Magnetic disk device and control method

Abstract

To smoothly perform communication with a host device even when backup processing is executed.SOLUTION: A magnetic disk device of an embodiment comprises: a controller which executes backup processing for writing data received from a host device in a magnetic disk via a cache area by using second power generated by a power supply circuit while first power supplied from an external power supply is supplied, invalidating communication with the host device when supply of the first power is interrupted, and saving content of the cache area in a first memory by using third power generated by the power supply circuit; and a power supply monitoring circuit which monitors the supply of the first power, wherein the power supply monitoring circuit maintains connection with the external power supply even when the supply of the first power is interrupted, and the controller enables the communication with the host device when it is determined that the supply of the first power is restored by the power supply monitoring circuit.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] FIELD An embodiment of the present invention relates to a magnetic disk device and a control method. [Background technology]

[0002] The magnetic disk drive has a power loss protection (PLP) function that disables communication with the host device and evacuates data being written to the disk and stored in cache memory to a non-volatile storage area when the power supply from the external power source is interrupted. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-044277 [Patent Document 2] Japanese Patent Application Laid-Open No. 2008-282137 [Patent Document 3] US Patent Application Publication No. 2003 / 0028733 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of one embodiment is to provide a magnetic disk device that can smoothly communicate with a host device even when the PLP function is executed. [Means for solving the problem]

[0005] a power supply circuit that generates a second power from a first power supplied from an external power source and generates a third power based on regenerative energy generated when the motor is stopped when the supply of the first power is interrupted; a non-volatile first memory; a volatile second memory having a cache area; a controller that, while the first power is being supplied, writes data received from a host device to the magnetic disk via the cache area using the second power generated by the power supply circuit; and, when the supply of the first power is interrupted, disables communication with the host device and executes a backup process that saves the contents of the cache area to the first memory using the third power generated by the power supply circuit; and a power supply monitoring circuit that monitors the supply of the first power, wherein the power supply monitoring circuit maintains connection to the external power source even when the supply of the first power is interrupted, and the controller enables communication with the host device when the power supply monitoring circuit determines that the supply of the first power has been restored. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a schematic diagram showing an example of the configuration of a magnetic disk device according to the first embodiment. [Figure 2] FIG. 2 is a diagram illustrating an example of the configuration of a magnetic disk device showing the configuration of an SVC according to the first embodiment. [Figure 3] FIG. 3 is a diagram illustrating an example in which only the 5V power supply is restored in the configuration of the magnetic disk device according to the first embodiment. [Figure 4] FIG. 4 is a flowchart illustrating an example of a procedure of a control process according to the first embodiment. [Figure 5] FIG. 5 is a flowchart illustrating an example of a procedure of a control process according to the second embodiment. [Figure 6] FIG. 6 is a flowchart illustrating an example of the procedure (continuation) of the control process according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0007] A disk device and a control method according to an embodiment will be described in detail below with reference to the accompanying drawings, but the present invention is not limited to the embodiment.

[0008] (First embodiment) FIG. 1 is a schematic diagram showing an example of the configuration of a magnetic disk device 1 according to an embodiment. The magnetic disk device 1 is connected to a host device 2. The magnetic disk device 1 can receive access commands such as write commands and read commands from the host device 2.

[0009] The magnetic disk device 1 includes a magnetic disk 11 having a magnetic layer formed on its surface. The magnetic disk device 1 accesses the magnetic disk 11 in response to an access command. The access includes writing data and reading data.

[0010] Data is written and read via a magnetic head 22. Specifically, in addition to a magnetic disk 11, the magnetic disk device 1 includes a spindle motor (SPM) 12, a ramp 13, an actuator arm 15, a voice coil motor (VCM) 16, a servo controller (SVC) 21, a magnetic head 22, a hard disk controller (HDC) 23, a host interface (host I / F) 31, a preamplifier 24, a read / write channel (RWC) 25, a processor 26, sensors 27, a FROM (Flash Read Only Memory) 28, a DRAM (Dynamic Random Access Memory) 29, a 12V eFuse 41, a 5V eFuse 43, and a PLP regulator 42.

[0011] The magnetic disk 11 is rotated at a predetermined rotational speed by the SPM 12 attached coaxially.

[0012] The SVC 21 is an integrated circuit that functions as a driver for driving the SPM 12 and the VCM 16. The processor 26 controls the rotation of the SPM 12 and the VCM 16 via the SVC 21. Details of the SVC 21 will be described later.

