JPS6231401B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a rotating magnetic storage device, and particularly to a magnetic storage device having a magnetic disk.

[Background of the invention]

In recent years, a contact start/stop method is being adopted in magnetic disk drives. In this method, with the head stationary in the contact start/stop zone on the magnetic disk,
The magnetic disk is rotated and the head is levitated by the air flow accompanying the rotation, and then the head is moved by a drive device so that it is positioned on a desired data track within a data recording zone (data zone). With this method, after rotating and stopping the magnetic disk many times, it occurred that the data information could not be reproduced.

When we investigated the cause of this, we found the following. During the start, the head slides against the disk until it floats, which can cause damage to the contact start/stop zone of the disk. At this time, the coating film (magnetic powder hardened with resin) of the recording medium may adhere to the head or be scattered over the data zone. When the head accesses a desired data track in this state, the powder abrades the coating on the data track.
That is, the coating on the data track is worn away. This happens many times as the magnetic disk repeatedly rotates and stops, and the coating on the data track becomes increasingly worn. Eventually, it was discovered that important data information became unplayable.

[Purpose of the invention]

The present invention was made with attention to this fact, and the coating film on the data track of a magnetic disk wears out to the limit (referred to as the wear limit) at which it becomes difficult to reproduce data information from this data track. ) is provided, in which it is possible to know even when data information is being reproduced, whether or not it has been reached.

[Summary of the invention]

The present invention detects whether the magnetic disk has exceeded its wear limit by separating a predetermined pattern signal from the detection signal of the magnetic head and comparing the magnitude of this pattern signal with a predetermined reference value. When the wear limit is exceeded, it is possible to avoid losing the timing to take measures such as replacing the magnetic disk with a new one.

[Embodiments of the invention]

Hereinafter, the present invention will be explained in detail with reference to Examples.

FIG. 1 shows a magnetic disk used in the present invention. 1 is the contact start/stop zone, 2
3 is a data zone, 3 is an area where a predetermined pattern signal is recorded, and 4 is a data track.

FIG. 2 is an enlarged view of a part of the region 3. As shown in FIG. 31, 32, 33, and 34 are partial regions obtained by dividing the region 3 in the radial direction, and are magnetized in the direction of the arrow to form a predetermined pattern signal. n, n+1, and n+2 are data tracks.

In FIG. 3, a disk drive device 11 rotates the magnetic disk 7 and servo disk 10 shown in FIG. A data signal and a pattern signal are reproduced by the magnetic head 6, amplified by an amplifier 14, and outputted as a signal S. The magnetic head 8 reads position information from the servo disk 10. Based on this position information, the position detector 9 outputs a determination signal R indicating whether the magnetic head 6 is present in the area where the predetermined pattern signal is recorded. Based on the signal R, the signal separation circuit 15
(referred to as the first means) converts the signal S into the data signal D
and pattern signal P. Signal D is reproduced by data signal reproduction circuit 16. Average value circuit 1
Step 7 calculates the average value P _n of the signal P within the time specified by the signal R. The A/D conversion circuit 18 converts the analog signal P _n into a digital signal P _nd . A digital signal H (referred to as a reference value) corresponding to the wear limit of the magnetic disk is stored in advance in the memory 20 (referred to as a second means). In the determination circuit 21 (referred to as the third means), the signals P _nd and H
It is determined whether H>P _nd .
Then, only when H>P _nd holds true, a signal A indicating that the magnetic disk exceeds the wear limit is output. Based on the signal A, the alarm device 22 issues an alarm such as lighting a lamp or sounding a buzzer. For example, from the operator console to the operator,
Informs you that wear has exceeded the limit.

The circuit 19 is a circuit for storing the digital value H in the memory 20. When a new disk 7 is set and a desired data track is read out, the operator sends an update command signal T for the memory 20 to the circuit 19 using the input device 12. At the timing when the circuit 19 receives the signal T,
Take in the signal P _nd and set a predetermined coefficient k (0<k<
1), a signal H corresponding to the wear limit of the magnetic disk is generated and stored in the memory 20.

In the above embodiment, the predetermined pattern signal is provided only in the region 3 shown in FIG. 1, but it may be provided in a plurality of regions having a predetermined width in the radial direction.
Further, it is better to make the partial area of area 3 as small as possible. In other words, it is better to reverse the magnetization at a frequency as high as possible. The reason for this is that the distance between the magnetic head disks may cause scratches (wear).
This is because when the distance is increased by , the increase in the distance becomes larger as the frequency increases.

Furthermore, since the pattern signal may be present within each data track or in the vicinity thereof, this tracking signal can also be used as a pattern signal in a magnetic disk in which a tracking signal is recorded corresponding to each data track. In this case, the tracking signal and the data signal can be easily separated by generating a discrimination signal from the servo disk, similar to the separation of the pattern signal.

In addition, the reference value corresponding to the wear limit of the magnetic disk is determined in advance through experiments, etc.
The value may be stored in memory 20 in advance, either just one value or for each data track. Further, the value may be stored in advance as data for each data track or a part thereof, and read out and set in the second means. When different reference values are provided for each data track, the reference value corresponding to the currently read data track must be read out from the second means.

〔Effect of the invention〕

As explained above, according to the present invention, countermeasures (temporary saving of data information, replacement of head disk assembly, etc.) when a magnetic disk exceeds its wear limit can be taken without wasting time. It becomes possible.

[Brief explanation of the drawing]

1 to 3 are explanatory diagrams of the present invention.

Claims (1)

[Scope of Claims] 1. A rotating magnetic recording medium in which predetermined pattern signals are recorded in or near each data track, and detecting the data signals written on each of the data tracks and the predetermined pattern signal. In the magnetic storage device, the pattern signal is recorded at a predetermined position, and the pattern signal is recorded at a predetermined position, and the pattern signal is recorded at a predetermined position, and the pattern signal is a first means for separating a predetermined pattern signal; a second means for storing a predetermined reference value corresponding to the wear limit of the magnetic recording medium; and a size of the signal obtained from the first means and the predetermined reference value. A magnetic storage device, characterized in that a third means is provided for comparing the reference value of and determining whether the magnitude of the signal obtained from the first means is equal to or less than the predetermined reference value. 2. The magnetic storage device according to claim 1, wherein the third means includes means for issuing an alarm according to the result of the determination. 3. The magnetic storage device according to claim 1, wherein a tracking signal is recorded in the magnetic recording medium corresponding to each data track, and the tracking signal is used as the pattern signal.