JP3246436B2 - Format efficiency improvement method for magnetic disk drives - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for improving the format efficiency of a magnetic disk drive using a data surface servo method.
In particular, the present invention relates to a format efficiency improving method for a magnetic disk device that does not require a write-to-read recovery time area (hereinafter, referred to as a recovery area) provided at the head of a servo area.

2. Description of the Related Art A conventional data surface servo type magnetic disk drive can read a servo area even after writing data to any sector position of a magnetic disk medium.
In order to secure a recovery time during which the read circuit is stabilized, the recovery area is set after the M-th (M is a natural number of 1 or more) sector and before the M-th servo area, that is, the M-th sector and the M-th sector. It is provided between the second servo area and the third servo area (for example, see Japanese Patent Application Laid-Open No. 8-28887615).

The standard format of a magnetic disk medium is shown in FIG.

Data is written on a plurality of tracks which are concentric circles about the center of the magnetic disk medium. The track is divided into a plurality of equal angles, and a servo area in which information for positioning in the radial and circumferential directions is written at the head of the divided portion (data surface servo method). Track SRV-0 to SRV-63 in FIG.
In one of the servo areas up to this point, an index signal indicating the circumferential start point of the track is written.

[0005] Between the servo area and the next servo area, 5
The data is divided so that 12 bytes of data can be secured, and this is called a sector (Sectors 1 and 2 of the Track in FIG. 2).
vector). If one sector (512 bytes) cannot be secured when the remaining portion is small when the sector is divided, one sector is divided into two or more, and the portion that cannot be accommodated is secured in the next sector. (T in FIG. 2
(see Sector 3-1 (240 bytes) and Sector 3-2 (272 bytes)) (that is, 1 in Sector 3-1 and Sector 3-2).
Sector (512 bytes)). Sec at this time
or3 is called "divided sector",
It is called "split sector".

As shown in the detailed view of the SRV-1 of Track in FIG. 2, a recovery area is usually required at the head of the servo area (SRV-1).

The reason for this is that, in order to recognize the current position of the user, information on all servo areas (Tr in FIG. 2) is always used.
The information after the SRV AGC in the detailed diagram of the ACK SRV-1 (hereinafter referred to as servo information) must be readable. The recovery area is not particularly necessary when the sector is not being read / written. This is not particularly necessary when only reading a sector, and the recovery area is required only when the Sec of Track in FIG.
The reason is that when a sector is written to a sector or a split sector immediately before the servo area as in tor3-1, the reason is a read / write LSI (Large Scaled) used in a magnetic disk device.
This is because physical characteristics such as (Integration) have a characteristic that a read operation cannot be performed for a certain time (recovery time) immediately after a write operation.
In order to be able to read the servo information of all servo areas, a recovery area is required at the beginning of all servo areas.

[0008]

A first problem is that, in the prior art, the format efficiency of the magnetic disk drive of the data surface servo system is low. The reason is,
This is because the recovery areas must be provided at the head of the servo area by the number of servo areas.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a format improvement method for a magnetic disk device which improves the format efficiency by eliminating the need for a recovery area of the magnetic disk device of the data surface servo system.

It is another object of the present invention to provide a format improvement method for a magnetic disk drive which reduces a decrease in reliability caused by increasing a format efficiency by eliminating a recovery area. .

[0011]

The format efficiency improving method of the magnetic disk drive according to the present invention is a data surface servo method.
Read N consecutive servo information (N is an integer of 1 or more)
Ri in a magnetic disk apparatus that allow errors, magnetic
The format of the disk media is
This is a format in which there is no coverage area. When writing data , the write sector position is the (N + 1) th consecutive write sector position.
It is not the (N + 1) th sector before the servo area,
Or the servo whose write sector position is the consecutive (N + 1) th
(N + 1) th sector before the area, but write
Time from end position to (N + 1) th servo area
If it is longer than the recovery time, write data
Write to magnetic disk medium, write sector position is continuous
(N + 1) th sector, from the write end position
Time until the (N + 1) th servo area is recovered
If the length is shorter than the write time, means for storing the write sector position and write data in the storage means as the buffer sector position and buffer data, and reading the buffer sector position and buffer data stored in the storage means when the magnetic disk drive is idle. The buffer data
Written to the buffer sector position of the magnetic disk medium
See, means for erasing the buffer sector position and the buffer data stored in the storage means, when data is read
The read sector position is stored in the storage means.
If it is different from the buffer sector position,
Read the data at the read sector position from the medium and read
The buffer sector whose sector position is stored in the storage means.
Is stored in the storage means,
Means for reading buffer data corresponding to the buffer sector position .