[0013] The magnetic head 22 writes and reads information to and from the magnetic disk 11 using a write head 22w and a read head 22r provided thereto. The magnetic head 22 is attached to the tip of an actuator arm 15. The magnetic head 22 is moved in the radial direction of the magnetic disk 11 by a VCM 16 driven by an SVC 21. Note that a plurality of write heads 22w and / or read heads 22r provided to the magnetic head 22 may be provided for a single magnetic head 22.

[0014] When the magnetic disk 11 is stopped from rotating, the magnetic head 22 is moved onto the ramp 13. The ramp 13 is configured to hold the magnetic head 22 at a position spaced apart from the magnetic disk 11.

[0015] The preamplifier 24 is an integrated circuit that writes and reads data via the magnetic head 22. During a read operation, the preamplifier 24 amplifies and outputs a signal read from the magnetic disk 11 by the magnetic head 22, and supplies the signal to the RWC 25. During a write operation, the preamplifier 24 amplifies a signal corresponding to the data to be written, which is supplied from the RWC 25, and supplies the signal to the magnetic head 22.

[0016] The host I / F 31 is a communication interface with the host device 2 . The HDC 23 controls the transmission and reception of data between the host device 2 and the HDC 23 via the host I / F 31, and controls the DRAM 29, etc.

[0017] The DRAM 29 is used as a buffer for data transmitted to and received from the host device 2. That is, a cache area 291 is allocated to the DRAM 29, and the DRAM 29 functions as a cache memory. The cache area 291 is used to temporarily store write-target data that has been received from the host device 2 and has not yet been written to the magnetic disk 11. The DRAM 29 is also used to temporarily store data that has been read from the magnetic disk 11.

[0018] The DRAM 29 is also used as an operating memory by the processor 26. The DRAM 29 is used as an area into which firmware is loaded and an area in which various management data is temporarily stored. The DRAM 29 is an example of a second memory.

[0019] The RWC 25 performs code modulation on the data to be written that is supplied from the HDC 23 and stored in the cache area 291, and supplies the code-modulated data to the preamplifier 24. The RWC 25 also performs code demodulation, including error correction, on the signal that is read from the magnetic disk 11 and supplied from the preamplifier 24, and then outputs the code-demodulated signal to the HDC 23 as digital data.

[0020] The processor 26 is, for example, a CPU (Central Processing Unit). The processor 26 is connected to sensors 27, a FROM (Flash Read Only Memory) 28, and a DRAM 29.

[0021] Firmware (program data), various operating parameters, etc. are stored in the FROM 28. The firmware may be stored on the magnetic disk 11. The FROM 28 is an example of a first memory.

[0022] The sensors 27 are sensor modules that detect environmental information, and include, for example, an acceleration sensor module for detecting vibrations or impacts applied to the magnetic disk device 1, or a temperature sensor module for detecting the temperature of the magnetic disk device 1.

[0023] The processor 26 performs overall control of the magnetic disk device 1 in accordance with firmware stored in the FROM 28 or the magnetic disk 11. For example, the processor 26 loads firmware from the FROM 28 or the magnetic disk 11 into the DRAM 29, and controls the SVC 21, the preamplifier 24, the RWC 25, the HDC 23, and the like in accordance with the firmware loaded into the DRAM 29.

[0024] The HDC 23, the host I / F 31, the RWC 25, and the processor 26 are configured as a single integrated circuit, a System-On-a-Chip (SoC) 30. The SoC 30 may also include other elements (such as a ROM 28 or a DRAM 29) in addition to the above.

[0025] Note that some or all of the functions of the processor 26 may be realized by a hardware circuit such as a field-programmable gate array (FPGA) or an application-specific integrated circuit (ASIC).

[0026] FIG. 2 is a diagram showing an example of the configuration of the magnetic disk device 1, illustrating the configuration of the SVC 21 according to the first embodiment.

[0027] The I / F connector 45 is a general term for various terminals, and is provided on the housing of the magnetic disk device 1. The host device 2 is provided with a 12V power supply and a 5V power supply as external power supplies. Here, the 12V power supply is an example of a first external power supply, and the 5V power supply is an example of a second external power supply.

[0028] The 12V eFuse 41 is connected to a 12V power supply via an I / F connector 45. The I / F connector 45 to which the 12V eFuse 41 is connected is a 12V power supply terminal. The 12V eFuse 41 is also connected to the SVC 21. The power supplied from the 12V power supply is input to the 12V eFuse 41 via the I / F connector 45 (i.e., the 12V power supply terminal).

