Magnetic disk device and control method

Abstract

The invention provides a magnetic disk device and a control method. The present invention makes it possible to smoothly communicate with a host device even when a backup process is executed. A magnetic disk device according to an embodiment includes a controller that writes data received from a host device into a magnetic disk via a cache region using second power generated by a power supply circuit while first power supplied from an external power source is being supplied, and when the supply of the first power is cut off, disables communication with the host device, and when the supply of the second power is cut off, disables communication with the host device. A backup processing unit that executes a backup process for transferring the content of the cache region to the first memory using a third power generated by the power supply circuit; and a power supply monitoring circuit that monitors the supply of the first power, the power supply monitoring circuit maintains connection with an external power supply even when the supply of the first power is cut off, and the controller enables communication with the host device when it is determined by the power supply monitoring circuit that the supply of the first power is restored.

Description

[0001] This application claims the benefit of priority based on Japanese Patent Application No. 2024-035580 (filing date: March 8, 2024), the entire contents of which are incorporated herein by reference. Technical Field

[0002] Embodiments of the present invention relate to a magnetic disk device and a control method. Background Art

[0003] The magnetic disk drive has a PLP (Power Loss Protection) function. If the power supply from the external power source is cut off, the PLP function disables communication with the host device and transfers data stored in the cache memory and currently being written to the disk to a non-volatile storage area. Summary of the Invention

[0004] An embodiment of the present invention provides a magnetic disk device that can smoothly communicate with a host device even when a PLP function is executed.

[0005] A magnetic disk drive according to an embodiment includes: one or more magnetic disks; a motor for rotating the one or more magnetic disks; a power supply circuit for generating a second electric power based on a first electric power supplied from an external power source, and generating a third electric power based on regenerative energy generated when the motor stops when the supply of the first electric power is cut off; a non-volatile first memory; a volatile second memory having a cache area; a controller for writing data received from a host device to the magnetic disk via the cache area using the second electric power generated by the power supply circuit while the first electric power is supplied, and for disabling communication with the host device when the supply of the first electric power is cut off, and performing a backup process for transferring the contents of the cache area to the first memory using the third electric power generated by the power supply circuit; and a power supply monitoring circuit for monitoring the supply of the first electric power, the power supply monitoring circuit maintaining connection with the external power source even when the supply of the first electric power is cut off, and the controller enabling communication with the host device when the power supply monitoring circuit determines that the supply of the first electric power has been restored. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 This is a schematic diagram showing an example of the configuration of the magnetic disk device according to the first embodiment.

[0007] Figure 2 This is a diagram showing an example of the configuration of a magnetic disk device showing the configuration of an SVC according to the first embodiment.

[0008] Figure 3 This diagram shows an example of a case where only the 5V power supply is restored in the configuration of the magnetic disk drive according to the first embodiment.

[0009] Figure 4 This is a flowchart showing an example of the procedure of the control process in the first embodiment.

[0010] Figure 5 This is a flowchart showing an example of the procedure of the control process according to the second embodiment.

[0011] Figure 6 This is a flowchart showing an example of the procedure (subsequent processing) of the control process according to the second embodiment.

[0012] Description of Reference Numerals

[0013] 1: Magnetic disk device, 2: Host device, 11: Magnetic disk, 12: SPM, 13: RAMP, 15: Actuator arm, 16: VCM, 21: SVC, 22: Magnetic head, 22r: Read head, 22w: Write head, 23: HDC, 24: Preamplifier, 25: RWC, 26: Processor, 27: Sensor type, 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. DETAILED DESCRIPTION

[0014] Hereinafter, the disk device and control method according to the embodiment will be described in detail with reference to the accompanying drawings. However, this embodiment does not limit the present invention.

[0015] (First embodiment)

[0016] Figure 1 This is a schematic diagram showing an example of the configuration of the magnetic disk device 1 according to the embodiment.

[0017] 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.

[0018] 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 accordance with an access command. Access includes writing and reading data.

[0019] Data is written and read via the magnetic head 22. Specifically, the magnetic disk device 1 includes, in addition to the magnetic disk 11, 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.

[0020] The magnetic disk 11 is rotated at a predetermined rotational speed by the SPM 12 coaxially mounted thereon.

[0021] 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 rotation of the VCM 16 via the SVC 21. Details of the SVC 21 will be described later.