The format efficiency improving method of the magnetic disk drive of the present invention is a data surface servo method , and N consecutive (N is
Permit servo information reading error (integer of 1 or more)
In the magnetic disk device it is, a magnetic disk medium off
If the recovery area exists at the beginning of the servo area
A non-volatile storage means having a function of retaining stored contents even when the power is turned off , and a servo in which the write sector position is consecutive (N + 1) -th when writing data.
Is not the (N + 1) th sector before the area, or
The write sector position is in the consecutive (N + 1) th servo area.
This is the (N + 1) th sector before, but the write end position
From the position to the (N + 1) th servo area is recovered.
If the time is longer than the retime, the write data is
Write to disk media and write sector position is continuous (N +
1) the sector, which is (N +
1) Time to the servo area is longer than the recovery time
If it is shorter, the write sector position and write data
Said means to be stored in the nonvolatile storage means as a buffer sector position and the buffer data, reads the buffer sector position and the buffer data stored in the nonvolatile storage unit when the idle of the magnetic disk apparatus of a magnetic disk medium the buffer data writes in the buffer sector position, said means for erasing the buffer sector position and the buffer data stored in the nonvolatile storage means, when data is read in, the lead sector position is the non-volatile components
Buffer sector position stored in the temporary storage means.
In the case of the read sector from the magnetic disk medium.
Data is read, and the read sector position is
Matches the buffer sector position stored in the memory
In this case, the data stored in the non-volatile storage
Means for reading buffer data corresponding to the buffer sector position .

Further, the format efficiency improving method of the magnetic disk drive of the present invention is a data surface servo method, and has a continuous N
In a magnetic disk drive that permits servo information reading errors (N is an integer of 1 or more), the format of the magnetic disk medium is a format in which a recovery area does not exist at the beginning of a servo area, and write data is transferred to the magnetic disk. A write circuit for writing to a write sector position of a medium, a read circuit for reading data at a read sector position from the magnetic disk medium, and an unwrite for storing the buffer sector position and buffer data or erasing the buffer sector position and buffer data The buffer circuit receives a write command signal, a write position signal, and a write data signal from a host device, and the write sector position indicated by the write position signal is in the (N + 1) -th sector before the (N + 1) -th servo area. No or light sector position If the time from the write end position to the (N + 1) th servo area is longer than the recovery time in the (N + 1) th sector before the consecutive (N + 1) th servo area, it is indicated by a write data signal. Write data is written to the magnetic disk medium by controlling the write circuit, and the write sector position is continuous (N + 1).
When the time from the write end position to the (N + 1) th servo area is shorter than the recovery time, the write sector position and the write data are stored in the non-write buffer circuit as the buffer sector position and the buffer data. When the magnetic disk drive is idle, the buffer sector position and buffer data are read from the unwritten buffer circuit, and the write circuit is controlled to write the buffer data to the buffer sector position of the magnetic disk medium. A write control circuit for erasing the buffer sector position and buffer data stored in the buffer circuit, and receiving a read command signal and a read position signal from a higher-level device, and setting the read sector position indicated by the read position signal to the unwritten buffer circuit. Memory If the read sector position is different from the buffer sector position, the read circuit is controlled to read the data at the read sector position from the magnetic disk medium and send it to the host device as a read data signal. A read control circuit for reading out buffer data corresponding to the buffer sector position stored in the unwritten buffer circuit and sending it to the host device as a read data signal when the buffer sector position matches the stored buffer sector position. It is characterized by the following.

Furthermore, the format efficiency improving method of the magnetic disk device of the present invention is a data surface servo system, wherein N consecutive (N is an integer of 1 or more) servo information reading errors are permitted in a magnetic disk device. The format of the magnetic disk medium is a format in which a recovery area does not exist at the beginning of the servo area, and a write circuit for writing write data to a write sector position of the magnetic disk medium; and reading data at a read sector position from the magnetic disk medium A read circuit, a nonvolatile non-write buffer circuit for storing the buffer sector position and the buffer data and erasing the buffer sector position and the buffer data, and receiving a write command signal, a write position signal and a write data signal from a host device; , Indicated by the light position signal Light sector position is continuous that (N +
1) The sector is not the (N + 1) -th sector before the servo area, or the write sector position is the (N + 1) -th sector before the continuous (N + 1) -th servo area. If the time to the) th servo area is longer than the recovery time, write data indicated by the write data signal is written to the magnetic disk medium by controlling the write circuit, and the write sector position is consecutive (N + 1) th sector. If the time from the write end position to the (N + 1) th servo area is shorter than the recovery time, the write sector position and the write data are stored in the nonvolatile non-write buffer circuit as the buffer sector position and the buffer data, When the magnetic disk drive is idle, the non-volatile non-write buffer Reading the buffer sector position and buffer data from the circuit, controlling the write circuit to write the buffer data to the buffer sector position of the magnetic disk medium, and erasing the buffer sector position and buffer data stored in the non-volatile non-write buffer circuit Receiving a read command signal and a read position signal from a higher-level device, and if the read sector position indicated by the read position signal is different from the buffer sector position stored in the nonvolatile non-write buffer circuit, When the read circuit is controlled to read the data at the read sector position from the magnetic disk medium and send it as a read data signal to the host device, and the read sector position matches the buffer sector position stored in the nonvolatile non-write buffer circuit. The non-volatile Read buffer data corresponding to the buffer sector position stored in the non-write buffer circuit characterized by comprising a read control circuit for sending to the host device as a read data signal.

According to the format efficiency improving method of the magnetic disk device of the present invention, the writing which makes the servo area of the magnetic disk medium unreadable at the time of data writing is detected, the writing to the magnetic disk medium is stopped, and the write sector position and the stopped write sector position are determined. The write data is stored as a buffer sector position and buffer data in a non-volatile storage means other than the magnetic disk medium, and even if the power is turned off,
It keeps storing the stored buffer sector position and buffer data. When the magnetic disk drive enters an idle state, the buffer sector position and buffer data are read from the non-volatile storage means, and the buffer data is written to the buffer sector position on the magnetic disk medium. When a read command is issued before writing the buffer data to the magnetic disk medium, the buffer data stored in the non-volatile storage means is read and transmitted as read data.
This eliminates the need for the recovery area, which is a cause of lowering the format efficiency, thereby improving the format efficiency of the magnetic disk medium, and does not reduce the reliability of data.

On the other hand, the magnetic disk medium of the present invention is used in a magnetic disk device which permits consecutive N (N is an integer of 1 or more) servo information reading errors by a data surface servo method, and has a head of a servo area. Write to Reed Rica
It is characterized in that the format has no variable time area.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a circuit block diagram showing a format efficiency improving method of a magnetic disk drive according to one embodiment of the present invention. The format efficiency improving method of the magnetic disk device according to the present embodiment
A write circuit 6 for writing to a write sector position of a magnetic disk medium, a read circuit 7 for reading data at a read sector position from a magnetic disk medium of a lower circuit 5, a buffer circuit for storing a buffer sector position and buffer data, and a buffer sector position and a buffer. A non-volatile non-write buffer circuit 3 for erasing data, a write command signal, a write position signal, and a write data signal from the host device 4 are received, and the write sector position indicated by the write position signal is the (N + 1) th servo. It is not the (N + 1) th sector before the area, or the write sector position is continuous (N
If the time from the write end position to the (N + 1) th servo area is longer than the recovery time in the (N + 1) th sector before the (+1) th servo area,
The write data indicated by the write data signal is written to the magnetic disk medium of the lower circuit 5 by controlling the write circuit 6, and the write sector position is the consecutive (N + 1) th sector and the (N + 1) th servo from the write end position. If the time to the area is shorter than the recovery time, the write sector position and the write data are stored in the non-volatile write buffer circuit 3 as the buffer sector position and the buffer data. The buffer sector position and buffer data are read from the buffer circuit 3, the write circuit 6 is controlled to write the buffer data to the buffer sector position of the magnetic disk medium in the lower circuit 5, and the buffer sector position stored in the non-volatile non-write buffer circuit 3 is read. And buffer data When the write control circuit 1 to be erased and the read command signal and the read position signal from the host device 4 are received, and the read sector position indicated by the read position signal is different from the buffer sector position stored in the non-volatile non-write buffer circuit 3 The read circuit 7 controls the read circuit 7 to read the data of the read sector position from the magnetic disk medium of the lower circuit 5 and sends it to the host device 4 as a read data signal, and the read sector position is stored in the non-volatile non-write buffer circuit 3. And the read control circuit 2 which reads buffer data corresponding to the buffer sector position stored in the non-volatile non-write buffer circuit 3 and sends it to the host device 4 as a read data signal when the same buffer sector position is present. Have been.

