JPS5845669A - Tracking method for flexible magnetic disc device - Google Patents

Abstract

PURPOSE:To attain accurate tracking, by forming a signal for position discrimination and compensating direction discrimination with a mean value differentially amplifying an output of an R/W head of a head and feeding back a compensation drive signal to a carriage. CONSTITUTION:When a movement between tracks is instructed 1, the carriage driving is logically discriminated 2 and a carriage motor driver 3 drives a carriage motor 4 to a specified direction. A mean value 11 differentially amplifying 10 an output of an R/W head 6 of a head 5 forms a position discriminating signal 12 and a compensating direction discrimination signal 13 and inputs them to a correction drive control circuit 15. The circuit 15 outputs a compensation drive instruction when a movement instruction detector 14 has no output and feeds back the output to the driver 3 and inputs a reference level to a position discriminator 12. Thus, when no movement instruction 1 is given, a closed loop circuit is formed to execute accurate tracking.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tracking method for recording information on a medium at high density in a magnetic disk device using a flexible disk.

This is called a magnetic disk device (hereinafter referred to as I-P1) D that uses a conventional flexible disk. ) is shown in FIG. 1.

In Fig. 1, 1 is a gear ridge movement command input line, 2 is a gear ridge drive logic circuit section (hereinafter referred to as C) that analyzes the movement command.
I) It's called L. ), 3 is referred to as a carriage motor driver section (hereinafter referred to as Ml). ), 4 is a carriage motor (hereinafter referred to as CM), and 5 is a gear ridge (not shown) driven by 0M4 via a lead screw (not shown), etc.
The head section mounted on I-, 6 is the read/write core (
Hereinafter, it will be referred to as 1t/W core. ), 7 is an erase core (hereinafter referred to as (2) core), 8 is a read/write circuit section, and 9 is an erase circuit section.

Therefore, when a movement command between trunks is input to movement command input line 1, CDL 2 determines the carriage movement direction and outputs a signal to CDL 3. In Ml)3, based on the signal from C'l)T and 2, (2M4 is determined and rotated in the J direction.The method of rotating CMll is a well-known technique. Therefore, a detailed explanation will be omitted. When the CM 4 is rotated, the head section 5 mounted on the carriage driven by the CM 1 moves a predetermined distance. Generally, a step motor is used for the CM 4. For example, it is configured to correspond to one step or two step drive for one trunk pinch movement.The head section 5 is equipped with T(, /W cocoa, E core 7)]1- The L/'W core 6 senses the induced current during reading and drives the write current during writing.
It is connected to the read/write circuit section 8.

In addition, the E core 7 has the state of magnetization magnetically written on the disk when writing data. /Wa 7 erases data to a state of no data and supplies an erase current to prevent interference between trunks during reading, and is connected to the erase circuit section 9. As explained earlier, after writing data with n, /W cocoa, 11] Disk with core 7'' 2/1
1. Since the data in the part corresponding to the outer A rule of /W Cocoa is erased, R, /W Cocoa acts on the disk with light, and then 1 Recoa 7 acts on the disk in various arrangements. ing.

As mentioned above, in the case of a magnetic disk drive using a flexible disk, there is no feedbank for tracking control, and it relies solely on mechanical accuracy.

For example, there are 711 called mini phronopetisques52
In the case of a 5-inch flexible disk, it is double-sided and has a trunk density of 481 racks/inch (hereinafter referred to as TP).
It is abbreviated as II. ), and the recording density is very sparse, as is clear from the fact that the distance between the centers of the racks is approximately 0.52 mm, so the storage capacity when unformatted is 4.
There was a drawback that it could only be raised up to 3751 units/disc. One of the major causes is the temperature-induced expansion and contraction of the flexible disk medium (up to 395βn at a temperature difference of 35°C). Some unpowered 525-inch mini floppy disks with a storage capacity of 1 Mbyte/disk have been announced, but these all rely on mechanical programming accuracy and are therefore not reliable. At present, there are problems, and it is said that the limit of mechanical improvements is 1 MB/disk.

Of course, attempts are being made in various places to dramatically increase recording density by changing the old quality of the magnetic film of the medium, i.e., diskette, and changing the direction of magnetization from horizontal to vertical, but it is impossible to change the medium itself. It cannot be used interchangeably in the industrial world because it is not compatible with the diskettes that are currently in wide use.

The purpose of the present invention is to eliminate these drawbacks by using the currently used 8-inch or 525-inch flexible disk media as is, and to increase the storage capacity by nearly an order of magnitude compared to the current state. It employs a tracking method to track the data collected, forming a kind of closed loop, and will be explained in detail below.

