JPS6289274A - Flexible disk device - Google Patents

Abstract

PURPOSE:To cope with the high recording density as well while keeping the existing constitution of the mechanism and the recording format, by switching in many steps the delay of the time when the erasion is started for both edges of a data area in the radius direction against the writing start of data. CONSTITUTION:The erase-on delay time is set in many steps so that it is set at 300mus with the most outer circumferential track 0 and then increased toward the inner circumference by 100mus at every 20 tracks. In such a way, the erase-on delay time of a flexible disk device can be set within a prescribed setting range even in case the inversion density of a magnetic flux is increased with the distance (x) between the record/reproduction gap and the erasion gap and the revolving variance of a recording medium set as conventional. Thus the recording density is improved while keeping the conventional, recording/reproducing head and the size and accuracy of a driving motor for the recording medium since the erase-on delay time is switched in steps.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a technique for increasing the recording density of a flexible disk device.

[Conventional technology]

When writing data to a recording medium, the writing style (format) is determined, and there is a positional deviation in the recording medium rotation direction between the gap for recording/reproducing and the gap for erasing both edges of the data area. There is. These relationships are shown in FIG. Figure 5 (1 shown in al is ID
Area 1a, G2 area tb, DaTa as data area
Area 1c.

A sector having a G3 area 1d, etc., TR is a track, 2 is a recording/playback head, 3 is a track (FIG.
4 represents the erase gap. Also, in FIG. 5 (c+), ``represents the track radius.

In sector 1, it is necessary to erase both radial edges ICI and IC2 of D a T a a area 1c, but I
The D area 1a is erasing prohibited, so the erasing current must be discharged while the erasing gear knob 4 or 62 is in the area 1b. Furthermore, since the erasing gap 4 is located at the rear of the recording/reproducing gear knob 3 by an amount X in the recording medium rotation direction vD shown in FIG. This time delay is called erase-on delay time (Teon).
In other words, this is called erasure start time delay. Due to the above regulations, the erase-on delay time is subject to the following conditions (at, (b)
) is required.

Regarding the minimum value of condition (at: Teon), the erase current must not rise while the erase gap 4 is in the ID region 1a. That is, the following equation must be satisfied.

X mix T eon;.・■mrn〈j2G2
max H' HHfl), X, Iax+ Teon
lI, l, ·ω' r mi. (1-0,010ri<8
・G2-r, =-(1-0,01α)/Ft',
TeOnmin 〉(X +nax/ (ω 'm*n
(1-0,01α))>(8・G2/Ft・ω)...
(2) or Te0nIII7>0 (3) Condition (bl: The erase current must rise at the time when the data area starts for the maximum value of Teon. That is, the following equation must be satisfied.

Xff1in〉TeOnmax ”IIIX ””
+4)-', Te0nffiBX>xmin/ (
ω' rmax (1+0.01α)) (5) However, the meanings of each symbol in the above formulas (1) to (5) are as follows.

X: Distance between the recording/playback gear knob and the erase gap (see Figure 5 (b)) ■ = recording medium rotational linear velocity (r・ω) (see Figure 5 (al)) r Nidrak radius (see Figure 5 FC+) ω: Rotation speed (see Figure 5 FC+) α: Recording medium rotation fluctuation G2: Area, Hyde number of G2 - 22 Hyde FL: Magnetic flux reversal density Rcz: Length conversion of G2 (8・G2・r/FL) − As an example, FIG. 6 shows the calculation results of the erase-on delay time when recording is performed under the following conditions (C1) in a 3.5-inch flexo pull disk device.

