  floats off the magnetic disk  101  at a substantially constant gap distance. 
     The hard disk drive  100  may include a disk drive that is called a load/unload disk drive. If the rotation of the magnetic disk  101  stops, the head  105  contacts the surface of the magnetic disk  101 , causing absorption phenomenon. This can produce problems, such as the occurrence of a flaw in the data area, and an inability to rotate the magnetic disk. Thus, when the rotation of the magnetic disk  101  stops, the actuator  106  retracts the head  105  from the data area into the ramp mechanism  115 . In certain embodiments, the actuator  106  pivotally moves in the direction toward the ramp mechanism  115 , which causes the tab  116  at the tip of the actuator  106  to slide and move on the surface of the ramp mechanism  115  until the tab  116  sits on a parking surface of the ramp mechanism  115 . This is how the head  105  is unloaded. When the head  105  is loaded, the actuator  106  supported by the parking surface leaves the ramp mechanism  115  and then moves above the surface of the magnetic disk  101 . For the Contact Start and Stop (CSS) hard disk drive, the head  105  retracts into a CSS zone on the inner circumference side of the magnetic disk  101 . 
     Although the illustrated hard disk drive  100  includes one magnetic disk  101 , the hard disk drive  100  may include a plurality of magnetic disks. For example, if data is stored on both sides of a plurality of magnetic disks, the plurality of magnetic disks can be integrally held by the hub  104  at given intervals in a direction of the rotating shaft of the spindle motor  103 . A plurality of actuator arms may be used for holding a plurality of heads that can, in turn, scan each storing surface. Thus, the number of the actuator arms may be equal to the number of the storing surfaces. The actuator arms may be secured to the actuator  106  at positions where they overlap one another at given intervals from the actuator arms  108 . 
       FIG. 2  is an exploded perspective view of a configuration of the hard disk drive  100  according to an illustrative embodiment of the invention.  FIG. 2  shows the alignment of the base  102 , the spindle motor  103 , the magnetic disk  101 , and the top clamp  201  within the hard disk drive  100 . As shown in  FIG. 2 , the base  102  may include a bottom  202  to which the components of the hard disk drive  100  can be mounted and a wall  203  that surrounds the circumference of the bottom  202 . 
     The drive  100  may include an inside-the-base space  204  that is surrounded by the wall  203 . The space  204  may include a plurality of areas such as a disk accommodation area  204   a  that accommodates a disk assembly including the magnetic disk  101  and the spindle motor  103 . The space may include an actuator accommodation area  204   b  that accommodates the actuator  106  used to move the head  105  to a desired position above the magnetic disk  101  or to a desired position away from the magnetic disk  101 . 
     The spindle motor  103  may be positioned in a concave part  205  that is formed substantially in the center of the bottom  202  of the disk accommodation area  204   a  in a direction from the inside to the outside of the base  102 . The spindle motor  103  may be secured to the bottom  202  of the base  102  at this position. The magnetic disk  101  may be mounted on the hub  104  of the spindle motor  103 . Both the top clamp  201  and the hub  104 , which may be screwed, can hold the magnetic disk  101  securely, so that the magnetic disk  101  is secured to the spindle motor  103 . 
     The base  102  which may be formed by pressing a magnetic material plate such as cold reduced carbon steel (SPCC). For the presswork, a member can be pressed using a pressing machine. In certain embodiments, punching, die forging, plate bending, or the like, are performed. The presswork enables a metal plate, made by rolling, to be shaped into a desired form. A plate may be formed using a mold. Punching, drilling, drawing, bending, and the like, are known as a processing method that may be employed to shape a metal plate. The presswork is easier than casting and, therefore, may be desirable and more cost effective. 
     In certain embodiments, the spindle motor  103  includes a fluid dynamic bearing (FDB) motor. The fluid dynamic bearing motor may include a motor in which fluid such as oil is used for a bearing of a rotating shaft. In the bearing, only fluid exists between a rotating unit and a fixed unit, allowing the rotating unit to rotate smoothly. A fluid dynamic bearing motor contributes to a longer life of the motor as compared with a ball bearing motor. A fluid dynamic bearing motor is also superior in providing silent or low noise operation. A fluid dynamic bearing motor can reduce oscillations by use of a damping effect on high order oscillations. The fluid dynamic bearing motor, for certain applications, can provide superior positioning accuracy. In one embodiment, the spindle motor  103  has an in-hub structure that includes a stator and a rotor magnet. Additionally, the spindle motor  103  may include an axial rotation structure in which a rotating shaft is secured to the rotating hub side. 
