JPH1125591A - Magnetic disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve formatting efficiency of a magnetic disk without variance of a position judged to be a sector position. SOLUTION: This device has a magnetic head 1 under positioning control by a data surface servo system; a magnetic disk where a track is divided into plural sectors, and also servo information and data information are recorded; an R/W channel part 3 for outputting a reference clock signal (g) to a host circuit; and a synchronization circuit 7 for synchronizing a read data signal (e), synchronized with a read/reference signal (f), with the reference clock signal (g). Then, the read data signal (e) synchronized by the synchronization circuit 7 is read in by the host circuit, and also the sector position is determined based on the reference clock signal (g).

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, and more particularly, to a magnetic disk drive that determines a sector position based on a count value of a data system clock.

[0002]

2. Description of the Related Art In a magnetic disk device of this type, positioning control of a magnetic head on a disk is performed based on servo information prerecorded on the magnetic disk. The magnetic head positioning control system includes a servo surface servo system and a data surface servo system, and the latter system includes a sector servo system in which servo data is recorded in each sector created on a disk by a format.

As a magnetic disk device using the sector servo system, there is a magnetic disk device as disclosed in Japanese Patent Application Laid-Open No. 64-19567, for example. In this magnetic disk device, in the track format, servo data of the sector servo method is recorded in advance in an area other than a predetermined area of a sync field and an area of a writable area arranged at the head of each sector. It has a magnetic disk. As shown in FIG. 3, for example, the format configuration of the track on the disk is such that servo data 121 according to the sector servo method is recorded between the ID field 113 and the gap 114 of each sector. Here, the gap 111 is a gap for partitioning between the sectors, and is for securing a time necessary for switching the magnetic head (transition from the write state to the read state). Sync 112 is an area in which a clock pulse for locking up the data separation circuit of the controller is recorded. Sync 115 is Syn
This area has the same function as the nc 112, and is an area that can be rewritten by the user together with the data field 116. With this configuration, it is possible to secure a sufficient time for the magnetic head to transition from the write state to the read state.

Next, a description will be given of a configuration for determining a sector position at the time of read / write control of a conventional magnetic disk device having the above-described configuration. FIG. 4 is a block diagram showing a main configuration of a portion for determining a sector position of a conventional magnetic disk drive.

In FIG. 4, a read / write control circuit 2
Controls read / write by the magnetic head 1, reads information on a magnetic disk (not shown),
The information is written on the magnetic disk based on the write data input from the upper circuit. This lead /
The write control circuit 2 is connected via an R (read) / W (write) channel unit 3 to a data input / output control unit 6 that controls input and output of data to and from a higher-level circuit. R / W
The channel section 3 is based on a reference clock from the reference clock generation circuit 5 and has a read clock signal for causing the upper circuit to read the read data read by the magnetic head 1 and a reference clock signal for determining a sector position. Occurs. Data input / output controller 6
Is, for example, SCSI (small computer system interfac
e) The controller sends the read data read by the magnetic head 1 to the upper circuit, sends the write data from the upper circuit to the read / write control circuit 2, and sends the read data from the R / W channel unit 3. The transmitted reference clock signal for determining the sector position is also transmitted to an upper circuit.

[0006] Between the R / W channel section 3 and the data input / output control section 6, a first signal in which a write data signal from an upper circuit and a read data signal from the read / write control circuit 2 are transmitted in a time-division manner. And a second signal line in which a read clock signal for taking in the read data signal to the host circuit and a reference clock signal for taking in the write data signal to the read / write control circuit 2 are time-divisionally switched. I have.

The servo control circuit 4 extracts a servo mark signal a relating to servo information from a read data signal e obtained by reading information recorded on the magnetic disk by the magnetic head 1, and based on the servo mark signal a, It performs positioning control of the magnetic head 1 such as tracking. The servo control circuit 4 sends a servo mark signal a to a higher-level circuit via a data input / output control unit 6.

In the magnetic disk drive configured as described above, the second signal line (read / reference signal f)
Normally, a reference clock signal is transmitted except during a read operation. During this time, the upper circuit counts the clock of the reference clock signal to determine the sector position, or the write data from the upper circuit Read / synchronize with clock signal
It is sent to the write control unit 2. At the time of reading, the reference clock signal of the second signal line is switched to the read clock signal, the read data signal e read by the magnetic head 1 is sent out on the first signal line, and synchronization with the read clock signal is established. And read into the upper circuit.