[0022] The magnetic head 22 writes and reads information to and from the magnetic disk 11 using its write head 22w and read head 22r. The magnetic head 22 is attached to the front end of the actuator arm 15. The magnetic head 22 moves in the radial direction of the magnetic disk 11 via the VCM 16 driven by the SVC 21. Alternatively, a plurality of either or both of the write head 22w and read head 22r may be provided for each single magnetic head 22.

[0023] When the rotation of the magnetic disk 11 stops, for example, the magnetic head 22 moves onto the ramp 13. The ramp 13 is configured to hold the magnetic head 22 at a position separated from the magnetic disk 11.

[0024] 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 the signal read from the magnetic disk 11 by the magnetic head 22, outputs the amplified signal, and supplies it to the RWC 25. Furthermore, during a write operation, the preamplifier 24 amplifies the signal corresponding to the data to be written, supplied from the RWC 25, and supplies the amplified signal to the magnetic head 22.

[0025] The host I / F 31 is a communication interface with the host device 2 .

[0026] The HDC 23 controls data transmission and reception with the host device 2 via the host I / F 31 , controls the DRAM 29 , and the like.

[0027] DRAM 29 is used as a buffer memory for data transmitted and received with the host device 2. Specifically, a cache area 291 is allocated to DRAM 29, and DRAM 29 functions as a cache memory. Cache area 291 is used to temporarily store data received from the host device 2 that has not yet been written to the magnetic disk 11. DRAM 29 is also used to temporarily store data read from the magnetic disk 11.

[0028] The DRAM 29 is used as a memory for operation by the processor 26. The DRAM 29 is used as an area for loading firmware and an area for temporarily storing various management data. The DRAM 29 is an example of a second memory.

[0029] The RWC 25 modulates the write target data supplied from the HDC 23 and stored in the cache area 291, and supplies the modulated data to the preamplifier 24. Furthermore, the RWC 25 demodulates the signal read from the magnetic disk 11 and supplied from the preamplifier 24, including error correction, and then outputs the demodulated signal as digital data to the HDC 23.

[0030] The processor 26 is, for example, a CPU (Central Processing Unit), to which sensors 27 , a FROM (Flash Read Only Memory) 28 , and a DRAM 29 are connected.

[0031] The FROM 28 stores firmware (program data) and various operating parameters. Alternatively, the firmware may be stored in the magnetic disk 11. The FROM 28 is an example of a first memory.

[0032] The sensors 27 are sensor modules that detect environmental information and include, for example, an acceleration sensor module for detecting vibration or shock applied to the magnetic disk device 1 , or a temperature sensor module for detecting the temperature of the magnetic disk device 1 .

[0033] The processor 26 controls the entire magnetic disk device 1 according to the firmware stored in the FROM 28 or the magnetic disk 11. For example, the processor 26 loads the 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 according to the firmware loaded into the DRAM 29.

[0034] The HDC 23, the host I / F 31, the RWC 25, and the processor 26 constitute a single integrated circuit (SoC) 30 (System-On-a-Chip). The SoC 30 may include other elements (eg, FROM 28 or DRAM 29) in addition to these elements.

[0035] In addition, part or all of the functions of the processor 26 may also be implemented by a hardware circuit such as an FPGA (Field-Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit).

[0036] Figure 2 This is a diagram showing an example of the configuration of the magnetic disk device 1 , showing the configuration of the SVC 21 according to the first embodiment.

[0037] The I / F connector 45 is a general term for various terminals, and is provided in the housing of the magnetic disk device 1 .

[0038] A 12V power supply and a 5V power supply are provided as external power supplies in the host device 2. 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.

[0039] The 12V eFuse (electronic fuse) 41 is connected to a 12V power supply via an I / F connector 45. Here, the I / F connector 45 connected to the 12V eFuse 41 is a 12V power supply terminal.

[0040] The power supplied from the 12V power supply is input to the 12VeFuse 41 via the I / F connector 45 (ie, the 12V power supply terminal).

[0041] The 12V eFuse 41 is an integrated circuit (IC) comprised of a MOSFET and other components, and includes an overcurrent protection function to prevent overcurrent from flowing through the power supply path within which it resides. The 12V eFuse 41 utilizes this overcurrent protection function to detect overcurrent and shut off power when overcurrent is detected. If the 12V power supply is shut off, the 12V eFuse 41 is disconnected. Furthermore, when the 12V power supply is restored, the 12V eFuse 41 is closed, allowing the power supplied from the 12V power supply to be supplied to the SVC 21.

