JPH0393003A - Magnetic disk controller - Google Patents

Abstract

PURPOSE:To compensate a peak shift most suitably by generating plural write signals, all of which have different peak shift compensation quantities and selecting one of the signals with an advance shift, a delay shift and the number of cylinders. CONSTITUTION:A signal deciding a cylinder number which accesses when a write action is instructed and giving the instruction of the number of the cylinders is outputted to a line 5. Thus, a disk starts a seak action, modulates the write signal into NRZ or MFM, for example, and the signal is outputted to a delay circuit 6. Then the signal of the delay shift 3 or the advance shift 4 is outputted to a selector control circuit 8. Thus, the selector control circuit outputs a selection signal 9 to a selector circuit 10. Then, one of delay signals which the delay circuit 6 selects is selected and is outputted to a write control circuit 12 as a compensated write signal 11.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a control method for a magnetic disk that performs recording by magnetizing a magnetic medium, and particularly relates to a magnetic disk control method that compensates for waveform distortion during recording and reproduction called peak shift. This invention relates to a disk control device.

[Prior Art] In a magnetic disk device, a phenomenon occurs in which independent waveforms of a plurality of write pulses to a magnetic recording surface interfere with each other, and the peak position of the read waveform shifts. This is generally called peak shift, and as a countermeasure, a write compensation circuit is provided that reduces the peak shift during read by shifting the write in the opposite direction to the shift direction during read. .

[Problems to be Solved by the Invention] However, in the conventional example described above, the write compensation amount, which is the distortion correction value corresponding to the peak shift amount, is fixedly set, and the direction of the correction is determined by the waveform distortion. There was a problem in that correction could only be made in two stages: ``delay'' and ``advance''. As a result, when the peak shift amount and the write correction amount are not equal, distortion occurs in the opposite direction, causing recording errors in magnetic recording as in the case of peak shift.

The present invention has been made in view of the above-mentioned conventional example, and it is possible to obtain a write signal compensated in multiple stages, and to select one of these write signals based on a delayed shift, an advanced shift, and a cylinder signal. The object of the present invention is to provide a magnetic disk control device that can write data using the following methods.

[Means for Solving the Problems] In order to achieve the above object, a magnetic disk control device of the present invention has the following configuration. That is, a magnetic disk control device that compensates a write signal to a magnetic disk,
delay signal generating means for generating a plurality of delayed signals in which write signals to the magnetic disk are delayed by different times; It has a selection means for selecting one of the signals, and a writing means for writing on the magnetic disk based on the write signal selected by the selection means.

[Operation] In the above configuration, a plurality of delay signals are generated by delaying the write signal to the magnetic disk by different times,
One of the plurality of delay signals is selected based on the advance shift, the delay shift, and the cylinder position at which the magnetic disk is accessed. Based on the write signal selected in this way, it operates to write on the magnetic disk.

[Embodiments] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[6! Explanation of the i-disk control device (Figure l)] Part 1
The figure is a block diagram showing a schematic configuration of a magnetic disk control device according to an embodiment.

It is generally known that the amount of peak shift depends on the linear recording density, but with floppy disks and hard disks, the same recording capacity is recorded on both the outermost track and the innermost track of the disk. is common. Therefore, the degree of recording per unit length (linear recording density) is highest at the innermost track of the disk, and the amount of beak shift 1 at that time is also greatest. This relationship is shown in FIG. Therefore, in this embodiment, optimal write compensation can be performed by switching the peak shift amount depending on the number of write cylinders, the delay shift, and the advance shift.

In the figure, reference numeral 1 denotes a disk control unit, which is used as a work area for CPU IO1 and CPUIO1, which output various control signals and execute control according to the control program stored in the ROM 102 shown in the flowchart of FIG. It has a RAM 103 and the like, and outputs write data to be written on a magnetic disk, a delayed shift signal, an advanced shift signal, and a cylinder signal. A write data signal line 2 transmits a modulated data signal modulated to NRZ%MFM or the like based on a write signal to the disk to the delay circuit 6. 3 is the delay shift control line, and 4 is the advance shift control line. 5 is a cylinder line, which outputs the cylinder number of the magnetic disk to be accessed. 6 is a delay circuit which outputs seven types of delay signals each having a different delay time, as shown in FIG. Here, the central delay time n indicates a signal when there is no delay (neutral). Reference numeral 8 denotes a selector control circuit which inputs the lead shift 4, lag shift 3 and cylinder line 5 from the disk control unit 1, and outputs a selection signal 9 in accordance with these values.