The host device 4 is connected to the write control circuit 1 via a controller write signal line a and connected to the read control circuit 2 via a controller read signal line c.

The write control circuit 1 is connected to the non-volatile non-write buffer circuit 3 via a non-write buffer write signal line b, and connected to the write circuit 6 via a write signal line f.

The read control circuit 2 is connected to the non-volatile non-write buffer circuit 3 via a non-write buffer read signal line d, and to the read circuit 7 via a read signal line j.

The non-volatile non-write buffer circuit 3 is composed of a non-volatile storage element having a function of maintaining stored contents even when the power is turned off. When the non-volatile non-write buffer circuit 3 is a volatile storage element, if the power is momentarily interrupted when the non-volatile non-write buffer circuit 3 has a buffer sector position and buffer data, the non-volatile non-write buffer circuit 3 transfers the data to the magnetic disk medium. Since the buffer data that has not yet been written to the buffer circuit 3 is erased and the reliability of the data is reduced, the nonvolatile non-write buffer circuit 3 maintains the reliability by using a nonvolatile storage element. The non-volatile non-write buffer circuit 3 is controlled by the write control circuit 1 and stores a write sector position and write data given from the write control circuit 1 via the non-write buffer write signal line b as a buffer sector position and buffer data, The buffer sector position and buffer data are sent to the write control circuit 1, and thereafter, the buffer sector position and buffer data are erased. The non-volatile non-write buffer circuit 3 is controlled by the read control circuit 2 and sends out buffer sector positions and buffer data to the read control circuit 2.

The write circuit 6 includes a write disk signal line k
And is connected to the lower circuit 5 via. Write circuit 6
Is controlled by the write control circuit 1 and writes data sent from the write control circuit 1 to the write sector position of the magnetic disk medium in the lower circuit 5.

The read circuit 7 includes a read disk signal line l
And is connected to the lower circuit 5 via. Lead circuit 7
Is controlled by the read control circuit 2 to read data from the magnetic disk medium of the lower circuit 5 via the read disk signal line l and read the read signal line j as read data.
To the read control circuit 2 via

The magnetic disk medium has a format in which there is no recovery area provided at the head of the servo area to secure a recovery time until the read circuit 7 becomes stable after writing data.

The format efficiency improvement method of the magnetic disk drive according to the present embodiment normally requires data writing, but if there is no recovery area, the data is written in the servo area. When reading cannot be performed, the write sector position and the write data are stored in the non-volatile non-write buffer circuit 3, and when the operations such as reading / writing and seeking are stopped (hereinafter, referred to as an idle state), the data is magnetically renewed. It is written on a disk medium.

By the way, in the magnetic disk device, it is originally necessary to always read the servo information in the servo area. However, in consideration of the yield of the magnetic disk medium, only the magnetic disk medium having no scratch in the servo area can be used. And the yield will drop. In order to avoid a decrease in the yield, usually, the process is continued without causing an apparatus error even if several pieces of continuous servo information cannot be read.

Then, the number at which servo information reading errors may occur consecutively is determined from the capability of the magnetic disk drive. The number of consecutive servo information reading errors that may occur (hereinafter referred to as the number of consecutive servo information reading errors permitted) is N (an integer of 1 or more).

The magnetic disk drive to which the format efficiency improving method according to the present embodiment is applied employs a data surface servo method, in which N consecutive (N is an integer of 1 or more) servo information reading errors are permitted. It is a disk device.

For example, if N = 1, a device error will not occur even if a servo information reading error occurs every other servo device, and a device error will occur when two consecutive servo information reading errors occur.

Therefore, if N consecutive servo information reading errors are permitted, N consecutive servo information need not be read, and data writing to the sector immediately preceding the N consecutive servo information is permitted. Is done.

However, if data is written to the sector immediately before the (N + 1) -th consecutive servo information, the continuous (N +
1) A servo information reading error occurs in each of them, resulting in a device error.

In order to avoid this, in the format efficiency improving method of the magnetic disk device according to the present embodiment, data writing to the sector immediately before the (N + 1) th servo information is not performed, but the write sector position and write The data is stored in the non-volatile write buffer circuit 3 as a buffer sector position and buffer data, and when the magnetic disk device is in an idle state, the buffer data is newly written as write data to the buffer sector position of the magnetic disk medium in the lower circuit 5. I have.

