JPH0258769A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To perform data writing and readout under the optimum conditions by switching writing timing correcting quantities corresponding to the short- circuited or released state of an identification short-circuiting plug. CONSTITUTION:The head disk assembly (HDA) identifying signal 102 of a HDA 10 is outputted to a detection circuit 20 and the control signal 103 of the circuit 20 is outputted to a write circuit 30 and inputted to the HDA 10. The write circuit 30 inputs write data 100 and write clocks 101 and is composed of a pattern decoder 31, delay circuit 32, selector 33, and driver 34 connected in series. The control signal 103 from the detection circuit 20 is inputted to the selector 33. By controlling the selector 33 of the write circuit 30 with the control signal 103, writing timing correcting quantities are switched. Therefore, data writing and readout can be performed under the optimum conditions.

Description

[Detailed description of the invention] “Industrial application field” The present invention relates to a magnetic disk device.

In particular, the HeadDis assembly
k As5e+++bly: Hereinafter abbreviated as HDA. ) The present invention relates to a magnetic disk device that can set write conditions corresponding to the following.

[Conventional technology] Conventional magnetic disk devices do not meet the writing conditions (DA).
It was set externally, that is, by the electronic circuit package, etc.

[Problems to be Solved] In the conventional magnetic disk drives mentioned above, the write conditions are set by the electronic circuit package, etc., but the characteristics change due to lot variations of the magnetic head or magnetic disk, and it is difficult to find the optimal write conditions. If the value deviates from the set value, correction may not be possible.

In other words, if the characteristics of the magnetic head or magnetic disk change, is it possible to change the write conditions set in the electronic circuit package, etc. to deal with this change, or will compatibility be lost? It had serious problems.

The present invention has been made in view of the above-mentioned problems.
The purpose of the present invention is to provide a magnetic disk device that can always write and read data under optimal conditions without compromising compatibility in response to changes in characteristics of magnetic heads and magnetic disks.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a magnetic disk drive having an HDA in which a magnetic head and a magnetic disk are sealed, in which one end is grounded and the other end is an output terminal. one or more HDA identification short circuit plaques connected to the HDA identification short circuit, a detection circuit that detects the short circuit or open state of the HDA identification short circuit plugs and outputs a control signal corresponding to the state; and a control circuit from the detection circuit. The configuration includes a write circuit that switches the write timing correction amount according to a signal.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a circuit diagram of an embodiment of the present invention.

In this embodiment, the HDA identification signal 102 which is the output of the HDA 10 is connected to the detection circuit 20, and the control signal 103 which is the output of the detection circuit 20 is connected to the write circuit 30. Then, the output of the write circuit 30 is HDA 1
Connected to 0.

The write circuit 30 receives write data 100 and a write clock 101 as input. pattern coater 3
1. A delay circuit 32, a selector 33, and a driver 34 are connected in series, and a control signal 103 from the detection circuit 20 is connected to the selector 33.

FIG. 2 is a detailed circuit diagram of a portion of HDA 10 and detection circuit 20 shown in FIG.

One of the features of the present invention is that HDAl 0 has one or more HDA identification shorting plugs with one end grounded and the other end connected to the output terminal. It has identification short circuit plaques PI, P2.

This HDA identification short circuit plaque P, 1. H which is the output of P2
The DA identification signal 102 is connected to the power supply +V1 via resistors R21 and R22, and is also connected to the voltage comparator 25.
．． It is connected to 26 primary forces. Voltage comparator 25.
26 is connected to the connection point of resistors R23 and R24 connected in series between the power source +1 and ground.

The control signal 103, which is the output of the voltage comparator 25.26, is
As described above, it is connected to the selector 33 in the write circuit 30.

The HDA identification short-circuit plaque P1゜P2 mentioned above is
Depending on the characteristics of the magnetic head and magnetic disk mounted on HDAl 0, it is set whether to short-circuit or open.

Next, the operation will be explained.

The detection circuit 20 uses a reference voltage set by resistors R23 and R24 and an HDA identification signal Pl in order to detect whether the HDA identification short circuit plugs P1 and P2 are short-circuited or open.

The voltage of the HDA identification signal 102, which is the connection point between P2 and the resistors R21 and R22, is compared by voltage comparators 25 and 26.

The write timing correction amount is switched by controlling the control signal 103 as the output of the voltage comparators 25 and 26 which is the result of this comparison, or by controlling the selector 33 of the write circuit 30.

The write circuit 30 performs write timing correction on the write data 100, which is data to be written on the magnetic disk, in the direction opposite to the preliminary peak shift without timing, in order to correct the peak shift caused by pattern interference. After that, write data is supplied to the HDA 10.

When write data 100 synchronized with the write clock 101 is input to the write circuit 30, the pattern coater 3
1 is decoded into a bit for correcting the write timing and other bits, and output to the delay circuit 32.

The delay circuit 32 delays the output of the pattern decoder 31 by two or more types of write timing correction amounts for each bit, and outputs the delay to the selector 33 .

The selector 33 selects the optimum write timing correction amount based on the control signal 103 from the detection circuit 2o described above, and outputs it to the driver 34.

The driver 34 converts the signal to a level suitable for driving the magnetic head (or write predriver) in the HDAIO and outputs it to the HDA 10.

[Effects of the Invention] As explained above, the present invention provides one or more HDA identification short-circuit plaques inside the HDA, and switches the write timing correction amount according to the short-circuit or open state of the identification short-circuit plaques. This has the advantage that it is possible to always write and read data under optimal conditions without compromising compatibility in response to changes in the characteristics of the magnetic head or magnetic disk.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing one embodiment of the present invention, and Fig. 2 is a circuit diagram showing an embodiment of the present invention.
2 is a detailed circuit diagram of a portion of the HDA 10 and detection circuit 20 shown; FIG. 10: HD A (Head Disk Asse)
mbly) 20, detection circuit 25.26: voltage comparator 30° writing circuit 31° pattern decoder 32, delay circuit 33: selector 34: driver PL, P2: HDA identification short circuit plaque R21 to R24: resistance agent patent attorney Watari Kihei Bebe

Claims (1)

[Claims] In a magnetic disk device having a head disk assembly in which a magnetic head and a magnetic disk are sealed,
One or more head disk assembly identification shorting plugs are provided inside the head disk assembly, one end of which is grounded and the other end of which is connected to an output terminal, and the head disk assembly identification shorting plugs are short-circuited. Alternatively, a magnetic field characterized by comprising a detection circuit that detects an open state and outputs a control signal corresponding to the state, and a write circuit that switches the write timing correction amount according to the control signal from the detection circuit. disk device.