JPH0524561B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for ensuring information compatibility with storage media having different track densities in a flexible disk device for information storage.

A flexible disk device is a small and convenient rotating magnetic recording information storage device having the schematic structure shown in Fig. 1.The storage medium is a removable and replaceable flexible disk cartridge, that is, a magnetic recording medium is placed in a polyester plastic film. A disk 1 to which a metal oxide is attached is housed in a rectangular jacket 2.

Flexible disk 1 in the jacket is DC
It is rotated at a constant speed by a motor 3 and a spindle 4.

There is one magnetic head 7 for the single-sided type, and two for the double-sided type.
The disk 1 faces the disk 1 and is in contact with the disk 1 during operation. A carriage 8 holding the head 7 is moved on a guide rod 9 in the diametrical direction of the disk, and the head is positioned by a step motor 5 via, for example, a steel belt mechanism 6 as shown in FIG.

In FIG. 1, reference numeral 10 denotes a medium identification detector, and its role in the prior art and the present invention will be described later. 11 is the rotation speed detector of the DC motor 3;
12 is the DC motor 3, step motor 5, head 7, medium identification detector 10, and rotation speed detector 11.
The peripheral circuits that exchange and process data and control signals between the devices include various circuits such as those shown in FIG. 2, for example.

The basic roles of each circuit and each component not labeled with reference numerals in FIG. 2 are well known to those skilled in the art, and there are only a few parts that are directly related to this invention. The explanation will be omitted here, and will be mentioned if necessary in the following explanation.

Now, in recent years, advances in magnetic recording technology have been remarkable, and the recording density of information devices such as magnetic disk devices and flexible disk devices has been significantly improved.

As a means of increasing the density, a method of increasing the linear recording density per track and a method of increasing the track density are used. Even in exchange medium-type flexible disk devices used as files, this improvement in track density is rapid, and compared to the conventional one in small machines.
The number of tracks per inch (hereinafter referred to as TPI) is
48TPI used to be the standard, but last year 96TPI was increasing, and this trend is increasing.

Now, one problem here is that when the track density changes, the entire device changes, and it is difficult to reuse media recorded on a new 96 TPI device to be played back or recorded on a conventional 48 TPI device. Currently, they are used only in each device. If media recorded by a 48 TPI device and a 96 TPI device can be mutually recorded and reproduced, there will be great economic benefits. This invention solves this problem.

Here, conventional techniques related to increasing the density of flexible disk devices will be described.

Conventionally, when increasing the density of flexible disks, there have been cases where differences in magnetic properties such as coercive force and coating thickness of recording media are differentiated. This is done by providing a notch at a specific position on the jacket to detect data errors when using high-density media in conventional equipment, or conversely by using normal media in high-density equipment. It is something. The first device configuration is
A medium characteristic identification detector 10 is provided as shown in the figure, and this information is transmitted to a medium identification circuit 101 shown in FIG.
By notifying the host computer via the signal connector 13, writing or reading operations are prohibited in the event of misuse.

In addition, the same 96TPI device can be used for both high-density media and regular media, and in the case of regular media, restrictions such as not using the inner track where the linear recording density is high, and write currents that match the differences in media characteristics. There have also been reports of cases in which switching is performed.

However, it has not been seen in the past that these identification signals are used to switch the track density. FIG. 2 shows a conventional example particularly adapted to high density, and the devices widely used in the past do not particularly have a medium identification detector.

Regarding compatibility with devices or media having different track widths, conventionally it has been possible for a 96 TPI device to read 48 TPI information written at the same media characteristics, that is, the same linear recording density.
This is because the center position of the 48 TPI track is made to coincide with the center position of the even numbered track of 96 TPI.

However, information written by a 96TPI device
Previously, it was impossible to read with a 48TPI device. This means that even if information is written at 96 TPI only on even-numbered tracks, various noises such as old information on odd-numbered tracks can be removed using a wide head of 48 TPI, even though the effective information track width is 1/2. This is because the signal is read and becomes interfering noise, lowering the signal-to-noise ratio.

In other words, in the prior art, it was possible to read a disc recorded at 48 TPI with a 96 TPI device, but it was impossible to read a disc written on a 96 TPI device with a 48 TPI device.
The media were not compatible with each other for writing in the precise sense.

This invention was made in order to eliminate the drawbacks of the conventional flexible disk device as described above, and is housed in a large number of disks manufactured by the conventional flexible disk device in a system such as a small computer. The purpose is to make use of a large amount of software assets and continue to use them for reading and rewriting in the new system.

This invention proposes the following means for rewriting an ordinary 48 TPI disk in a new 96 TPI large capacity device in a form readable by a conventional 48 TPI device.

