JPS63108524A - Run-out zone deciding method for magnetic disk - Google Patents

Abstract

PURPOSE:To decide a run-out zone without fail by repeating the detecting action of the number of erase gaps and an action to move a magnetic head at the interval of one or two tracks and detecting other constant number of the erase gaps. CONSTITUTION:An erase gap detecting circuit 11 inputs a reading signal from an information recording and reproducing part 9, counts the number of the erase gaps of respective tracks and outputs the counted value. A microcomputer 13 reads the counting, and when the counting is not 16 pieces, magnetic heads 6a and 6b are moved to the outside for two tracks. Thus, the heads 6a and 6b are moved to the outside for two tracks and arrive at a track -1 of the run-out zone. Since 16 erase gaps G1-G16 are formed at the run-out zone, this is discriminated and the head position is decided by the run-out zone.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method for determining a runout zone of a magnetic disk using a cartridge-type magnetic disk as a storage medium.

[Prior art] A magnetic disk is housed in a disk cartridge.

2. Description of the Related Art A magnetic disk drive is known in which a disk cartridge is formed to be detachably attached to a drive device, thereby making it possible to replace the magnetic disk.

An example of the track configuration of such a magnetic disk is shown in FIG. In the figure, the data zone is

There are data tracks 0 to 612 for recording user information,
In addition to the normal data area, each track has an erase gap Gl near the index position IX.

A servo information area is formed in which servo information for detecting the position of the magnetic head is recorded. Tracks -1 to -4 in which fixed information is recorded in the runout zone
There is an erase gap of 6 for each of them.
1 to Gl(+) and servo information areas S1 to S516 are formed, and servo information is recorded in each servo information area S+-5t6 of track-2.

When the disk drive is started, the magnetic head is first positioned on track 2, servo information is read, and the amount of eccentricity of the magnetic disk is determined based on the read signal. Thereafter, when recording and reproducing data on the data track, the position of the magnetic head is controlled based on the amount of eccentricity determined above so that the magnetic head accurately follows a predetermined track.

By the way, in order to first position the magnetic head on track 2, it is necessary to determine the position of the run-out zone.To do this, as shown in FIG.
First, the magnetic head is moved by a predetermined distance, targeting a certain track, for example track 15.

In this case, since the magnetic head is moved a certain distance from the mechanical reference position of the drive device, it is not accurate, and the magnetic head may deviate from the target track 15 by several tracks or be located between two tracks. When the magnetic head is at an intermediate position between two tracks, information on both tracks is read, but the erase gap G1 can be detected.

Therefore, first, the number of erase gaps detected during one rotation of the magnetic disk by the read signal from the magnetic head is counted. When the magnetic head is in the data zone, usually only one erase gap is detected, so at this time it is moved toward the outer track with the lower number by 1/2 of the track interval, and then the detection 1 judgment and the detection 1 judgment as described above are performed. Repeat the movement.

This moves the magnetic head to the runout zone. The erase gap is 61~G in the runout zone.
Since 16 pieces are formed up to 16, when 16 pieces are detected, that position is determined to be the start position of the run-out zone.

Therefore, by moving the magnetic head by a predetermined amount from this position, the magnetic head can be set at the position of track-2, and the predetermined process for determining the amount of eccentricity can be performed.

By the way, when detecting the erase gap in the above, if the magnetic head is located at the exact center between tracks i and i-1 as shown by Ho in FIG. You will read two pieces of information. In this case, since the two pieces of information are each random pieces of information, when read by a magnetic head, the two read signals may overlap and become large, or conversely cancel each other out and not be detected.

In this case, if a state in which no read signal is detected occurs 15 times or more during one rotation of the magnetic disk, the operation will be similar to the case where 16 erase gaps are detected, and the run-out zone will be detected even though it is in the data track zone. Since it is erroneously determined that it is, there is a problem that the determination operation is not reliable.

[Objective] An object of the present invention is to provide a runout zone determination method that can solve the above problems and reliably determine the runout zone.

[Configuration] Therefore, the present invention moves the magnetic head at intervals of one or two tracks, reads servo information recorded on the track to control the head position on-track, and then detects the erase gap and moves the magnetic head at intervals of one or two tracks. The moving operation is started.

