JPH0677283B2 - Write current control method for magnetic disk - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Outline] Cylinder information is managed because a uniform read / write margin cannot be secured with the same write current because the linear recording densities are different on the inner circumference side and the outer circumference side of a magnetic disk. A bit capable of designating a write current value according to the cylinder information is set in the qualifier of the seek command to a non-existing magnetic disk device and sent out to make the read / write margin uniform.

[Industrial application field]

The present invention relates to a write current control method for a magnetic disk, which makes it possible to switch the write current between the inner circumference side and the outer circumference side of the magnetic disk when writing data on the magnetic disk and make the read / write margin uniform. .

Generally, in a magnetic disk device, a plurality of magnetic disk discs are stacked and attached to a rotating shaft, and a magnetic head is provided for each recording surface of each magnetic disc disk. The magnetic head is moved by the same carriage to access tracks on the same radius of each magnetic disk disc.

Since a set of tracks on the same radius forms a cylindrical shape, it is called a cylinder. The outer circumference and the inner circumference of the magnetic disk have different circumferences, and the outer cylinder and the inner cylinder record on the track. The linear recording density of data is different.

Therefore, it is difficult to keep the read / write margin constant between the outer cylinder and the inner cylinder. However, the read / write margin is made uniform by switching the data write current value between the inner circumference side and the outer circumference side of the magnetic disk, decreasing the current value on the inner circumference side and increasing the current value on the outer circumference side. You can do it.

Incidentally, some magnetic disk devices are instructed only in the moving direction of the magnetic head and its distance, and do not know in which cylinder the magnetic head is currently positioned.

For example, a magnetic disk unit with a 3380 interface
Since the magnetic disk controller manages the cylinder information, the magnetic disk controller causes the magnetic disk device to switch the data write current value in order to make the read / write margin uniform between the outer cylinder and the inner cylinder. It is necessary to be able to direct.

[Conventional technology]

Conventionally, a magnetic disk device using a 3380 interface that is generally used does not have cylinder information in the magnetic disk device.

Further, there is no definition of a bit for instructing current switching in a command relating to seek for positioning control of the magnetic head sent from the magnetic disk control device having cylinder information to the magnetic disk device and a qualifier that modifies the command. .

[Problems to be solved by the invention]

As described above, the conventional magnetic disk device cannot determine in which cylinder the magnetic head is positioned, and the magnetic disk device itself cannot switch the write current according to the cylinder value.

Further, the magnetic disk control device that manages cylinder information has no method for instructing the magnetic disk device to switch the write current.

Therefore, there is a problem in that it is not possible to use a wide range on the magnetic disk disk where the linear recording densities of data greatly differ, and the number of cylinders is limited, so that it is not possible to cope with an increase in the recording capacity of the magnetic disk.

[Means for solving problems]

 FIG. 1 is a diagram for explaining the principle of the present invention.

The magnetic disk controller 10 shown in FIG. 1 (a) sends to the magnetic disk device 11 a command relating to seek for positioning the magnetic head in the target cylinder. The magnetic disk device 11 has a 3380 interface, and the control means 12 of the magnetic disk control device 10 sends out a command code as shown in FIG. 1 (c) in the sequence shown in FIG. 1 (b).

That is, 3 bits are used for the tag, 8 bits of command and qualifier are used for the bus, and the command of the bus and its qualifier are taken into the magnetic disk device 11 depending on the state of the tag bit.

As shown in FIG. 1 (b), the command code is sent to the bus when the tag bits 0 to 2 of 3 bits are all "1", and when the magnetic head is positioned in the cylinder, the command code shown in FIG. The code "64" is transmitted as shown in (c). That is, the 4 bits of bit numbers 0 to 3 are 0110 and "6".
The four bits of bit numbers 4 to 7 are 0100 to represent “4”.

When the tag bit 0 is “0” and both the tag bits 1 and 2 are “1”, it indicates that the bus is blank, and the tag bits 0 and 1 are both “0” and the tag bit 2 is “1”. At this time, the modifier transmitted to the bus is taken into the magnetic disk device 11. As shown in (c) of FIG. 1, this qualifier indicates that the bit number 0 indicates the moving direction of the magnetic head. For example, "1" indicates an inner peripheral direction, and "0" indicates an outer peripheral direction. Indicates that.

