JPS6239507B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in magnetic disk devices.

FIG. 1 is a simple explanatory model diagram showing the configuration of a conventional magnetic disk device. In a conventional disk device as shown in the figure, especially a large-capacity device, two data cores 2, 2' per disk surface are attached to one head guide arm 1, and one surface of the disk 3 is designated as an inner peripheral area. The outer peripheral area is divided into two areas, and each core 2, 2' records information.
It is in charge of regeneration. A guide arm 1 is attached to the carriage 4 and moves the head assembly including the cores 2, 2' in the direction of arrow 5 to cover the entire surface of the disk. Up until now, data cores 2 and 2' have been manufactured with exactly the same dimensions, and their track widths are the same.
Furthermore, the movement of the carriage 4 was controlled so that recording and reproduction were performed over the entire surface of the disk 3 at the same track pitch.

However, since the disk 3 normally rotates at a constant number of rotations and the recorded information is transferred at a constant frequency, the information recording density on the disk inevitably increases in the inner peripheral area of the disk 3 where the circumferential speed is slow. is significantly higher than that in the outer peripheral area.
Therefore, due to the occurrence of various losses in magnetic recording, the reproduction output in the inner circumferential area is lower than that in the outer circumferential area. This relationship is shown in FIGS. 2 and 3.

That is, FIG. 2 is a graph showing that the recording density decreases from the inner circumference to the outer circumference, but the peripheral speed increases. In the figure, A is a characteristic straight line of recording density, and B is a characteristic straight line of peripheral speed. Figure 3 shows
It is a graph showing that the reproduction output increases from the inner circumference to the outer circumference.

As can be seen from the above, the reliability of information is significantly reduced, especially in the inner peripheral area, and the S/N ratio is deteriorated. In order to prevent a drop in output, attempts have been made to narrow the flying gap between the head and the disk or to increase the number of windings in the data cores 2 and 2', but these have each resulted in a collision between the head and the disk. ) and an increase in inductance, which made it extremely difficult to design an overall well-balanced design.

This invention has been made in view of the conventional technical circumstances as described above, and an object of the invention is to provide a reliable and sufficient reproduction output even in the inner circumferential area without causing any other adverse effects. The object of the present invention is to provide a magnetic disk device that can be obtained at a good price.

The main points of the structure of this invention are as follows.

First, as shown in FIG. 4, it is generally known that there is a proportional relationship between the track width of the data core and the playback output. Although the track width of the data core 2' is made larger than that of the data core 2', by simply doing so, it is not possible to record a predetermined number of tracks on a fixed area of the disk. Therefore, on the contrary, since the output from the data core 2' existing in the outer peripheral area is sufficiently large as shown in Fig. 3,
By further reducing the track width of this data core 2', it becomes possible to record a predetermined number of tracks on a fixed area of the disk, and also to
Since the track pitch differs in the outer circumferential area, a servo function is provided to position the track accordingly.

Next, one embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 5 is an explanatory diagram showing how tracks are arranged on a magnetic disk surface according to the present invention.

Please refer to FIG. In order to widen the track width 6 in the inner circumferential area 10 on the surface of the magnetic disk 3 and correspondingly prevent mutual interference between adjacent tracks,
Also increase track pitch 7. On the other hand, in the outer peripheral area 11, the track width 8 can be narrowed and the track pitch 9 can be reduced by the amount that mutual interference between adjacent tracks is reduced. The track pitch can be controlled by changing the moving distance of the carriage 4 according to each area by distinguishing between recording and reproducing operations in the inner and outer peripheral areas. By doing so, a more uniform reproduction output can be obtained over the entire area.

Next, since the track pitch differs between the inner and outer areas, a new track positioning servo function is required, which is different from the conventional one. A configuration for meeting such demands will be explained with reference to FIG. 6.

FIG. 6 is a simple explanatory model diagram showing a novel track positioning servo mechanism used in the magnetic disk device according to the present invention.