[0042] The 5V eFuse 43 is connected to a 5V power supply via an I / F connector 45. Here, the I / F connector 45 to which the 5V eFuse 43 is connected is a 5V power supply terminal.

[0043] The power supplied from the 5V power supply is input to the 5VeFuse 43 via the I / F connector 45 (ie, the 5V power supply terminal).

[0044] The 5V eFuse 43 is an integrated circuit (IC) that includes a MOSFET and other components and provides overcurrent protection to prevent overcurrent from flowing through the power supply path it resides in. The 5V eFuse 41 uses this overcurrent protection function to detect overcurrent and shut off power when it detects it. If the 5V power supply is shut off, the 5V eFuse 43 is turned off. Furthermore, when the 5V power supply is restored, the 5V eFuse 43 is turned on, allowing the power supplied from the 5V power supply to be supplied to the SVC 21.

[0045] The PLP regulator 42 supplies power to the SVC 21 for the PLP function described later. When the power supply from the 12V power supply is cut off, the PLP regulator 42 supplies the back electromotive force of the SPM 12 supplied from the spindle motor control circuit 212 described later. In addition, when the power supply from the 12V power supply is not cut off, the PLP regulator 42 receives the power from the 12V power supply supplied from the FET 211, generates power (an example of the second power) based on the supplied power, and supplies the generated power to the SVC 21. Here, "generated power" includes, for example, rectification, step-up, or step-down processing. The PLP regulator 42 can also supply the supplied power to each part as it is.

[0046] If the power supply from the host device 2 is cut off, the power supply monitoring circuit 213 (described later) can detect that the power supply from the host device 2 has been cut off. When the power supply monitoring circuit 213 detects that the power supply from the host device 2 has been cut off, the PLP regulator 42 receives regenerative energy generated by 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.

[0047] 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 SPM 12 is an example of the third power.

[0048] The current supply to the SPM 12 is stopped during the rotation of the magnetic disk 11. The energy generated by the back electromotive force of the SPM 12 is recovered as regenerative energy by the spindle motor control circuit 212. Furthermore, 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.

[0049] In this manner, the PLP regulator 42 generates power for various components based on the regenerative energy generated when the SPM 12 is stopped. This allows the magnetic disk drive 1 to operate using the regenerative energy for a brief period after the power supply from the host device 2 is cut off. During this period, the magnetic disk drive 1 executes the PLP function.

[0050] The PLP function is a function that, when a power outage from the host device 2 is detected while data is being written to the magnetic disk 11, causes data in the cache memory of the DRAM 29 to be transferred to the nonvolatile memory, thereby preventing the data from being lost from the magnetic disk device 1. In the present embodiment, the PLP function processes data in the cache area 291 by transferring it to the FROM 28.

[0051] Here, "dumping" refers to temporarily recording data in another recording area. "Dumping" simply means "temporarily recording data in another recording area," and can include, for example, transferring or copying. "Dumping" can also include data processing such as compression, encoding, and format conversion. Hereinafter, the process of transferring data in cache area 291 to FROM 28 will sometimes be referred to as backup processing.

[0052] like Figure 2 As shown, the SVC 21 mainly includes a 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 .

[0053] The FET 211 is a field effect transistor 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 from the 12V power supply to the spindle motor control circuit 212. When the FET 211 is turned off by an on / off control signal from the power supply monitoring circuit 213, the FET 211 blocks the power from the 12V power supply.

[0054] The spindle motor control circuit 212 controls the rotation of the SPM 12 .

[0055] The power monitoring circuit 213 monitors the power supply from the host device 2. Specifically, the power monitoring circuit 213 monitors the power supply from the 12V power supply and the power supply from the 5V power supply. Specifically, the power monitoring circuit 213 is connected to the 12V eFuse 41 to monitor the power supply voltage of the 12V power supply and to monitor whether the 12V power supply has been shut off or recovered from a power outage. The power monitoring circuit 213 is connected to the 5V eFuse 43 to monitor the power supply voltage of the 5V power supply and to monitor whether the 5V power supply has been shut off or recovered from a power outage.

[0056] When the power 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, turning off the FET 211. Furthermore, when the power 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 allows for backup of the PLP function.

[0057] Hereinafter, “the supply of power from the host device 2 is cut off” may be referred to as “power off”.

[0058] 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 .

[0059] 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 generated power to the DRAM 29 .

[0060] 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 generated power to the SoC 30 .