Examples of the present invention will be described in detail below.

FIG. 1 is a block diagram of a magnetic disk device to which a runout zone determination method according to an embodiment of the present invention is applied. This device is unitized and installed in a computer system (not shown), and power is supplied from the main body of the device. 1 is attached to the drive device 2, and the disk support 1
A is chucked to a spindle 3a of a spindle motor 3, and a six-spindle motor drive circuit 4 driven by the spindle motor 3 rotates the spindle motor 3 at a constant speed. A read/write magnetic head (hereinafter simply referred to as head) 6a brings the carriage 5 into contact with each data recording surface of the magnetic disk l.

6bt! : mounted and driven by step motor 7.

The step motor drive circuit 8 rotates the step motor 7 by a predetermined amount. Also, although not shown,
From the rotation angle of the step motor 7, the heads 6a, 6b
A reference position sensor is provided to detect the reference position of.

The information recording/reproducing circuit 9 sends a write signal to the heads 6a, 6b and also extracts the read signal, and the servo signal detection circuit 10 detects a servo signal from the extracted read signal. Further, the erase gap detection circuit 11 detects the number of erase gaps formed in each track.

The interface circuit 12 is connected to a host computer (not shown) via a disk controller (not shown),
Control signals, status signals, read data, or write data are exchanged with the disk controller. The microcomputer 13 receives predetermined signals from each of the circuits described above and controls each of the circuits.

The track configuration of the magnetic disk 1b is the same as that shown in FIG. 4.

With the above configuration, when this magnetic disk device is started,
First, a runout zone determination operation is performed to position the heads 6a, 6b at the start position of the runout zone of the magnetic disk lb. FIG. 2 shows a flowchart of this operation. In the initial state immediately after startup, the heads 6a,
6b is located at a reference position on the drive device 2 side. The microcomputer 13 controls the step motor drive circuit 8 to move the head 6a toward the track 15 of the magnetic disk 1b.
, 6b are moved a certain distance (process 20). At this time, the target track 15 is the magnetic disk lb.
Even if there is a deviation in the position of the carriage 5 or the reference position of the carriage 5, the heads 6a, 6 are always in the data track zone.
This is to make it possible to position b.

Next, the information recording/reproducing circuit 9 is instructed to select one of the heads 6a or 6b specified in advance, and is controlled to extract the read signal from that head (process 21).
As a result, the extracted read signal is input to the servo signal detection circuit 10 and the erase gap detection circuit 11.

As shown in FIG. 4, in the servo information area s1.

Two types of servo information arranged at every other track are recorded, and if one of the servo information is Sa and the other is sb, the servo signal detection circuit 10 reads the servo information Sa and Sb. The levels Va and Vb of both detection signals are output. Microcomputer 1
3 reads these levels Va and Vb and controls the step motor drive circuit 8 so that both levels are equal, and the head 6a is controlled by conventional servo control.
, 6b on-track to the nearest track.

By the way, when the disk cartridge 1 is installed in the drive device 2, the spindle 3a and the magnetic disk 1b are usually misaligned in center, that is, eccentricity occurs. Now, suppose that the center O5 of the spindle 3a and the center Ob of the magnetic disk 1b are shifted by a distance d as shown in FIG.
The servo information Sa and Sb formed on the track Ti are destroyed.
T! Since the heads 6a and 6b are rotated as shown by SSi, the positions II of the heads 6a and 6b are positioned so as to pass over this broken line position Si. Then head 6
Although heads 6a and 6b will not be accurately on-track to track Ti, they will not be so off-track that they will deviate to the adjacent track Ti-1 and the heads 6a and 6b will read the information simultaneously (process 22).

Next, the microcomputer 13 slightly controls the head position 11 in one direction, and the servo information Sa, S
For example, in the case of FIG. 3, when the head position I11 is moved inward, the level Va of the detection signal of the servo information Sa increases, and Va>Vb. Become. On the other hand, as is clear from the arrangement of the servo information shown in FIG.
b are arranged alternately between the tracks, so when the head position 12H is moved inward as described above, the level Va>Vb holds for odd-numbered tracks, and the level Vb>Va holds for even-numbered tracks.

