JPH02208877A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To correct dislocation of a reproducing head due to a different degree of thermal expansion of an arm by confirming an offset for positioning in using a servo surface from a deviation between an optimum read amplitude and an amplitude of a regenerative signal, and correcting the reproducing head. CONSTITUTION:Which cylinder and which head are used is confirmed by a microprocessor (MPU) 3 during the time of access of a head to a disk surface under access from a host device 12. Now, an optimum amplitude value i1 in its head position is inputted to the MPU 3 according to a data table 101. Then, this is compared with a real amplitude value i2 obtained from a read signal 301, and an offset driving value i3 obtained from this deviation is outputted to drive a D/A converter and then to modify the offset of the head. By this method, the dislocation due to the different thermal expansion of the arm can be corrected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic disk device, and particularly to a head positioning control system.

[Conventional technology]

In conventional magnetic disk drives, head positioning is performed using only head positioning information written on a servo disk.

[Problem to be solved by the invention]

In the conventional magnetic disk drive described above, head positioning is performed using only the head positioning information written on the servo surface disk, so thermal off-track, that is, thermal expansion of the arms that support the individual heads, occurs. There was no means to correct positional deviations caused by differences in dust.

Therefore, there is a drawback that it becomes impossible to read target information at high or low temperatures.

[Means to solve the problem]

In the disk device of the present invention, a microprocessor is installed in the head positioning control circuit section of the magnetic disk device.

(hereinafter referred to as MPU), a read-only memory (hereinafter referred to as FROM) connected to the MPU and storing a control program and optimal read amplitude data (to be described later), and a R/W head included in the magnetic disk device. A/D that converts the read signal amplitude read from the medium into a digital signal
converter, means for transmitting the output of the A/D converter (hereinafter abbreviated as amplitude variable) to the MPU, and the PR
A firmware function that compares the amplitude variable with the optimum read amplitude data in the OM, a firmware function that transmits the comparison result to the head offset drive circuit section as head offset drive information, and a firmware function that transmits the comparison result as head offset drive information to the head offset drive circuit, and It has means for notifying the host device that the optimum position has been reached.

〔Example〕

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

First, the overall outline of the use of this embodiment will be explained with reference to FIG.

FIG. 2 mainly shows the blocks of the control system. Commands from the host device 12 are input to the interface circuit section 1, and from there are transferred to processing by the MPU 3. The interface circuit section 1 selects a head and a cylinder based on the attributes of input/output data.A target cylinder address signal 201 and a cylinder address set signal 202 are input to the cylinder address register 4, and preparation for access is made. This address drives the head drive circuit 7, which in turn drives the head-disk assembly 10 to move the head onto the target cylinder.

On the other hand, a target head address signal 203 and a head address set signal 204 are input to the head address register 5. This drives the head selection circuit 8 and selects the head to be used. Although the above configuration and processing are similar to those of the conventional method, the characteristic configuration of this embodiment will be described next.

The head drive circuit 7 inputs digital head offset drive data 307 output from the MPU 3 in addition to the target cylinder address variable signal 303 to the D/A converter 11.
It is driven by a signal converted to analog.

Also, read signal 3 from the accessed head
The level of 01 is sent to the MPU 3 via the readout circuit section 6 and the A/D converter 9.

Next, details of this embodiment will be explained with reference to FIG. FROM2 has an optimum read signal amplitude data table 101, and when data is written to the disk, it is updated according to the reproduction level of the cylinder at that time. As shown in FIG. 3, this table 101 is a function of cylinder addresses and head addresses.

M is performed from the input/output information for MPU3 explained above.
The processing of PU3 will be explained.

When the head is accessed from the host device 12 and the disk surface is accessed, the MPU 3 determines which cylinder and
Checking which head is being used. Therefore, the MPU 3 inputs the optimum amplitude value 11 at that head position using the data table 101. This is compared with the actual amplitude value 12 obtained from the read signal 301, and an offset drive value i3 is output based on the deviation, and the D/A converter 11 is driven to correct the head offset.

〔Effect of the invention〕

As explained above, in the present invention, an optimum read signal amplitude data group is created in advance in PROM using the cylinder address at which the head should be positioned and the head address to be selected as variables, and the MPU receives the data from the host device. At the time of a read command, the optimum read signal amplitude data for that track is extracted using the target shilling and head address as variables, the data is compared with the amplitude variable read by the head and converted into a digital signal, and the head is read according to the result. By offset driving the head, it is possible to move the head to the optimal position for the read operation, which has the effect of improving thermal off-track.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the present invention, FIG. 2 is a block diagram of a magnetic disk device including the present invention, and FIG. 3 is an image diagram of the optimum read amplitude data table of the present invention. l...Interface circuit section, 2...
・Read-only memory (PROM), 3...Magnetic disk control unit microprocessor, 4...
- Cylinder address register, 5... Head writing address register, 6... Readout circuit section, 7... Head drive circuit section, 8...
Head selection circuit section, 9...A/D converter,
10...Head disk assembly, 11
...offset 1Kib D/A converter, 1
2... Host device, 101... Optimal read signal amplitude data group, 102... Offset drive program, 103... Control firmware, 201... ...Target cylinder address signal, 202...Cylinder address set signal, 203...Target head address signal, 204...Head address set signal , 301... Read signal, 302...
Read signal amplitude signal, 303...Target cylinder address variable signal, 304...Target head...
Address variable signal, 305... Optimal read signal amplitude read signal, 306... Selected optimum read signal amplitude, 307... Head offset drive data, 308...・Positioner drive signal, 309...Positioning servo signal, 310・
...Head select signal, 311...
Positioning end signal to target cylinder, 312...
・Target head address selection end signal, 313...
...Control program read bus signal, 31
4...Status signal, 315...Offset data transmission signal, 316...Amplitude variable.

Claims (1)

[Claims] In a magnetic disk device having a plurality of magnetic disks and using one surface of the magnetic disks as a servo surface for positioning, there is provided a cylinder recognition means for identifying a cylinder to which a reproducing head corresponds; an optimum read amplitude recognition means for checking the amplitude of the signal when completely on-track; a reproduction signal amplitude checking means for checking the amplitude of the reproduction signal of the playback head; and an optimum read amplitude by the optimum read amplitude checking means and the reproduction. A magnetic device characterized by comprising: offset correction means for confirming an offset in positioning using the servo surface from a deviation from the amplitude of the reproduced signal by the signal amplitude recognition means, and driving the reproduction head to correct this offset. disk device.