JPH0770014B2 - Flexible disk device - Google Patents

Description

The present invention relates to a technique for increasing the recording density of a flexible disk device.

[Prior Art] When writing data to a recording medium, the writing mode (format) is defined, and the recording medium is provided between the gap for recording / reproducing and the gap for erasing both edges of the data area. There is misalignment in the direction of rotation. These relationships are shown in FIG. In FIG. 5 (a), 1 is an ID area 1a, a G2 area 1b, a DaTa area 1c as a data area, and a G3 area 1
A sector having d etc., TR is a track, and in FIG. 5 (b), 2 is a recording / reproducing head, 3 is a recording / reproducing gap, and 4 is an erasing gap. Further, in FIG. 5 (c), r represents a track radius.

In sector 1, DaTa region 1c has its radial edges 1c1,
1c2 needs to be erased, but the ID region 1a is erase-prohibited, and therefore the erase current depends on the erase gap 4 in the G2 region 1b.
You have to stand up while you are in. Since the erasing gap 4 is behind the recording / reproducing gap 3 by x in the recording medium rotation direction vD shown in FIG.
It is necessary to delay the start of erasing with respect to the start of writing. This time delay is called erase-on delay time (Teon), that is, erase start time delay. The erase-on delay time is required to satisfy the following conditions (a) and (b) because of the above regulation.

Condition (a): Minimum value of Teon The erase current must not rise while the erase gap 4 is in the ID region 1a. That is, the following formula must be satisfied.

X _max -Teon _min・ V _min <l _G2max ... ・ (1) ∴X _max -Teon _min・ ω ・ r _min (1-0.01α) <8 ・ G2 ・ r _min
・ (1-0.01α) / Ft ∴Teon _min ＞ [X _max / (ω ・ r _min (1-0.01α))]-
(8 ・ G2 / Ft ・ ω) ・ ・ ・ ・ (2) or Teon _min > 0 ・ ・ ・ ・ (3) Condition (b): About the maximum value of Teon The erase current must rise at the time when the data area starts. I have to. That is, the following formula must be satisfied.

X _min ＞ Teon _max・ V _max・ ・ ・ ・ (4) ∴Teon _max ＞ X _min / (ω ・ r _max (1 + 0.01α)) ・ ・ ・
-(5) However, the meaning of each symbol in the above formulas (1) to (5) is as follows.

x: Distance between recording / playback gap and erase gap (5th
(See FIG. 5B) v: Recording medium rotation linear velocity (r.ω) (See FIG. 5A) r: Track radius (See FIG. 5C) ω: Rotation speed (See FIG. 5C) )) Α: Recording medium rotation fluctuation G2: Area, G2 byte number = 22 bytes Ft: Magnetic flux reversal density l _G2 : G2 length conversion (8 · G2 · r / Ft) As an example, 3.5 inch flexible disk device FIG. 6 shows the calculation result of the erase-on delay time when recording is performed under the following condition (c).

Condition (c) Magnetic flux reversal density Ft = 7958 Magnetic flux reversal / radian Rotation speed 300 rpm (rotation speed ω = 2π · 5) Distance between recording / reproducing gap and erasing gap x = 0.6 ± 0.05 mm Recording medium rotational fluctuation α = ± 2% Number of tracks 80 Track spacing 0.1875mm Outermost track radius 39.5mm Innermost track radius 23.1875mm Double-sided type (track shift between top and bottom is 8 tracks) In Fig. 6, the horizontal axis is the track number and the vertical axis is the erase-on delay. Indicates the time. The erase-on delay time setting range SA1 for the outermost track (0 track) and the innermost track (79 track) is 0 track: 0 to 434.5 (μs) 79 track: 206.5 to 695.2 (μs). Therefore, the erase-on delay time Teon can be set to be the same for the innermost track and the outermost track, and it is sufficient to set it to 300 μs ± 50 μs, for example.

However, when the recording density in the circumferential direction, that is, the magnetic flux reversal density Ft is increased, there arises a problem if the erase-on delay time Teon is the same in the innermost track and the outermost track. As an example, leave the other conditions unchanged,
FIG. 7 shows the case of the following condition (d) in which the magnetic flux reversal density Ft is doubled.

