JPH01229468A - Disk device - Google Patents

Abstract

PURPOSE:To improve the reliability for storage of information by varying the write track length of the same information to the two disks and therefore avoiding such a case where the same information is written into the part of the innermost circumference track where the write and read errors are rather easily produced. CONSTITUTION:For instance, the write of information is started at and after the outermost circumference track 17a with a 1st disk 15 and then started at and after the innermost circumference track 17b with a 2nd disk 16 respectively. The track lengths of both disks 15 and 16 are changed for the same information. As a result, the same information is never written to the innermost circumference track of each disk where the write and read errors are rather easily produced. Thus the write and read errors are not concentrated to the specific information and the overall storage performance of information can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a disk device that duplicates and stores information using a plurality of disks.

(Prior Art) In information processing systems, various types of devices for storing information are known, and disk-shaped disks, that is, magnetic disks and optical disks are most commonly used.

Information processing systems used in the operations of financial institutions are no exception. However, there is an extremely high demand for data storability. That is, if erroneous information is mixed in with the various information stored on the disk, it will cause serious trouble to the business. Therefore, in order to ensure that the disk device can write and read information, duplication is performed.

FIG. 2 shows a block diagram of a conventional duplex disk device 5. As shown in FIG.

In the figure, a disk device 5 has a disk switching device 20, a first head drive device 11 and a second head drive device 1.
2, the first head 13, the second head 14, and the first
15 and a second disk 16.

The disk switching device 20 is a circuit that selects a disk on which information is to be written based on instructions from a processor (not shown). The first head drive device 11 and the second head drive device 12 drive the first head 13 and the second head drive device, respectively.
This circuit drives the head 14 in the radial direction of the disk 15, 16.

The first head 13 and the second head 14 are heads for writing information to the first disk 15 and the second disk 16, respectively. The first disk 15 and the second disk 16 have a plurality of concentric disks (for example, 8 disks).
0 tracks 17 are formed. Each track 1
7 has a serial number, for example, the outermost track 1
7a has the minimum track number "00°", and the innermost track 17b has the maximum track number "79°". The track length decreases from the outermost track 17a to the innermost track 17b, but the same amount of information is written in each track. Therefore, the information recording density increases as one approaches the innermost track 17b, and the information recording density decreases as one approaches the outermost track 17b.

This disk device 5 configured to perform information duplication always writes the same information on the first disk 15 and the second disk 16. That is, the first disk 15 is connected to the second disk 16 so that even if the information on the first disk 15 is destroyed, the corresponding information can be read from the second disk 16.

For example, when information is input from the processor, the disk switching device 20 first operates the first head drive device 11 to write information on the track 17 of the first disk 15. When this writing is completed, the disk switching device 2o drives the second head drive device 12, and the head 14 transfers the same information to the track 17 of the second disk 16 located at the same position as the track 17 of the first disk 15. Write.

(Problems to be Solved by the Invention) Incidentally, in any disk, writing and reading errors are most likely to occur near the innermost track 17b where the information recording density is high. This is because the amount of information per unit length increases as the track is located closer to the inner circumference of the disk, and even a slight scratch that cannot be seen with the naked eye, for example, can damage that information.

FIGS. 3 and 4 are graphs showing the relationship between the track position of the disc and the reliability of information storage.

FIG. 3 is a graph showing the reliability of information storage when information is written on one disc. Furthermore, FIG. 4 is a graph showing the reliability of information storage when the same information is written on two disks of a duplex disk device. In each graph, the horizontal axis indicates the track position, and the vertical axis indicates reliability.

In FIG. 3, it can be seen that the reliability decreases as the tracks of the disk become more inward, that is, as the track length becomes shorter. Furthermore, as can be seen from Figure 4, when the same information is written using two disks, the overall reliability improves significantly, but the track position is inside, that is, the track length is The shorter the length, the lower the reliability.

In this case, even if the disk is duplicated, there is a risk that errors will be concentrated in information written near the innermost track.

The present invention has been made in view of the above points, and it is an object of the present invention to provide a disk device that does not concentrate write and read errors on specific information and improves storage performance as a whole. .

(Means for Solving the Problems) A disk device of the present invention includes a first disk in which a plurality of tracks for writing information are formed on concentric circles, and a second disk having the same configuration as the first disk. , a write control device that writes one unit of the same information to both the first disk and the second disk, the write control device writes one unit of information to the first disk and the second disk. , when writing to the second disk, select write tracks such that the track used for writing to the first disk and the track used for writing to the second disk have different track lengths. It is something to do.

(Function) The above-mentioned device has the advantage that when writing information to the first disk and writing the same information to the second disk, the information is not written on tracks of the same length. So, each track is selected. This equalizes the error rate and allows highly reliable information storage.

(Embodiment) FIG. 1 is a block diagram showing an embodiment of a disk device of the present invention.

This device includes a first track selection device 21 and a second track selection device 2 in the disk device described in FIG.
2 is added.

This disk switching device 20 and the first track selection device 2
1 and the second track selection device 22.
It constitutes 0. Note that the disk switching device 20, the first head drive device 11, and the second head drive device 12 are as follows:
This device has the same configuration as the device shown in FIG. 2, and redundant explanation will be omitted.

Now, when writing information to the first disk 15 for the first time, the first track selection device 21 provided in the write control device 10 determines whether the writing start track should be the innermost track 17b or the outermost track. This circuit selects whether to use 17a or not. Further, the second track selection device 22 is also a circuit similar to the first track selection device 21.

FIG. 5 shows in detail the first track selection device 21 on the first disk 15 side of the disk device shown in FIG.