[0061] Here, the PLP regulator 42 , the 1.8V regulator 214 , the 1.5V regulator 215 , and the 0.9V regulator 216 are examples of a power supply circuit.

[0062] The HDC 23 is an example of a controller. The HDC 23 may be composed of a CPU (Central Processing Unit), a logic circuit, or both. The HDC 23 controls the entire magnetic disk device 1 based on commands received from the host device 2 .

[0063] While receiving power from the host device 2 , the HDC 23 performs normal operations using power supplied from the 0.9V regulator 216 . Normal operations include sending and receiving commands and data to and from the host device 2 via the host I / F 31 and accessing (writing and reading) the magnetic disk 11 .

[0064] For example, during 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 then 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. Furthermore, the HDC 23 transmits data output from the RWC 25 to the host device 2.

[0065] When the external power supply is turned off and the power supply is cut off (ie, when a power outage occurs), the HDC 23 ends normal operation and negates the host I / F enable signal to disable communication with the host device 2 .

[0066] Here, the host I / F enable signal is a signal for instructing the host I / F 31 to enable or disable communication. By asserting the host I / F enable signal, the host I / F 31 becomes enabled, enabling communication with the host device 2. On the other hand, by deasserting the host I / F enable signal, the host I / F 31 becomes disabled, disabling communication with the host device 2. Here, the host I / F enable signal is a signal for controlling communication with the host device 2. By asserting the host I / F enable signal, communication with the host device 2 becomes enabled, and by deasserting the host I / F enable signal, communication with the host device 2 becomes disabled.

[0067] The HDC 23 then executes backup processing related to the PLP function. The power supply interruption (i.e., the occurrence of a power outage) caused by the disconnection of the external power supply is notified by the power supply monitoring circuit 213. After receiving notification of the power interruption, the HDC 23 can execute the backup processing while the backup enable signal is active. The HDC 23 executes the backup processing using power supplied from the PLP regulator 42, that is, using power generated from the regenerative energy generated when the SPM 12 is stopped.

[0068] In this embodiment, the HDC 23 maintains connection to the external power supply even when power supply is cut off, and enables communication with the host device 2 when the power monitoring circuit 213 determines that power supply has been restored.

[0069] Specifically, even if the power monitoring circuit 213 detects that either or both of the power supply from the V12 power supply and the power supply from the V5 power supply have been disconnected, the HDC 23 maintains connection to the disconnected V12 power supply and the V5 power supply and initiates backup processing. In other words, if the power supply from the V12 power supply is disconnected, if the power supply from the V5 power supply is disconnected, or if the power supply from both the 12V power supply and the 5V power supply is disconnected, the HDC 23 turns on the 12V eFuse 41 and the 5V eFuse 43 and initiates backup processing. This allows the power monitoring circuit 213 to detect the restoration of the 12V power supply and the 5V power supply.

[0070] Here, in Figure 2 The example of the 12V eFuse 41 shows an example where the 12V power supply is restored, but there is also a case where the 5V power supply is restored.

[0071] Figure 3 1 is a diagram showing an example of a case where only the 5V power supply is restored in the configuration of the magnetic disk device 1 according to the first embodiment. Figure 3 The example of the 5V eFuse 43 shows an example in which the 5V power supply is restored, but there is also a case in which both the 12V power supply and the 5V power supply are restored.

[0072] As described above, in this embodiment, during backup processing, connections to the 12V and 5V power supplies are maintained via the 12V eFuse 4 and 5V eFuse 43. Therefore, the power monitoring circuit 213 can detect when power has been restored from the V12 or V5 power supply. When the power monitoring circuit 213 detects that power has been restored from the disconnected V12 or V5 power supply, the HDC 23 asserts the host I / F enable signal, enabling communication with the host device 2.

[0073] Since communication with the host device 2 is possible during the backup process, write data may be sent from the host device 2. Therefore, the HDC 23 receives the write data sent from the host device 2 during the backup process and stores the received write data in the FROM 28.

[0074] Next, a description will be given of a control process of the magnetic disk device 1 according to the present embodiment having the above configuration.

[0075] Figure 4This is a flowchart illustrating an example of control processing steps in the first embodiment. Assume that while the magnetic disk drive 1 is executing normal processing, the external power supply (i.e., the 5V power supply or the 12V power supply) is disconnected (S11). Consequently, 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 disconnected (S12). The power supply monitoring circuit 213 then turns on the 12V eFuse 41 and the 5V eFuse 43 (S13).