[0029] The 12V eFuse 41 is an integrated circuit that includes a MOSFET and has an overcurrent protection function that prevents overcurrent from flowing in the power supply lane it is connected to. The 12V eFuse 41's overcurrent protection function detects overcurrent and cuts off power when an overcurrent is detected. When the 12V power supply is cut off, the 12V eFuse 41 turns off. When the 12V power supply is restored, the 12V eFuse 41 turns on and supplies power from the 12V power supply to the SVC 21.

[0030] The 5V eFuse 43 is connected to a 5V power supply via an I / F connector 45. The I / F connector 45 to which the 5V eFuse 43 is connected is a 5V power supply terminal. The 5V eFuse 43 is also connected to the SVC 21. The power supplied from the 5V power supply is input to the 5V eFuse 43 via the I / F connector 45 (that is, the 5V power supply terminal).

[0031] The 5V eFuse 43 is an integrated circuit that includes a MOSFET and has an overcurrent protection function that prevents overcurrent from flowing in the power supply lane it is connected to. The 5V eFuse 41 uses its overcurrent protection function to detect overcurrent and cut off power when an overcurrent is detected. When the 5V power supply is cut off, the 5V eFuse 43 turns off. When the 5V power supply is restored, the 5V eFuse 43 turns on and supplies power from the 5V power supply to the SVC 21.

[0032] The PLP regulator 42 supplies power to the SVC 21 for the PLP function, which will be described later. When the power supply from the 12V power supply is interrupted, the PLP regulator 42 supplies the back electromotive force of the SPM 12, which is supplied from the spindle motor control circuit 212, which will be described later. Furthermore, when the power supply from the 12V power supply is not interrupted, the PLP regulator 42 receives power from the 12V power supply, which is supplied from the FET 211, generates power (an example of second power) based on the supplied power, and supplies the generated power to the SVC 21. Here, generating power includes, for example, processes such as rectification, voltage step-up, or voltage step-down. The PLP regulator 42 may supply the supplied power directly to each component.

[0033] When the supply of power from the host device 2 is interrupted, the power supply monitoring circuit 213, which will be described later, can detect that the supply of power from the host device 2 has been interrupted. When the power supply monitoring circuit 213 detects that the supply of power from the host device 2 has been interrupted, the PLP regulator 42 receives regenerative energy generated in the SPM 12 via the spindle motor control circuit 212. The PLP regulator 42 then generates power based on the regenerative energy received from the SPM 12 and supplies the generated power to the SVC 21. In other words, the PLP regulator 42 generates power based on the back electromotive force from the SPM 12 and supplies the generated power to the SVC 21.

[0034] Here, the power supplied from the V12 power supply is an example of the first power and the fourth power. The power supplied from the V5 power supply is an example of the first power and the fifth power. The power generated based on the back electromotive force from the SPM12 is an example of the third power.

[0035] The current supply to the SPM 12 is stopped while the magnetic disk 11 is rotating. The energy resulting from the back electromotive force of the SPM 12 is recovered as regenerative energy by the spindle motor control circuit 212. In addition, the kinetic energy of the rotating magnetic disk is converted into electrical energy by the SPM 12, and this electrical energy is recovered as regenerative energy by the spindle motor control circuit 212.

[0036] In this way, the PLP regulator 42 generates power to be supplied to each component based on the regenerative energy generated when the SPM 12 is stopped. Therefore, the magnetic disk device 1 can operate using the regenerative energy for a period of time after the power supply from the host device 2 is cut off. During this period, the magnetic disk device 1 executes the processing of the PLP function.

[0037] The PLP function is a function that, if a cutoff in the power supply from the host device 2 is detected while data is being written to the magnetic disk 11, prevents the data from being lost from the magnetic disk device 1 by saving the data in the cache memory of the DRAM 29 to a non-volatile memory. In this embodiment, the PLP function process saves the data in the cache area 291 to FROM 28.

[0038] Here, "saving" means temporarily recording data in another recording area. Saving can be any method as long as it temporarily records data in another recording area, and may be, for example, transferring or copying. Saving may also include processes that process data, such as compression, encoding, and format conversion. Hereinafter, the process of saving data in cache area 291 to FROM 28 may be referred to as backup processing.

[0039] As shown in FIG. 2, the SVC 21 mainly includes an FET 211, a spindle motor control circuit 212, a power supply monitoring circuit 213, a 1.8V regulator 214, a 1.5V regulator 215, and a 0.9V regulator 216.