     While the spindle motor  103  described above is the in-hub type spindle motor that accommodates the stator and the magnet unit inside the hub, the spindle motor  103  may include other types of spindle motors such as an inner rotor type spindle motor in which a magnet unit is firmly fixed to the circumference of a hub and a stator is placed outside the hub. The spindle motor  103  may include an axial rotation type spindle motor in which a shaft rotates together with a rotor and/or includes a spindle motor having a shaft fixing structure in which a shaft is secured to the base. The present invention can be applied not only to hard disk drives, but also to various types of storage disk drives for driving and rotating a storage disk for storing data, such as an optical disk drive. 
     A hard drive may have a size, without limitation, of about or less than 3.5″, 2.5″, 2″, 1.8″, 1″, 0.5″, and 0.25″. One example of a miniature hard drive is the 1″-6 Giga-byte (GB) or 8 GB Microdrive 3K8, made by Hitachi, Ltd. of Tokyo, Japan. A hard drive may include a hard drive controller such as, without limitation, the ST HDD motor controller family (e.g., L7207) made by STMicroelectronics of Geneva, Switzerland. A hard drive and/or hard drive controller may utilize a protocol to communicate with a host computer system or other device such as, without limitation, the ATA command set. 
       FIG. 3  shows a simplified functional block diagram of a computer system or device  300  according to an illustrative embodiment of the invention. The block diagram provides a generalized block diagram of a computer system such as may be employed, without limitation, by the hard drive  100 , media device  500  and desktop computer system  600 . The computer system  300  may be representative of a host computer system that is in communication with a hard drive such as hard drive  100 . Alternatively, the computer system  300  may be representative of a computer architecture for a hard drive itself, such as the hard drive  100 . Thus, a hard drive can support its own processing environment and utilize its own computer system to perform functions such as, without limitation, control the operation of a disk motor, control communications to and from the hard drive, monitor the performance of the hard drive, perform diagnostic testing or recordings of the hard drive, and control data write and read operations. 
     The computer system  300  may include a processor  302 , storage device  304 , user interface  308 , display  310 , CODEC  312 , bus  318 , memory  320 , communications circuitry  322 , a speaker or transducer  324 , a microphone  326 , and a sensor  330 . Processor  302  may control the operation of many functions and other circuitry included in the computer system  300 . Processor  302  may drive display  310  and may receive user inputs from the user interface  308 . In the instance where the computer system  300  controls the operation of a hard drive, a display  310 , speaker  324 , microphone  326 , and user interface  306  may not utilized. 
     Storage device  304  may store media (e.g., music and video files), software (e.g., for implanting functions on device  300 ), and any other suitable data. Storage device  304  may include one more storage mediums, including for example, a hard-drive, permanent memory such as ROM, semi-permanent memory such as RAM, or cache. 
     Memory  320  may include one or more different types of memory which may be used for performing device functions. For example, memory  320  may include cache, ROM, and/or RAM. Bus  318  may provide a data transfer path for transferring data to, from, or between at least storage device  304 , memory  320 , and processor  302 . Coder/decoder (CODEC)  312  may be included to convert digital audio signals into an analog signals for driving the speaker  324  to produce sound including voice, music, and other like audio. The CODEC  312  may also convert audio inputs from the microphone  326  into digital audio signals. The CODEC  312  may include a video CODEC for processing digital and/or analog video signals. 