Condition fc) ■Magnetic flux reversal density Ft = 7958 magnetic flux reversal/radian ■Rotation speed 300 rpm (rotation speed ω-2π・5) ■Distance between recording/playback gear, pu and erase gear 7 x = Q, 6±
0.05mm ■ Recording medium rotation fluctuation α - upper 2% ■ Number of tracks 80 ■ 1-rank interval 0.1875 mm ■ Outermost track radius 39.5 mm ■ Track radius for mm 23.1875 mm ■ Both types (
(The track deviation between the top and bottom surfaces is 8 tracks.) In FIG. 6, the horizontal axis shows the track number and the vertical axis shows the erase-on delay time. The erase-on delay time setting range SAI for the outermost track (0 track) and the innermost track (79 track) is: 0 track: 0 to 434.5 (μ5) 79 track: 206.5 to 695.2 (μS) ). Therefore, it is possible to set the erase-on delay time Teon the same for the innermost track and the outermost track, and for example, it is sufficient to set it to 300 μs±50 μs.

However, the recording density in the circumferential direction, that is, the magnetic flux reversal density Ft
If the erase-on delay time Teon is increased, a problem arises if the erase-on delay time Teon is the same for the innermost track and the outermost track. - As an example, the following condition (di) is shown in FIG. 7 in which the magnetic flux reversal density Ft is doubled while the other conditions remain the same.

Condition (d) ■Magnetic flux reversal density Ft = 15916 (1 flux reversal/radian) ■Other conditions (same as C1) In this case, erase-on delay time at the outermost track (Ol/rank) and the innermost track (79 tracks) Teon's setting range SA2 is 0 tracks: 20
3.6-434.5 (μ5) 79 tracks: 558.5
~695.2 (μS), making it impossible to set the same erase-on delay time for the outermost track l/rank and the innermost track. Conventionally, as a countermeasure for cases such as the above,
A method has been used to reduce the distance x between the recording/reproducing gap and the erasing gap to reduce the recording medium rotation fluctuation α. As an example, in the case of the following condition tel, the eighth
As shown in the figure.

Condition (e) ■Dongdong inversion density Ft = 15916 (ff flux inversion/radian ■Distance between recording/reproducing gap and erasing gap X = 0.3
5±0.05mm ■Recording medium rotation variation α-±1% ■Other conditions are the same as condition (C) In this case, erase-on delay time T eon for the outermost track (0 track) and the innermost track (79 track) The setting range SA3 is O track: 0~
239.4 (μ5) 79 tracks: 202.1 to 383.0 (μS), and as shown in the m number of erase-on delay time settings SEL, the erase-on delay time is set to 202 on the outermost track and the innermost track. It can be set to the same value between .7 and 239.4 μs.

However, the distance between the recording/reproducing gap and the erasing gap
If the head is shrunk, it becomes difficult to process it in the head manufacturing process, which lowers the yield and leads to an increase in costs. Further, in order to reduce rotational fluctuations of the recording medium, it is necessary to improve the accuracy of the motor that rotates the recording medium, which also leads to an increase in costs.

[Problem that the invention seeks to solve]

If the erase-on delay time Teon is set to be the same for the outermost track and the innermost track as in the conventional example described above, it is necessary to make changes to the head and motor, and all of the changes are This has the disadvantage of leading to an increase in costs.

In addition, as another measure to cope with the increase in density like condition (d), in equation (2), if the G2 area 1b is increased in proportion to the increase in magnetic flux switching density Ft in the recording format, (2+, ( 3), (The conditions of formula 51 are the same as those for the normal density of condition tc+, so there is no need to change the head structural dimensions X ffi,..., X mi□.

However, in a normal controller LSI, the G2 area 1b
is fixed at 22 hides, and it is more practical to not change this hide number. Furthermore, if the G2 area 1b is increased, the recording efficiency will deteriorate a little. Therefore, this method is impractical.

The present invention has been made in view of these points, and its purpose is to provide a flexible disk device that can accommodate high recording densities while maintaining the current mechanical configuration and recording format configuration. .

[Means for solving problems]

In order to achieve such an object, the present invention provides a switching means for switching in multiple stages the time delay for starting to erase both radial edges of a data area with respect to the start of data writing when writing data to a recording medium. This is how it was done.

[Effect]

In the present invention, the erase-on delay time is switched in multiple stages.

