Disk device

Abstract

The present invention provides a magnetic disk device that improves the reliability and availability of connection with a host. The magnetic disk device comprises: a magnetic disk; a magnetic head; a communication unit capable of communicating with a host and sending a signal to the host at a first interval; a power monitoring unit that monitors the state of a first power supply; a volatile memory; a non-volatile memory; and a control unit that, when it is detected based on monitoring by the power monitoring unit that the power supplied from the first power supply has become disconnected, starts processing to back up the data stored in the volatile memory to the non-volatile memory, and controls the communication unit so that the signal is sent at a second interval that is longer than the first interval.

Description

[0001] Related Application

[0002] This application claims priority based on Japanese Patent Application No. 2021-152214 (filing date: September 17, 2021), and the present application incorporates the entire contents of the basic application by reference. Technical Field

[0003] The embodiment relates to a magnetic disk device. Background Art

[0004] Sometimes, the power supply is temporarily disconnected during the operation of the magnetic disk device. In such a case, the data stored in the volatile memory will be lost, so the data stored in the volatile memory is backed up in the nonvolatile memory. Summary of the invention

[0005] When backing up the above-mentioned data, power is supplied from the power supply for backup, but since the power is concentrated on the backup process, no response processing to the host is performed. Specifically, in addition to stopping the clock supply of the circuit blocks not used in the data backup or reducing the frequency, the disk device also disables the host interface to reduce the power in the data backup operation as much as possible. Therefore, in the case of recovery during the data backup operation, the host interface does not operate, so the host cannot recognize the disk device, resulting in a phenomenon in which the host times out and disconnects the disk device. In other words, even if the power supply of the disk device is restored after a temporary power outage, the host may not be able to recognize the disk device.

[0006] An object of the present invention is to provide a magnetic disk device having improved reliability and availability of connection with a host computer.

[0007] A magnetic disk device in one embodiment comprises: a magnetic disk; a magnetic head for reading / writing data from / to the magnetic disk; a communication unit capable of communicating with a host and sending a first signal to the host at a first interval; a power monitoring unit for monitoring the state of a first power supply; a volatile memory for storing data related to the read / write processing of the magnetic head on the magnetic disk; a non-volatile memory; and a control unit for starting a process of backing up the data stored in the volatile memory to the non-volatile memory when it is detected based on monitoring by the power monitoring unit that the power supplied from the first power supply has become disconnected, and controlling the communication unit so that the first signal is sent at a second interval that is longer than the first interval. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 This is a diagram showing an example of the configuration of a magnetic disk device according to an embodiment.

[0009] Figure 2 This is a flowchart showing an example of processing executed by the control unit when the power supply of this embodiment is turned off.

[0010] Description of Reference Numerals

[0011] 1…disk device, 2…disk, 3…spindle motor, 13…hard disk controller, 14…MPU, 15…driver IC, 16…SDRAM, 17…FROM, 18…host, 19…power supply, 131…PLP circuit unit, 151…power supply monitoring unit, 152…backup power supply unit. DETAILED DESCRIPTION

[0012] The following is a description of the embodiments with reference to the accompanying drawings. In addition, the disclosure is only an example, and the invention is not limited by the contents described in the following embodiments. Deformations that can be easily thought of by a person skilled in the art are of course included in the scope of the disclosure. In order to make the description clearer, there are also cases where the size, shape, etc. of each part are changed relative to the actual implementation scheme and schematically represented in the drawings. There are also cases where the same figure numbers are marked on corresponding elements in multiple drawings and detailed descriptions are omitted.

[0013] (First embodiment)

[0014] Figure 1 This is a diagram showing an example of the configuration of the magnetic disk device according to the first embodiment.

[0015] like Figure 1 As shown, the magnetic disk device 1 is configured as a hard disk drive (HDD), for example, and includes a magnetic disk 2, a spindle motor (SPM) 3, an actuator 4, a voice coil motor (VCM) 5, a magnetic head 10, a head amplifier IC 11, an R / W channel 12, a hard disk controller (HDC) 13, a microprocessor (MPU: control unit) 14, a driver IC 15, an SDRAM 16, a FROM 17, and a power supply (first power supply) 19. In addition, the magnetic disk device 1 can be connected to a host computer (host) 18. The magnetic head 10 includes a write head 10W, a read head 10R, and a spin torque oscillator (STO) 100 as a high-frequency oscillation element. In addition, the R / W channel 12, the HDC 13, and the MPU 14 can also be incorporated into a 1-chip integrated circuit.

[0016] The magnetic disk 2 has, for example, a substrate formed into a disk shape and made of a non-magnetic body. On each surface of the substrate, a soft magnetic layer made of a material exhibiting soft magnetic properties as a base layer, a magnetic recording layer having magnetic anisotropy in a vertical direction relative to the disk surface and a protective film layer in the upper layer are sequentially stacked. Here, the direction of the magnetic head 10 is set as the upper layer.