[0076] Next, the power supply monitoring circuit 213 activates the 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).

[0077] Next, the power monitoring circuit 213 determines whether 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 based on the back electromotive force of the SPM 12 and supplies the generated 5V power to the SVC 21 (S17). The HDC 23 then executes the PLP function and performs the backup process (S18). The process then proceeds to S25.

[0078] In S16, when 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 based on the power of the restored external power supply (12V power supply or 5V power supply) and supplies the generated 5V power to SVC21 (S19).

[0079] Next, the HDC 23 enables communication with the host device 2 ( S20 ).

[0080] 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.

[0081] Here, the idle B state is a state where the magnetic head 22 is retracted and the SPM 12 is rotating at normal speed (for example, 7200 rpm). The idle C state is a state where the magnetic head 22 is retracted and the SPM 12 is rotating at low speed (for example, 3200 rpm).

[0082] When the operation mode of the magnetic disk device 1 is in any of the standby state, idle B state, and idle C state, data backup is not required (S21: No), and the processing moves to S27. The HDC 23 restarts the magnetic disk device 1 (S27) and ends the processing.

[0083] When the operation mode of the magnetic disk device 1 is not in the standby state and is not in the idle B state or the idle C state, data backup is required (S21: Yes), and the HDC 23 performs the PLP function and performs backup processing (S22).

[0084] Next, HDC 23 determines whether a write command has been received from host device 2 (S23). If a write command has been received from host device 2 (S22: Yes), the write data is stored in FROM 28 (S24). If a write command has not been received from host device 2 (S23: No), the process of S24 is not performed.

[0085] 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.

[0086] On the other hand, if the PLP operation has timed out (S25: YES), the HDC 23 completes the PLP operation (S26) and then restarts the magnetic disk device 1 (S27), and the process ends.

[0087] In the comparative example magnetic disk drive, if the external power supply is shut off during operation, the PLP function utilizes the back electromotive force of SPM 12 to perform a backup process, writing the data stored in DRAM 29 to FROM 28. In this case, unnecessary circuits and communication interfaces are disabled to maintain the back electromotive force. However, in this case, magnetic disk drive 1 cannot be restarted or communicate with host device 2 before the PLP function times out. Therefore, if the host device 2's timing is short, the timeout may prevent host device 2 from recognizing magnetic disk drive 1.

[0088] Therefore, in the magnetic disk device 1 of this embodiment, the power monitoring circuit 213 maintains the connection with the external power supply even when the power supply from the external power supply is cut off, and the HDC23 enables the communication with the host device 2 when the power monitoring circuit 213 determines that the power supply from the external power supply has been restored.

[0089] Therefore, according to this embodiment, even during the period when the power supply from the external power supply is cut off and the PLP function and backup processing are being executed, the restoration of the external power supply can be monitored, and communication with the host device 2 becomes effective. Therefore, according to this embodiment, even when the external power supply that was cut off is restored, the occurrence of a timeout of 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 smoothly performed.

[0090] In addition, in the magnetic disk device 1 of the present 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 the connection with the V12 power supply and the V5 power supply even when either or both of the power supply from the V12 power supply and the power supply from the V5 power supply are cut off. When the HDC23 determines 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, the HDC23 enables communication with the host device 2.

[0091] Therefore, according to this embodiment, even during the period when the power supply from the V12 power supply or the power supply from the V5 power supply is cut off and the PLP function and backup processing are being executed, the restoration of the power supply from the V12 power supply or the power supply from the V5 power supply is monitored, and communication with the host device 2 is enabled. Therefore, according to this embodiment, it is possible to avoid the occurrence of a timeout of the host device 2 due to the host device 2 being disconnected from the magnetic disk device 1 even when the V12 power supply is cut off or the V5 power supply is restored, thereby smoothly performing communication with the host device 2.

[0092] In addition, in the magnetic disk device 1 of this embodiment, the power supply monitoring circuit 213 connects the 12VeFuse 41 connected between the V12 power supply and the power supply monitoring circuit 213, and the 5VeFuse 43 connected between the V5 power supply and the power supply monitoring circuit 213 even when either or both of the power supply from the V12 power supply and the power supply from the V5 power supply are cut off.