[0009]

In the above-mentioned conventional magnetic disk drive, data signals are input / output to / from a higher-level circuit while switching between a read clock signal and a reference clock signal. Therefore, when determining the sector position after performing the read, the transfer from the read clock signal to the reference clock signal is performed on the second signal line. In this case, immediately after switching from the read clock signal to the reference clock signal, the frequency of the reference clock signal fluctuates, so that the position determined as the sector position fluctuates. In order to absorb this variation, the conventional magnetic disk device formats the magnetic disk so as to increase the gap length (see FIG. 3), which is an ineffective portion of a sector, resulting in poor format efficiency. Was.

It is an object of the present invention to provide a magnetic disk device which solves the above-mentioned problem and can improve the format efficiency of a magnetic disk without changing the position determined as a sector position.

[0011]

In order to achieve the above object, a magnetic disk drive of the present invention is formatted so as to divide a track into a plurality of sectors and a magnetic head whose positioning is controlled by a data surface servo method. A magnetic disk on which servo information and data information for determining sector positions are recorded, and a read data signal obtained by reading the servo information and data information by the magnetic head is synchronized with a read clock signal, A data signal other than the read data signal is synchronized with a first reference clock signal having a predetermined frequency different from the read clock signal, and switching between the read clock signal and the first reference clock signal while the upper circuit is switched. The input and output of data signals A clock signal output means for outputting a second reference clock signal of a predetermined frequency to the host circuit; and a second reference clock for a read data signal synchronized with the read clock signal. Synchronizing means for synchronizing with a signal, wherein the upper circuit reads the read data signal synchronized by the synchronizing means and determines a sector position based on the second reference clock signal. And

In the above magnetic disk drive, the synchronizing means receives a servo mark signal from which the servo information is read and a reference clock signal as inputs and counts a time interval between the servo mark signals by a reference clock signal. A servo interval counting means for outputting the servo interval count value, a FIFO stage number calculating means for calculating a FIFO stage number according to a frequency difference between the read clock signal and the second reference clock signal, and A FIFO circuit may be provided which has a plurality of FIFO memories for temporarily storing data signals, and which inputs and outputs data using the FIFO memories of the number of FIFO stages calculated by the FIFO stage number calculation means.

In this case, the FIFO stage number calculating means includes:
The current rotational speed of the spindle motor for rotating the magnetic disk is obtained from the servo interval count, and F is calculated from the rotational speed.
It may be configured to calculate the number of IFO stages.

(Action) In the present invention as described above,
The second reference clock signal output from the clock output means is constantly output to the upper circuit, and the upper circuit determines the sector position based on the second reference clock signal. There is no need to switch from the read clock signal to the reference clock signal as in the related art, and the head of the sector position does not change.

Further, in the present invention, the second means is provided by the synchronization means.
The reference clock signal and the read data signal are synchronized, so that the upper circuit can read the read data signal e.

[0016]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing a main configuration of a portion for determining a sector position of a magnetic disk drive according to an embodiment of the present invention. In FIG. 1, the same components as those of the magnetic disk device shown in FIG. 4 described above are denoted by the same reference numerals, and the description of the components is omitted here.

If the read data signal can be taken into the upper circuit by using the reference clock signal and the reference clock signal is always sent to the upper circuit when the sector position is determined, the read clock signal can be changed to the reference clock signal. , The problem of the change of the sector position due to the change of the position can be solved.

The magnetic disk drive of this embodiment is the same as that of FIG.
In the configuration shown in (1), the reference clock signal g is always output from the R / W channel unit 3 to the upper circuit, and the read / write signal e and the reference clock signal g are synchronized. The circuit 7 is provided. The reference clock signal g is a clock signal of a predetermined frequency generated based on the reference clock signal from the reference clock generation circuit 5, and here is the same signal as the reference clock signal output at times other than read in the read / reference signal f. It is.

In this magnetic disk drive, the read data signal e is synchronized with the reference clock signal g by the synchronizing circuit 7 and is output to the upper circuit via the data input / output control unit 6. In the upper circuit, the read data signal e is read using the reference clock signal g. The reference clock signal g is constantly output to the upper circuit, and the sector position is determined based on the clock count value of the reference clock signal g. As described above, in the present embodiment, the transfer from the read clock signal to the reference clock signal is not performed when the sector position is determined.

Next, a specific configuration of the above-described synchronization circuit 7 will be described. FIG. 2 is a block diagram showing an example of the configuration of a synchronization circuit constituting the magnetic disk drive of the present invention.