First of all, it is necessary to use a new magnetic head that is compatible with, for example, 48 TPI recorded information being readable by 96 TPI, and 96 TPI recorded information being readable by 48 TPI conventional equipment.

Second, a means is provided to identify the recording track density of the flexible disk being used.
This means may be provided inside the device, such as by the shape of the jacket.

The third feature is to have means for electrically switching the effective recording track width of the magnetic head when rewriting onto the disk based on the track density signal identified above. Here, it is assumed that the effective recording track width includes the erasure bandwidth normally used in flexible-task devices.

Fourth, the track density signal identified above is transmitted to the host computer in some way and is used to switch the number of tracks available to the host computer.

Although the requirements of the present invention are satisfied as described above, the following conditions may be added as necessary.

In other words, fifthly, the TPI whose movement amount for head positioning is identified by the above-mentioned track density identification signal.
The drive shall have a means for switching according to the

Sixthly, the recording current or the electrical characteristics of the readout circuit can be switched using the track density identification signal. This is especially necessary when the linear recording density of the high capacity medium and the conventional medium is different, or when the magnetic properties of the medium are different.

Seventhly, if the disks with different track densities have different data transfer frequencies due to the difference in recording density, the transfer frequency of a controller such as a host computer is determined by the track density identification signal.
The synchronous circuit center frequency of the data demodulation circuit is also switched.

Furthermore, as an eighth feature, the number of revolutions of the disk may be switched based on the track density identification signal. This allows disks with different linear recording densities to be recorded and played back at the same transfer frequency, and it is also possible to select the optimum rotation speed for each disk.

Next, one embodiment of the present invention will be described.

FIG. 3 is a block diagram of a flexible disk device according to the present invention.

In this case, the medium identification detector 10 uses an optical sensor to distinguish the shape of the jacket 2 of the flexible disk shown in FIG. This indicates a disk with a density version, for example 96 TPI. This detection can also be done by microswitches or other methods.

Detected by this detector 10, medium identification circuit 10
The electrical signal indicating the high track density identified in 1 is sent to the disk controller in the host computer via the signal connector 13, and is also sent to the erase head current as shown by the thick solid line in Figure 3. The signal is supplied to a drive circuit 71, a recording/reproducing circuit 72, a step motor drive circuit 51, and the like.

The magnetic head 7 used in the conventional device has the magnetic pole structure shown in FIG. 4, but in this embodiment, it has the magnetic pole structure shown in FIG. 5 as an example. In FIGS. 4 and 5, 21 is a recording/reproducing head core, 22 is a recording/reproducing gap, 23 is an erasing head core, and 24 is an erasing gap. In the head of this embodiment shown in FIG. 5, the erase head core and gap are each divided into two parts 23a, 23b and 24a, 24b. Note that 25 and 26 are nonmagnetic spacers, and 27 and 28 are slide shoes.

The erase head current drive circuit 71 has the configuration shown in FIG. 6, for example, and the track density switching signal is, for example,
If the signal is "1" at 48TPI, current will flow through both erase A and erase B during recording, and erase gap 24 will be applied.
Both a and 24b are excited to erase the old signal over a wide width corresponding to 48 TPI.

When the track density switching signal is 96 TPI, the current corresponding to erase B is gated so that it does not flow, and the gap 24a corresponding to erase A is gated during recording.
only is energized and a narrow width corresponding to 96 TPI is erased.

Every new recording signal is written in the recording/reproducing gap 22, which has a width optimized for 96 TPI. Therefore, when recording at 48TPI, the width is about half that of when written by a normal 48TPI device, so when reading this signal with a normal 48TPI device, the signal output is about half. However, since the disk that comes into contact with the wide gap 22 of the 48TPI device is widely erased by the aforementioned erase gaps 24a and 24b, no noise component is reproduced in this wide head 21, and the signal-to-noise ratio is The deterioration was only about half, which is within the range that would pose no problem for a normal 48TPI device.
If a track is written without the gap 24b being energized, there will be no problem as long as it is read with this new head, but if it is read with a 48 TPI wide head, the unerased old signals on both sides will become noise components and be superimposed on the signal. The noise-to-noise ratio deteriorates significantly, making it unreadable.

Note that the circuit shown in FIG. 6 includes timers 1, 2, and 3, which are erase current delay circuits for guaranteeing the distance between the recording/reproducing gap and the erasing gap, but the operation of this invention is not clear. The explanation will be omitted since it is not particularly relevant.

By combining the head shown in FIG. 5 and the circuit shown in FIG. 6 as described above, information recorded with the new 96TPI device can be reproduced with the conventional 48TPI device without any problem.