The next bit number 1 is a bit used by the present invention. This bit indicates an area. For example, "1" indicates the inner circumference side and "0" indicates the outer circumference side. Bit number 2-4
Is unused, bit number 5 indicates that the moving amount of the magnetic head is, for example, 1024 cylinders, and bit number 6 indicates 51.
Bit number 7 indicates 256 cylinders for 2 cylinders.

The qualifier taken in as shown in FIG. 1 (b) represents the moving amount of the magnetic head as shown in (c) of FIG. 1. Bit number 0 corresponds to 128 cylinders, bit number 1 corresponds to 64 cylinders, and bit number. 2 for 32 cylinders, bit number 3 for 16
Cylinders, bit number 4 indicates 8 cylinders, bit number 5 indicates 4 cylinders, bit number 6 indicates 2 cylinders, and bit number 7 indicates movement by 1 cylinder.

The control means 12 is configured to instruct the magnetic disk device 11 about the magnitude of the write current by the bit number 1 of the modifier.

[Action]

With the above-mentioned structure, the control means 12 divides the magnetic disk disk area into the magnetic disk device 11 and sets the write current value for the cylinders from the outer peripheral side to X-1 with reference to the preset cylinder number X. , X and the write current value for the cylinder on the inner peripheral side can be separately instructed.

〔Example〕

 FIG. 2 is a diagram for explaining an embodiment of the present invention.

FIG. 2A shows the area of the magnetic disk disk, where the outermost cylinder number of the data write area is 0 and the innermost cylinder number is Y, the write current determined in advance from the read / write margin. X is the cylinder number to switch the value
And

Then, the range from cylinders 0 to X-1 is set as the region 0, and the range from cylinders X to Y is set as the region 1.

FIG. 2 (b) shows a part of the qualifier shown in FIG. 1 (c). Bit number 0 indicates that the magnetic head should be moved to "1" to move to the inner circumference side of the magnetic disk. Then, the bit number 1 is set as the area "1", and the writing current is instructed to be reduced.

This is the case where the cylinder to which the magnetic head is positioned is present in area 1 of FIG. 2 (a), and if the cylinder to which the magnetic head is positioned is present in area 0,
The bit number 1 of the qualifier specifies the area "0" and instructs to increase the write current.

FIG. 2 (c) shows a part of the qualifier shown in FIG. 1 (c). Bit number 0 indicates that the magnetic head should be moved to the outer peripheral side of the magnetic disk with the moving direction of the magnetic head being "0". , Bit number 1 is an area "0", and it is instructed to increase the write current.

That is, the case where the cylinder to which the magnetic head is positioned is present in the area 0 in FIG. 2 (a).

The control means 12 shown in FIG. 1 (a) uses the cylinder X as a reference when sending the command regarding the seek, and the cylinder 0
~ Cylinder X-1 is distinguished from cylinder X to cylinder Y, and the bit number 1 of the qualifier is set as described above.

For the 3380 interface, use the above "64" as a command.
In addition to the above, “47” is used as a diagnostic command and “6” is used as a command to instruct the positioning of the magnetic head up to the sector.
Although there is 6 ", it is the same as designating the area at the bit number 1 in FIG. 1 (c).

〔The invention's effect〕

As described above, according to the present invention, the data area of the magnetic disk is divided, and the write current to the inner cylinder having a large linear recording density is reduced, so that the read / write margin can be made uniform, and further Since a cylinder is provided on the inner circumference side to record data, it is possible to cope with an increase in storage capacity.

[Brief description of drawings]

 FIG. 1 is a diagram for explaining the principle of the present invention, and FIG. 2 is a diagram for explaining an embodiment of the present invention. In the figure, 10 is a magnetic disk control device, 11 is a magnetic disk device, and 12 is a control means.

Claims (1)

[Claims] 1. A magnetic disk device (11) which does not manage cylinder information, and a magnetic disk which manages cylinder information and sends a command relating to seek and its qualifier to control this magnetic disk device (11). In the control device (10), the data recording area of the magnetic disk is divided based on the cylinder value for positioning the magnetic head in the magnetic disk control device (10), and the write current value is switched between the outer circumference side and the inner circumference side. A control means (12) for performing is provided, and based on the judgment of the control means (12), the write current is increased on the outer peripheral side of the data area of the divided magnetic disk to the qualifier given to the magnetic disk device (11). , A write current control method for a magnetic disk characterized by setting a bit which gives an instruction to make it smaller on the inner circumference side.