〔Example〕

An embodiment of the flexible disk device of the present invention will be described below. FIG. 4 shows an example of setting SE2 of the erase-on delay time in this embodiment for the above-mentioned condition (dl), written with a broken line. The setting of the recording medium rotation variation α has not been changed either. Therefore, from the outermost track (0 track) to the innermost track (79I-
The setting range SA4 of erase-on-delay time Teon up to rack) is: 0 track + 203.6 to 43, 4.5 (μ5) 20 tracks = 264.4 to 4.80.1 (μ5) 40 tracks: 340. 2~536.4 (μ5) 601-rack:
437.3 to 607.6 (μS) 7 tracks: 558
．． Each may be arbitrarily set between 5 and 695.2 (μS).

In FIG. 4, the erase-on delay time is set to 300 .mu.s at the R outer track (0 track) and to increase in steps by 100 .mu.s every 20 tracks toward the inner periphery. In this way, by switching the settings to multiple stages, the settings for the distance The erase-on delay time of the flexible disk device can be set within the specified setting range.

FIG. 1 is a system diagram showing one embodiment of a flexible disk device according to the present invention. This device includes an amplifier down counter 5 for setting the erase on time, an up/down counter 6 for setting the erase off time, a toranoqua 7 up/down counter 7 for determining the head position, and a switching means for selecting erase on or erase off. It has a multiplexer 8 and a counter 9 that finally generates the erase timing.

Next, the operation of this device will be explained. When the head reaches the outermost track 0, a track O signal d is generated from another circuit of this device and inputted to the terminal T4. In response to this signal d, counters 5 and 6 are set to initial conditions based on initial condition data a and b input to terminals TI and T2. At the same time, the track counter 7 is decremented.

This ensures that during operation of this device, the track counter 7
The track 1R1ia corresponding to the head position is constantly updated by a step pulse e inputted to the beam 11 T5.
The erase-on time and erase-off time are updated according to the output of the track position. Addition and subtraction of these up/down counters 5, 6δ and 7 are as follows:
Turns on (active) and off (inactive) the direction select signal r input from the outside to terminal T6.
determined by The multiplexer 8 selects either the output of the counter 5 or the output of the counter 6 according to the ON (active) or OFF (inactive) condition of the write gate signal g input from the outside to the terminal T7. The selected signals are output to a counter 9 that finally generates an erase timing.

Finally, the counter 9 counts the clock signal C generated by another circuit and inputted to the terminal T3 to meet the conditions of the multiplexer 8, and outputs it from the terminal T8 as an erase timing signal. .

In the embodiment L, the outermost track 0 is used as the reference, but the innermost track 79 may be used as the reference. Further, although the stepwise switching is set at equal track intervals and equal time intervals, the track intervals may not be equally divided into one hour interval. For example, it is easy to store the optimum erase-on delay time for a given track band in a memory linked to the multiplexer 8, and to set the optimum erase-on delay time using information from the track up/down counter 7. It is.

Here, an example of a specific method for generating erase-on and erase-off delay times will be described. This will be explained with reference to FIGS. 2 and 3. FIG. 2 is a system diagram showing another embodiment of the flexible disk device, which includes an interrupt calculation circuit 10 and a fixed storage section 11. The interrupt calculation circuit 10 includes an interrupt circuit 10a, a calculation circuit 10b, registers 10c, 10d,
10e, etc., including a clock signal c, an l-rack O signal d, an inner step signal el, an outer step signal e2. Write gate on signal i1. Write gate off signal 12 is input. The fixed record t0 section 11 is a program 11a consisting of programs PA, PB, PC, PD, and PE'.

It is composed of an erase-on delay time memory 11b consisting of memories TKO-TK79, an erase-off delay time memory Ilc, and the like.

This device generates erase-on and erase-off delay times corresponding to track positions, and will be described here as being intended only for generating erase timing. In this device, a register 10e forming an interrupt calculation circuit 10 is used as a track up/down counter.

The signals input to this register 10e include a step pulse for driving the head positioning shaft motor and a signal for determining its direction.For convenience of explanation, the register 10e includes a step pulse e1 for the inner circumferential direction and a signal for the outer circumferential direction. It is assumed that a step pulse e2 is input. When the step pulse e1 in the inner circumferential direction arrives, program PB in program lla is activated and register 1
．． When one track is added to Oe and a step pulse e2 in the outer circumferential direction arrives, program PC in program lla is activated and one track is subtracted from register 10e.