FIG. 2 is a block diagram showing an embodiment of the present invention, 1
0 is a differential amplifier for reading a separate signal from the R/W core 6, 11 is an average value circuit consisting of an absolute value amplifier and a low-pass filter to average the read data peak value, and 12 is a peak hold circuit and level. A position discriminator consisting of a comparator circuit detects the position of the read head from the average value of read data; 13 a correction direction discriminator consisting of a sample hold circuit and a level comparator circuit; 14 a correction direction discriminator discriminating the head position correction direction; Movement command detector for determining position correction control timing, 1
Reference numeral 5 denotes a correction drive control circuit for creating and outputting a position correction drive command based on data from the position discriminator 12, correction direction discriminator 13, and movement command detector 14. Numbers 1 to 9 in Fig. 2 are the same as those in Fig. 1, and their functions are also almost the same, so the operation will be explained focusing on the newly added parts according to the present invention. do. Furthermore, although the present invention can be applied to general magnetic disk devices using flexible disks, the explanation will be given by taking a mini floppy disk device (hereinafter referred to as a mini floppy disk device) using a 525-inch flexible disk as an example. Proceed. Mini ii"'f) 11) In general, in the device, 10 copies of antibacterial signals, addresses, and recorded data are written into the medium in a process called formatting, but regarding this formatting, Which function is performed by the same function as the conventional circuit shown in FIG. Therefore,
The diskette expands and contracts depending on the temperature at which data is written, but the absolute position of the written data differs depending on the state of expansion and contraction at that temperature.

When writing data to a location on a flexible disk that has been matted as described above,
) In device D, the cylinder number is given to signal line 1 as a movement command and input to CD'L2.

CDI,2 determines whether to move the carriage toward the center or toward the outer edge depending on which cylinder number the head section 5 is currently on, and provides a signal to M'l)3. 0M4 is driven by MD3 to move the cartridge to a point that is thought to be the location of the cylinder number, and read the address mark of that cylinder. The address mark "-2" records the cylinder number, head number, record number, and record length. If a match is made with the record length, the desired recording data is written in the following data section, but if a match is not made, the gear IJ nozzle is driven again to move the gear ridge to the cylinder whose cylinder number matches. Afterwards, the recorded data is written.The same applies to the reading of the recorded data.Generally, when writing or reading recorded data, it is necessary to It is always necessary to read the address mark of that cylinder.

Now, the read signal read out from the R,/W head 6 is supplied to the read/write circuit section 8, and at the same time is guided to a separately provided differential amplifier 10, where the read signal is amplified and then supplied to the average value circuit 11. Ru. Here, the absolute value of the read signal, which is an alternating current signal, is taken and the average value of the read signal is determined by passing it through a low-pass filter. FIG. 3 shows signal waveforms of each main part during head positioning. 3(a) shows the output waveform of the differential amplifier 10, and FIG. 3(1)) does not show the output waveform of the average value circuit 11.

Here, when the head is completely aligned with the desired trunk, it corresponds to the maximum value of the waveform shown in FIG. 3 (1)), and when the head is located between the track and the trunk, it corresponds to the maximum value of the waveform shown in FIG.
Corresponds to the minimum value of the waveform shown in 1)).

The output of this average value circuit 11 is supplied to a position discriminator 12 and a correction direction discriminator 13, and the position discriminator 12 uses the average value output signal as a head position signal, and uses a peak hold circuit and a correction direction discriminator 13, which will be described later. It consists of a reference level comparator circuit, which generates a pulse output as shown in FIG. 3(C), and supplies this to the correction drive control circuit 15. This correction drive control circuit 15 drives the correction drive command 0M4 via M'l)3 when the pulse output is not present, and does not output the correction drive command when the pulse output is present. It is composed of L. Furthermore, the presence or absence of a movement command is detected by monitoring the cycle of the movement command with the movement command detector 14 so that the corrected drive command does not overlap with the original movement command, and when there is an original movement command and in the write mode. In this case, the correction drive control circuit 15 is instructed to prohibit the output of the correction drive command. Further, the output of the correction drive control circuit 15 is also connected to a correction direction discriminator 13, and the correction direction discriminator 13 uses the average [
The output signal of the direct circuit 11 is sequentially sampled by a sample hold circuit and its level is held.
A level comparator circuit compares the level sampled and held according to the previous correction drive command and the current level at the sample timing according to the correction drive command (7'J), and the direction of the correction drive command is determined. An example of the output waveform of the correction direction discriminator 13 when the head is continuously moved is shown in FIG. Output signal: The correction drive control circuit 15 operates to position the head at the nearest track center while checking the correction direction each time it outputs a correction drive command.

Note that Ml) 3 in the above embodiment is realized by adding a current detection circuit etc. to a general pulse motor drive circuit and performing minute drive control between steps using a conventional vernier drive method. I will omit the explanation as it will be easily understood by engineers in this field. Furthermore, since the data recording density is naturally different between tracks toward the center and toward the outer edge of the flexible disk, the peak value of read data will be different between the inner and outer sides of the flexible disk. If the reference level of the position discriminator 12 is constant, the pulse width of the output pulse changes, causing an error in the position data.
By counting the output pulses of the position discriminator 12 in advance in the correction drive control circuit 15, the reference level for detecting the track position from the peak sense circuit of the position discriminator 12 from one half of the flexible disk is corrected. It is also possible to control the pulse width to be constant by taking into account the following.