     User interface  308  may allow a user to interact with the computer system  300 . For example, the user interface  308  can take a variety of forms, such as a button, keypad, dial, a click wheel, or a touch screen. Communications circuitry  322  may include circuitry for wireless communication (e.g., short-range and/or long range communication). For example, the wireless communication circuitry may be Wi-Fi enabling circuitry that permits wireless communication according to one of the 802.11 standards. Other wireless network protocols standards could also be used, either in alternative to the identified protocols or in addition to the identified protocol. Other network standards may include Bluetooth, the Global System for Mobile Communications (GSM), code division multiple access (CDMA), and long-term evolution (LTE) based wireless protocols. Communications circuitry  322  may also include circuitry that enables the computer system  300  to be electrically coupled to another device (e.g., another computer or an accessory device) and communicate with that other device. 
     In the instance where the computer system  300  is representative of a computer architecture for a hard drive, the sensor  330  may be a current sensor that monitors the amount of current used to drive one or more disk motors of the hard drive. In the instance where the computer system  300  is representative of a personal computer (e.g., desktop computer) or media device  500 , the storage  304  may be a hard drive such as hard drive  100 . 
     A computing system or device  300  may include any system or device that uses a processor to perform electronic computations or operations. A computing system may include a mainframe, server, workstation, hand-held computing device, wireless communications device, personal computing device, and the like. A computing system or device may include any computing device or computer-controlled device capable of interacting or interfacing with a person. Types of computing devices may include personal computers, consumer electronics, personal media devices, personal communications devices, personal display devices, vehicle control systems, financial transactions systems, and any like computing device capable of interfacing with a person. 
     Consumer electronic devices may include, without limitations, televisions, stereo systems, video gaming systems, disk players, cameras, video cameras, and task-specific computing devices. Personal computers may include, without limitation, desktop computers, laptop computers, portable computers, workstations, server interfaces, and handheld computers. Media devices may include, without limitation, cellular telephones, MP3 players, portable video players, media capable cellular telephones, and satellite media players. Personal communications devices may include wireless communications devices, cellular telephones, satellite phones, personal digital assistants (PDA), and other like communications devices. Vehicle control systems may include, without limitation, consumer electronic devices, personal media devices, personal communication devices, vehicle operating systems, and vehicle monitoring systems. Financial transaction systems may include, without limitation, automatic teller machines (ATM), store purchase/check-out systems, credit card transaction systems, and remote purchase systems. 
       FIG. 4A  shows a diagram of a storage device  400  according to an illustrative embodiment of the invention. In one embodiment, the storage device  400  is an intelligent storage device including a processor  402 , a motor controller  404 , a motor driver  406 , a current sensor  408 , a memory  410 , a communications interface  412 , at least one computer readable medium  414  (e.g., a magnetic disk), an actuator  416 , a read/write head  418 , and/or a disk motor  420 . A bus  422  may interconnect interface  412 , read/write head  418 , RAM  410 , and/or the sensor  408 . The interface  412  may enable electronic communications between the storage device  400  to a host, such as computer system  300  of  FIG. 3 . 
     In one embodiment, the interface  412  routes information and/or data to and from the at least one computer readable medium  414 . The interface  412  may also include an embedded processor  402  with suitable firmware for logging certain characteristic operational information, controlling the hard drive operations, controlling read/write operations, receiving sensor  408  signals, and analyzing sensor  408  signals. The device  400  may include a motor controller  404  that controls the operation of the motor driver  406  and motor  420 . One operation may be to regulate the rotation speed of the medium  414 . In one embodiment, the processor  402  and motor controller  404  functions are integrated into a single chip or element. In certain embodiments, at least one non-volatile buffer is located in a reserved area of the at least one computer readable medium  414 . For example, the at least one buffer may include an error data, timestamp data, hard drive ID data, host system configuration data, hard drive status data, and shock event detection data. 
     In certain embodiments, the sensor  408  includes a current sensor that measures the drive current from the motor driver  406  to the motor  420 . By measuring the motor drive current or motor drive signal, the sensor  408  can detect certain events, such as shock events that can effect the motor drive signal. For example, when the device  400  is subjected to a shock (e.g., the device is dropped), the physical shock can cause the motor  420  to slow down. The slow down can, in turn, cause an interruption to the current flow from the motor driver  406  to the motor  420 . The slow down of the motor  420  will further cause an increase in current demand by the motor  420  to return the medium  414  back to its selected and/or regulated rotation speed (e.g. 7200 RPM). 