When the head reaches the outermost track O, a track O signal d is generated from a separate circuit of the apparatus, and upon receiving this signal d, the program PA is activated.

The flow of the program PA is shown in FIG. 10e constantly updates track position information corresponding to the head position.

Next, when the write gate is turned on (active) to update the recorded content, the interrupt circuit 10a is activated and the program P
Start D. The flow is shown in Fig. 3 fb). First, in step 31, data corresponding to the erase-on time Del at that time is selected and retrieved from the erase-on delay time memory Hb in accordance with the contents of the register 10e at the time of startup of this program PD, and the data is extracted from the erase-on delay time memory Hb.
Load to 0C. Next, in step 32, the contents of the register IOC are subtracted by the clock signal C from the outside. This subtraction causes the contents of register IOC to become 1″
0'' and a carry down signal is generated, as shown in step 33, this signal causes the register 10d as a switching means to be sent. As a result, as shown in step 34, when the register 10d is turned on, its output is taken out to the outside and used as the erase timing to start flowing the erase current. This erase timing is delayed by a certain time after the arrival of the write gate-on signal, but this time changes for each track position or for each group of track positions.

Next, when the write gate is turned off, another program PE is started, and in the same manner as described above, the erase off time De2 is retrieved from the erase off delay time memory IIC of the fixed storage section 11, and as shown in step 41, the erase off time De2 is stored in the register. Load into IOC.

The operations in steps 42 and 43 are similar to steps 32 and 33, and in step 34, the register 10c outputs an erase timing signal for turning off the erase current.

The erase-off time De2 requires the longest time on the innermost track, but there is usually no value in using it even if it is shortened on the outer track, so there is no particular need to change it. However, there is no problem in switching in proportion to the erase-on time Del.

〔Effect of the invention〕

As explained above, when writing data to a recording medium, the present invention provides a switching means for switching in multiple stages the time delay for starting to erase both radial edges of a data area with respect to the start of data writing. Since the on-delay time is switched in stages, conventional recording/playback heads,
This has the effect of increasing the recording density while maintaining the outer shape, dimensions, and accuracy of the recording medium rotation morph.

[Brief explanation of drawings]

FIG. 1 is a system diagram showing one embodiment of a flexible disk device according to the present invention, FIG. 2 is a system diagram showing another embodiment, and FIG. 3 is a flowchart for explaining the operation of another embodiment. Figure 4 is a graph showing an example of setting the erase-on delay time, Figure 5 is an explanatory diagram showing the data writing format on the recording medium and each gap, and Figures 6 to 8 are graphs showing erase-on delay time settings under each condition. It is a graph showing a setting range and an example of the setting. 1... Sector, TR... Track, 2...
Recording/playback head, 3... Recording/playback gear, 4
... Erase gap, 5,6°7.9 ... Counter, 8 ... Multiplexer, 10 ... Interrupt calculation circuit, 11 ... Fixed storage section.

Claims (4)

[Claims] (1) In a flexible disk device that writes data on a ring-shaped track of a disk-shaped recording medium,
A flexible device characterized in that it is equipped with a switching means for switching in multiple stages a delay time in which a time to start erasing both radial edges of a data area of a sector formed in a part of the track is delayed relative to a start of data writing. disk device. (2) The flexible disk according to claim 1, wherein the switching means lengthens the erasure start time by a fixed amount of time for every fixed number of tracks in the inner circumferential direction based on the erase delay at the outermost track position. Device. (3) The switching means shortens the erasure start time by a fixed amount of time for every fixed number of tracks in the outer circumferential direction based on the erase start time delay at the innermost track position. flexible disk device. (4) The switching means determines the optimum erasing start time delay for each track number band, stores the time information in an internal semiconductor memory, and retrieves this based on the information of the track up/down counter for erasing during operation. 2. The flexible disk device according to claim 1, wherein a start time delay is set.