JPH04341976A - Information recorder - Google Patents

Abstract

PURPOSE:To improve the recording capacity of a zone recording system disk device by making the radius of the innermost circumferential track of a disk smaller than the half of the radius of the outermost circumferential track. CONSTITUTION:In a disk-form information recorder in which an information recording area between the innermost circumferential information track and the outermost circumferential information track is divided radially into plural zones, and the information capacity of each information track in each zone is made equal to each other, and in addition, the information capacity of the zone is made larger as it goes to the outer side, the ratio alpha of the radius rinn of the innermost circumferential information track to the radius rout of the outermost circumferential track is made smaller than 0.5. Here, for making the information capacity of the outer circumference side zone larger as it goes to the outer side, the linear recording density of the innermost circumferential information track of each zone is made nearly equal.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording apparatus using a disk substrate such as a magnetic disk drive, and more particularly to an information recording apparatus suitable for large-capacity recording.

0002

2. Description of the Related Art Information recording devices such as magnetic disk devices that record information on disk-shaped recording media are widely used as external recording devices for computers. Conventionally, in these recording devices, a system in which the recording capacity per track is constant for both tracks on the inner circumference side and tracks on the outer circumference side of the disk has been common. In this method, the linear recording density of information becomes lower as the track is closer to the outer circumference. Therefore, there is a known method of increasing the recording capacity per disk surface by making more effective use of the recording surface. This method is a method in which the recording area is divided in the radial direction into several zones each including a plurality of tracks, and the recording capacity per track is increased toward the outer circumferential zone, and has been put into practical use in some areas. Such a recording method is called a zone density recording method, a zone recording method, or the like. Examples of literature written about zone recording methods include the electronic
Design November. 13.1986 (Elec
toronic Design; Nov. 13.19
86) pp. 141-144's "Constant Density Recording Comes Alive"
With New Chips” (Consta
nt density recording comes
"alive with new chips").Hereinafter, in this specification, the conventionally common method in which the track capacity on the inner and outer circumferences is constant is referred to as a constant track capacity method, and the recording area is divided into multiple zones. The method of changing the track capacity for each zone is called the zone recording method.

First, conditions for maximizing the capacity per side in the conventional constant track capacity method will be explained. In the case of constant track capacity method, the radius of the innermost track rin
By setting n to 1/2 of the radius rout of the outermost track, the recording capacity per surface is maximized. That is,
The maximum achievable linear recording density and track density are respectively Dl(
The recording capacity Ct (bits) per track is determined by the radius rinn of the innermost track (Equation 1).

0004

[Formula 1] Ct=2π×rinn×Dl

(Math. 1) Also, the number of data tracks that can be recorded N
If the track density is constant, t can be expressed as (Equation 2).

[0005]

[Formula 2] Nt=(rout-rinn)×Dt

(Math. 2) Therefore, the areal recording capacity Capt is

[0006]

[Formula 3] Capt=Ct×Nt
=2π×rinn×(rout−rinn
)×(Dl×Dt) (Equation 3). (Number 3
) is a quadratic expression with respect to rinn, so the condition for maximizing Capt is obtained by differentiating (Equation 3) with rinn.

[0007]

[Formula 4] rinn=0.5×rout

(Equation 4) is obtained. This is a condition for maximizing surface recording capacity using the constant capacity track method. (Number 4
) into (Equation 3), the maximum surface capacitance Capt(ma
x) is

[0008]

[Formula 5] Capt(max)=πrout2×
(Dl×Dt)/2
It is expressed by (Math. 5). Next, the maximum surface recording capacity Capt (
max) and rinn/rout. ri
Setting nn/rout=α, substituting into (Equation 3) and (Equation 5), and taking the ratio β, we get

[0009]

[Formula 6] β=Capt/Capt(max)=
4α(1-α) (
Equation 6) is obtained. (Equation 6) has the maximum value β = 1 when α = 0.5, β = 0.99 when α = 0.55, and β when α = 0.45.
=0.99. From the above results, in the constant track capacity method, the areal capacity Capt on the disk surface is maximized by setting the ratio of the radius of the innermost track rinn to the radius rout of the outermost track to 0.5, but when rinn It can be seen that even if the ratio of rout changes by about 0.5 to ±10%, the areal capacitance changes by only about 1%. From these relationships, in conventional magnetic disk drives using a constant track capacity method, the radius rinn of the innermost track is 1/2 of rout.
It was normal to design it slightly larger than the original size. In other words, by making rinn slightly larger than 0.5 of rout, it is possible to increase the capacity per track while keeping the surface capacity at almost the maximum, increasing the data transfer speed, and also reducing the seek stroke of the head. This is because it can be made smaller, which is advantageous from the viewpoint of access.