[0017] The magnetic disk 2 is fixed to a spindle motor (SPM) 3 and rotated at a predetermined speed by the SPM 3. In addition, it is not limited to one disk, and multiple magnetic disks 2 may be set on the SPM 3. The SPM 3 is driven by a drive current (or drive voltage) supplied from a driver IC 15. The magnetic disk 2 records and reproduces data patterns by a magnetic head 10. The magnetic disk 2 has a monitoring area 200. The monitoring area 200 is an area for storing information related to the reading / writing of data. The monitoring area 200 is set, for example, at a part of the outermost circumference or the innermost circumference in the radial direction of the magnetic disk 2.

[0018] The actuator 4 is rotatably provided and supports the magnetic head 10 at its top end. The magnetic head 10 is moved and positioned on a desired track of the magnetic disk 2 by rotating the actuator 4 using a voice coil motor (VCM) 5. The VCM 5 is driven by a driving current (or driving voltage) supplied from a driver IC 15.

[0019] The magnetic head 10 includes a slider, a write head 10W formed on the slider, a read head 10R, and an STO 100. A plurality of magnetic heads 10 are provided according to the number of magnetic disks 2.

[0020] The head amplifier IC11 includes circuits related to driving the STO 100, detecting oscillation characteristics, etc. For example, the head amplifier IC11 includes an STO control unit 111. The head amplifier IC11 performs driving of the STO 100, detecting a driving signal, etc. Moreover, the head amplifier IC11 supplies a write signal (write current) corresponding to write data supplied from the R / W channel 12 to the write head 10W. In addition, the head amplifier IC11 amplifies the read signal output from the read head 10R and transmits it to the R / W channel 12.

[0021] The STO control unit 111 controls the current supplied to the STO 100 of the write head 10W. In addition, the head amplifier IC11 also includes a recording coil control unit that controls the recording current supplied to the coil of the write head 10W according to the write signal, a regeneration signal detection unit that detects the signal (read data) regenerated by the read head 10R, and a heater control unit that controls the power supply to the heater that adjusts the distance between the magnetic disk 2 and the magnetic head 10.

[0022] The R / W channel 12 is a signal processing circuit that processes signals associated with readout (read) / write (write). The R / W channel 12 includes a read channel that performs signal processing of read data and a write channel that performs signal processing of write data. The R / W channel 12 converts the read signal into digital data and demodulates the read data from the digital data. The R / W channel 12 encodes the write data transmitted from the HDC 13 and transmits the encoded write data to the head amplifier IC 11.

[0023] The hard disk controller 13 controls the writing of data to the disk 2 and the reading of data from the disk 2 via the magnetic head 10, the head amplifier IC 11, the R / W channel 12 and the MPU 14. The HDC 13 constitutes an interface between the disk device 1 and the host 18, and performs the transmission control of read data and write data. In addition, the connection with the host 18 is set to be a standard connection of serial connection SCSI (SAS) and serial ATA (SATA), but is not limited to them. In addition, the HDC 13 receives a command (write command, read command, etc.) transmitted from the host 17, and sends the received command to the MPU 14.

[0024] Furthermore, the hard disk controller 13 has a power loss protection circuit unit (hereinafter referred to as "PLP circuit unit") 131 as a communication unit. The PLP circuit unit 131 is a circuit that backs up data when the power is disconnected. Here, in the present embodiment, power disconnection refers to a state in which power is no longer supplied from the power supply 19 to the magnetic disk device 1. More specifically, it means that current no longer flows from the power supply 19 to the magnetic disk device 1, and if there is no power supplied from the backup power supply unit 152 described later, the operation of the magnetic disk device 1 stops. In addition, the PLP circuit unit 131 also sends a signal indicating that the magnetic disk device 1 is normally connected, that is, a first signal to the host 18. In the present embodiment, the first signal is a COMINIT signal, and the COMINIT signal is, for example, a burst signal that is continuous for a predetermined number of times. In addition, in the present embodiment, the PLP circuit unit 131 has a normal mode in which a COMINIT signal is sent at a first interval and a backup mode in which a COMINIT signal is sent at a second interval that is longer than the first interval. If the host 18 does not detect the COMINIT signal for a certain period of time, it will time out and the disk device 1 cannot be recognized. Therefore, the second interval is set to be shorter than the time until the host 18 determines the time out. By the host 18 detecting the COMINIT signal sent from the disk device 1 at predetermined intervals, the host 18 can recognize that the disk device 1 is connected in a communicable manner. In this way, when the disk device 1 is recognized by the host 18, if the user operates the host 18 to open a predetermined screen, the existence of the disk device 1 is displayed on the screen.

