JPH0616346B2 - Magnetic recording medium - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording medium, and particularly to determining whether or not a magnetic recording medium on which data is recorded is a duplicate product. The present invention relates to a magnetic recording medium that can be used.

(Prior Art) With the widespread use of personal computers, word processors, and the like in recent years, various kinds of software have been recorded on magnetic recording media and are distributed throughout society.

As well known, there are various types of magnetic recording media such as a magnetic drum, a magnetic tape, and a magnetic flexible disk cartridge. Above all, the magnetic flexible disk cartridge (hereinafter referred to as floppy disk)
Has been used more and more because it has many advantages such as easy handling, fast data transfer rate, and low cost.

The method of recording on a floppy disk will be briefly described below.

FIG. 1 is a schematic view showing the recording surface of a floppy disk.

In the figure, a plurality of tracks 40 are concentrically formed on the recording surface of a floppy disk. Each track 40 has a plurality of sectors (1 to N) as shown in the figure.
Is divided into

FIG. 2 is a schematic diagram showing an example of the format of one track shown in FIG. In the figure, the same reference numerals as those in FIG. 1 represent the same or equivalent parts.

In FIG. 2, the starting point of the track is the index 30.
Indicated by. Each sector of the track is composed of an ID field part, a data field part, and a gap.

That is, for example, sector 1 has ID field portion 1
1, a front gap 5A, a data field portion 21, and a rear gap 5B arranged between the data field portion 21 and the ID field portion 12 of the sector 2.

Also, a gap 5 is arranged between the index 30 and the ID field portion 11.

By the way, LSi for a proppy disk controller (FDC) used in a general personal computer or the like.
(For example, NEC μPD765A, Fujitsu MB88
76) firstly records only the ID field part in each sector of the track, and then records the data field part.

Therefore, when recording the data field portion, a phase shift occurs at the start point 8 and the end point 9, that is, the splicing point, of the data field portion due to uneven rotation of the floppy disk.

However, since the normal read command sends only the read information of the data field portion to the host computer, the information of the data field portion can be accurately read even if the phase shift occurs at the junction point.

(Problems to be Solved by the Invention) The above-described conventional technique has the following problems.

As described above, in the general floppy disk controller, even if the phase shift occurs at the start point and the end point of the data field portion, the information in the data field portion can be accurately read. If the information can be read from the floppy disk, the information can be stored in another floppy disk, that is, duplicated.

However, the duplication of software by the user is not preferable for the manufacturer who records the software on a floppy disk and sells it because it causes the sales of the floppy disk to be suppressed or reduced.

In addition, there is a risk that the data field part of the floppy disk (hereinafter referred to as the “original”), which is sold by the manufacturer and stores the software, may be rewritten by the user. There is also a concern that the credibility of the maker will be seriously damaged if it is rented.

The present invention has been made to solve the above problems.

(Means and Actions for Solving Problems) In order to solve the above problems, according to the present invention, an ID field portion and a data field portion are continuously recorded on an original magnetic recording medium. And a program that specifies reading of data in the area of the magnetic recording medium where the data is first read so that the ID field and the data field are read continuously.
By taking a means of recording a program for detecting the phase shift at the junction of the data field section, it is possible to determine that the magnetic recording medium is a duplicate product when the phase shift is detected. It is characterized in that it has produced the effect.

Furthermore, after the program for detecting the phase shift at the junction point of the data field portion, when a phase shift is detected, a means for recording a program for prohibiting reading of the magnetic recording medium is also taken. When the medium is a duplicate, its use is prohibited, and it has a feature that it has an effect that it is possible to substantially prevent the duplication of the original.

(Example) Below, this invention is demonstrated in detail.

In the present invention, it is premised that the information writing in the ID field portion and the data field portion of the original floppy disk is continuously performed for each sector. The writing can be performed by using, for example, a 475 type initializer manufactured by ADC (Applied Data Communications).

If the ID field portion and the data field portion are continuously written, naturally, there is no phase shift at the start point and the end point of the data field portion.

When the user creates a duplicate based on the original thus created or when the original is rewritten, as described above, the ID field part and the data field part are recorded separately. The rotation speed of the floppy disk at the time of rewriting or copying is slightly different, but it is different from the rotation speed of the floppy disk at the time of creating the original, so that the start and end points of the data field portion of the copied floppy disk are , A phase shift occurs. Further, the phase shift also occurs due to uneven rotation of the floppy disk.

Now, as described above, it is impossible to detect the presence or absence of the phase shift at the joining point by the normal read command of the proppy disk.

However, Read Diagnos
tic) command or Read Track
Since all the information in the gap part, the ID field part, and the data field part after the data field part of the sector immediately after the index signal can be continuously read by the instruction, there is a gap between the data field part and the gap part. If there is a phase shift, the phase shift can be detected.

That is, since a bit shift occurs in the read data after the joining due to the phase shift of the joining point at the start point and the end point of the data field portion, it is possible to detect whether or not the bit shift occurs during the data reading. It is possible to determine whether the floppy disk is an original or a duplicate, or whether the data content of the original is rewritten.