Condition (d) Magnetic flux reversal density Ft = 15916 Magnetic flux reversal / radian Others are the same as condition (c) In this case, the setting range of erase-on delay time Teon in the outermost track (0 track) and the innermost track (79 track) SA2 is 0 tracks: 203.6 to 434.5 (μs) 79 tracks: 558.5 to 695.2 (μs), and it is impossible to set the same erase-on delay time for the outermost track and the innermost track. Conventionally, as a countermeasure against the above-mentioned case, a method has been adopted in which the distance x between the recording / reproducing gap and the erasing gap is reduced to reduce the recording medium rotation variation α. As an example, FIG. 8 shows the case of the following condition (e).

Condition (e) Magnetic flux reversal density Ft = 15916 Magnetic flux reversal / radian Distance between recording / reproducing gap and erasing gap x = 0.35 ± 0.05 mm Recording medium rotation fluctuation α = ± 1% Others are the same as condition (c) The erase-on delay time Teon setting range SA3 for the outer track (0 track) and the innermost track (79 track) is 0 track: 0 to 239.4 (μs) 79 track: 202.7 to 383.0 (μs). As shown in SE1 of an example of time setting, the erase-on delay time can be set to be the same between 202.7 and 239.4 μs for the outermost track and the innermost track.

However, the distance between the recording / reproducing gap and the erasing gap x
If it is shortened, the processing becomes difficult in the head manufacturing process, the yield is reduced, and the cost is increased. Further, in order to reduce the rotational fluctuation of the recording medium, it is necessary to improve the accuracy of the motor that rotates it, which also leads to an increase in cost.

[Problems to be solved by the invention]

As in the conventional example described above, the erase-on delay time
If Teon is set to be the same on the outermost track and the innermost track, it is necessary to make changes to the head and motor, and all of these changes have the disadvantage of increasing costs.

In addition, as another measure for dealing with the high density such as the condition (d), in the formula (2), the G2 area in the recording format is used.
If 1b is increased in proportion to the increase in magnetic flux reversal density Ft,
The conditions of the expressions (2), (3), and (5) are the same as those of the condition (c) of the normal density, and therefore, the structural dimensions of the head are
It is not necessary to change X _max and X _min .

However, in a normal controller LSI, the G2 area 1b is fixed to 22 bytes, and it is more practical not to change the number of bytes. Further, if the G2 area 1b is increased, the number of effective recording bytes after formatting on one track decreases, and the recording efficiency deteriorates. Therefore, this method is not practical.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a flexible disk device capable of supporting high recording density while maintaining the existing mechanical mechanism and recording format configuration. .

[Means for solving problems]

In order to achieve such an object, according to the present invention, the time to start erasing both edges in the radial direction of the data area of the sector formed in a part of the track is delayed with respect to the start of writing data in multiple stages. A switching means for switching is provided. The switching means is set to an initial value when the head moves to the outermost track or the innermost track, and the pulse input according to the movement of the head is moved in the moving direction of the head. A track counter that outputs track information corresponding to the head position by adding or subtracting based on this, and a count value is set to an initial value when the head moves to the outermost or innermost track, and the track counter The delay time corresponding to the head position can be dealt with by adding or subtracting a fixed value according to the track information of the head and the moving direction of the head. A delay time calculation counter for calculating a count value, as well as counting a predetermined clock,
A delay signal output counter that outputs a signal indicating a delay time using the count value from the delay time calculation counter as a comparison condition.

[Action]

In the present invention, the track counter outputs the track information corresponding to the head position by adding or subtracting the pulse input according to the movement of the head based on the moving direction of the head, and the delay time calculation counter When the head moves to the outermost track or the innermost track, the count value is set to the initial value, and a certain value is added or subtracted according to the track information from the track counter and the moving direction of the head. A count value corresponding to the delay time according to the head position is calculated, a predetermined clock is counted by the delay signal output counter, and a signal indicating the delay time is output using the count value from the delay time calculation counter as a comparison condition. To be done.

