JP2001135018A - Data write-in security control system and magnetic disk device using the system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure the write-in of the write data held in a buffer RAM before resetting in case that a magnetic disk device detecting vibration is reset by a host system or a user while the device waits the restoration of the vibration. SOLUTION: When the vibration is detected, the unwritten data existing in the buffer RAM are written temporarily in a write-in area for vibration detecting time provided on a magnetic disk, and when the vibration is restored, the data are transcribed to the position to be written is primarily, and the write-in of the data are guaranteed. The write-in area for vibration detecting time has the capacity capable of writing the whole data in the buffer RAM, and even when out-of-track occurs due to the vibration during the write-in of the write-in area for vibration detecting time, for preventing the data written in a peripheral track from being superscribed and erased, an interval between adjacent write data write-in tracks is sufficiently enlarged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk drive mounted on a device which requires recording and reproduction of information.

[0002]

2. Description of the Related Art In recent years, magnetic disk drives and devices equipped with the magnetic disk drives have been reduced in size and weight, and magnetic disk drives have been used in devices which are assumed to be used in moving objects such as portable personal computers and car navigation devices. The device is mounted. As typified by the use in a moving object, a use environment in which the vibration applied to the magnetic disk device exceeds the limit value of the disk-accessible vibration intensity of the device for a long time frequently occurs. It has become like.

On the other hand, in a magnetic disk device, data processing is controlled by a cache using a buffer RAM in order to improve the information processing speed. Generally, when writing data, the write head from the host system is temporarily stored in the buffer RAM, and at the same time, the write head is moved to the position to be written on the magnetic disk. If writing is possible, writing is started immediately. Under such a cache control method, there is a case where the data transfer from the host system to the buffer RAM is completed before the data writing to the magnetic disk is completed. In this case, the data transfer to the buffer RAM is performed by the host system. A method is widely used in which a write completion is reported at the time of completion of the command, and the processing of the next command is continuously started.

If an excessive vibration is applied from the outside to the magnetic disk device having the above-described cache control, that is, if the write head is vibrated so that the write head cannot be accurately positioned at the target write position, the vibration is In the magnetic disk device, a state of waiting for writable while holding write data in the buffer RAM, that is, waiting for vibration convergence is maintained.

[0005] In such a case, in the conventional technique, the data on the magnetic disk is guaranteed by not accessing the magnetic disk at the time of detecting the vibration, and the access is resumed after the vibration is converged.

[0006]

As described above, in order to guarantee the data on the magnetic disk against the vibration, it can be realized by not accessing the magnetic disk until the convergence of the vibration is confirmed. However, depending on the host system, there is a case where the magnetic disk device determines that the magnetic disk device is uncontrollable and resets the device when the magnetic disk device continues to process the command for a long time. Alternatively, there is a case where a timeout is reported to the user, and the user resets the system. At this time, the write data held in the buffer RAM of the magnetic disk device is also erased. In the magnetic disk device adopting the cache control as described above, the data reporting the end of writing to the host system is deleted. However, a phenomenon occurs that the data is not actually written on the magnetic disk.

In the conventional data security method for vibration,
It is not possible to guarantee that the write data in the buffer RAM that has not yet been written to the magnetic disk is written to the magnetic disk, and there is a discrepancy between the recognition of the host system and the data actually stored on the magnetic disk device. Occurs.

An object of the present invention is to guarantee that write data in an unwritten buffer RAM, which is waiting for writing due to vibration, is written on a magnetic disk.

[0009]

According to the control method of the present invention,
Buffer RA for detecting vibration beforehand on the magnetic disk
A temporary write area for write data in M is provided, a function to detect a vibration state is provided, and at the time of vibration detection, unwritten data in the buffer RAM and information of a position where the data should be written are detected at the time of vibration detection. Write to the write data temporary write area in the buffer RAM of the buffer RAM. When vibration convergence is detected, the relevant data is written to the position where it should be written only when valid data exists in the write data temporary write area in the buffer RAM at the time of vibration detection. Transfer, and in that case, buffer RA at the time of vibration detection
The problem is solved by erasing data temporarily written in the write data temporary write area in M and not accepting a data write request from a host system when vibration is detected.

Further, the write data temporary write area in the buffer RAM at the time of vibration detection proposed in the present invention has a capacity for writing all data in the buffer RAM, and the write data in the buffer RAM at the time of vibration detection. Even if a track shift occurs due to vibration during writing in the temporary writing area, an adjacent buffer RAM is used so that data written in a peripheral track is not overwritten and erased.
It is characterized in that there is a sufficient space between the inner write data writing tracks.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a conceptual diagram of a write data temporary write area in a buffer RAM which is provided in advance on a magnetic disk when a vibration is detected. The control method of the present invention is shown in the flowchart of FIG. This will be described below with reference to the follow chart of FIG.

The magnetic disk device reads and writes data in response to a request from a host system (2--
1). Here, when the vibration is detected (2-2), control is performed so that the request from the host system is not accepted until the vibration has converged (2-3), and at the same time, the access to the magnetic disk is interrupted (2-4). At this time, if there is unwritten data in the buffer RAM,
The data and information on the position where the data is originally written are written to the write data temporary write area (1-3) in the buffer RAM at the time of detecting the vibration (2-5). Thereafter, monitoring of the vibration state is continued (2-6). If the vibration state continues for a long time, the magnetic disk device may be reset by the host system or the user (2-7).

Generally, when reset, the buffer R
The data in the AM is cleared (2-8). Thereafter, when it is detected that the vibration state has converged (2-6), first, it is confirmed that valid data exists in the write data temporary write area in the buffer RAM at the time of vibration detection (2-9).
If unwritten data is detected, the data and the information on the position where the data should be written are read from the write data temporary write area in the buffer RAM at the time of detecting the vibration (2-10). Then, data is transferred to the data area (1-2) according to the position information (2-11). After these series of controls are completed, the host system is again ready to accept requests (2-12).

[0014]

According to the present invention, by temporarily writing data in the buffer RAM to a specific area on the magnetic disk, the buffer RAM for resetting and initializing due to vibration which cannot be guaranteed by the conventional method. It is possible to guarantee the writing of the unwritten data within.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a write data temporary write area in a buffer RAM when a vibration provided on a magnetic disk is detected.

FIG. 2 is a schematic flowchart showing the control of the present invention.

[Explanation of symbols]

1-1: Magnetic disk, 1-2: Normal data area, 1-3:
Write data temporary write area in buffer RAM when vibration is detected, 1-4: data write track interval in normal data area, 1-5: data write track interval in write data temporary write area in buffer RAM when vibration is detected.

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Yoshikatsu Fujii 2880 Kozu, Kozuhara-shi, Kanagawa Pref.Hitachi, Ltd. Storage Systems Division, Hitachi, Ltd. F-term in the System Division (Reference)

Claims (1)

[Claims] 1. A means for preventing the loss of unwritten data in a buffer RAM by temporarily writing unwritten data held in a buffer RAM to a specific position on a magnetic disk when a vibration is detected, and a vibration convergence. A data writing security control method comprising means for temporarily transferring data written at a specific position upon detection of a vibration to a position where the data should be written, and a magnetic disk drive using this control method.