JPS641874B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic disk device.

FIG. 1 is a top view showing the concept of a magnetic disk device, and FIG. 2 is a side view. See both figures. A plurality of magnetic disks 1 are rotatably attached to one common rotating shaft 2 concentrically. On the other hand, two magnetic head positioning devices, 3 and 4 in this case, are provided to support the magnetic head and position the magnetic head to the information recording track on the magnetic disk surface for reading and writing. . The magnetic head positioning device (hereinafter sometimes simply referred to as the positioning device) 3 includes:
The positioning device 4 has a servo head 7 and a data head 8, and the positioning device 4 has a servo head 5 and a data head 6. The servo head 7 reads servo information from the servo information recording surface 9 of the magnetic disk, and since this information represents the position of the head 7 on the disk surface, means (not shown) operate based on this information. The positioning device 3 is then positioned at a predetermined position with respect to the magnetic disk 1, whereby the servo head 7 can take a predetermined position on the disk surface. When the positioning is completed in this way, data is written to and read from the disk surface by the data head 8.

The same applies to the positioning device 4, in which the servo head 5 is located on the servo information recording surface 10 of the disk.
The servo information is read from the servo information, and after positioning is completed, the data head 6 writes the information to the magnetic disk. A read is made.

Now, when writing is performed, the index indicating the starting point of the information recording track on the magnetic disk surface is detected, and then writing is performed.

FIG. 3 is a perspective view showing the structure of a conventional disk, and the index 11 on the servo information recording surface 9 and the index 12 on the servo information recording surface 10 are relative to each other on the circumference viewed from the center of the disk. were located in the same location. Therefore, the data head 8 in the positioning device 3
There was a situation in which the data writing on the magnetic disk surface by the data head 6 in the positioning device 4 and the data writing on the magnetic disk surface by the data head 6 in the positioning device 4 could not be performed consecutively in time. This situation will be explained in detail with reference to FIGS. 5 to 7.

FIG. 5 is a timing diagram of a write operation on a track by a data head when the magnetic disk rotates once. First, after detecting the index on the track, during the next low level _T5 period,
It confirms its own head number and writes data during the subsequent high level period. Truck 1
The last low level T ₀ period of the cycle period T ₁ may be zero if there is a large amount of write data.

FIG. 6 shows that the data head 6 has four heads 6.
6 is a timing diagram of a write operation in the case of a, 6b, 6c, and 6d (all not shown); FIG. Although there are four heads, there is only one read/write amplifier, so each head is sequentially switched and data is written to each track for each head by rotating the disk once each time. That is, after the positioning is completed, the total time required for writing in each head, starting from head 6a and ending with head 6c, is equal to the period during which the disk rotates four times, and is therefore _4T1 . During the subsequent T ₂ period, the positioning device supporting the head is positioned to another position, and the following 4T ₁
Data is written again in the period , and the same process is repeated thereafter. In other words, since the period T ₂ required to position the positioning device to another position is required,
Continuous writing of data is not possible.

FIG. 7 is a timing diagram when data is written by switching between a total of two sets of data heads each supported by two positioning devices. That is, after the servo head 7 supported by the positioning device 3 detects the index 11 and the data head 8 (assumed to include four heads) writes, another period 4T ₁ (A) occurs. In this case, when switching to one positioning device 4 and writing data, as is clear from FIGS. 1 to 3, after period 4T ₁ (A), the index on the servo information recording surface 9 is When the servo head 7 detects the disk again, the index 12 on the servo information recording surface 10 is at the same position relative to the index 7 on the circumference as seen from the center of the disk, so this index 12 is detected by the positioning device. 4
It takes half a rotation of the disk before it is detected by the servo head 5. The period required for this half rotation
After T ₃ the servo head 5 carried by the positioning device 4 detects the index 12, followed by a writing period 4T ₁ (B) by the data head 6. In other words, the period required to wait for half a rotation of the disk
Because of T ₃ , continuous writing is still not possible.