     Under the Constant Power Law and related principles, the total power input into a system must be equal to the total power output from a system. In the case of a hard drive motor where the motor is capable of delivering a rated power output, the output power capacity of the combination of the motor and an associated coupling device (provided that the coupling device is appropriately rated) is the rated motor power minus the loss of power due to the coupling device. Torque T is directly proportion to power and inversely proportional to speed of the motor. Thus, Torque can be measured by the following formula:
 
 T=K×P/N   (1)
         where K is a constant, P is power, and N is rotation speed. In the case of a FDB motor, the constant power law applies, but the power in the driven load may be reduced as the speed increases.       

     If a drive with a FDB motor, e.g., motor  420 , is physically shocked, the motor  420  will slow down. This, in turn, causes an interruption to the drive current flow to the motor  420 , which causes an increase in current demand to return the medium  414  back to its selected steady-state speed and/or RPM. 
     By measuring the change in current using the current sensor  408 , the processor  402  (or processor  302  of  FIG. 3 ) can correlate and/or determine the severity and/or intensity of the shock event. The detection of a shock event and determination of the severity of the shock event can enable the processor  402  or host computer system to perform an operation in response to the detected shock event. For example, the processor  402  may take actions to protect certain data not yet written to the medium  414 . One action may be to store certain data in the memory  410  until a diagnostic check is performed on the medium  414 . Another action may include storing shock event data in the memory  410  or medium  414  to memorialize the shock event for later analysis. The shock event data may include, without limitation, the peak current, event current profile, shock intensity, shock intensity profile, timestamp data, event start time, and/or event end time. In one embodiment, the motor current may be recorded and/or represented as a voltage or other like current detection signal. An event current profile may include a datagram showing current intensity over a period of time such as the shock event time period. 
     In certain embodiments, the processor  402  and/or an external processor of a host system may include an algorithm or formula for correlating a detected current level or intensity with a corresponding shock intensity. In one embodiment, the correlation of current level, current level change, and/or current level event profile with shock intensity is determined by empirical testing and/or experimental analysis. The processor  402  may use a look up table that associates current levels, current level changes, and/or current level profiles with shock intensity. The processor  402  may determine the shock intensity based on a closest match with a known current level in the look up table. The processor  402  may use a linear and/or non-linear formula or function that provided a best fit prediction of shock intensity for a detected current signal. The correlation of motor drive current or motor drive current change to the intensity of a shock event may be determined based on the type of hard drive, the manufacturer and type of the hard drive, the type and model of hard drive, the manufacturing origin of the hard drive, the components of the hard drive, and/or on an individual drive basis. 
       FIG. 4B  shows a simplified diagram of an exemplary current sensor  450  according to an illustrative embodiment of the invention. The sensor  450  includes a current sensing resistor Rs and a current sensing amplifier  452 . In one embodiment, the resistor Rs is in electrical series with the stator coils L 1 , L 2 , and L 3  of a three phase spindle motor such as, for example, motor  420 . Thus, the current flow through Rs generates a voltage that is proportional to the motor current flow to the stator coils L 1 , L 2 , and L 3 . The amplifier  452  measures the voltage drop across Rs and outputs a current sensing signal and/or voltage Vs that is provided to the processor  402 . The processor  402  may then process the current sensing signal to determine the shock intensity associated with a shock event. Further details regarding this type of current sensor are provided in U.S. Pat. No. 6,917,172, the entire contents of which are incorporated herein by reference. It should be understood, however, that other types of known current sensors may be employed. 
     In certain embodiments, a shock threshold may be defined based on a maximum acceptable shock intensity whereby no corrective action or safeguards are required for the device  400 . The threshold may include a motor current or motor current change threshold associated with the maximum acceptable shock intensity. 
     Any number of operations may be performed by the device  400  upon detection of a shock event. For example, the device may provide an alert or notification to an external device, such as a host computer system, that a shock event has occurred. The host computer system could perform any number of operations in response to the notification such as, without limitation: suspend read and/or write operations with the device  400 ; switch read and/or write operations to another storage device; perform a diagnostic operation to determine whether the device  400  has been damaged or any data has been corrupted; and/or provide a shock event notification to a service entity or system user to replace the device  400 . 