[0040] The FET 211 is a field-effect transistor and is connected between the spindle motor control circuit 212 and the 12V eFuse 41. When the FET 211 is turned on by an on / off control signal from the power supply monitoring circuit 213, the FET 211 supplies power supplied from the 12V power supply to the spindle motor control circuit 212. When the FET 211 is turned off by the on / off control signal from the power supply monitoring circuit 213, the FET 211 cuts off the power supplied from the 12V power supply. The spindle motor control circuit 212 controls the rotation of the SPM 12 .

[0041] The power supply monitoring circuit 213 monitors the power supply from the host device 2. That is, the power supply monitoring circuit 213 monitors the power supply from the 12V power supply and the power supply from the 5V power supply. Specifically, the power supply monitoring circuit 213 is connected to the 12V eFuse 41, monitors the power supply voltage of the 12V power supply, and monitors whether the 12V power supply is powered off or has recovered from a power outage. The power supply monitoring circuit 213 is connected to the 5V eFuse 43, monitors the power supply voltage of the 5V power supply, and monitors whether the 5V power supply is powered off or has recovered from a power outage.

[0042] When the power supply monitoring circuit 213 detects that the power supply from the host device 2 has been cut off, it negates the on / off control signal output to the FET 211 to turn off the FET 211. When the power supply monitoring circuit 213 detects that the power supply from the host device 2 has been cut off, it asserts the on / off control signal to the PLP regulator 42. This makes it possible to back up the PLP function. Hereinafter, the interruption of the power supply from the host device 2 may be referred to as a power loss.

[0043] The 1.8V regulator 214 generates 1.8V power based on the power from the 12V eFuse 41, the 5V eFuse 43, and the PLP regulator 42, and supplies the generated power to the FROM 28.

[0044] The 1.5V regulator 215 generates 1.5V power based on the power from the 12V eFuse 41 , the 5V eFuse 43 , and the PLP regulator 42 , and supplies the 1.5V power to the DRAM 29 .

[0045] The 0.9V regulator 216 generates 0.9V power based on the power from the 12V eFuse 41, the 5V eFuse 43, and the PLP regulator 42, and supplies the 0.9V power to the SoC 30.

[0046] Here, the PLP regulator 42, the 1.8V regulator 214, the 1.5V regulator 215, and the 0.9V regulator 216 are examples of power supply circuits.

[0047] The HDC 23 is an example of a controller. The HDC 23 may be configured with a CPU (Central Processing Unit), a logic circuit, or both. The HDC 23 controls the entire magnetic disk device 1 in response to commands received from the host device 2.

[0048] While receiving power from the host device 2, the HDC 23 performs normal operation using power supplied from the 0.9V regulator 216. The normal operation includes sending and receiving commands and data to and from the host device 2 via the host I / F 31, and reading and writing data from and to the magnetic disk 11. This includes access (write, read) to

[0049] For example, in normal operation, when the HDC 23 receives data requested to be written by a write command from the host device 2, it stores the received data in the cache area 291. The HDC 23 causes the RWC 25 to write the data in the cache area 291 to the magnetic disk 11. In other words, the HDC 23 writes the data received from the host device 2 to the magnetic disk 11 via the cache area 291. The HDC 23 also transmits the data output from the RWC 25 to the host device 2.

[0050] When the external power supply is turned off and the power supply is cut off (i.e., when a power loss occurs), the HDC 23 terminates normal operation, negates the host I / F enable signal, and disables communication with the host device 2.

[0051] Here, the host I / F enable signal is a signal that instructs the host I / F 31 to enable or disable communication. By asserting the host I / F enable signal, the host I / F 31 is enabled and communication with the host device 2 is enabled. On the other hand, by negating the host I / F enable signal, the host I / F 31 is disabled and communication with the host device 2 is disabled. Here, the host I / F enable signal is a signal that controls communication with the host device 2. By asserting the host I / F enable signal, communication with the host device 2 is enabled, and by negating it, communication with the host device 2 is disabled.

[0052] The HDC 23 then executes backup processing related to the PLP function. A power supply interruption (i.e., the occurrence of a power loss) due to an interruption of the external power supply is notified by the power supply monitoring circuit 213. After receiving the notification of the power supply interruption, the HDC 23 can execute backup processing while the backup enable signal is asserted. The HDC 23 executes backup processing by using the power supplied from the PLP regulator 42, i.e., the power generated from the regenerative energy generated when the SPM 12 is stopped.