This first track selection device 21 includes a switch 30.
, signal lines a and b, and a track inversion circuit 31 are provided.

The track inversion circuit 31 is a circuit that sets the writing start position to the innermost track 17b when information is first written to the first disk 15.

Specifically, the control signal for setting a track usually consists of a digital signal of several bits. For example, if the content of the signal for setting a track is 6, and the total number of tracks is 80, the calculation (79-6) is performed and the result, 73, is output. Usually, the signal for setting this track is a digital signal of several bits, so this can be realized by a simple logic circuit.

The second track selection device 22 of the second disk 16 also has a similar circuit configuration. When the first track selection device 21 selects the connection of the switch 30 to the side a, the second track selection device 22 selects the connection of the switch 30 to the b side, making the selections opposite to each other.

Now, returning to FIG. 1, when writing information using the disk device configured as described above, first, the processor transmits an information write request command to the disk switching device 20, and the first track selection device 21 is operated. let The first track selection device 21 operates the first head drive device 11 to start writing information from the outermost track 17a of the first disk 15, for example. The first head driving device 11 moves the head 13 to the outermost track 17'.
a, and writes information to the first disk 15 while receiving information transfer from the storage device 3. and,
For example, information is written in sequence up to the innermost track 17b, with one block as one unit. After that, write the information on the back side.

When writing of information to the first disk 15 is completed, the disk switching device 20 operates the second track selection device 22. The second track selection device 22 operates the second head drive device 12 to start writing information from the innermost track 17b of the second disk 16, contrary to the first track selection device 21. . The second head driving device 12 moves the head 14 onto the innermost track 17b and writes the information previously written on the first disk 15 while being transferred from the storage device 3. When the writing of information up to the outermost track 17a is completed, writing of information starts again from the innermost track 17b on the back side. After writing this information, the disk switching device 20
The operation of the disk device is stopped.

As explained above, for example, writing of i information to the first disk 15 starts from the outermost track 17a, and writing of information to the second disk 16 starts from the innermost track 17b. By starting with the same information and changing the track lengths of the first disk 15 and the second disk 16, the same information can be written to the innermost track of the disk where writing and reading errors are relatively likely to occur. No more getting caught.

FIG. 6 shows a graph of the reliability of information storage of the disk device 20 according to the present invention.

In the figure, the horizontal axis indicates the track position of the disk, and the vertical axis indicates reliability.

The part indicated by the broken line in the figure shows the reliability of the conventional device explained in FIG. Furthermore, the portion indicated by the solid line indicates the reliability according to the present invention.

As shown in the figure, the information on the two disks is
For example, by starting from the outermost track for a first disk and from the innermost track for a second disk, the entire information written on the disk can be Can maintain reliability.

The disk device of the present invention is not limited to the above embodiments.

FIG. 7 shows a flowchart of the operation of another embodiment of the disk switching device 20.

The disk switching device 20 of the embodiment described above unconditionally sets the write start track on the disk to the outermost track 17a with the track number "○O" (step Sl). Then, one of the first track selection device 21 and the second track selection device 22 determines the track number. However, if this operation is included in the control program for the disk switching device 20, the first track selection device 21 and the second track selection device 22 can be omitted. That is the program in this flowchart. First, in step S1, the write start track is set to track number "○○".Next, in step s2, it is determined whether the information will be written on the first disk 15 or the second disk 16.

As a result, when writing to the first disk, the first head drive device 11 is controlled while the write start track is set to track number "o o". Moreover, when writing to the second disk, the process moves to step S3.

In step S3, the information writing start track is set to track number °'79''.Thereby, the first track selection device 21, the second control and the rack control device 2
There is no need to provide 2.

Furthermore, it is not necessary to provide a pair of the first track selection device 21 and the second track selection device 22. The selection may be made all at once using one device.

Furthermore, when writing to the first disk 15 and the second disk 16, the writing start position is the outermost track 1.
7a or the innermost track 17b, and may be arbitrarily selected so that the same information is written on the two disks, that is, the track lengths are different.

(Effects of the Invention) The disk device of the present invention configured as described above has the following advantages:
Since the same information is not written to the innermost track portion where writing and reading errors are relatively likely to occur, the reliability of information storage can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a disk device of the present invention, FIG. 2 is a block diagram of a conventional disk device, and FIG. 3 is a graph showing the reliability of information written on the disk. FIG. 4 is a graph showing the reliability of information written on the disk in a conventional disk device, FIG. 5 is a block diagram of the disk device of the present invention, and FIG. 6 is a graph showing the reliability of the disk of the disk device according to the present invention. FIG. 7 is a flowchart of a control device according to another embodiment of the present invention. DESCRIPTION OF SYMBOLS 10... Write control device, 11... First head drive device, 12... Second head drive device, 13... First head, 14... Second head, 1
5... first disk, 16... second disk,
17...Track, 17a...Outermost track, 1
7b... Innermost track, 20... Disc switching device, 21... First track selection device, 22... Second track selection device. Patent distributor: Oki Electric Industry Co., Ltd.Disc device of great inventionFig. Figure 27 of the thin professional disk

Claims (1)

[Claims] 1. A first disk having a plurality of concentric tracks for writing information; a second disk having a similar configuration to the first disk; and the first disk. a write control device that writes one unit of the same information to both of the second disks, and the write control device writes one unit of information to both the first disk and the second disk. When writing to the disk, a writing track is selected such that the track used for writing to the first disk and the track used for writing to the second disk have different track lengths. Device. 2. The write control device writes the information on the first disk sequentially starting from the outermost track, and writes the information on the second disk starting from the innermost track. Item 1
Disk device as described.