Generally, as shown in the timing diagram of Fig. 7, when the positioning devices 3 and 4 are switched to write data on different disk surfaces, the problem arises that the order of the data gets confused and control becomes difficult. Because there is
Instead of using the method shown in FIG. 7, it is common to use a single positioning device as described with reference to the timing diagram of FIG. 6.
However, in special applications, such as payroll calculations, where it is necessary to write data continuously, even if the positioning device is switched, the data cannot be written continuously over time. It is desirable to perform writing.

This invention was made in response to the above-mentioned demands against the background of the above-mentioned technical circumstances, and therefore, an object of the invention is to To provide a magnetic disk device capable of continuously reading and writing data to a magnetic disk without waiting time required for head positioning when switching from a magnetic head to a magnetic head on another positioning device.

The main point of the structure of the present invention is to support a plurality of magnetic disks and a magnetic head that are concentrically attached to one rotating shaft, and to transfer the magnetic information to information recording tracks on the surface of the disk for reading and writing. In a magnetic disk device comprising a plurality of magnetic head positioning devices for positioning the heads, when the magnetic head in a certain positioning device is in a position to detect an index indicating the starting point of an information recording track on a certain magnetic disk surface, etc. The magnetic head in the positioning device is similarly configured to be in a position to detect the index of another disk surface.

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

FIG. 4 is a perspective view showing essential parts of an embodiment of the present invention. Refer to the same figure. Index 11 on servo information recording surface 9 of magnetic disk 1
It will be understood that the index 12 on the servo information recording surface 10 is relatively shifted by 180 degrees in the circumferential direction as seen from the center of the disk. In a magnetic disk device as shown in FIG. 1, in which the positioning devices 3 and 4 are 180 degrees apart in the circumferential direction as seen from the center of the disk, a magnetic disk (multiple disks) as shown in FIG. ), data can be written continuously without waiting time.

FIG. 8 is a timing diagram of data writing in the embodiment of the present invention. The operation of one embodiment of the present invention will be described with reference to FIGS. 1, 2, and 4. After the servo head 7 supported by the positioning device 3 detects the index 11 on the servo information recording surface 9 and a writing period 4T ₁ (A) by the data head 8 has elapsed, the servo head 7 detects the index 11 again. Although it is in a position to
The index 12 on the servo information recording surface 10 is
Since the index 11 is at a position 180 degrees offset from the index 11 in the circumferential direction as seen from the center of the disk, the servo head 5 supported by another positioning device 4 is also at a position where it can detect the index 12 at this time. Therefore, after the write period 4T ₁ (A) by the data head 8 supported by the positioning device 3, the write period 4T ₁ (B) by the data head 6 supported by the positioning device 4 immediately begins without any waiting time. , and continuous writing can be performed.

As explained above, according to the present invention, in a magnetic disk device, by switching and using a plurality of positioning devices that support a magnetic head, data can be continuously written to a magnetic disk without waiting time. There is an advantage.

[Brief explanation of drawings]

FIG. 1 is a top view showing the concept of a magnetic disk device, FIG. 2 is a side view, FIG. 3 is a perspective view showing the structure of a conventional disk, and FIG. 4 shows the main parts of an embodiment of the present invention. FIG. 5 is a timing diagram of the write operation to the track by the data head when the magnetic disk rotates once, FIG. 6 is a similar timing diagram when the data head consists of four heads, and FIG. The figure is a timing diagram when data is written by switching between two sets of data heads each supported by two positioning devices.
The figure is a similar timing diagram for an embodiment of the invention. In the figure, 1 is a magnetic disk, 2 is a rotating shaft,
Numerals 3 and 4 are magnetic head positioning devices, 5 and 7 are servo heads, 6 and 8 are data heads, 9 and 10 are servo information recording surfaces, and 11 and 12 are indexes.

Claims (1)

[Claims] 1. It supports a plurality of magnetic disks concentrically attached to a rotating shaft and a plurality of magnetic heads, and has a plurality of head positioning devices that position the magnetic heads on the magnetic disks for reading and writing information. In a magnetic disk device in which the plurality of magnetic disks are divided into a plurality of groups according to the number of head positioning devices, and each group is provided with a data recording surface and a servo information recording surface, each head positioning device stores servo information. A magnetic disk device characterized in that index signals are shifted and recorded on the servo information recording surface so that the index signals of the servo information are detected simultaneously.