[0025] The MPU 14 is a main controller of the magnetic disk device 1 , and performs control of read / write operations and servo control required for positioning the magnetic head 10 .

[0026] The driver IC 15 controls the driving of the spindle motor 3 and the voice coil motor 5 according to the control of the MPU 14. The voice coil motor 5 is driven so that the magnetic head 10 is placed on a target track on the magnetic disk 2.

[0027] In addition, the driver IC 15 has a power supply monitoring unit 151 and a backup power supply unit (second power supply) 152. The power supply monitoring unit 151 monitors the state of the power supply 19. More specifically, the power supply monitoring unit 151 monitors whether power is supplied from the power supply 19 to the magnetic disk device 1. In addition, the power supply monitoring unit 151 sends the monitoring result to the MPU 14. In the present embodiment, the power supply monitoring unit 151 sends a fault signal to the MPU 14 when the power supply 19 is in a disconnected state. The backup power supply unit 152 supplies power for executing the process of backing up the data stored in the SDRAM 16 to the FRPOM 17 when the power supply 19 becomes disconnected. In the present embodiment, in order to continue the rotation of the spindle motor 3 for a certain period of time even when the power supply 19 becomes disconnected, the back electromotive force of the spindle motor 3 is used to generate the power of the backup power supply 152, thereby ensuring the power for the backup process. In addition, the backup power supply 152 is not limited to the method of using the back electromotive force of the spindle motor 3. For example, a backup power supply device may be provided separately from the power supply 19.

[0028] SDRAM16 is a volatile memory. SDRAM16, for example, holds data when MPU14 executes processing. Since SDRAM16 is volatile, if it is no longer supplied with power from power supply 19, the held data disappears. On the other hand, FROM17 is a non-volatile memory. FROM17 holds programs and parameters required for the processing of MPU14. In addition, when the power supply 19 is disconnected, the backup data of SDRAM16 is stored in FROM17. The backup data stored in FROM17 is written back to SDRAM16 after the power supply 19 is restored. Power supply 19 is a power supply device of magnetic disk device 1, and supplies power to each device in magnetic disk device 1.

[0029] Next, the processing when the power is turned off will be described. Figure 2 This is a flowchart showing an example of processing executed by the MPU 14 when the power supply 19 is in the power-off state.

[0030] The MPU 14 detects power off (ST101). More specifically, the MPU 14 detects power off based on the monitoring state of the power supply by the power supply monitoring unit 151. Specifically, the MPU 14 detects whether the power supply 19 is in the power off state based on whether a failure signal is received from the power supply monitoring unit 151.

[0031] When the MPU 14 detects that the power supply is disconnected (ST101), it switches to the backup power supply (ST102). Since the power supply 19 is not supplying power, the MPU 14 activates the backup power supply unit 152. Thus, the backup power supply based on the back electromotive force of the spindle motor 3 is supplied to the magnetic disk device 1. Therefore, even if the power supply is disconnected, data backup can be achieved.

[0032] Next, the MPU 14 starts backing up the data (ST103). That is, the MPU 14 starts backing up the data held in the SDRAM 16 to the FROM 17.

[0033] Next, the MPU 14 changes the magnetic disk device 1 from the normal mode to the backup mode (ST104). More specifically, the MPU 14 controls the PLP circuit unit 131 to change the sending interval of the COMINIT signal sent from the PLP circuit unit 131 to the host 18 from the first interval to the second interval. In addition, except for the processing used in the backup of data and the processing of sending the COMINIT signal by the PLP circuit unit 131, the backup power supply of the backup power supply unit 152 is not used. Thus, the consumption of the backup power supply can be suppressed. In addition, since the COMINIT signal is sent at the second interval longer than the first interval, the consumption of the backup power supply can be suppressed compared with the case where the COMINIT signal is sent at the first interval.

[0034] Then, when the data backup is completed (ST105), the MPU 14 determines whether the power supply 19 has been restored (ST106). Specifically, the MPU 14 determines whether the power supply 19 has been restored based on whether a fault signal is received from the power supply monitoring unit 151, similarly to the aforementioned step ST101. If no fault signal is detected, it is determined that the power supply 19 has been restored, and if a fault signal is detected, it is determined that the power supply 19 has not been restored.

[0035] When it is determined that the power supply 19 has been restored (ST106: Yes), MPU14 changes the disk device 1 from the backup mode to the normal mode (ST107). Then, MPU14 switches the power supply circuit (ST108). That is, the power supply from the backup power supply unit 152 is switched to the power supply from the power supply 19. As a result, the disk device 1 returns to normal operation. Therefore, since no reset is performed, the backup data is not written back to the SDRAM 16, and the disk device 1 can be restored at a high speed. On the other hand, when it is determined that the power supply 19 has not been restored (ST106: No), MPU14 ends the processing in the state where the power is disconnected. In other words, the operation of the disk device 1 stops.