As described above, according to the above embodiment, in step 11, after the head unit gear ridge movement command is output and the gear ridge is positioned in the specified vicinity, the cylinder address mark section on the flexible disk is read, and further, in the case of read mode. is detected by the movement command detector 14 when desired recorded data following the cylinder address mark is being read.
Detects that the original 1-h movement order is no longer present. When the output of the correction drive control circuit 15 is enabled and the output of the position discriminator I2 is in the "0" state as shown in FIG. 3(C). The correction drive control circuit 15 determines that the head is moving away from the desired trunk on the flexible disk and outputs a correction drive command.Thereby, the correction drive control circuit 15 determines whether the correction drive direction is a direction approaching the desired trunk. It is detected by the output of the direction discriminator 13, and if the result is a certain direction, a correction drive command in the opposite direction is further output from the correction drive side i1 circuit 15.In addition, the output of the position discriminator 12 is When the state is "1" in FIG. 3(C), it is assumed that the head has not deviated from the desired track, and the correction drive command is not output. Note that in order to uniquely determine the initial direction of the correction direction, the correction direction discriminator 13 does not only use the correction drive command (even the original drive command also samples the position signal level from the average value circuit 11). Hold '1'' and move.

As mentioned above, when correcting the head position of the Mini I"'r)1'), etc., the position feed bank of the head position is always applied while reading the cylinder address mark or recorded data of the flexible disk, resulting in a kind of closed loop. This enables highly accurate positioning.

Although the above embodiment has been described with respect to a so-called mini Ti''DD using a 525-inch flexible disk, this is of course not limited to 5.25-inch (it can also be used for an FDD using an 8-inch flexible disk).

Furthermore, in the above embodiment, the gear ridge motor (CM) 4 is rotated and the head gear ridge is driven via a lead screw or the like.
) 4 is not a rotary motor but a linear motor, the present invention can be applied without any problem. Note that the output of the position discriminator 12, which acts as a position detector, is 5'l/min of the peak hold circuit of the signal from the average value circuit 11.
Be influenced by Noh.

Therefore, if a stable peak value cannot be obtained as shown in Fig. 3 (1)), an accurate trunk position cannot be obtained as a result, and to avoid this, the correction drive command is alternately applied in both directions around the peak value After the correction drive control circuit 15 vibrates the carriage motor in a relatively large movement range, stable position detection is performed by stopping the correction drive at the center, and at the same time, a pulse motor is applied to the carriage motor. When used, by vibrating the motor, it becomes possible to eliminate variations in positioning accuracy due to the 7-reaction torque of the head drive mechanism.

As explained above, the trunk density is determined in order to use basic information to track the track trajectory and position the rad carriage. It is possible to dramatically increase the capacity from /18TP1 (at this time, the storage capacity is 437.5"z < 16 sectors/track on a disk/disc).

Another major feature of the method of the present invention is that it does not require positioning servo information. In other words, in the case of the dedicate node servo method used in 8-inch fixed disks, positioning servo information is written on one side of the disk surface in advance to control the magnetic head, but this method requires an expensive interface. This makes it very similar to floppy disk devices. Also, in the case of the embedded servo system, which is a type of 8-inch fixed disk, servo information is incorporated between data information,
Since this method differs from the standard data format for floppy disk drives, there are no more than 11 data.

The purpose of the present invention is to provide a floppy disk device with the highest recording density of 1".The purpose of the present invention is to dramatically increase the track density. If this technology is applied to existing equipment, it will be possible to dramatically increase reliability.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a head drive system of a conventional PDD, Fig. 2 is a block diagram showing an embodiment of the present invention, and Fig. 3 is an essential diagram for explaining the operation of the embodiment of Fig. 2. It is a partial key signature waveform diagram. 1... Gear ridge movement command human power 1 gland, 2... Carriage drive logic circuit section, 3... Gear ridge motor driver, 4... Carriage motor, 5... Belly button F section, 6... Lead・Write core, 7... Erase core, 8... Read/write circuit section, 9... Erase circuit section, 10... Differential amplifier, 11... Average value circuit, 12... Position discrimination 13... Correction direction discriminator, 14... Movement command detector, 15... Correction drive control circuit. Patent applicant: Oki Electric Co., Ltd. Patent application agent: Megumi Yamamoto, patent attorney

Claims (1)

[Claims] A carriage drive logic circuit section that analyzes movement commands from the outside, a gear ridge motor driver section connected to the output thereof, a gear ridge motor driven by the output of the first cough driver section, and a Jl mounted on the carriage section. In a dragging method for a flexible magnetic disk device having a head section including a read/write core and an nose core, and a read/write circuit that reads data from the read/write core, data prerecorded on a disk is used. An average value circuit extracts read output from the read/write head via a differential amplifier circuit, a position discriminator that discriminates the position of the head according to the output of the average value circuit, and a correction that discriminates the correction movement direction of the head. (1) Performing a correction movement on the carriage motor driver during a period in which there is no movement command from the outside according to the outputs of the direction discriminator, the position discriminator, and the correction direction discriminator.
1. A method for dragging a flexible magnetic disk device, comprising: a correction drive control circuit that issues an Ann command; and performing head dragging in a closed loop manner.