The microcomputer 13 determines whether the track positioned by this method is an odd number or an even number.
3) If the number is even (N in process 23), the head 6a,
6b is moved outward by one track (from process 24 to process 23) 2. As a result, it is always on-track to an odd numbered track (Y in process 23). The erase gap detection circuit 11 receives the read signal from the information recording/reproducing section 9, counts the number of erase gaps in each track, and outputs the counted value. The microcomputer 13 reads the counted value and if it is not "16" (processing 25
N), the heads 6a and 6b are moved outward by two tracks (process 26), and the process returns to process 25. Here, processing 22 does not perform servo control like processing 22.
This is because if the position is moved by the equivalent of two tracks based on the on-track position in , a large positional shift will not occur and the time required for servo control will be reduced.

As a result, the heads 6a and 6b are moved outward two tracks at a time until they reach track-1 in the run-out zone. Since 16 erase gaps 61 to G1g are formed in the run-out zone as shown in FIG. 4, these are determined in the process 25 (
In step 25 (Y), the head position is determined to be in the run-out zone.

Thereafter, the heads 6a and 6b are further moved outward by a certain distance and operate in the same manner as in the prior art to read each servo information recorded on track-2, but the explanation thereof will be omitted.

As described above, according to this embodiment, the head position is first on-track controlled to odd-numbered tracks, and then the erase gap is detected, while the head position is moved outward two tracks at a time. Due to this.

As shown in FIG. 3, the head position H is on-track controlled for each track so that the positions of the servo information Sa and Sb serve as the reference. At this time, although the eccentric distance @d is shown large for convenience in the figure, it is considerably smaller than 1/2 of one normal track interval. Therefore, heads 6a, 6b
This eliminates the possibility that the track Ti deviates greatly from the track Ti and the information of the adjacent track is read out. This prevents the erasing gap from being erroneously detected due to simultaneous reading of recorded information on two tracks as in the conventional case.

Although FIG. 3 of this embodiment shows an example in which servo control is not performed after the head movement in process 27, it goes without saying that servo control may be performed.

In addition, although we first positioned on odd-numbered tracks and moved two tracks at a time, the run-out zone is the same even if we position on even-numbered tracks and reach track -2, or move one track at a time. Can be detected.

[Effects] As described above, according to the present invention, after on-track control of the head is performed, erase gap detection and head movement are performed.

The erase gap can always be detected correctly, making it possible to reliably determine the runout zone.

[Brief explanation of the drawing]

FIG. 1 is a block configuration diagram of a magnetic disk device to which a magnetic disk runout zone determination method according to an embodiment of the present invention is applied, FIG. 2 is a flowchart showing the runout zone determination operation of the device, and FIG. 3 is a head 61 is an explanatory diagram of the position, FIG. 4 is a track configuration diagram of a magnetic disk, FIG. 5 is a flowchart showing a conventional run-out zone determination method, and FIG. 6 is an explanatory diagram of a track information reading operation.
...Cartridge, 1a...Disk support, lb
... Magnetic disk, 2... Drive device, 3... Spindle motor, 3a... Spindle, 4... Spindle motor drive circuit, 5... Carriage. 6a, 6b... Magnetic head, 7... Step motor, 8... Step motor drive circuit, 9... Information recording/reproducing circuit, 10... Servo signal detection circuit, 11
. . . erase gap detection circuit, 12 . . . interface circuit, 13 . . . microcomputer. Agent Patent Attorney Crest 1) Makoto ＼. Figure 2 Figure 3

Claims (1)

[Claims] A magnetic head is arranged on a magnetic disk having a data zone consisting of a plurality of data tracks having a certain number of erase gaps, and a run-out zone consisting of a plurality of tracks having another certain number of erase gaps. In this method, a read signal is extracted from the magnetic head every time the magnetic head is moved at regular intervals, and the number of erase gaps is detected using the read signal to determine the run-out zone.The head position is determined by reading the servo information recorded on the track. After performing on-track control, the operation of detecting the number of erase gaps and the operation of moving the magnetic head at intervals of one track or two tracks are repeated to detect the other fixed number of erase gaps. 1. A method for determining a run-out zone of a magnetic disk, the method comprising determining a run-out zone using the following methods.