〔Example〕

An embodiment of the flexible disk device of the present invention will be described below. FIG. 4 shows an example of the erase-on delay time setting SE2 in the present embodiment, which is written in broken lines, under the condition (d) described above. Record /
The settings of the distance x between the reproducing gap and the erasing gap and the recording medium rotation variation α are not changed. Therefore, from the outermost track (0 track) to the innermost track (79 tracks)
Erase-on delay time up to Teon setting range SA4
Is 0 tracks: 203.6 to 434.5 (μs) 20 tracks: 264.4 to 480.1 (μs) 40 tracks: 340.2 to 536.4 (μs) 60 tracks: 437.3 to 607.6 (μs) 79 tracks: 558.5 to 695.2 (μs) Each may be set arbitrarily.

In FIG. 4, the erase-on delay time is set in a stepwise manner so that it is 300 μs on the outermost track (0 track) and 100 μs every 20 tracks toward the inner track. In this way, if the setting is switched in multiple stages, the distance x between the recording / reproducing gap and the erasing gap and the setting of the recording medium rotation fluctuation remain the same as before, and even if the magnetic reversal density becomes high, it is determined. The erase-on delay time of the flexible disk device can be set within the set range.

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

Next, the operation of this device will be described. When the head comes to the outermost track 0, a track 0 signal d is generated from another circuit of this device and is input to the terminal T4. In response to this signal d, the counters 5 and 6 are set to the initial conditions by the initial condition data a and b input to the terminals T1 and T2. At the same time, the track counter 7 is reset.
This allows the track counter 7 to operate during operation of this device.
Constantly updates the track information corresponding to the head position by the step pulse e input to the terminal T5. Further, the counters 5 and 6 update the erase-on time and erase-off time corresponding to the track position by the output of the track counter 7. These up-down counters
The addition and subtraction of 5, 6 and 7 are determined by ON (active) and OFF (inactive) of the direction select signal f input from the outside to the terminal T6.
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, and finally selects The selected signal is output to the counter 9 that generates erase timing.

As described above, the counter 9 finally counts the clock signal c generated by another circuit and input to the terminal T3 as much as the condition of the multiplexer 8 is satisfied, and outputs it as the erase timing signal h from the terminal T8.

In the above embodiment, the outermost track 0 is used as a reference, but the innermost track 79 may be used as a reference. Also, although the stepwise switching was set at equal track intervals and equal time intervals,
The track interval and the time interval may not be evenly divided. For example, it is easy to store the optimum erase-on delay time in an arbitrary track band in a memory that works with the multiplexer 8 and set the optimum erase-on delay time based on information from the track up / down counter 7. Is.

Here, an embodiment of a specific method for generating the erase-on and erase-off delay time will be described. This will be described with reference to FIGS. 2 and 3. FIG. 2 is a system diagram showing another embodiment of the flexible disk device, which has an interrupt operation circuit 10 and a fixed storage unit 11. The interrupt arithmetic circuit 10 is an interrupt circuit 10a,
Comprised of an arithmetic circuit 10b, registers 10c, 10d, 10e, etc., a clock signal c, a track 0 signal d, an inner circumferential direction step signal e
1, the outer peripheral direction step signal e2, the write gate on signal i1, and the write gate off signal i2 are input. The fixed storage unit 11 is a program 11a composed of programs PA, PB, PC, PD, PE and memories TK0 to T
The erase-on-delay time memory 11b and the erase-on-delay time memory 11c are composed of K79.

This device generates an erase-on / erase-off direct time corresponding to the track position, and is described here as an object only for generating erase timing. In this device, the register 10e forming the interrupt arithmetic circuit 10 is used as a track up / down counter. As signals input to this register 10e, there are a step pulse for driving the head positioning step motor and a signal for determining the direction thereof, but for convenience of explanation, the register 10e has an inner peripheral step pulse e1 and an outer peripheral direction. Step pulses e2 and are input. When the step pulse e1 in the inner circumferential direction arrives, the program PB in the program 11a is activated and the register 1
One track is added to 0e, and when the step pulse e2 in the outer peripheral direction arrives, the program PC in the program 11a is started and one track is subtracted from the register 10e.

When the head reaches the outermost track 0, a track 0 signal d is generated from another circuit of the apparatus, and the program PA is started upon receiving this signal d. FIG. 3 (a) shows the flow of the program PA. First, as shown in step 21,
The register 10e is reset to the 0 track position. Next, as shown in steps 22 and 23, the register 10e constantly updates the track position information corresponding to the head position during the operation of the apparatus.