[0093] Therefore, according to this embodiment, even when the power supply from the V12 power supply or the power supply from the V5 power supply is cut off while the PLP function and backup processing are being executed, the restoration of the power supply from the V12 power supply or the power supply from the V5 power supply can be reliably monitored. Therefore, according to this embodiment, it is possible to avoid the occurrence of a timeout of the host device 2 due to the host device 2 being disconnected from the magnetic disk device 1 even when the V12 power supply is cut off or the V5 power supply is restored, thereby ensuring smoother communication with the host device 2.

[0094] In the magnetic disk device 1 of this embodiment, when communication with the host device 2 is enabled during execution of the backup process of the PLP function, the HDC 23 receives write data transmitted from the host device 2 and stores the received write data in the FROM 28 .

[0095] Therefore, according to this embodiment, even when the V12 power supply is cut off or the V5 power supply is restored, the host device 2 can avoid timing out when a write command is sent from the host device 2 to the disk device 1, thereby enabling smoother communication with the host device 2.

[0096] (Second embodiment)

[0097] In the first embodiment, even when the external power supply is turned off, the connection to the external power supply is maintained to enable communication with the host device 2. When the external power supply is restored, if a write command is received from the host device 2 during the execution of the PLP operation, the write data is written to the FROM 28. In this second embodiment, information related to the status of the magnetic disk device 1, such as the progress of the PLP operation, is further transmitted to the host device 2.

[0098] The magnetic disk device 1 of this embodiment is configured as follows Figures 1 to 3 The same is true for the first embodiment shown.

[0099] The HDC 23 of this embodiment has the same functions as those of the first embodiment, and further, during the execution of the backup process of the PLP function, when communication with the host device 2 is enabled, information related to the status of the magnetic disk device 1 is sent to the host device 2.

[0100] Here, the information on the status of the magnetic disk device 1 includes at least one of the progress status of the backup process of the PLP function and the operation mode of the magnetic disk device 1 .

[0101] Furthermore, when receiving a backup process interruption instruction from the host device 2 after transmitting information on the status of the magnetic disk device 1 to the host device 2 , the HDC 23 of this embodiment terminates the PLP function backup process without waiting for the PLP function backup process to time out.

[0102] Next, a description will be given of a control process of the magnetic disk device 1 according to the present embodiment having the above configuration.

[0103] Figure 5 、 Figure 6 This is a flowchart showing an example of the procedure of the control process according to the second embodiment.

[0104] The processes ( S11 to S24 ) from when the 5V power supply is shut off or the 12V power supply is shut off to when a write command is accepted and write data is stored are performed in the same manner as in the first embodiment.

[0105] After S24, the HDC 23 transmits the progress of the PLP operation to the host device 2 as information on the state of the magnetic disk device 1 (S31). Here, the HDC 23 may transmit the operation mode of the magnetic disk device 1 to the host device 2.

[0106] Next, the HDC 23 determines whether an interruption instruction for the PLP operation (i.e., the backup process) has been received from the host device 2 (S32). If an interruption instruction for the PLP operation (backup process) has not been received from the host device 2 (S32: No), the process proceeds to S25 and the same process as the first embodiment is performed.

[0107] On the other hand, when receiving an interruption instruction of the PLP operation (ie, backup processing) from the host device 2 (S32: YES), the HDC 23 interrupts the PLP operation without waiting for the PLP operation to time out, restarts the magnetic disk device 1 (S27), and the process ends.

[0108] As described above, in the magnetic disk device 1 of this embodiment, the HDC 23 transmits information on the status of the magnetic disk device 1 to the host device 2 when enabling communication with the host device 2 while executing the backup process of the PLP function.

[0109] Therefore, according to this embodiment, even while the PLP function and backup processing are being executed while the power supply from the external power source is cut off, information related to the status of the magnetic disk device 1 is transmitted to the host device 2 when the cut-off external power source is restored. Therefore, according to this embodiment, it is possible to avoid a timeout of the host device 2 due to the host device 2 being disconnected from the magnetic disk device 1, thereby enabling smoother communication with the host device 2.

[0110] In the magnetic disk device 1 of the present embodiment, the information on the status of the magnetic disk device 1 includes at least one of the progress status of the backup process of the PLP function and the operation mode of the magnetic disk device 1 .

[0111] Therefore, according to this embodiment, even when the power supply from the external power supply is cut off while the PLP function and backup processing are being executed, when the cut-off external power supply is restored, at least one of the progress status of the backup processing of the PLP function and 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 of the host device 2 due to the separation of the host device 2 from the magnetic disk device 1 can be avoided, thereby enabling smoother communication with the host device 2.