[0053] In this embodiment, the HDC 23 further maintains connection with the external power source even if the power supply is interrupted, and enables communication with the host device 2 when the power supply monitoring circuit 213 determines that the power supply has been restored.

[0054] Specifically, even if the power supply monitoring circuit 213 detects that either or both of the power supply from the V12 power supply and the V5 power supply have been cut off, the HDC23 maintains the connection to the V12 power supply and the V5 power supply to which power has been cut off and starts backup processing. That is, when the power supply from the V12 power supply is cut off, or when the power supply from the V5 power supply is cut off, or when the power supply from both the 12V power supply and the 5V power supply is cut off, the HDC23 turns on the 12V eFuse 41 and the 5V eFuse 43 and starts backup processing. This allows the power supply monitoring circuit 213 to detect the recovery of the 12V power supply and the recovery of the 5V power supply.

[0055] Here, in the example of the 12V eFuse 41 in FIG. 2, the 12V power supply is restored, but there are also cases where the 5V power supply is restored.

[0056] 3 is a diagram showing an example in which only the 5V power supply is restored in the configuration of the magnetic disk device 1 according to the first embodiment. In the example of the 5V eFuse 43 in FIG. 3, an example in which the 5V power supply is restored is shown, but there are also cases in which both the 12V power supply and the 5V power supply are restored.

[0057] As described above, in this embodiment, during backup processing, the 12V eFuse 4 and 5V eFuse 43 maintain connection to the 12V power supply and the 5V power supply. Therefore, when the power supply from the V12 power supply or the V5 power supply is restored, the power supply monitoring circuit 213 can detect this restoration. When the power supply monitoring circuit 213 detects that the power supply from the cut-off V12 power supply or the V5 power supply has been restored, the HDC 23 asserts the host I / F enable signal to enable communication with the host device 2.

[0058] This enables communication with the host device 2 during backup processing, and write data may be sent from the host device 2. Therefore, during backup processing, the HDC 23 receives write data sent from the host device 2 and stores the received write data in FROM 28.

[0059] Next, a control process performed by the magnetic disk device 1 according to this embodiment configured as above will be described. FIG. 4 is a flowchart illustrating an example of a procedure of a control process according to the first embodiment. Suppose that the external power supply (i.e., the 5V power supply or the 12V power supply) is shut off while the magnetic disk device 1 is performing normal processing (S11). As a result, the power supply monitoring circuit 213 detects a fault and determines that the power supply from the 5V power supply or the 12V power supply has been cut off (S12). The power supply monitoring circuit 213 then turns on the 12V eFuse 41 and the 5V eFuse 43 (S13).

[0060] Next, the power supply monitoring circuit 213 asserts an on / off control signal to the PLP regulator 42, thereby switching the process to execution of the PLP function (S14). Thereafter, the HDC 23 disables communication with the host device 2 (S15). Next, the power supply monitoring circuit 213 determines whether the power supply has been restored by the restoration of the external power supply (12V power supply or 5V power supply) (S16). If the external power supply has not been restored (S16: No), the PLP regulator 42 generates 5V power from the back electromotive force of the SPM 12 and supplies the generated 5V power to the SVC 21 (S17). Then, the HDC 23 executes the operation of the PLP function to perform backup processing (S18). Thereafter, the process proceeds to S25.

[0061] In S16, if the external power supply (12V power supply or 5V power supply) is restored and the power supply from the external power supply is restored (S16: Yes), the PLP regulator 42 generates 5V power from the power of the restored external power supply (12V power supply or 5V power supply) and supplies the generated 5V power to the SVC 21 (S19).

[0062] Next, the HDC 23 enables communication with the host device 2 (S20). Next, the HDC 23 determines whether data backup is necessary (S21). Specifically, the HDC 23 determines whether the operation mode of the magnetic disk device 1 is in the standby state, the idle B state, or the idle C state.

[0063] Here, the idle B state is a state in which the magnetic head 22 is retracted and the SPM 12 is rotating at a normal speed (e.g., 7200 rpm), and the idle C state is a state in which the magnetic head 22 is retracted and the SPM 12 is rotating at a low speed (e.g., 3200 rpm).

[0064] If the operating mode of the magnetic disk device 1 is either the standby state, the idle B state, or the idle C state, data backup is not required (S21: No), the process proceeds to S27, the HDC23 restarts the magnetic disk device 1 (S27), and the process ends.