Here, a method of copying a floppy disk by a general personal computer and the phase shift of the joining point in this case will be described.

FIG. 3 is a schematic diagram showing the data arrangement and format of sector 1. FIG. 3A is a data array diagram of sector 1, which is similar to the lower part of FIG. 2, and FIG. 3B is a diagram showing the format of sector 1.

For convenience of explanation, it is assumed that the data writing to the floppy disk is done in the IBM format. Even if the format format changes, the essence of the phase shift detection according to the present invention does not change.

When copying a floppy disk with a general personal computer or the like, first, ID information is written to a blank floppy disk by a format command. At this time, non-meaningful information is written in the portions other than the ID field portion 11 instead of being blank. That is, in the gap portions 5A and 5B, 4E in hexadecimal notation,
Data of 01001110 in binary notation is written in the data field portion 21, for example, data of 40 in hexadecimal notation and 01000000 in binary notation is written.

At this point, the front gap 5A, the data field portion 2
Since data is continuously written in 1 and the rear gap 5B, no phase shift occurs in the data in the splicing portions A and B at the front and rear ends of the data field portion 21. In other words, no mismatch occurs between the two signals of the data 40 in the data field portion 21 and the data 4E in the front gap 5A and the rear gap 5B.

Next, the data copy operation of the floppy disk (hereinafter referred to as the mother disk) in which the software program to be copied is recorded is started on the formatted floppy disk (hereinafter referred to as the child disk). This mother disk may be a primary-copy soft disk made by a copy company having a legitimate authority, or an illegally-made secondary copy soft disk.

In this copy operation, the data in the ID field portion and the gap portion, which are unnecessary as software data, is not transferred, but only the data in the data field portion is transferred. That is, referring to FIG. 3B, the data in the data field portion of the mother disk is recorded between the splicing portions A and B of the child disk.

If the driver for driving the floppy disk does not have uneven rotation or change in rotational speed during the data transfer of the data field portion, as shown in FIG. 4, the data in the data field portion of the mother disk is the child disk. The recording is started from the splicing portion A (that is, the break between the 4E signal and the 40 signal), and the recording is ended at the splicing portion B.

However, since the floppy disk driver generally has uneven rotation and uneven rotation speed, the data copy of the data field portion does not always start from the break between the 4E signal and the 40 signal. That is,
When the driver rotates slowly, as shown in FIG. 5, the data copying of the data field portion is started before the splicing portion A (portion A ′), and
When the driver rotates quickly, as shown in Fig. 6, it starts after the splicing A (part A "). In this case, the end of the data copy also precedes the splicing part B (part B). It shifts to ′) or to the rear (part B ″).

That is, at the time of copying the mother disk, there may be a discontinuity of signal (phase shift) at the splicing portion, which was not present before the copying.

When the child disk thus copied is read by a normal read command, the inconsistency in the splicing portion is skipped as it has no influence on the data itself. However, if read by the read diagnostic command, data that should originally be 4E is detected as different data at the rear end of the front gap 5A and the front end of the rear gap 5B. In the present invention, the mismatch signal break in the splicing portion is detected,
It is determined whether or not the disc whose reading has started is a duplicate.

Here, the mismatch occurring in the splicing portion B between the data field portion 21 and the rear gap 5B will be described in more detail.

FIG. 7 is a detailed diagram of data in the splicing portion between the data field portion 21 and the rear gap 5B before copying. In FIG. 7, the data is shown in both binary and hexadecimal representations.

As shown in FIG. 7, before copying, the data at the rear end of the data field portion 21 is 40 (hexadecimal notation), and the data at the front end of the rear gap 5B is 4E (16). Hexadecimal expression). That is, no mismatch has occurred in the splicing portion B.

On the other hand, when the driver of the floppy disk rotates slowly, the splicing portion at the rear end of the data field portion 21 is, as described with reference to FIG. It shifts before B. If this deviation is, for example, 1 bit, when a floppy disk copied in this way is read by the read diagnostic command,
As shown in FIG. 8, since the last bit 0 of the data recorded in the data field portion 21 before copying is added before the data 4E (hexadecimal notation) recorded in the rear gap 5B. After that, the data of the gap 5B is 2
Hexadecimal expression 00100111, that is, Hexadecimal expression 27
Is read as.

Also, if the floppy disk driver rotates quickly,
As described above with reference to FIG. 6, the data field portion 2
The splicing portion at the trailing end of 1 shifts later than the splicing portion B before copying, as indicated by the symbol B ″. If this shift is, for example, 1 bit, the floppy disk thus copied. Is read by the read diagnostic instruction, the frontmost bit of the data 4E (hexadecimal notation) recorded in the rear gap 5B is lost, as shown in FIG. The data is 1001 in binary
Read as 1100, or 9C in hexadecimal representation.

Next, when the data shift in the splicing portion is 0.
Consider the case of 5 bits.

FIG. 10 is a diagram in which bit patterns are also shown in FIG.

As shown in FIG. 10, the bit pattern is "1".
Data bit and a clock bit between "0" and "0".