Referring to FIG. 3, the process of writing data is performed by setting a continuous servo read error permitted number setting step S1.
01 and the number of continuous servo reading errors initialization step S
102, a recovery time determination step S103,
Write-in-recovery-time determination step S104, recovery-time-elapse determination step S105, continuous servo read error number increment step S106, continuous servo read error number / continuous servo read error permitted number comparison step S107, and writing to the magnetic disk medium It comprises step S108, recovery time elapse determination step S109, storage step S110 in the non-volatile write buffer circuit, and recovery time elapse determination step S111.

Referring to FIG. 4, the process of writing buffer data to the magnetic disk medium includes an idle state determining step S201, a buffer sector position and buffer data reading step S202, a target sector determining step S203, and a buffer data writing step. S
204 and a buffer sector position and buffer data erasing step S205.

Referring to FIG. 5, data read processing includes a read sector position / buffer sector position comparison step S301 and a magnetic data medium data read step S301.
302, and a non-volatile non-write buffer circuit buffer data read step S303.

Next, the operation of the format efficiency improving method of the magnetic disk device according to the present embodiment configured as described above will be described.

At the time of data write, the host device 4 sends a write command signal, a write position signal and a write data signal via the controller write signal line a to the write control circuit 1.
To send to.

When the write command signal, the write position signal, and the write data signal arrive, the write control circuit 1 determines the write sector position based on the write position signal, and
It is determined whether the area is not the (+1) th servo area or the (N + 1) th servo area is a position that sufficiently satisfies the recovery time. Send data,
Otherwise, the data is sent to the non-volatile non-write buffer circuit 3.

More specifically, the write control circuit 1 initializes the continuous servo read error permission number M0 to N (step S101), and then initializes the continuous servo read error number M1 up to the present time to 0 (step S102). .

Next, the write control circuit 1 determines whether the current time is within the recovery time (step S103). If the current time is within the recovery time, the write command signal and the write position are transmitted via the controller write signal line a within the recovery time. It is determined whether a signal and a write data signal have been input (whether the write is within the recovery time) (step S10).
4). If the write is not within the recovery time, the write control circuit 1 determines whether or not the recovery time has elapsed (step S105). If the recovery time has not elapsed, the control returns to step S104, and if the recovery time has elapsed. If it is, control is returned to step S102.

If the write is within the recovery time in step S104, the write control circuit 1 increments the number M1 of continuous servo read errors up to the present by one (step S106), and the number M1 of continuous servo read errors up to the present. And the number of continuous servo read errors M0 is compared (step S107).

In step S107, if the number M1 of continuous servo read errors up to the present is not greater than the number M0 of continuous servo read errors, the write control circuit 1 outputs a write position signal and a write data signal to the write signal line f. The write data is written to the write sector position of the magnetic disk medium in the lower circuit 5 without outputting a signal to the unwritten buffer write signal line b (step S10).
8). That is, if the write control circuit 1 writes data at a position where the recovery time is insufficient in the Nth sector before the Nth servo area, the recovery time is insufficient, the read circuit 7 is not stabilized, and the Nth Although the servo area cannot be read normally, since it is permitted as a magnetic disk device (since it is configured so that it can be compensated by another method), it sends the write sector position and write data to the write circuit 6 as it is, and The write data is written to the write sector position of the magnetic disk medium of No. 5. Next, the write control circuit 1 determines whether or not the recovery time has elapsed (step S109). If the recovery time has not elapsed, the control returns to step S108. If the recovery time has elapsed, the control returns to step S103. return.

In step S107, if the number M1 of continuous servo reading errors up to the present is larger than the number M0 of continuous servo reading errors, the write control circuit 1 does not output the write position signal and the write data signal to the write signal line f. The write position signal and the write data signal are output to the non-write buffer write signal line b, and are stored in the nonvolatile non-write buffer circuit 3 as the buffer sector position and the buffer data (step S110). That is, the write control circuit 1 determines that the write sector position is the N-th servo area, and if writing to the write sector position, the recovery time is insufficient, the read circuit 7 is not stabilized, and normal data reading becomes difficult. The Nth servo information cannot be read continuously, and the N servo information cannot be read continuously, causing an error. Therefore, the write sector position and the write data are not output to the write circuit 6, and the write sector position and the write data are not output. To the nonvolatile non-write buffer circuit 3. Next, the write control circuit 1 determines whether or not the recovery time has elapsed (step S111). If the recovery time has not elapsed, the write control circuit 1 returns the control to step S110, and if the recovery time has elapsed, the control returns to step S102. return.