[0036] According to the magnetic disk device 1 configured as described above, when it is detected that the power supply 19 has become disconnected based on the monitoring result of the power supply 19 by the power supply monitoring unit 151, the MPU 14 starts the process of backing up the data stored in the SDRAM 17 to the FROM 17, and controls the PLP circuit 131 so that the COMINIT signal sent from the PLP circuit 131 is sent at a second interval longer than the first interval. That is, after detecting the failure signal, the magnetic disk device 1 immediately switches the power supply from the power supply 19 to the backup power supply unit 152 to start the data backup operation, and the PLP circuit unit 131 sends the COMINIT signal to the host 18 at the second interval until the backup process is completed. In this way, it is possible to prevent the magnetic disk device 1 from being unable to be recognized by the host 18. In addition, at this time, the hard disk controller 13 stops the processing (for example, the reception processing of the command from the host 18) other than the processing used in the data backup and the processing of sending the COMINIT signal by the PLP circuit unit 131, so that the power consumption of the backup power supply can be suppressed.

[0037] In addition, when the backup process of the data from SDRAM 16 to FROM 17 is completed, the magnetic disk device 1 determines whether the power supply 19 has been restored. If it is determined that it has been restored, the power supply is switched from the backup power supply unit 152 to the power supply 19. Therefore, when the magnetic disk device 1 is restored from a momentary stop, the magnetic disk device 1 does not need to write back the data to SDRAM 16, and can be restored at a high speed. In addition, a momentary stop refers to a state where the power supply is temporarily turned off due to some reasons, which is distinguished from a state where the power supply 19 of the magnetic disk device 1 is turned off due to a user's instruction to turn off the power.

[0038] In addition, although some embodiments of the present invention are described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other ways, and various omissions, substitutions, and changes can be made without departing from the scope of the subject matter of the invention. These embodiments and their variations are included in the scope and subject matter of the invention, and are included in the invention described in the claims and their equivalents.

Claims

1. A magnetic disk device comprising: disk; A magnetic head for reading / writing data from / to the magnetic disk; A communication unit capable of communicating with a host and sending a first signal to the host at a first interval; A power supply monitoring unit, monitoring the state of the first power supply; A volatile memory for storing data related to the read / write processing of the magnetic head on the magnetic disk; Non-volatile memory; and a control unit that, when detecting that the power supplied from the first power source has become disconnected based on monitoring by the power monitoring unit, starts a process of backing up the data stored in the volatile memory to the nonvolatile memory, and controls the communication unit so that the first signal is sent at a second interval longer than the first interval, The time defined by the second interval is shorter than a time during which the host determines that the connection with the magnetic disk device has timed out.

2. The magnetic disk device according to claim 1, The control unit transmits the first signal at the second interval until the process of backing up the data is completed.

3. The magnetic disk device according to claim 1, When the control unit determines that the first power supply has been restored based on the monitoring result of the power supply monitoring unit when the process of backing up the data is completed, the control unit controls the communication unit to transmit the first signal at the first interval instead of the second interval.

4. The magnetic disk device according to claim 1, The first signal is a signal indicating that the magnetic disk device is normally connected to the host.

5. The magnetic disk device according to claim 1, Equipped with a second power supply, The control unit operates based on the power supplied from the second power supply when detecting that the power supplied from the first power supply has been turned off.

6. The magnetic disk device according to claim 5, When the data backup process is completed and when it is determined based on the monitoring result of the power monitoring unit that the power has been restored, the control unit operates based on the power supplied from the first power source instead of the power supplied from the second power source.

7. The magnetic disk device according to claim 5, A spindle motor is provided to rotate the magnetic disk. The electric power of the second power supply is generated from a back electromotive force of the spindle motor.

8. The magnetic disk device according to claim 7, When it is detected based on monitoring by the power supply monitoring unit that the power supplied from the first power supply is turned off, the power supplied from the second power supply is used in the process of backing up the data and transmitting the first signal at the second interval.

9. A magnetic disk device comprising: disk; A magnetic head for reading / writing data from / to the magnetic disk; A communication unit capable of communicating with a host and sending a first signal to the host at a first interval; A volatile memory for storing data related to the read / write processing of the magnetic head on the magnetic disk; Non-volatile memory; and a control unit that, when the power supply is turned off, writes at least a portion of the data stored in the volatile memory to the nonvolatile memory, and controls the communication unit so that the first signal is transmitted at a second interval longer than the first interval, The time defined by the second interval is shorter than a time during which the host determines that the connection with the magnetic disk device has timed out.

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