On the other hand, in a zone recording type magnetic disk device, the simple relationships shown in (Equation 1) to (Equation 6) do not generally hold. The zone recording method is basically ri
Divide the area between nn and rout into multiple zones,
The linear recording density of the track on the inner circumference of each zone is the innermost circumference ri
By making the linear recording density Dl approximately equal to the linear recording density Dl of nn, the track capacity of the outer zone is increased more than that of the inner track, thereby improving the constant track capacity method so that the outer track can be used effectively. This is a recording method.

[0011]

[Problems to be Solved by the Invention] However, the conventional zone recording method has not been improved by focusing on the possibility of increasing the surface recording capacity by increasing the area of the information recording area, and the disk shape of the constant track capacity method has not been improved. The goal was to improve the capacity of the outer track. The first object of the present invention is to provide a high-capacity information recording device that is not available in the conventional zone recording method. A second object of the present invention is to provide an information recording device intended to further ensure highly reliable recording.

0012

[Means for Solving the Problems] In order to achieve the first object, the present invention divides the information recording area between the innermost information track and the outermost information track into a plurality of zones in the radial direction. , in a disk-shaped information recording device in which the information capacity of each information track in each zone is equal and the information capacity is larger in the outer zone, the radius of the innermost information track is rinn, and the information of the outermost circumference is When the radius of the track is rout,

[0013]

[Formula 7] α=rinn/rout≦0.5

(Equation 7). In order to increase the information capacity of the zones closer to the outer circumferential side, the linear recording density of the innermost circumferential information tracks of each zone may be made approximately the same. Furthermore, in order to facilitate the condition (Equation 7), the ratio of the center hole diameter of the disk to the outer diameter of the disk is made smaller than before. More specifically, the information recording medium has an outer diameter of 2Rout (
A disk-shaped piece with a radius Rout) and an inner diameter of 2 Rinn (radius Rinn),

[0014]

[Math. 8] Rinn
≦ 0.25×Rout
(Equation 8). Here, the information recording medium may be a magnetic disk. In addition, in order to improve the magnetic properties of sputtered (thin film media) disks used in magnetic disk drives, the surface of the disk substrate is textured, a type of fine groove-like scratch, along the circumferential direction of the disk. Sometimes a process to attach it is applied. In a magnetic disk device that satisfies the condition (Equation 7), the texture processing of the disk substrate is applied to almost the entire surface of the substrate. More specifically, when the outer diameter of the information recording medium is 2Rout (radius Rout) and the inner diameter, that is, the inner diameter of the center hole is 2Rinn (radius Rinn).

[0015]

[Equation 9] Rinn+1.0(mm
) ≦ r ≦ Rout-1.0 (mm)
Texture processing is applied to the area of radius r expressed by (Equation 9).

[0016]

[Operation] In a disk-shaped information recording device, the information recording area between the innermost information track and the outermost information track is divided into multiple zones in the radial direction, and the information capacity of each information track in each zone is reduced. The zone recording method is a typical example of making the information capacity equal and increasing the information capacity toward the outer zone. The zone recording method is basically a recording method that makes the linear recording density of the innermost track of each zone approximately equal.
The larger the area of the information recording portion on the disc, the greater the surface recording capacity. Generally, the radius rout of the outermost track is set to a value as large as possible, given the size of the disc, within the range allowed by the mechanical dimensions of the recording/reproducing head. Therefore, in order to increase the information recording area, the smaller the radius rinn of the innermost track, the more effective it is. Therefore, in a magnetic disk device using the zone recording method, α=0.5, unlike in the case of a constant track capacity method.
Rather than maximizing the areal recording capacity at (Equation 7), it is possible to increase the areal recording capacity by making α as small as possible with α≦0.5. That is, this makes it possible to improve the surface recording capacity of the constant track capacity method for a disk shape with α≧0.5, which is not possible with the conventional zone recording method.

In addition, in order to reduce α in (Equation 7), it is effective to increase the outermost track radius rout or to decrease the innermost track radius rinn, but rinn is the size of the center hole. , and for the radius Rinn of the center hole,

[0018]

[Math. 10] rinn
＞Rinn
(Equation 10). Therefore, ri
In order to reduce nn, it is effective to reduce Rinn, but currently produced magnetic disks have R
The inn/Rout value is 0.26 or more, which is not necessarily sufficient to increase the recording capacity in the zone recording method. Therefore, by setting the size of the disk substrate to (Equation 8), it is possible to further increase the recording capacity.