[0112] In addition, in the magnetic disk device 1 of this embodiment, when the HDC 23 receives an interrupt instruction for the backup process from the host device 2 after sending information related to the status of the magnetic disk device 1 to the host device 2, it ends the backup process without waiting for the backup process to time out, that is, ends the PLP operation.

[0113] Therefore, according to this embodiment, during the period when the power supply from the external power supply is cut off and the PLP function is executed and the backup processing is performed, when the cut-off external power supply is restored, when an interrupt indication of the backup processing is received from the host device 2, the backup processing is terminated without waiting for the backup processing to time out, thereby enabling communication with the host device 2 to be carried out more smoothly.

[0114] While several embodiments of the present invention have been described, these embodiments are provided as examples only and are not intended to limit the scope of the invention. These novel embodiments may be implemented in various other forms and may be omitted, replaced, or modified without departing from the gist of the invention. These embodiments and their variations are intended to be within the scope and spirit of the invention and encompassed by the invention set forth in the claims and their equivalents.

Claims

1. A magnetic disk device comprising: More than 1 disk; a motor for rotating the one or more magnetic disks; a power supply circuit that generates second power from first power supplied from an external power supply and, when the supply of the first power is cut off, generates third power based on regenerative energy generated when the motor is stopped; A non-volatile first memory; A volatile second memory having a cache area; a controller that, while the first power is being supplied, uses the second power generated by the power supply circuit to write data received from the host device to the magnetic disk via the cache area, and, when the supply of the first power is cut off, disables communication with the host device and uses the third power generated by the power supply circuit to perform a backup process of transferring the contents of the cache area to the first memory; as well as a power supply monitoring circuit for monitoring 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 cut off. 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.

2. The magnetic disk device according to claim 1, The external power supply includes a first external power supply that supplies fourth power as the first power, and a second external power supply that supplies 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 one or both of the supply of the fourth power and the supply of the fifth power are cut off. The controller enables communication with the host device when the power supply monitoring circuit determines that either the supply of the fourth power or the supply of the fifth power that was interrupted has been restored.

3. The magnetic disk device according to claim 2, The magnetic disk device further comprises: a first electronic fuse connected between the first external power source and the power supply circuit and the power supply monitoring circuit, the first electronic fuse being capable of supplying the fourth power to the power supply circuit by being turned on and being capable of shutting off the supply of the fourth power to the power supply circuit by being turned off; and a second electronic fuse connected between the second external power source and the power supply circuit and the power supply monitoring circuit, wherein the second electronic fuse can supply the fifth power to the power supply circuit by being turned on and can cut off the supply of the fifth power to the power supply circuit by being turned off. The power supply monitoring circuit closes the first electronic fuse and the second electronic fuse even when one or both of the supply of the fourth power and the supply of the fifth power are cut off.

4. The magnetic disk device according to claim 1, The controller receives write data transmitted from the host device when communication with the host device is enabled during execution of the backup process, and stores the received write data in the first memory.

5. The magnetic disk device according to claim 1, The controller transmits information on the status of the magnetic disk device to the host device when communication with the host device is enabled during execution of the backup process.

6. The magnetic disk device according to claim 5, The information on the status of the magnetic disk device includes at least one of the progress status of the backup process and the operation mode of the magnetic disk device.

7. The magnetic disk device according to claim 5, After transmitting information on the status of the magnetic disk device to the host device, the controller, upon receiving an instruction to interrupt the backup process from the host device, terminates the backup process without waiting for the backup process to time out.

8. A control method, executed by a magnetic disk device, The magnetic disk device comprises: More than 1 disk; a motor for rotating the one or more magnetic disks; a power supply circuit that generates second power from first power supplied from an external power supply and, when the supply of the first power is cut off, generates third power based on regenerative energy generated when the motor is stopped; A non-volatile first memory; as well as A second memory having a volatile cache area, While the first power is being supplied, the data received from the host device is written to the magnetic disk via the cache area using the second power generated by the power supply circuit. When the supply of the first power is cut off, communication with the host device is disabled, and a backup process of transferring the contents of the cache area to the first memory is performed using the third power generated by the power supply circuit. monitoring the supply of the first power, Even when the supply of the first power is cut off, the connection with the external power source is maintained. When it is determined that the supply of the first power has been restored, communication with the host device is enabled.

Images