     The device  400  could perform any number of operations in response to the detection of a shock event by the processor  402  including, without limitation: suspend read/write operations; initiate an internal diagnostic routine or error check of the device&#39;s hardware and/or the data on the medium  414 ; switch read/write operations to another disk; provide notification of a shock event to an external source; memorialize the shock event by storing shock event data in a select memory such as on the medium  414 ; and/or provide shock event data to an external source, e.g., a test technician, upon request. 
     Certain existing hard drives are currently manufactured with a motor current sensor to enable, for example, regulation and control of medium rotation speed. One advantage of the present invention is that an existing hard drive may be configured with additional firmware and/or software to enable its processor to perform shock event detection and analyses using existing device hardware without the need to add, for example, a current sensor circuit. 
     The device  400  may be manufactured such that the device  400  supports one or more hard drive standards such as, without limitation, ATA, SCSI, and like standards. In certain embodiments, the interface  412  supports protocols and provides mechanisms that enable the device  400  to communication with a host system or other devices. The device  400  may support self-monitoring, analysis, and reporting technology (SMART) to assist in failure analysis prior to sending a hard drive back to the manufacturer. 
       FIG. 5  is a perspective view of a media device  500  according to an illustrative embodiment of the invention. The device  500  includes a housing  502 , a first housing portion  504 , a second housing portion  506 , a display  508 , a keypad  510 , a speaker housing aperture  512 , a microphone housing aperture  514 , a headphone jack  516 , and frame sidewall  522 . In certain embodiments, the frame sidewall  522  is the exposed portion of a frame residing within or adjacent to the housing  502  that provides structural support for the media device  500  and various internal components. The media device may include a computer architecture such as shown in  FIG. 3  and, therefore, include a storage device such as storage device  400 . 
     In one embodiment, the housing  502  includes a first housing portion  504  and a second housing portion  506  that are fastened together and/or to the frame sidewall  522  to encase various components of the media device  500 . The housing  502  and its housing portions  504  and  506  may include polymer-based materials that are formed by, for example, injection molding to define the form factor of the media device  500 . In one embodiment, the housing  502  surrounds and/or supports internal components such as, for example, a display  508 , one or more circuit boards having integrated circuit components, internal radio frequency (RF) circuitry, an internal antenna, a speaker, a microphone, a hard drive, a processor, and other components. Further details regarding certain internal components are discussed herein with respect to  FIG. 3 . The housing  502  provides for mounting of a display  508 , keypad  510 , external jack  516 , data connectors, or other external interface elements. The housing  502  may include one or more housing apertures  112  to facilitate delivery of sound, including voice and music, to a user from a speaker within the housing  502 . The housing  502  may include one or more housing apertures  514  to facilitate the reception of sounds, such as voice, for an internal microphone from a device user. 
     Computing devices and/or media devices of this type may include a touchscreen remote control, such as a Pronto made available by Royal Philips Electronics of the Netherlands or a handheld GPS receiver made available by Garmin International, Inc. of Olathe, Kans. In certain embodiments, the display  508  includes a graphical user interface (GUI) to enable a user to interact with the device  500 . The personal computing device  500  may also include an image sensor such as a camera capable of capturing photographic images and/or video images. 
     In one embodiment, a computing device may be a portable computing device or media device  500  dedicated to processing media such as audio and video. The media device  500  may include a media player (e.g., MP3 player), a game player, a remote controller, a portable communication device, a remote ordering interface, an audio tour player, or other suitable personal device. The media device  500  may be battery-operated and highly portable so as to allow a user to listen to music, play games or video, record video or take pictures, communicate with others, and/or control other devices. In addition, the media device  500  may be sized such that it fits relatively easily into a pocket or hand of the user. By being handheld, the media device  500  is relatively small and easily handled and utilized by its user and thus may be taken practically anywhere the user travels. 