This synchronizing circuit comprises a servo interval counting circuit 1
0, the number of FIFO stages 11, and the FIFO circuit 12. The servo interval counting circuit 10 receives the signal servo mark signal a (the signal from which the servo information is read) output from the servo control circuit 4 and the reference clock signal from the reference clock generation circuit 5 as inputs, and calculates the time of the servo mark signal a. The interval is counted by a reference clock signal, and the counted value is output as a servo interval count signal c. FIFO
The number-of-stages calculation 11 receives the servo interval count signal c, and calculates the number of FIFO stages corresponding to the frequency difference between the read clock signal e and the reference clock signal g from the servo interval count value. The FIFO circuit 12 has a plurality of FIFO memories for temporarily storing a read data signal e.
The read data signal e is temporarily stored using the FIFO memory of the FIFO stage number calculated by the FIFO stage number calculation circuit 11.

In the synchronous circuit configured as described above, the read data signal e input in synchronization with the read / reference signal f is added to the reference clock signal g by the FIFO circuit 12 so that the upper circuit can read the data. The data can be transferred to the synchronized read data signal h. The synchronization read data signal h is output to the upper circuit via the data input / output control unit 6.

When the frequency of the read / reference signal f is different from the frequency of the reference clock signal g, there is a possibility that the read data signal e, which is read data, may be missed. For this reason, in the present embodiment, the FIFO circuit 12
Is used to store the read data signal e synchronized with the read / reference signal f and store the read data signal e synchronized with the read / reference signal f by the FIFO memory having the number of FIFO stages corresponding to the frequency difference between the read clock signal e and the reference clock signal g. A read data signal h is output.

Here, if the number of FIFO stages in the FIFO circuit 12 is too large, the delay of the read data increases, and the system performance decreases. In order to prevent this, in the present embodiment, the FIFO circuit 3
In order to optimize the number of stages, the number of FIFO stages is determined by counting the number of rotations of the spindle motor at the time of current data reading, that is, the time interval of servo information.

[0026]

According to the present invention configured as described above, since the change of the leading portion of the sector position due to the transfer from the read clock signal to the reference clock signal does not occur as in the prior art, the sector is invalidated. The gap length, which is a portion, can be made shorter than that of the conventional one, and there is an effect that the format efficiency is increased.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a main configuration of a portion for determining a sector position of a magnetic disk drive according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration example of a synchronization circuit included in the magnetic disk drive of the present invention.

FIG. 3 is a diagram showing an example of a position of a track format of a magnetic disk.

FIG. 4 is a block diagram showing a main configuration of a portion for determining a sector position of a conventional magnetic disk drive.

[Explanation of symbols]

 Reference Signs List 1 magnetic head 2 read / write control circuit 3 R / W channel unit 4 servo control circuit 5 reference clock generation circuit 6 data input / output control unit 7 synchronization circuit 10 servo interval counting circuit 11 FIFO stage number calculation circuit 12 FIFO circuit

Claims (3)

[Claims] 1. A magnetic head whose positioning is controlled by a data surface servo method, and a magnetic disk which is formatted so as to divide a track into a plurality of sectors and records servo information and data information for determining a sector position. The read data signal obtained by reading the servo information and the data information by the magnetic head is synchronized with a read clock signal, and the data signals other than the read data signal have different frequencies from the read clock signal. In a magnetic disk drive synchronized with a first reference clock signal of a predetermined frequency and switching a read clock signal and a first reference clock signal to input and output a data signal to and from an upper circuit, A second riff of a predetermined frequency A clock signal output unit for outputting a reference clock signal; and a synchronization unit for synchronizing a read data signal synchronized with the read clock signal with the second reference clock signal. Reading a read data signal synchronized by the synchronization means and determining a sector position based on the second reference clock signal. 2. The magnetic disk drive according to claim 1, wherein the synchronization unit receives a servo mark signal from which the servo information is read and a reference clock signal as inputs, and sets a time interval between the servo mark signals as a reference clock signal. A servo interval counting means for outputting the counted servo interval count value; a FIFO stage number for inputting the servo interval count value and calculating a FIFO stage number corresponding to a frequency difference between the read clock signal and the second reference clock signal. Calculating means; and a plurality of Fs for temporarily storing the read data signal.
A magnetic disk drive, comprising: an FIFO memory; and a FIFO circuit for inputting / outputting data with the FIFO memory having the number of FIFO stages calculated by the FIFO stage number calculation means. 3. The magnetic disk drive according to claim 2, wherein said FIFO stage number calculating means obtains a current rotational speed of a spindle motor for rotating and driving said magnetic disk from a servo interval count, and calculates a FIFO stage number from said rotational speed. The magnetic disk drive is configured to calculate the following.