On the other hand, when the magnetic disk device enters an idle state in which the seek operation, the write operation, and the read operation are not performed (step S20).
(1), and reads the buffer sector position and buffer data from the non-volatile non-write buffer circuit 3 via the non-write buffer write signal line b (step S20).
2) A target sector is searched from the magnetic disk medium of the lower circuit 5 (step S203), and the buffer circuit is controlled by the write circuit 6 to write the buffer data to the buffer sector position of the magnetic disk medium of the lower circuit 5 (step S20).
4). That is, at this point, all the write data has been written to the magnetic disk medium.

Next, the write control circuit 1 erases the buffer sector position and the buffer data where the writing to the magnetic disk medium has been completed from the non-volatile non-write buffer circuit 3 via the non-write buffer write signal line b (step S205). ).

The host device 4 is connected to the controller read signal line c.
When the read position signal and read command signal are output to
The read control circuit 2 compares the read sector position indicated by the read position signal with the buffer sector position stored in the non-volatile non-write buffer circuit 3 (step S30).
1) If they do not match, control the read circuit 7 to read the data at the corresponding read sector position from the magnetic disk medium of the lower circuit 5 and send it to the host device 4 via the controller read signal line c as a read data signal. (Step S302).

The read control circuit 2 determines whether the read sector position matches the buffer sector position stored in the non-volatile non-write buffer circuit 3 (step S5).
Yes at 301), since the buffer data stored corresponding to the buffer sector position has not yet been written to the magnetic disk medium of the lower circuit 5, the corresponding buffer data is read from the non-volatile non-write buffer circuit 3, and A read data signal is sent to the host device 4 through the controller read signal line c (step S30).
3).

By performing the above operation, the recovery area of the magnetic disk drive of the data surface servo system can be eliminated, and the format efficiency can be improved.

Also, by using a nonvolatile storage element for the nonvolatile non-write buffer circuit 3, it is possible to prevent a decrease in the reliability of the magnetic disk drive.

[0051]

Next, an embodiment of a format efficiency improving method for a magnetic disk drive according to the present embodiment will be described with reference to the drawings.

Hereinafter, the magnetic disk drive to which the format efficiency improving method of the present embodiment is applied is a data disk servo method, and is a magnetic disk drive which permits consecutive N = 2 servo information reading errors. Assume that In other words, the process continues even if two consecutive pieces of servo information cannot be read, but if three consecutive pieces of servo information cannot be read, an error occurs and the process is stopped.

The description will be made assuming that the data write is continuous data. It is also assumed that the write sector length or split sector length immediately before the servo area is longer than the recovery time.

According to the format efficiency improving method of the magnetic disk device of the present embodiment, as shown in FIGS. 6 and 7, data write to the sector immediately before the first servo information is performed as usual (Sector 3). -1) Data writing to the sector immediately before the second servo information is also performed as usual (Sector 5), and data writing to the sector immediately before the third servo information is not performed (Sector 8-1).
And Sector 8-2), the write sector position and the write data are stored in the non-volatile non-write buffer circuit 3, and the buffer data is written again to the buffer sector position of the magnetic disk medium during the idle state, so that the data can be written without causing an apparatus error. Can be written.

Further, by using an area obtained by quantizing the “actually necessary recovery area” at the boundaries of sectors as the recovery area, normal writing can be guaranteed (see FIGS. 6 and 7).

In addition, since the sector length or the split sector length may be shorter than the recovery time, actually, it is necessary to stop writing from a position that sufficiently satisfies the recovery time.

FIG. 8 shows a case where the length of Sector 8-1 in FIG. 6 is insufficient.

As shown in FIG. 9, the write control circuit 1 has no write command, read command, seek command, etc. sent from the host device 4 via the controller write signal line a, and the magnetic disk device In the idle state, the buffer sector position and buffer data are read from the non-volatile non-write buffer circuit 3 via the non-write buffer write signal line b, and the write circuit 6 is controlled to control the buffer sector of the magnetic disk medium of the lower circuit 5. The buffer data is written to the position, and the buffer sector position and the buffer data stored in the non-volatile non-write buffer circuit 3 are erased.

The read control circuit 2 receives a read command signal and a read position signal from the host device 4 via the controller read signal line c, and the read sector position indicated by the read position signal is stored in the non-volatile non-write buffer circuit 3. It is determined whether or not the buffer sector position matches the current buffer sector position. If the read sector position is different from the buffer sector position, the read control circuit 2 controls the read circuit 7 to read data at the read sector position from the magnetic disk medium of the lower circuit 5 as shown in FIG. It is sent to the host device 4 as a read data signal. If the read sector position is the same as the buffer sector position stored in the non-volatile non-write buffer circuit 3, the read control circuit 2 sets the buffer stored in the non-volatile non-write buffer circuit 3 as shown in FIG. The buffer data corresponding to the sector position is read out and sent to the host device 4 as a read data signal.