     The media device  500  may also be integrated within the packaging of other devices or structures such a vehicle, video game system, appliance, clothing, helmet, glasses, wearable apparel, stereo system, entertainment system, or other portable devices. In certain embodiments, device  500  may be docked or connected to a wireless enabling accessory system (e.g., a wi-fi docking system) that provides the device  100  with short-range communicating functionality. Alternative types of devices  500  may include, for example, a media player such as an iPod® or iPhone that are made available by Apple® Inc., of Cupertino, Calif., pocket-sized personal computers such as an iPAQ Pocket PC available by Hewlett Packard Inc., of Palo Alto, Calif. and any other device capable of communicating wirelessly (with or without the aid of a wireless enabling accessory system). 
     In certain embodiments, the media device  500  may synchronize with, for example, a remote computing system or server to receive media (using either wireless or wireline communications paths) or to provide shock event data to the remote computing system. Wireless syncing enables the device  500  to transmit and receive media and data without requiring a wired connection. Media may include, without limitation, sound or audio files, music, video, multi-media, and digital data, in streaming and/or discrete (e.g., files and packets) formats. 
     During synchronization, a host system may provide media to a client system or software application embedded within the device  500 . In certain embodiments, media and/or data is “downloaded” to the device  500 . In other embodiments, the device  100  is capable of uploading media to a remote host or other client system. Further details regarding the capabilities of certain embodiments of the device  500  are provided in U.S. Pat. No. 7,627,343, the entire contents of which are incorporated herein by reference. 
       FIG. 6  is a perspective view of a personal computer system  600  in the form of a desktop personal computer (PC) according to an illustrative embodiment of the invention. In this embodiment, as opposed to the embodiment of  FIG. 1A , the PC system  600  includes a computing system housing  602 , a display assembly  604 , a camera  606 , keyboard  608 , and pointer device  610 , e.g., a mouse. The system  600  may include a computer architecture such as shown in  FIG. 3 . Thus, the system  600  may include a hard drive such as hard drive  100  of  FIG. 1 . 
       FIG. 7  is a flow diagram of a process  700  for detecting a shock event according to an illustrative embodiment of the invention. First, a motor driver  406  provides current to the motor  420  to enable rotation of the medium  414  at a desired speed (Step  702 ). Then, the current sensor  408  monitors the current level and outputs a current signal (Step  704 ). The current signal may include a current level, a set of current levels, a datagram or plot of current level over a period of time, a change in current level, a set of changes in current level, a datagram of changes in current level over a period of time. Next, the processor  402  processes the current signal to determine whether a shock event occurred (Step  706 ). The processor  402  may continuously or periodically receive a current signal from the sensor  408 . As part of the processing, the processor  402  may collate a set of current levels, determine a datagram or plot of current level over a period of time, determine a change in current level, determine a set of changes in current level, and/or determine a datagram of changes in current level over a period of time. 
     It will be apparent to those of ordinary skill in the art that methods involved in the present invention may be embodied in a computer program product that includes a computer usable and/or readable medium. For example, such a computer usable medium may consist of a read only memory device, such as a CD ROM disk or conventional ROM devices, or a random access memory, such as a hard drive device or a computer diskette, or transportable memory device having a computer readable program code stored thereon. 
     From the foregoing description, persons skilled in the art will appreciate that the various configurations described herein may be combined without departing from the present invention. It will also be recognized that the invention may take many forms other than those disclosed in this specification. Accordingly, it is emphasized that the invention is not limited to the disclosed methods, systems and devices, but is intended to include variations to and modifications thereof which are within the spirit of the following claims.

Metadata:
Filing Date: 20120125
Publication Date: 20130709
Grant Date: 20130709
Priority Date: 20080702
Inventors: COLLIGAN THOMAS R.
Assignee: APPLE INC
CPC Classifications: [{"code": "G11B25/043", "inventive": true, "first": false, "tree": "[]"}, {"code": "G11B5/5582", "inventive": true, "first": false, "tree": "[]"}, {"code": "G11B5/5582", "inventive": true, "first": false, "tree": "[]"}, {"code": "G11B33/08", "inventive": true, "first": true, "tree": "[]"}, {"code": "G11B25/043", "inventive": true, "first": false, "tree": "[]"}, {"code": "G11B33/08", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 41464309