Furthermore, in the zone recording method, the wider the recordable area of the disk surface, the higher the recording capacity. For this reason, as shown in (Equation 9) for both the inner and outer edges of the disk, by applying texture processing to the sputter disk substrate on the entire surface of the disk except for the 1.0 mm processing margin area, almost all of the disk surface can be textured. Stable magnetic characteristics and stable head flying characteristics can be obtained over the entire surface, making it possible to realize a zone recording type magnetic disk device that is stable and has a high recording capacity.

[0020]

[Embodiments] Examples of the present invention will be described below with reference to the drawings. FIG. 2 is a diagram showing the configuration of a general magnetic disk device to which the present invention is applied. A magnetic disk device generally has at least one magnetic disk 1 (
a spindle 5, a spindle motor 6 that rotates the spindle 5 to which the magnetic disk 1 is attached, a magnetic head 2 for recording and reproducing information on the disk surface, and a head arm for supporting the head 2. 3. A carriage 4 for moving the head group in the radial direction of the disk to access the target track, a base 7 for holding these mechanical systems, and an electric circuit system for transmitting reproduction signals from the magnetic head 1. A recording/reproducing circuit 8 that performs amplification, discrimination, and control of recording signals, etc., a modulation/demodulation circuit 9, an interface circuit 10 that is a window for data exchange with a host computer (not shown), and a carriage control that controls access and following. circuit 11, motor control circuit 12,
and a control circuit 13 that controls the entire device.

FIG. 1 is similar to FIG. 2 for explaining the features of the present invention.
The magnetic disk 1 is shown enlarged. Disk 1 has an outer diameter (
A center hole with a diameter of 2 Rout and 2 Rinn in diameter is bored in its center for passing the spindle through. rinn represents the radius of the innermost track, and rout represents the radius of the outermost track. rinn for zone recording method
and rout into multiple zones. The example in Figure 1 shows the case where it is divided into eight zones, where z1 to
z8 indicates each zone.

[0022] As shown in (Equation 7), the present invention provides rinn
/rout ≦ 0.5,
The first numerical example is shown in (Table 1).

[0023]

[Table 1]

Table 1 shows a numerical example of the present invention for a magnetic disk disk generally called 5.25 inch size. The standard size of a 5.25-inch magnetic disk disc is an outer diameter of 130 mm (Rout = 65 mm) and a center hole diameter of 40 mm (Rinn = 20 mm). The outermost track radius rout is set as large as the size of the magnetic head allows, but specifically, it is about 1 to 5 mm smaller than Rout. In this example, rout is 6
It was set to 2 mm. Examples A1, A2, and A3 are cases where rinn is 26 mm, 31 mm, and 20 mm, respectively, and α (rinn/rout) is 0.5 or less in all examples. Here, the zone recording method assumes that the area between rinn and rout is equally divided into eight zones, and the linear recording density of the innermost track in each zone is constant (50 kBPI). Here, effect index 1 in the table is equal to rinn and ro.
The ratio of areal capacity to that of the constant track capacity method where the linear recording density of the innermost track (radius rinn) is 50 kBPI under the ut condition, and the effect index 2 is the condition where the areal capacity is maximum in the constant track capacity method ( It shows the ratio of the areal capacity (Capt(max)) in the case of α=0.5) and the areal capacity in the zone recording method. In the case of the conventional constant track capacity method, it was common to set α≧0.5, but (
As is clear from the results in Table 1), in the case of the zone recording method, the smaller the α value is from 0.5, the larger the increase in capacity expressed by the effect index becomes. In addition,
Example numbers A1 and A2 are examples for the current standard size 5.25-inch disc, but A3 has a center hole with an inner diameter of 30 mm (Rinn=15 mm and Rinn/R
This is an example when out=0.23). In this case, it is possible to reduce rinn to about 20 mm, so that the capacity can be further increased. In addition, A
1. It is desirable to perform texturing on an area with a radius r of 21 mm≦r≦64 mm in the example of A2 and 16 mm≦r≦64 mm in the example of A3, and to flatten the disk surface to a certain extent in this area.