Next, when the write gate is turned on (active) to update the recorded contents, the interrupt circuit 10a is activated and the program PD
To start. The flow is shown in FIG. 3 (b). First, in step 31, the erase-on time D at that time is corresponded to the contents of the register 10e at the time of starting this program PD.
The data corresponding to e1 is selected from the erase-on delay time memory 11b, fetched, and loaded into the register 10c. Next, at step 32, the content of the register 10c is subtracted by the clock signal c from the outside. If the value of the register 10c becomes "0" by this subtraction and a carry-down signal is generated, the register 10d as the switching means is set by this signal as shown in step 33. 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 an erase timing for starting the flow of the erase current. The erase timing is delayed for a certain time after the write gate-on signal arrives, but the time changes for each track position or each group of track positions.

Next, when the write gate is turned off, another program PE is started, and the erase-off time De2 is fetched from the erase-off delay time memory 11c of the fixed storage unit 11 in the same manner as described above, and as shown in step 41, the register Load to 10c. The operations of steps 42 and 43 are the same as steps 32 and 33. In step 34, the register 10c outputs the erase timing signal h for turning off the erase current.

The erase-off time De2 requires the longest time on the innermost track, but it is not necessary to switch it because it is usually not useful even if it is shortened on the outer track. However, it does not matter if switching is performed in proportion to the erase on time De1.

〔The invention's effect〕

As described above, according to the present invention, when the data is written on the recording medium, the erase means is provided with a switching means for switching the delay of the time to start erasing both radial edges of the data area with respect to the start of writing the data in multiple stages. Since the on-delay time was switched stepwise, the conventional recording / playback head,
There is an effect that the recording density can be improved with the outer shape, size, and accuracy of the recording medium rotating motor, and the delay time corresponding to the current head position is calculated and clocked by a relatively small counter as a circuit element. Therefore, it is possible to realize the small size and labor saving generally required for the flexible disk device, and it is possible to realize the high precision which enables the high speed access.

[Brief description of drawings]

FIG. 1 is a system diagram showing an 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 flow chart for explaining the operation of the other embodiment. FIG. 4 is a graph showing an example of setting the erase-on delay time, FIG. 5 is an explanatory diagram showing the data writing mode on the recording medium and each gap, and FIGS. 6 to 8 are the erase-on delay time under each condition. It is a graph which shows a setting range and its setting example. 1 ... sector, TR ... track, 2 ... recording / playback head, 3 ... recording / playback gap, 4 ... erase gap,
5,6,7,9 …… Counter, 8 …… Multiplexer, 10 ……
Interrupt arithmetic circuit, 11 ... Fixed storage section.

Front page continued (72) Inventor Makoto Isozaki 325 Kamimachiya, Kamakura City, Kanagawa Mitsubishi Electric Computer Co., Ltd. (72) Inventor Tetsuro Hirono 2-25 Sakaemachi, Koriyama City, Fukushima Prefecture Koriyama Manufacturing Co., Ltd. (72) Inventor Hirohisa Miura 2-25 Sakaemachi, Koriyama City, Fukushima Prefecture Koriyama Manufacturing Co., Ltd. (56) References JP-A-60-133505 (JP, A) JP-A-59-135663 (JP, A) JP-A-59-129908 (JP, A) JP-A-57-44207 (JP, A) JP-A-62-86507 (JP, A) JP-A-62-6407 (JP, A) JP-A-60-224149 (JP, A)

Claims (1)

[Claims] 1. In a flexible disk device for writing data on a ring-shaped track of a disk-shaped recording medium, the time to start erasing both radial edges of a data area of a sector formed on a part of the track is equal to that of the data. A switching means for switching the delay time delayed from the start of writing in multiple stages is provided, and the switching means is set to an initial value when the head moves to the outermost track or the innermost track, and the head moves. A track counter which outputs track information corresponding to the head position by adding or subtracting a pulse input according to the head movement direction, and when the head moves to the outermost or innermost track Is set to an initial value, and the track information from the track counter and the A delay time calculation counter that calculates a count value corresponding to the delay time corresponding to the head position by adding or subtracting a fixed value according to the moving direction of the head, and the delay time calculation counter that counts a predetermined clock And a delay signal output counter that outputs a signal indicating the delay time with the count value from the above as a comparison condition.