[0060]

The first effect is that servo information can be read without securing a recovery time. As a result, the recovery area, which is an invalid servo area element that cannot be used as data, becomes unnecessary, and the format efficiency can be increased. The reason is that writing is not performed in a sector requiring a recovery time, and buffer data not written in the idle state is written to the buffer sector position of the magnetic disk medium.

The second effect is that when there is data that has not been written on the magnetic disk medium, the data can be guaranteed even if the power is turned off before writing the data. Thereby, the reliability of the magnetic disk device can be maintained. The reason is that a non-volatile storage element is used as a storage unit for data that has not been written.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram showing a format efficiency improving method of a magnetic disk drive according to an embodiment of the present invention.

FIG. 2 is a diagram showing a standard format of a magnetic disk medium.

FIG. 3 is a flowchart showing a data write process in the format efficiency improving method of the magnetic disk device according to the embodiment.

FIG. 4 is a flowchart showing a process of writing buffer data to a magnetic disk medium in the format efficiency improving method of the magnetic disk device according to the present embodiment.

FIG. 5 is a flowchart showing a data read process in the format efficiency improving method of the magnetic disk device according to the present embodiment.

FIG. 6 is a timing chart at the time of continuous sector write.

FIG. 7 is a timing chart at the time of continuous writing of only the sector before the servo area.

FIG. 8 is a timing chart at the time of continuous sector writing when the recovery time is long.

FIG. 9 is a timing chart when memory data is written to sector8.

FIG. 10 is a timing chart at the time of reading data not in the non-volatile non-write buffer circuit.

FIG. 11 is a timing chart at the time of reading data in a non-volatile non-write buffer circuit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Write control circuit 2 Read control circuit 3 Non-volatile non-write buffer circuit 4 Upper device 5 Lower circuit 6 Write circuit 7 Read circuit a Controller write signal line b Non-write buffer write signal line c Controller read signal line d Non-write buffer read signal line f Write signal line j Read signal line k Write disk signal line l Read disk signal line

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G11B 20/12 G11B 20/10 G11B 21/10

Claims (7)