In the figure, a disk 13 is a servo disk on which servo information is written, and two cores 12 and 12' mounted on a guide arm 14 are both servo heads. Servo core 12 corresponds to data core 2, and servo core 12' corresponds to data core 2' and generates respective positioning signals. That is, servo information is pre-recorded at the location corresponding to servo core 12 at the same pitch as track pitch 7 in FIG. Servo information is written in pitch. Therefore, when seeking a track in the outer peripheral area using data 2', the movement of the carriage 4 is controlled by the signal from the servo core 12', and the data core 2'
When seeking a track in the inner peripheral area and exchanging signals from there, the movement of the carriage 4 is controlled by the signal from the servo core 12. In addition, in order to always know where each core is located in the track number based on the signals from each servo core 12, 12', the number of tracks that have been traversed by seeking corresponding to the track number is counted. Store this value in the counter. FIG. 7 is an explanatory diagram showing this relationship. That is, FIG. 7 is an explanatory diagram showing a servo information reading mechanism in one embodiment of the present invention.

In the figure, each servo core 12, 12' is
The servo information 15, 15' recorded in advance in the inner circumferential area 10a and outer circumferential area 11a on the servo information disk 13 is read and stored in signal counters 16, 16', respectively. This is as stated above. For this function, each of the two servo cores is provided with a counter so that they can be counted independently. By doing this, when switching from control by servo core 12 to control of servo core 12',
That is, when switching from a track in the inner area to a track in the outer area, the data core 2'
Alternatively, it is possible to always know where the servo core 12' is, and to quickly move from that position to a predetermined track without having to return to track #0 each time. Since the difference in track pitch between the inner and outer peripheral areas is not necessarily an integral multiple, even if the servo core 12 is on track, the servo core 12' is not necessarily on track. However, since it is possible to determine between which track numbers the vehicle is located based on the contents of the counter, it is possible to move to a predetermined track by the next command. The same holds true when the number of cores arranged on the disk surface is increased and the number of track width and track pitch division areas is increased to three or more.

As described above, the present invention has the advantage that sufficient reproduction output can be obtained with high reliability even in the inner peripheral area in a magnetic disk device without causing any other adverse effects.

[Brief explanation of the drawing]

FIG. 1 is a simple explanatory model diagram showing the configuration of a conventional disk device, FIG. 2 is a graph showing the relationship between the inner circumference and the peripheral speed (and recording density) on the magnetic disk surface, and FIG. Graph showing the relationship between the inner circumference and the playback output on the magnetic disk surface, 4th
The figure is a graph showing the relationship between the track width on the magnetic disk surface and the playback output. FIG. 5 is an explanatory diagram showing the track arrangement on the magnetic disk surface according to the present invention. FIG. FIG. 7 is a simple explanatory model diagram showing a novel track positioning servo mechanism used in the example. FIG. 7 is an explanatory diagram showing a servo information reading mechanism in an embodiment of the present invention. Explanation of symbols, 1...Head guide arm, 2,
2'...Data core, 3...Magnetic disk, 4...
...Carriage, 6, 8...Track width, 7, 9...
...Track pitch, 10...Inner area, 11...
...Outer area, 12, 12'...Servo core, 1
3... Servo disk, 14... Guide arm,
15, 15'... Servo information, 16, 16'... Counter.

Claims (1)

[Claims] 1 Divide the data recording surface of a magnetic disk into at least two areas: an inner area and an outer area, and make the track width and track pitch larger in the inner area, and make the track width and track pitch relative to each other in the outer area. In a magnetic disk device that is relatively small in size, a servo core corresponding to each of the at least two divided areas;
A servo disk is provided which is located opposite to these cores and has servo information recorded thereon corresponding to the track pitch of each area on the data recording disk surface, and the data core in each divided area on the data recording disk surface is provided. track positioning operation,
A magnetic disk device characterized in that the servo core corresponding to each region reads the servo disk and uses track position information obtained.