JPS61131208A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To perform stable recording even at an inner periphery where recording density is high by decreasing a write current at the inner periphery when one of magnetic heads for both sides is selected. CONSTITUTION:A direction selecting signal (a) has a logical level '1' and a magnetic head 5 moves to the inner periphery when a step signal (b) is inputted. Consequently, when the magnetic head 5 moves to the inner peripheral side of a specific cylinder, a cylinder signal (g) goes up to the logical level '1'. When a magnetic head selecting signal (d) has a logical level '0', a magnetic head for a side 0 is selected and the write signal becomes a prescribed current when the write current (e) is at the logical level '1', but the output (h) of an NAND 2 goes down to the logical level '0' and the write current decreases. The prescribed current, however, flows at the outer peripheral side of the cylinder even if a side 1 is selected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to: 1. a magnetic disk device; The present invention relates to a magnetic disk device that sometimes writes binary information to a magnetic disk and cannot read it.

The present invention is suitable for implementation in a floppy disk device of an information processing device.

[Conventional technology]

In conventional devices, either one of the magnetic heads on either side of the disk is selected or switched using a binary signal from the outside. Generally, in a floppy disk drive, the physical position of the magnetic head is slightly shifted on side O or side 1 of this binary signal, and the magnetic head on one side (here, side 1 side) is closer to the disk. It is located close to the center of rotation. Therefore, when the magnetic head approaches the center of rotation, the recording density increases rapidly, and the density is always higher on side l.

[Problem that the invention seeks to solve]

Therefore, if only one signal is used as in the past, side 1
An appropriate write current value must be selected to suit both the side 0 side and the side 0 side, and this is not necessarily an appropriate current value for the innermost circumference of the side 1 example.

The present invention solves the above-mentioned drawbacks, and aims to provide a disk device in which the current is switched so that the write current on the inner periphery of one side is optimized.

[Means for solving problems]

The present invention includes two magnetic heads disposed on both sides of a rotating magnetic disk, and means for selecting one of the two magnetic heads and applying a write current to the selected magnetic head. , in a magnetic disk drive comprising means for moving the two magnetic heads in the radial direction of the magnetic disk, and means for counting the movement position of the magnetic disk, one of the two magnetic heads; The present invention is characterized in that it includes means for changing the value of the write current when the value of the means for counting the movement position approaches a predetermined value in the axial direction.

[Effect]

The position counting means detects that one of the magnetic heads moves in the inner circumferential direction, and at this time, the value of the write current is switched and outputted so as to be suitable for high density.

When the step signal is input when the direction selection signal is logical to select one surface, the magnetic head moves in the inner circumferential direction. When the belly button F is on the inner circumference of the N cylinder, the N cylinder signal becomes "1", and when the magnetic head selection signal is "0", the magnetic head on the side 0 side is selected, and at this time the magnetic head selection signal is When it becomes "1", the NAND output becomes rOJ, the write current decreases, and stable recording becomes possible even near the inner circumference where the recording density is high.

〔Example〕

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

FIG. 1 is a block diagram of an apparatus according to an embodiment of the present invention.

Cylinder counter 1 consists of a digital force counter.
A track 0 signal C indicating that the track is on the 0 track is connected to its reset terminal.

In addition, a step signal, which is a signal for moving the magnetic head, is connected to the CP terminal, and the CU/CD terminal, which selects whether to perform count amplification (C0) or countdown (CD), is connected to input the step signal for moving the magnetic head. A direction selection signal, which is a signal indicating the direction of movement, is connected as an input. The N cylinder signal g, which is the output of the cylinder counter 1, becomes logic "1" when the magnetic head is located on the inner periphery of the N cylinder. The N cylinder signal g is input to one side of the NAND circuit 2, and the other input of the NAND circuit 2 is connected to a magnetic head selection signal d. It becomes "1". The switching signal output from the circuit 2 is connected to a current switching circuit 4, which is a constant current source, and is configured such that the write current decreases when the output is at logic "0". This current switching circuit 4 is connected to a write circuit 3 composed of a flip-flop, and the output of this write circuit 3 is further connected to a magnetic head 5. A write signal e for permitting writing and a write information signal f are manually connected to the write circuit 3, which is a circuit for performing writing, and selects either the magnetic head 5a or 5b based on the magnetic head selection signal d.

The operation of the A position of the following configuration will be explained using the time chart shown in FIG. Reference numeral a in the figure is a direction selection signal, and the magnetic head moves toward the inner circumference by inputting a step signal of logic "1".

As a result, when the magnetic head moves to the inner circumference from the N cylinder, the N cylinder signal g becomes logic "1". When the magnetic head selection signal d is logic rOJ, the magnetic head on the side 0 side is selected, and at this time, the write signal e is logic "1".
In this case, the write current becomes a specified current, but when the magnetic head selection signal d becomes logic rlJ, the output of NAND 2 becomes logic "0" and the write current decreases. However, at the outer periphery of the N cylinder, a specified current flows even if side 1 is selected.

〔Effect of the invention〕

As explained above, in the present invention, when one side of the magnetic heads on both sides is selected, by reducing the write current on the inner circumference, stable recording is possible even on the inner circumference where the recording density is high. This has the effect of increasing the reliability of the magnetic disk device.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an apparatus according to an embodiment of the present invention. FIG. 2 is a time chart of the first book portion signal. 1... Cylinder counter, 2... NAND circuit, 3...
...Write circuit, 4...Current switching circuit, 5...Magnetic head (a, b), N...Predetermined cylinder, a...Direction selection signal, b...Step signal, C... ...Track O signal, d...Magnetic head selection signal, e...Write signal, f...Write information signal, g...N cylinder signal,
h...Switching signal.

Claims (1)

[Claims] (1) two magnetic heads disposed on both sides of a rotating magnetic disk; means for selecting one of the two magnetic heads and applying a write current to the selected magnetic head; In a magnetic disk drive comprising means for moving each of the two magnetic heads in the radial direction of the magnetic disk, and means for counting the movement position of the magnetic head, one of the two magnetic heads is A magnetic disk drive characterized by comprising means for changing the value of the write current when the value of the means for counting the moving position approaches a predetermined value in the axial direction.