(57) [Claims] In a magnetic disk drive that permits N consecutive (N is an integer of 1 or more) servo information reading errors in a data surface servo system, the format of the magnetic disk medium is a recovery area at the beginning of the servo area. Does not exist, and the write sector position is continuous (N +
1) The sector is not the (N + 1) -th sector before the servo area, or the write sector position is the (N + 1) -th sector before the continuous (N + 1) -th servo area. If the time to the) th servo area is longer than the recovery time, the write data is written to the magnetic disk medium, the write sector position is the consecutive (N + 1) th sector, and the (N + 1) th write sector from the write end position. Means for storing the write sector position and write data in the storage means as the buffer sector position and buffer data when the time to the servo area is shorter than the recovery time; and a buffer stored in the storage means when the magnetic disk drive is idle. Read the sector position and buffer data and transfer the buffer data to the magnetic Means for writing to the buffer sector position of the disk medium and erasing the buffer sector position and buffer data stored in the storage means; and when reading the data, the read sector position and the buffer sector position stored in the storage means. If the read sector position is different, the data at the read sector position is read from the magnetic disk medium. If the read sector position matches the buffer sector position stored in the storage unit, the data is read from the buffer sector position stored in the storage unit. Means for reading out corresponding buffer data. 2. A data plane servo method, wherein N consecutive (N is 1)
In a magnetic disk drive that allows servo information reading errors of the above (integer), the format of the magnetic disk medium is a format that does not have a recovery area at the beginning of the servo area, and the function of retaining stored contents even when the power is turned off A non-volatile storage means having a write sector position (N +
1) The sector is not the (N + 1) -th sector before the servo area, or the write sector position is the (N + 1) -th sector before the continuous (N + 1) -th servo area. If the time to the) th servo area is longer than the recovery time, the write data is written to the magnetic disk medium, the write sector position is the consecutive (N + 1) th sector, and the (N + 1) th write sector from the write end position. Means for storing the write sector position and write data in the nonvolatile storage means as a buffer sector position and buffer data when the time to the servo area is shorter than the recovery time; and the nonvolatile storage means when the magnetic disk device is idle. The buffer sector position and buffer data stored in the Means for writing buffer data to the buffer sector position of the magnetic disk medium, and erasing the buffer sector position and buffer data stored in the nonvolatile storage means. When reading data, the read sector position is stored in the nonvolatile storage means. If the read sector position is different from the stored buffer sector position, the data at the read sector position is read from the magnetic disk medium. If the read sector position matches the buffer sector position stored in the nonvolatile storage means, Means for reading buffer data corresponding to the buffer sector position stored in the storage means. 3. A magnetic disk drive in which N consecutive (N is an integer of 1 or more) servo information reading errors are permitted by a data surface servo method, wherein the format of the magnetic disk medium is a recovery area at the beginning of the servo area. A write circuit that writes write data to a write sector position of the magnetic disk medium, a read circuit that reads data at a read sector position from the magnetic disk medium, and stores a buffer sector position and buffer data. An unwritten buffer circuit for erasing a buffer sector position and buffer data; a write command signal, a write position signal, and a write data signal from a higher-level device; (N + 1) before the servo area of It is not the first sector, or the write sector position is the (N + 1) th sector before the continuous (N + 1) th servo area, but the time from the write end position to the (N + 1) th servo area is longer than the recovery time. If it is longer, the write data indicated by the write data signal is written to the magnetic disk medium by controlling the write circuit, and the write sector position is the consecutive (N + 1) th sector and the (N + 1) th sector from the write end position. If the time to the servo area is shorter than the recovery time, the write sector position and the write data are stored in the non-write buffer circuit as the buffer sector position and the buffer data. Read buffer sector position and buffer data from buffer circuit A write control circuit for controlling the write circuit to write buffer data to a buffer sector position of the magnetic disk medium, and for erasing the buffer sector position and buffer data stored in the unwritten buffer circuit; When a read command signal and a read position signal are received and the read sector position indicated by the read position signal is different from the buffer sector position stored in the unwritten buffer circuit, the read circuit is controlled to read from the magnetic disk medium. The data at the sector position is read and sent to the host device as a read data signal. If the read sector position matches the buffer sector position stored in the unwritten buffer circuit, the data is stored in the unwritten buffer circuit. Buffer data corresponding to the buffer sector position And a read control circuit for reading the read data as a read data signal to a host device. 4. In a magnetic disk drive which permits N consecutive (N is an integer of 1 or more) servo information reading errors in a data surface servo system, the format of the magnetic disk medium is a recovery area at the beginning of the servo area. A write circuit for writing write data to a write sector position of the magnetic disk medium, a read circuit for reading data at a read sector position from the magnetic disk medium, and storing a buffer sector position and the buffer data. And a non-volatile write buffer circuit for erasing the buffer sector position and buffer data, and receiving a write command signal, a write position signal, and a write data signal from a higher-level device, and the write sector position indicated by the write position signal is continuous (N + 1). ) Before the servo area Although it is not the (N + 1) th sector or the write sector position is the (N + 1) th sector before the continuous (N + 1) th servo area, the time from the write end position to the (N + 1) th servo area is recovered. If the time is longer than the write time, the write data indicated by the write data signal is written to the magnetic disk medium by controlling the write circuit, and the write sector position is the (N + 1) th consecutive sector, and (N + 1) from the write end position. If the time to the third servo area is shorter than the recovery time, the write sector position and the write data are stored in the non-volatile non-write buffer circuit as the buffer sector position and the buffer data. The position of the buffer sector and the A write control circuit for reading buffer data, reading the buffer data, writing the buffer data to the buffer sector position of the magnetic disk medium by controlling the write circuit, and erasing the buffer sector position and the buffer data stored in the nonvolatile non-write buffer circuit; Receiving a read command signal and a read position signal from a host device, and controlling the read circuit if the read sector position indicated by the read position signal is different from the buffer sector position stored in the non-volatile non-write buffer circuit. The data at the read sector position is read from the magnetic disk medium and sent to the host device as a read data signal. If the read sector position matches the buffer sector position stored in the non-volatile non-write buffer circuit, the non-volatile non- Stored in the write buffer circuit A read control circuit for reading buffer data corresponding to the buffer sector position and transmitting the read buffer data as a read data signal to a host device. 5. A format efficiency improving method for a magnetic disk drive according to claim 3, wherein said N is 1. 6. The method according to claim 3, wherein N is 2. 7. A data plane servo method in which N consecutive (N is 1)
Used in the magnetic disk apparatus that allow servo information read error or an integer), La at the beginning of the servo area
A magnetic disk medium having a format in which an it- to-read recovery time area does not exist.