[0065] If the operating mode of the magnetic disk device 1 is not the standby state, the idle B state, or the idle C state, data backup is necessary (S21: Yes), and the HDC 23 executes the operation of the PLP function to perform backup processing (S22).

[0066] Next, the HDC 23 determines whether or not a write command has been received from the host device 2 (S23). If a write command has been received from the host device 2 (S22: Yes), the write data is saved in FROM 28 (S24). If a write command has not been received from the host device 2 (S23: No), the processing of S24 is not performed.

[0067] Next, in S25, the HDC 23 determines whether the PLP operation has timed out (S25). If the PLP operation has not timed out (S25: No), the process returns to S22, and the processes from S22 to S24 are repeatedly executed.

[0068] On the other hand, if the PLP operation times out (S25: Yes), the HDC 23 completes the PLP operation (S26), and then restarts the magnetic disk device 1 (S27), and the process ends.

[0069] In the magnetic disk device of the comparative example, if an external power supply is interrupted during operation, the PLP function uses the back electromotive force of the SPM 12 to perform backup processing, writing data stored in the DRAM 29 to the FROM 28. At this time, unnecessary circuits and communication interfaces are disabled to maintain the back electromotive force. However, in such a case, the magnetic disk device 1 cannot be restarted or communicate with the host device 2 until the PLP function times out. Therefore, if the timer of the host device 2 is short, the timeout may prevent the host device 2 from recognizing the magnetic disk device 1.

[0070] Therefore, in the magnetic disk device 1 of this embodiment, the power supply monitoring circuit 213 maintains connection with the external power source even if the power supply from the external power source is cut off, and the HDC 23 enables communication with the host device 2 when the power supply monitoring circuit 213 determines that the power supply from the external power source has been restored.

[0071] Therefore, according to this embodiment, even when the power supply from the external power source is cut off and the PLP function is being executed to perform backup processing, the recovery of the external power source is monitored, and communication with the host device 2 is enabled. Therefore, according to this embodiment, even when the cut-off external power source is restored, it is possible to avoid the occurrence of a timeout by the host device 2 due to the host device 2 being separated from the magnetic disk device 1, and to smoothly communicate with the host device 2.

[0072] Furthermore, in the magnetic disk device 1 according to this embodiment, the power supply monitoring circuit 213 monitors the power supply from the V12 power supply and the power supply from the V5 power supply, and maintains connection with the V12 power supply and the V5 power supply even if either or both of the power supply from the V12 power supply and the power supply from the V5 power supply are cut off, and the HDC 23 enables communication with the host device 2 when it is determined by the power supply monitoring circuit 213 that either the power supply from the V12 power supply or the power supply from the V5 power supply that was cut off has been restored.

[0073] Therefore, according to this embodiment, even when the power supply from the V12 power supply or the V5 power supply is cut off and the PLP function is being executed to perform backup processing, the power supply from the V12 power supply and the power supply from the V5 power supply are monitored for recovery, enabling communication with the host device 2. Therefore, according to this embodiment, even when the cut-off V12 power supply or V5 power supply is restored, it is possible to avoid the occurrence of a timeout by the host device 2 due to the host device 2 being disconnected from the magnetic disk device 1, and to smoothly communicate with the host device 2.

[0074] In addition, in the magnetic disk device 1 of this embodiment, the power supply monitoring circuit 213 turns on the 12V eFuse 41 connected between the V12 power supply and the power supply monitoring circuit 213, and the 5V eFuse 43 connected between the V5 power supply and the power supply monitoring circuit 213, even if either or both of the power supply from the V12 power supply and the power supply from the V5 power supply are cut off.

[0075] Therefore, according to this embodiment, even when the power supply from the V12 power supply or the V5 power supply is cut off and the PLP function is being executed to perform backup processing, it is possible to reliably monitor the restoration of the power supply from the V12 power supply and the V5 power supply. Therefore, according to this embodiment, even when the cut-off V12 power supply or V5 power supply is restored, it is possible to avoid the occurrence of a timeout by the host device 2 due to the host device 2 being disconnected from the magnetic disk device 1, and to perform communication with the host device 2 more smoothly.

[0076] In addition, in the magnetic disk device 1 according to this embodiment, when communication with the host device 2 is enabled while the PLP function backup process is being executed, the HDC 23 receives write data sent from the host device 2 and stores the received write data in FROM 28.

[0077] Therefore, according to this embodiment, even if the cut-off V12 power supply or V5 power supply is restored, even if the host device 2 sends a write command to the magnetic disk device 1, a timeout by the host device 2 can be avoided, and communication with the host device 2 can be carried out more smoothly.

[0078] (Second embodiment) In the first embodiment, even if the external power supply is cut off, the connection with the external power supply is maintained, communication with the host device 2 is enabled, and when the external power supply is restored, if a write command is received from the host device 2 while a PLP operation is being executed, write data is written to FROM 28. In this second embodiment, information regarding the status of the magnetic disk device 1, such as the progress of the PLP operation, is also transmitted to the host device 2.

[0079] The configuration of the magnetic disk device 1 according to this embodiment is the same as that of the first embodiment shown in FIGS.

[0080] The HDC23 in this embodiment has the same functions as the first embodiment, and furthermore, when communication with the host device 2 is enabled while backup processing is being performed using the PLP function, it sends information regarding the status of the magnetic disk device 1 to the host device 2.

[0081] Here, the information about the state of the magnetic disk device 1 includes at least one of the progress of the backup process by the PLP function and the operation mode of the magnetic disk device 1.

[0082] In addition, in this embodiment, after sending information regarding the status of the magnetic disk device 1 to the host device 2, if the HDC23 receives an instruction to interrupt the backup process from the host device 2, it terminates the backup process of the PLP function without waiting for the backup process of the PLP function to time out.

[0083] Next, a control process performed by the magnetic disk device 1 according to this embodiment configured as above will be described. 5 and 6 are flowcharts illustrating an example of a procedure of a control process according to the second embodiment.

[0084] The processing (S11 to S24) from when the 5V or 12V power supply is cut off until the write command is accepted and the write data is saved is executed in the same manner as in the first embodiment.

[0085] After S24, the HDC 23 transmits the progress of the PLP operation to the host device 2 as information about the state of the magnetic disk device 1 (S31). Here, the HDC 23 may transmit the operating mode of the magnetic disk device 1 to the host device 2.

[0086] Next, the HDC 23 determines whether or not an instruction to suspend the PLP operation (i.e., backup processing) has been received from the host device 2 (S32). If an instruction to suspend the PLP operation (backup processing) has not been received from the host device 2 (S32: No), the process proceeds to S25, and the same process as in the first embodiment is performed.

[0087] On the other hand, if an instruction to suspend the PLP operation (i.e., backup processing) is received from the host device 2 (S32: Yes), the HDC 23 suspends the PLP operation without waiting for the PLP operation to time out, restarts the magnetic disk device 1 (S27), and the process ends.

[0088] As described above, in the magnetic disk device 1 according to this embodiment, if communication with the host device 2 is enabled while the PLP function backup process is being executed, the HDC 23 transmits information about the state of the magnetic disk device 1 to the host device 2.

[0089] Therefore, according to this embodiment, even if the power supply from the external power source is interrupted and the PLP function is being executed to perform backup processing, when the interrupted external power source is restored, information regarding the status of the magnetic disk device 1 is sent to the host device 2. Therefore, according to this embodiment, it is possible to avoid the occurrence of a timeout by the host device 2 due to the host device 2 being disconnected from the magnetic disk device 1, and to perform communication with the host device 2 more smoothly.

[0090] Furthermore, in the magnetic disk device 1 according to this embodiment, the information relating to the state of the magnetic disk device 1 includes at least one of the progress of the backup process of the PLP function and the operation mode of the magnetic disk device 1.

[0091] Therefore, according to this embodiment, even if the power supply from the external power source is interrupted and the PLP function is being executed and backup processing is being performed, when the interrupted external power source is restored, at least one of the progress status of the backup processing of the PLP function or the operating mode of the magnetic disk device 1 is transmitted to the host device 2. Therefore, according to this embodiment, the occurrence of a timeout by the host device 2 due to the host device 2 being disconnected from the magnetic disk device 1 can be avoided, and communication with the host device 2 can be performed more smoothly.

[0092] Furthermore, in the magnetic disk device 1 of this embodiment, after sending information regarding the status of the magnetic disk device 1 to the host device 2, if the HDC 23 receives an instruction to interrupt the backup process from the host device 2, it terminates the backup process, i.e., the PLP operation, without waiting for the backup process to time out.

[0093] Therefore, according to this embodiment, if the power supply from the external power source is cut off and the PLP function is executed while the backup process is being performed and the cut-off external power source is restored, and an instruction to interrupt the backup process is received from the host device 2, the backup process is terminated without waiting for the backup process to time out, thereby enabling smoother communication with the host device 2.