If the splicing portion B is shifted 0.5 bits forward, the data bits are read as clock bits and the clock bits are read as data bits, as shown in FIG. Therefore, before copying, the rear gap 5B
The data recorded in 4E (hexadecimal notation) is 1
90 in hexadecimal notation (ie 1001000 in binary notation)
It is misread as 0). Similarly, when the splicing portion B is shifted by 0.5 bit later, the data 4E (hexadecimal notation) recorded in the rear gap 5B before copying is represented in hexadecimal notation as shown in FIG. At 21
(That is, the binary representation is 00100001).

In this way, by detecting the data in the rear gap 5B and determining whether or not the data is 4E, it is determined whether the floppy disk is the primary copy or the secondary copy. That is, it is possible to easily determine whether it is a legal product or an illegal product.

Of course, it is also possible to detect whether or not the magnetic recording medium is a duplicate by detecting the data at the rear end of the front gap 5A and determining whether or not the data is 4E.

According to the present invention, an ID field portion and a data field portion are continuously recorded on a floppy disk, and data is read from the floppy disk in the area where the data is first read. A program for designating continuous reading of the ID field part and the data field part, such as a diagnostic command, and the data read in this way detects the phase shift at the junction point of the data field part. A program for detecting whether or not the data of the rear gap 5B is 4E in hexadecimal notation is recorded.

By configuring the magnetic recording medium in this way, it is possible to determine whether or not the magnetic recording medium is a duplicate when reading data from the magnetic recording medium.

Even if the floppy disk is a copy made from the original, or the data content of the original is rewritten, the probability that there is no phase shift at the start and end points of the data field is usually. Since data writing is recorded in bits serially, if 1 byte = 8 bits, 1 sector is 1/8.

Therefore, if the phase shift is checked for only one sector, it is 1/8 that a duplicate or a rewritten data is erroneously judged as the original.

The probability is 1/64 if the phase shift is checked for 2 sectors and 1 / if it is checked for 3 sectors.
If the number of sectors to be checked is increased, as in 512, ..., The number will be correspondingly decreased, and it is possible to determine with high accuracy whether or not the floppy disk is a duplicate.

In this way, whether the floppy disk is the original,
If it is possible to determine whether it is a duplicate or the original data has been rewritten, even if the original floppy disk is copied or the original data is rewritten, the use of the floppy disk is prohibited. It can be impossible.

In other words, if the phase shift is detected, the program in which the information in the data field portion of the floppy disk cannot be read, in other words, the program in which the application program does not work, If it is recorded after the program for detecting the phase shift at the junction point, the use of the floppy disk can be disabled, and the duplication and rewriting of the floppy disk can be substantially prohibited.

(Effects of the Invention) As is clear from the above description, according to the present invention, the following effects are achieved.

(1) An ID field portion and a data field portion are continuously recorded on the original magnetic recording medium, and the data is read at the portion of the magnetic recording medium where the data is first read. , A program for designating continuous reading of the ID field portion and the data field portion, and a program for detecting a phase shift at the junction point of the data field portion are recorded. It is possible to discriminate whether it is the original, the duplicate, or the data field part is rewritten.

(2) Also, after the program for detecting the phase shift at the junction of the data field portion, a program for prohibiting reading of the magnetic recording medium is recorded when the phase shift is detected. Therefore, when the magnetic recording medium is a duplicate, the information in the data field portion of the magnetic recording medium cannot be read.

This makes it impossible to use a magnetic recording medium other than the original, and substantially prevents duplication of the magnetic recording medium and rewriting of the data field portion.

(3) Since the information in the data field portion of the duplicate magnetic recording medium is not read, it is not possible to create a duplicate from the duplicate. Therefore, not only the copy of the original but also the distribution and distribution of the duplicate can be prevented.

[Brief description of drawings]

FIG. 1 is a schematic plan view showing a data recording surface of a floppy disk, FIG. 2 is a schematic view showing an example of a format of one track shown in FIG. 1, and FIGS. 3 to 12 are phases in a splicing portion. It is a figure for explaining gap. 1 to N ... Sector, 5 ... Gap, 5A ... Front gap, 5B ... Rear gap, 8 ... Start point, 9 ... End point, 11, 12 ... ID field part, 21 ... Data field Part, 40 ... Truck, A, A ', A ",
B, B ', B "... Splicing part

Claims (2)

[Claims] 1. A magnetic recording medium in which an ID field portion and a data field portion are continuously recorded, wherein an ID field portion and a data field portion are provided in a portion of the magnetic recording medium where data is first read. A magnetic recording medium having an area in which information for continuously reading is recorded and an area in which information for detecting a phase shift at the junction of the data field portion is recorded. 2. An ID field part and a data field part are magnetic recording media in which recording is performed continuously, and the ID field part and the data field part are provided in a part of the magnetic recording medium where data is first read. Area in which information indicating that the phase is continuously read is recorded, an area in which information indicating that a phase shift at the junction point of the data field portion is detected is recorded, and when the phase shift is detected, the magnetic field A magnetic recording medium, comprising: an area in which information for prohibiting reading of the recording medium is recorded.