10 is a selector circuit which inputs the selection signal 9 from the selector control circuit 8, selects one of the delayed signals 7 from the delay circuit 6 according to its value, and outputs the compensated write signal 1l.
It is output to the write control circuit 12 as . 14 is a write signal, and 13 is a magnetic head. FIG. 3 is a block diagram showing a schematic configuration of the selector control circuit 8, which here consists of a lookup table 80. That is, input the delayed shift signal 3, advance shift signal 4, and cylinder line 5 as addresses of the table 80,
At almost the same timing as these signals, the table 8
The data stored at the address specified by 0 is output as the selection signal 9. Note that this lookup table 80 may be a ROM%PAL (program array logic) or a custom LSI.

FIG. 4 shows a selector circuit lO based on this selection signal 9.
FIG. 7 is a diagram showing the relationship between delayed signals 7 and 7 selected in FIG.

Further, FIG. 5 is a diagram showing the timing of the valid period of the selection signal 9 output from the selector control circuit 8, and the timing during which the delay shift 3 and advance shift 4 are output is shown as the timing at which the selection signal 9 becomes valid. has been done. Note that the write control signal indicates the timing at which the write signal 2 to the disk becomes enabled. FIG. 7 is a flowchart showing the write operation in the disk control unit l. ing.

First, when a write operation is instructed, the cylinder number to be accessed is determined in step S1 and outputted to the signal line 5 which indicates the number of cylinders. This causes the disk to start a seek operation. Next, proceed to step S2, and send the write signal to
For example, the delay circuit 6 modulates to NRZ or MFM.
At the same time, a signal for delay shift 3 or advance shift 4 is output to selector control circuit 8.

As a result, the selector control circuit outputs the selection signal 9 to the selector circuit 10, and one of the delayed signals selected by the delay circuit 6 is selected and output as a compensated write signal 11 to the write control circuit 12. In this embodiment, a delay signal of 7 stages is output, but the present invention is not limited to this, and the delay signal of 7 stages is output.
Any number is fine as long as it is higher than the level.

As explained above, according to this embodiment, a plurality of write signals each having a different peak shift correction amount are created, and one of the write signals is set based on the lead shift, the delay shift, and the number of cylinders. By making it possible to select the peak shift compensation, there is an effect that peak shift compensation can be performed optimally.

[Effects of the Invention] As explained above, according to the present invention, it is possible to obtain a write signal that is compensated in multiple stages, and from among these write signals, a delay shift, an advance shift, and a cylinder signal can be used. Since it is possible to selectively write, there is an effect that more reliable write compensation can be performed.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the schematic configuration of the magnetic disk control device of the embodiment; FIG. 2 is a diagram showing the timing of output signals from the delay circuit; FIG. 3 is a block diagram showing the configuration of the selector control circuit; Figure 4 is a diagram showing the relationship between the selection signal and the delayed signal selected by the selection signal, Figure 5 is a diagram to explain the effective period of the selection signal, and Figure 6 is a diagram showing the relationship between the cylinder position and the peak shift amount. FIG. 7 is a flowchart showing the operation of the disk control section. In the figure, 1... disk control unit, 2... write signal,
3...Late shift, 4...Advance shift, 5...Number of cylinders, 6...Delay circuit, 7...Delay signal, 8...
...Selector control circuit, 9...Selection signal, 10...
Selector circuit, 12...Write control circuit, l3...
A magnetic head and an 80° look-up table. Figure 2 8 Figure 3 Figure 6 Figure 7EI

Claims (1)

[Scope of Claims] A magnetic disk control device for compensating a write signal to a magnetic disk, comprising: a delay signal generating means for generating a plurality of delay signals in which the write signal to the magnetic disk is delayed by a different time; a selection means for selecting one of the plurality of delay signals based on an advance shift, a delay shift, and a cylinder position for accessing the magnetic disk; 1. A magnetic disk control device comprising: writing means for writing to a magnetic disk.