When the head shown in FIG. 5 is used as a 96 TPI device, there is of course no problem since the width of the recording/reproducing gap 22 and the width of the erasing gap 24a are optimized for the track density of 96 TPI. In addition, a disk with a conventional track density writing width of 48 TPI has a recording/reproducing gap 22 of the head shown in Fig. 5.
is placed on an even track of 96 TPI, then 48 TPI
Because it is located near the center of the recording width, stable readout is possible without picking up other signals.

Normally, there is no problem in the recording/reproducing circuit 72 even if the track density is changed, but in this embodiment, when the track density is high, the linear recording density is also doubled by using a special high-density medium. Therefore, it is necessary to set the recording current to match the high-density medium, and to change the bandwidth and other settings of the playback circuit system to suit this, as the data transfer frequency also doubles as the recording density increases. There is.

The step motor drive circuit 51 does not need to do anything in particular as a disk device if the host computer system outputs a feed signal of twice the feed pitch of 96 TPI in the case of 48 TPI based on the high track density medium identification signal. However, if the host computer side wants to control the device in exactly the same manner as a conventional 48 TPI device, in this embodiment the step motor can send two pulses for each track feed pulse.

For example, with the circuit configuration shown in Fig. 7, when 48 TPI is detected, the up-down counter counts two pulses per input step pulse, and the step motor driver is therefore driven two steps at a time. . As a result, if you reset to track 00 at first, it will always stop only at even track positions at 96TPI, and therefore
This almost coincides with the center of the recording track of the 48TPI disk.

In the above embodiment, the explanation was mainly between 96TPI and 48TPI, but in principle, for example, 144TPI
and an integer multiple of track density, such as 48 TPI. In this case, it is possible to correctly read one out of three tracks and provide bidirectional compatibility of written data by wide erasing.

Furthermore, as another embodiment of the present invention, when changing not only the track density but also the linear recording density, a means for switching the rotational speed of the disk based on the track density identification signal, such as a stable rotational speed of a direct drive type DC servo motor, is compared. By changing the voltage by switching the voltage dividing resistor, etc., it is possible to realize a device that can increase the linear recording density without changing the transfer frequency.

As described above, according to the present invention, a magnetic head capable of variable erasing width is used, the erasing width corresponding to the inserted disk is changed by switching the erasing drive circuit, and the necessary circuits are also switched. It can be configured to ensure bidirectional data compatibility in writing and reading for recording systems with two or more types of track widths. Therefore, it is possible to provide a new flexible disk device constituting a new large-capacity computer system that can make use of many software assets stored on the flexible disk in old computer systems.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the structure of a general flexible disk device with emphasis on the parts related to the present invention, FIG. 2 is a block diagram of the configuration of a conventional flexible disk device, and FIG. 3 is an embodiment of the present invention. FIG. 4 shows the magnetic field of the slider surface in contact with the medium of a conventional magnetic head for a flexible disk, and FIG. FIG. 6 is a plan view showing an example of gap arrangement, FIG. 6 is a configuration example of an erasing head drive circuit according to an embodiment of the invention, and FIG. 7 is a configuration example of a step motor drive circuit according to an embodiment of the invention. In the figure, 1 is a flexible disk, 7 is a head,
21 is a recording/reproducing head core, 23a and 23b are erase head cores, and 71 is an erase head drive circuit.

Claims (1)

[Claims] 1. The effective track width at the time of data writing (i.e., the gap width of the recording/reproducing head and the gap width of the recording/reproducing head) corresponding to a plurality of track densities (i.e., recording densities in the diametrical direction of the flexible disk). means for identifying the track density of the flexible disk; and a means for identifying the track density of the flexible disk; A flexible disk device comprising means for switching the effective track width of a magnetic head, and having data compatibility in both directions of data reading and data writing with respect to flexible disks with two or more types of track densities. . 2 To switch the effective track width when writing data,
A recording/reproducing head that is compatible with a high-density track width is used as is, and the effective width of the erasing heads for writing data provided on both sides of the recording/reproducing head is narrow when the track density is high, and when the track density is low. Claims characterized in that this is performed by electrically switching the thickness range of the magnetic core that is excited during erasing so that the effective head width including the erasing head is changed so that the density becomes wider. The flexible disk device according to item 1. 3. The flexible disk device according to claim 1 or 2, wherein the number of steps of the step motor per one pulse of the step input signal for head positioning is switched based on the track density identification signal. 4. Track density is identified by optically or mechanically identifying a notch or hole provided at a specific position of the flexible disk jacket. The flexible disk device according to any one of Item 3. 5. The flexible disk device according to any one of claims 1 to 4, further comprising means for switching the rotation speed of the flexible disk based on a track density identification signal.