JPS59203207A - Magnetic recording method - Google Patents

Abstract

PURPOSE:To erase efficiently the previous recording to record data with high reliability by subjecting a recording track area to saturated magnetization plural times to invert the direction of magnetization alternately. CONSTITUTION:An erasing head where one coil 12 is wound around an E-shaped core 11 is provided in the flow-in end of a floating head. The recording track area of a rotating magnetic face recording medium is subjected to saturated magnetization plural times (for example, twice) to invet the direction of magnetization alternately, thereby erasing the previous recording. Next, directions of magnetization are combined selectively to record data with saturated magnetization. Thus, the previous recording is erased efficiently, and data is recorded with a high S/N without the influence of the previous recording even if a recording medium having a high holding force is used or data is recorded with a high recording density.

Description

Detailed Description of the Invention (a) Technical Field of the Invention The present invention relates to a magnetic recording method, and particularly to a magnetic recording method for recording binary digital information on a magnetic disk or the like with excellent signal-to-noise ratio without being affected by the previous history of the recording medium. Method Vc11.

(b) Background of the Technology Magnetic disk devices, magnetic drum devices, and magnetic tape devices that store information on magnetic surfaces occupy a major position as external storage devices such as electronic storage devices.

In these devices, as illustrated in FIG. 1, binary information is stored by selectively combining the magnetization directions of the recording medium based on the polarity of the recording current, and the binary information is stored by detecting the magnetic flux generated in the magnetization reversal region. is played.

+# As the areal recording density of these storage devices increases with the aim of increasing the storage capacity and shortening access time in accordance with the progress of information processing systems, the antecedent characteristics of the recording medium are attracting attention. became.

(c) Prior art and problems In magnetic disk drives and magnetic drum drives, conventionally, prior to recording information, there is no process of erasing previously recorded information, and new information is recorded over old information. things are being done.

When reproducing new information recorded in this manner, customizing the previous history becomes a problem because the signal-to-noise ratio of the reproduced signal decreases or a read error occurs due to the old recording.

The previous history of the recording medium that affects the new record information is as follows:
There are factors.

The first is the old recording remaining outside the newly recorded track. This is because (1) the higher the frequency, the narrower the indentation width, (b) a shift in the track position, and (c) an unsaturated magnetized region on the outside of the saturated magnetized trunk. 2nd South is a diagram schematically showing an unsaturated magnetized region 3 formed outside a track 2 of a recording medium that has been saturated magnetized by the magnetic head 1.

The second factor is that when the recording current reverses its polarity,
As previously shown in Figure 1(b), it is actually impossible to reverse the polarity instantaneously, and a region that is not saturated magnetized is formed at the position of the transient state, and the old magnetization pattern remains. It depends. This second factor mainly occurs at the center of the track and causes a peak shift during reproduction.

The antecedent characteristics of the recording medium due to the two factors described above are one of the factors that hinder the improvement of the recording density of magnetic disk devices, etc., and devices have been developed to effectively eliminate them.

(d) Purpose of the Invention The present invention provides a recording method for efficiently erasing previous records and obtaining reliable records for magnetic surface storage devices such as magnetic disk devices and magnetic drum devices in which the recording medium performs rotational motion. The purpose is to provide.

(e) Structure of the Invention The non-inventive object is to perform saturation magnetization multiple times by alternately reversing the magnetization direction in the recording track area of a magnetic surface recording medium that performs rotational movement, and then to change the magnetization direction to the recording trunk area. This is achieved by a magnetic recording method that performs binary information recording by selectively combining saturation magnetization.

As is already known, recording by selectively combining the saturation magnetization directions of a recording medium can be referred to as Y1 if, for example, the entire surface of the recording medium is saturated magnetized in a constant magnetization direction. However, since the track information and the like of magnetic disks are generally recorded magnetically, it is impossible to erase the entire area, and erasing must be performed along the tracks.

Of the two causes of the antecedent history described above, the antecedent history at the center of the track due to the transient phenomenon of the recording current, which is the second factor, can be erased by one DC saturation magnetization along the track.

Further, among the factors (a) and (b) of the above-mentioned general 1, they can also be erased by one DC saturation magnetization.