In order to make the effects shown in Table 1 easier to understand, the effects shown in Table 1 will be further explained using FIG. FIG. 3 shows the ratio of surface recording capacity corresponding to the radius of the innermost track in Table 1. That is, in the figure, curves a and b are curves obtained by plotting the corresponding values of effect index 1 and effect index 2 against the value of rinn in Table 1, respectively, using the scale on the right vertical axis. It is. Therefore, curve a shows the ratio of the areal recording capacity of the zone recording system to the constant track capacity system, and curve b shows the ratio of the areal recording capacity of the zone recording system to the maximum areal recording capacity of the constant track capacity system. From curve b, the surface recording capacity of the zone recording method is 44% of the maximum surface recording capacity of the constant track capacity method when rinn is 31 mm, that is, α is 0.5.
It can be seen that the size becomes larger as rinn becomes smaller. The reason why curve a shows a larger value than curve b at a small value of rinn is that while in the zone recording method, as rinn becomes smaller, the areal recording capacity increases as shown in curve b, whereas, on the contrary, it remains constant. This shows that the areal recording capacity of the track capacity method decreases as rinn decreases. Curve c is a curve obtained by using the scale of the vertical axis on the left as a ratio of the areal recording capacity when the areal recording capacity of the zone recording method is set to 1 when rinn is 31 mm. rinn is 26m from the same curve
When m, that is, when α is 0.42, the surface recording capacity is 9%, and when rinn is 20 mm and α is 0.32, the surface recording capacity is 17.
% increase. In other words, the areal recording capacity of the zone recording method is more than 40% larger than that of the constant track capacity method when α is 1/2.
If α is approximately 1/3, the value will further increase by nearly 20%.

Tables 2 and 3 show second and third numerical examples of the present invention.

[0027]

[Table 2]

[0028]

[Table 3]

Table 2 shows a numerical example of the present invention for a magnetic disk disk generally called a 3.5-inch size, and Table 3 shows a numerical example of the present invention for a magnetic disk disk generally called a 2.5-inch size. The standard size of a 3.5 inch disc is Rou.
t=47.5mm, Rinn=12.5mm, and 2
．． Standard size of 5 inch size is Rout=32.5m
m, Rinn=10.0 mm. Example numbers B1, B2 and C1, C2 are examples of application of the present invention to standard size disks, and B3 and C3 have center hole diameters smaller than the standard size. In the B3 example, Rinn
/Rout=0.21, Rinn/Rou in the C3 example
t=0.25, and the capacity can be increased by making rinn smaller. It can be seen that in both examples, by making the α value smaller than 0.5, in the case of the zone recording method, it is possible to increase the surface recording capacity as in the case of (Table 1). In other words, numerically, compared to the areal recording capacity when α is 0.5, in Table 2, the areal recording capacity increases by 15% when α is 0.33, and in Table 3, when α is 0.37, the areal recording capacity increases by 15%. At that time it was 14
% increase. In other words, as in the case of Table 1, when α is 1/3, an increase in surface recording capacity of approximately 20% can be obtained. In addition, (Table 2
) in the example of B1 and B2, 13.5mm≦r≦46.5m
In the example of m, B3, 11mm≦r≦46.5mm, and (
In the example of C1 and C2 in Table 3), 11mm≦r≦31.5m
In the example of B3, it is desirable to perform texturing and constant flattening of the disk surface for an area with a radius r of 9 mm≦r≦31.5 mm.

[0030]

According to the present invention, it is possible to increase the recording capacity of a zone recording type disk device by making the radius of the innermost track of the disk less than 1/2 of the radius of the outermost track and the rack. Become. In fact, by slightly reducing the radius of the innermost track, the increase in recording capacity becomes non-negligible.

[Brief explanation of drawings]

FIG. 1 is a diagram illustrating the structure of a disc according to the present invention.

FIG. 2 is a diagram illustrating the overall configuration of a magnetic disk device of the present invention.

FIG. 3 is a diagram showing the ratio of surface recording capacity, and is a diagram illustrating an example of the effects of the present invention.

[Explanation of symbols]

Claims (5)

[Claims] Claim 1: An information recording medium on a disk substrate has a circumferential information track, and the information recording area between the innermost information track and the outermost information track is divided into a plurality of zones in the radial direction. , in an information recording device in which the information capacity of each information track in each zone is made equal, and the information capacity increases as each information track in an outer zone becomes larger, the radius of the innermost information track is rinn, and the radius of the outermost information track is An information recording device characterized in that when radius is rout, rinn/rout≦0.5. 2. The method of increasing the information capacity of each information track in the outer zone means that the linear recording density of the innermost information track in each zone is made approximately the same. 1. The information recording device according to 1. 3. The information recording medium has an outer diameter of 2 Rout,
It is disc-shaped with an inner diameter of 2 Rinn,
3. The information recording device according to claim 1, wherein Rinn≦0.25×Rout. 4. The information recording apparatus according to claim 1, wherein the information recording medium is a magnetic disk. 5. In the information recording device according to claim 4, when the outer diameter of the information recording medium is 2Rout and the inner diameter is 2Rinn, Rinn+1.0 (mm) ≦ r ≦ Rout−1.
．． An information recording device characterized in that a substrate surface is textured in an area with a radius r expressed as 0 (mm).