[0094] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0095] 1. Magnetic disk device 2. Host Device 11 Magnetic Disk 12 SPM 13 Lamp 15 Actuator Arm 16 VCM 21 SVC 22 Magnetic head 22r readhead 22w light head 23 HDC 24 Preamp 25 RWC 26 processors 27 Sensors 28 FROM 29 DRAM 30 SoC 31 Host I / F 41 12V eFuse 42 PLP regulator 43 5V eFuse 45 I / F connector 211 FET 212 Spindle motor control circuit 213 Power supply monitoring circuit 214 1.8V regulator 215 1.5V regulator 216 0.9V regulator 291 Cache Area

Claims

1. one or more magnetic disks; a motor that rotates the one or more magnetic disks; a power supply circuit that generates a second electric power from a first electric power supplied from an external power supply, and that generates a third electric power based on regenerative energy generated when the motor is stopped when the supply of the first electric power is interrupted; a first non-volatile memory; a volatile second memory having a cache area; a controller that, while the first power is being supplied, writes data received from a host device to the magnetic disk via the cache area using the second power generated by the power supply circuit, and, when the supply of the first power is interrupted, disables communication with the host device and executes a backup process that saves the contents of the cache area to the first memory using the third power generated by the power supply circuit; a power supply monitoring circuit that monitors the supply of the first power; the power supply monitoring circuit maintains connection with the external power supply even when the supply of the first power is interrupted; the controller enables communication with the host device when the power supply monitoring circuit determines that the supply of the first power has been restored; Magnetic disk device.

2. the external power source includes a first external power source that supplies a fourth power as the first power, and a second external power source that supplies a fifth power as the first power; the power supply monitoring circuit monitors the supply of the fourth power and the supply of the fifth power, and maintains connection with the first external power supply and the second external power supply even when either or both of the supply of the fourth power and the supply of the fifth power is interrupted; the controller enables communication with the host device when it is determined by the power supply monitoring circuit that either the fourth power supply or the fifth power supply that was cut off has been restored; 2. The magnetic disk drive according to claim 1.

3. a first electronic fuse connected between the first external power supply and the power supply circuit and the power supply monitoring circuit, which, when turned on, allows the fourth power to be supplied to the power supply circuit and, when turned off, cuts off the supply of the fourth power to the power supply circuit; a second electronic fuse connected between the second external power source and the power supply circuit and the power supply monitoring circuit, which, when turned on, allows the fifth power to be supplied to the power supply circuit and, when turned off, cuts off the supply of the fifth power to the power supply circuit; Furthermore, the power supply monitoring circuit turns on the first electronic fuse and the second electronic fuse even when either or both of the fourth power supply and the fifth power supply are cut off; 3. The magnetic disk drive according to claim 2.

4. When the controller enables communication with the host device during execution of the backup process, the controller receives write data transmitted from the host device and stores the received write data in a first memory.

2. The magnetic disk drive according to claim 1.

5. When the controller enables communication with the host device during the execution of the backup process, the controller transmits information regarding the status of the magnetic disk device to the host device.

2. The magnetic disk drive according to claim 1.

6. the information relating to the status of the magnetic disk device includes at least one of the progress of the backup process and the operating mode of the magnetic disk device; 6. The magnetic disk drive according to claim 5.

7. when the controller receives an instruction to suspend the backup process from the host device after transmitting information about the status of the magnetic disk device to the host device, the controller ends the backup process without waiting for a timeout of the backup process.

6. The magnetic disk drive according to claim 5.

8. A control method executed in a magnetic disk device, comprising: The magnetic disk device one or more magnetic disks; a motor that rotates the one or more magnetic disks; a power supply circuit that generates a second electric power from a first electric power supplied from an external power supply, and that generates a third electric power based on regenerative energy generated when the motor is stopped when the supply of the first electric power is interrupted; a first non-volatile memory; a volatile second memory having a cache area; while the first power is being supplied, the second power generated by the power supply circuit is used to write data received from a host device to the magnetic disk via the cache area; when the supply of the first power is interrupted, communication with the host device is disabled, and a backup process is executed to save the contents of the cache area to the first memory using the third power generated by the power supply circuit; monitoring the supply of the first power; maintaining a connection with the external power source even when the supply of the first power is interrupted; When it is determined that the supply of the first power has been restored, communication with the host device is enabled. A control method comprising:

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