However, the unsaturated magnetized region outside the track (c) cannot be removed by l1M4 by one or more on-trunk magnetizations in the same magnetization direction.

The present invention erases the unsaturated magnetized region outside the trunk by performing saturation magnetization multiple times in which the magnetization direction is alternately reversed in the recording track region, as described below.

As shown in FIG. 3, at point A on the track, saturated magnetization in the positive direction AO, at point B, saturated magnetization BO in the negative direction is recorded, and at point C outside the track, unsaturated magnetization in the positive direction COr, in the negative direction. unsaturated magnetization.

, and the absolute values of co and Do are equal.

If the track area is now subjected to DC saturation magnetization in the positive direction, for example, the magnetization state of each point will change according to the magnetization curve shown in the figure, and each point will become AI+BI+c.

and becomes o A+ = Ao + B+ = A
+=Ao, and the recording is erased in the saturated magnetization region.

However, in the unsaturated region, Dl for C,=CO
The magnetization direction matches C1, but the residual magnetization is small, and this difference in magnetization remains as a previous history.

In this state, if the track area is DC saturated magnetized in the negative direction opposite to the previous time, each of the points will be A2+
B2. They become C2 and B2. A2=B2-B. In the saturated magnetization region, the previous recording is naturally erased, and in the unsaturated magnetization region, the difference between C2 and B2 decreases compared to the difference between C1 and Dl.

By repeating the saturation magnetization in the track region by gradually reversing the direction alternately, the difference in magnetization between point C and the point can be gradually reduced. The effect of erasing can be obtained.

(f) Examples of the invention The present invention will be specifically explained below using examples.

The first example is as follows. A monolithic manganese zinc (MnZn) ferrite head with a conventional structure is used, and the coercive force is He-600COe).
The first L:I) information is recorded on the recording medium using a modulation method with a long magnetization reversal interval.

First, as a first comparative example, when writing the second information using a modulation method in which the number of magnetization reversals is twice that of the above modulation method without providing an erasing process as in the conventional case, the signal-to-noise ratio is 24 (dB). Further, as a second comparative example, when the second information is refined after one erasure, the signal-to-noise ratio is 30 (dB
).

On the other hand, in the embodiment of the present invention in which the direction after the first DC saturation magnetization is reversed to perform the second DC saturation magnetization, and then the second information is written, the signal-to-noise ratio is 41 (dB).

Furthermore, as a second embodiment, an erasing head having an E-shaped core 11 and one coil 12 as shown in FIG. When DC saturation magnetization was performed and the second information was written under the same conditions as in the first embodiment, a signal-to-noise ratio of 40 (dB) was obtained.

According to the method of the second embodiment, there is no need for the waiting time of two rotations of the recording medium for RP removal, which is required in the embodiment of the first embodiment.

(g) Effect of @Ming As explained above, according to the present invention, it is possible to efficiently erase old records on magnetic disks, magnetic drums, etc. that record binary information by combining the magnetization directions of the recording medium. Therefore, even if a high coercivity recording medium is used or recording is performed at a high recording density, recording can be performed with an excellent signal-to-noise ratio without the influence of previous history, and the reliability of information can be improved.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of binary information recording using a magnetic surface recording medium.
Figure 2 is an explanatory diagram of the unsaturated magnetized region outside the track, Figure 3
The figure is an explanatory diagram of an erasing method using DC magnetization a plurality of times to reverse the magnetization direction, and FIG. 4 is a plan view showing an example of the erasing head used in the embodiment of the present invention. In the figure, 1 is a magnetic head, 2 is a saturated magnetized track, 3 is an unsaturated magnetized region, 11 is a core, and 12 is a coil. , v−1昭<Q+ 2FiL悄Htott θ othalf ?
Country #3 Mamo 4 necessary

Claims (1)

[Claims] Saturation magnetization is performed multiple times by alternately reversing the magnetization direction in the recording track area of a magnetic surface recording medium that performs full rotational motion,
1. A magnetic recording method characterized in that binary data recording is performed by subsequently performing saturation magnetization in which magnetization directions are selectively combined in the recording track area.