JPH0442477A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To improve the processing speed by providing a conversion circuit for imparting head address numbers in order of size as to individual offset amts. of a magnetic head measured in advance. CONSTITUTION:Head address information of a magnetic head 4 to be selected is sent by a host device to a head address register 1, and an output signal of the head address register 1 is converted by a head address conversion circuit 2 and sent to a head driving circuit 3. A relevant magnetic head out of plural magnetic heads 4 is made active by the head driving circuit 3 in accordance with an inputted head address number to execute recording or reproducing of data. The conversion of head address numbers in the head address conversion circuit 2 is settled at the stage of an inspection after manufacturing the magnetic disk device by measuring the size of an offset amt. of each magnetic head 4 due to temp. and imparting the numbers in order of size as to individual offset amts. measured like this. By this method, the processing speed is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic disk device, and particularly to a magnetic disk device that performs a positioning operation of a magnetic head using positioning information recorded in a data track.

[Conventional technology]

The magnetic head positioning method of magnetic disk drives uses the positioning information recorded in the data track OL to perform magnetic head positioning operations.The magnetic head positioning method of magnetic disk devices uses the positioning information recorded in the OL in the data track to perform accurate positioning because the distance between the recorded data and the positioning information is short. Therefore, it is increasingly being used in high-density magnetic disk drives.

When a general magnetic disk device is used in a place with large temperature changes, the magnetic head may shift from the data track of the corresponding magnetic disk due to the difference in thermal expansion coefficients of the magnetic head, magnetic disk, and related mechanical parts, causing the recording Although data reading errors may occur, magnetic disk drives that employ the above-mentioned magnetic head positioning method can obtain positioning information from each data track, so when any magnetic head is selected, the deviation can be detected. Can be corrected.

[Problem to be solved by the invention]

However, in the conventional magnetic disk drive described above, it takes several milliseconds to read the positioning information using the selected magnetic head and correct the positional deviation. If a correction operation is performed every time a magnetic disk drive is used, it has the disadvantage of reducing the processing speed of the magnetic disk device.

[Means to solve the problem]

The magnetic disk device of the present invention has a plurality of magnetic heads and Y-heads, and performs a positioning operation of the magnetic head using positioning information recorded in a data track. A conversion circuit is provided that assigns head address numbers in order of the magnitude of offset amount due to temperature for each of a plurality of magnetic heads.

〔Example〕

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

FIG. 1 is a block diagram showing one embodiment of the present invention.

When recording or reproducing data, the magnetic disk device selects one of the plurality of magnetic heads 4 and uses the selected magnetic head to record or reproduce data on a designated track of the corresponding magnetic disk. conduct. Therefore, the host device sends the head address information of the magnetic head to be selected to the head address register 1, and the output signal of the head address register 1 is sent to the head address conversion circuit 2.
The signal is converted and sent to the head drive circuit 3.

The head drive circuit 3 activates the corresponding magnetic head of the plurality of magnetic heads 4 according to the input head address number to record or reproduce data.

Conversion of head address numbers in the head address conversion circuit 2 is carried out by measuring the magnitude of the offset amount due to temperature of each magnetic head during the inspection stage after manufacturing the magnetic disk device, and assigning numbers in the order of the magnitude. It is determined by

FIGS. 2(a) and 2(b) are characteristic diagrams showing the head address numbers before and after head address conversion and the corresponding offset amounts of the magnetic head in the embodiment of FIG. 1.

As shown in FIG. 2(a), before head address conversion,
There is no correlation between the head address number and the offset amount of the magnetic head, but as shown in Figure 2 (b), after head address conversion, the head address number is the offset amount of the magnetic head. They are ordered by size.

Normally, data in a magnetic disk device is stored in ascending order of head addresses, and data spanning multiple tracks is often accessed by switching magnetic head addresses in ascending order of numbers. In this embodiment, after selecting a certain magnetic head and correcting its position error, the position error that occurs when the next magnetic head is selected becomes smaller, so the data can be stored without having to correct the position error again. The probability of not causing a read error increases.

As you switch the magnetic heads one after another, the i! ! Since the error becomes large and causes a read error, the number of magnetic heads that are switched without correction is limited, and the position error is controlled to be corrected again before a read error occurs.

〔Effect of the invention〕

As explained above, the magnetic disk device of the present invention can be configured to adjust the magnetic head by providing a conversion circuit that assigns head address numbers in the order of the magnitude of the offset amount of each measured magnetic head. This has the effect of reducing the number of times of position error correction operations due to switching, and therefore improving the processing speed of the magnetic disk device.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, and FIG. 2 (
1A and 2B are characteristic diagrams showing head address numbers before and after head address conversion and offset amounts of the magnetic head corresponding thereto in the embodiment of FIG. 1; 1...Head address register, 2...-
-Head address conversion circuit, 3...Head drive circuit, 4...Magnetic head.

Claims (1)

[Claims] 1. In a magnetic disk device having a plurality of magnetic heads and performing a positioning operation of the magnetic heads using positioning information recorded in a data track, 1. A magnetic disk device comprising a conversion circuit that assigns head address numbers in order of magnitude of offset amount due to temperature for each magnetic head. 2. In a magnetic disk device that has a plurality of magnetic heads and performs a positioning operation of the magnetic heads using positioning information recorded in a data track, head address information of a magnetic head to be selected from a host device is obtained. It includes a head address register for input, and a head address conversion circuit that converts the output signal of the head address register into the order of the magnitude of the offset amount due to temperature of each of the plurality of magnetic heads measured in advance and outputs the result. A magnetic disk device characterized by: