JPH10106145A - Disk copy protecting method, disk reading mechanism and disk recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrict a read inhibit range to only a part of the range as well as the whole part by means of a generally popularized write mechanism. SOLUTION: Erroneous data length information on a data to be an access object as different from the actual data length is recorded in a directory record 602 of the disk recording medium where a digital data is recorded in accordance with a prescribed format, while correct data length information which can be recognized only by a specified read mechansim is recorded in a specified recording position. The specified read mechanism is provided with a recognition mechanism for recognizing the specified position where the correct data length information is recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copy protection method and a reading mechanism for a disk storage medium in which digital data is recorded according to a predetermined format, and a disk storage medium.

[0002]

2. Description of the Related Art As a disk storage medium on which digital data is recorded in accordance with a predetermined format, a CD-R on which an application program or a game program used in a personal computer (PC) is recorded.
OM is known.

This CD-ROM contains, for example, ISO-9
Digital data is recorded according to the 660 format. Digital data such as software and document data recorded on the CD-ROM can be freely read by a computer, and the read digital data can be read by a function provided by a computer operating system, such as a hard disk, a floppy disk, or the like. Can be easily copied to another recording medium such as a CD-ROM.

[0004] However, some digital data recorded on a CD-ROM must be prohibited from being copied for copyright protection. In view of this, various copy protection methods have been proposed in which reading is prohibited for a portion for which copying is to be prohibited, reading is disabled only when a specific condition is satisfied, and consequently copying is not possible.

For example, in JP-A-7-220321, an optical reproduction area and a magnetic recording / reproduction area are provided on a CD-ROM, and in JP-A-7-235130, A recording medium for providing a digitally unreadable error area to prevent duplication and a method for realizing a reproducing apparatus therefor are disclosed.

[0006]

However, in the conventional copy protection method disclosed in the above publication, since the physical format of the recording medium itself is special, it is widely used. However, there is a problem that it is difficult to create an original CD-ROM by a writing mechanism.

[0007] CD-RO such as game software
In many cases, the value of most digital data recorded in M cannot be determined without actually using it. For this reason, free trial versions of some features are widely distributed. However, in the above-described conventional copy protection method, the entire CD-ROM cannot be read,
In order to provide the user with the trial version, there is also a problem that it is necessary to newly create a CD-ROM dedicated to the purpose of the trial version.

Further, the same one CD-ROM is inserted into a CD
-There is also a demand to be able to be used by both a dedicated machine that can be booted from a ROM and a normal personal computer. In this case, the CD-ROM contains, in addition to the application program to be executed, the boot needed by the dedicated machine. The mechanism and OS must be included. However, from the viewpoint of a normal personal computer, such a CD
-The boot mechanism and the OS stored in the ROM are not only unnecessary, but the access should be prohibited from the viewpoint of copyright protection, and the personal computer must be configured to be able to read only application programs. Must. However, in the conventional copy protection method, there is a problem that it is not possible to satisfy the requirement that only the boot mechanism and the OS are inaccessible and the application programs are accessible.

That is, only a part of the digital data recorded on the CD-ROM can be accessed,
Alternatively, there is a problem that it is not possible to make only a part inaccessible.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and an object of the present invention is to easily create an original copy of a disk storage medium that cannot be duplicated by a widely used writing mechanism. It is another object of the present invention to provide a copy protection method and a reading mechanism for a disk storage medium, and a disk recording medium, in which a read prohibition range can be limited to a part of the disk storage medium as well as the whole.

[0011]

In order to achieve the above object, the present invention provides a method for recording erroneous data length information in a directory record according to a predetermined format, and for recording a disc recording medium at a specific location in a data area. In this example, index information of digital data to be recorded is recorded.

In addition, the disk recording medium has a function of accessing correct data length information recorded at a specific location.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings.

An OS (operating system)
An embodiment of the present invention assuming a PC-DOS (hereinafter referred to as DOS) as an example and an AT compatible machine (hereinafter referred to as a PC) as hardware will be described as an example.

The CD-ROM to which the present invention is applied stores, for example, an OS and a boot mechanism using a special-purpose machine satisfying specific conditions, and application programs such as game software. The present invention enables a dedicated machine to access the entire recorded contents including an OS and a boot mechanism in addition to an application program.
In the case of C, reading of only the application program (or a part thereof) is permitted, and the OS and the boot mechanism are used without being able to read.

Therefore, in the special-purpose machine, the operating procedure is to read the OS and the boot mechanism from the CD-ROM, and then to read the application program. In the PC, the OS is in the hard disk. After reading from the hardware disk, the operation procedure is to read the application program from the CD-ROM.

Therefore, a CD-ROM to which the present invention is applied
In a PC equipped with, the OS and the boot mechanism in the CD-ROM cannot be accessed, and in the dedicated machine, the OS and the boot mechanism in the CD-ROM can be accessed. Specifically, in a dedicated machine, a hard disk access request is
After providing a mechanism to convert to a ROM access request,
The OS and the boot mechanism in the D-ROM are accessed so that the application program can be read according to the correct data length information in the directory.

FIG. 1 is an explanatory diagram showing a mechanism in which an access request for a hard disk is converted into an access to a CD-ROM.

In FIG. 1, reference numeral 101 denotes a BIOS (Bas).
ic Input Output System). The BIOS 101 initializes hardware when power is turned on, and performs basic input / output, for example, hard disk access.

Reference numeral 102 denotes a hard disk access request issued from the BIOS 101. Specifically, “in”
This is a vector interrupt called "t13h" 103. When this vector interrupt “int 13h” 103 is issued,
The handler at the address described here is executed.

Reference numeral 104 denotes a vector interrupt "int 13h" 1 when a normal hard disk access is performed.
03 means that a pointer to the normal hard disk access routine 105 is set. 106
Is a hard disk accessed by the hard disk access routine 105.

107 is a hard disk access CD
When converted to a ROM access, this means that a pointer to the CD-ROM loader 108, which is a mechanism for accessing the CD-ROM 109, is set in the vector interrupt "int 13h" 103. This CD-RO
The internal configuration of the M loader 108 will be described later. To be precise, the pointer 107 points to the CD-
This is a handler routine in the ROM loader 108.

When the BIOS 101 issues a hard disk access request 102, the data is converted into an access to the CD-ROM 109 by the pointer 107.
From the perspective of the OS 101, it looks the same as accessing the hard disk 106.

Therefore, a software program using the hard disk access mechanism of the BIOS 101 can be operated on a CD-ROM basis without any modification for accessing the CD-ROM 109.
In other words, without modifying the program, DOS can be
It can be started from M109. DOS is CD-R
The flow from OM 109 to activation will be described later.

FIG. 2 shows the contents of the CD-ROM 109 accessed by the CD-ROM loader 108.

The CD-ROM 109 itself is an ISO-96
Digital data is recorded in a format specified in 60, and an image file 202 and a normal file or directory 203 are recorded under a root directory 201.

Normal file or directory 203
Is a normal file or directory that can be accessed by a mechanism provided as a standard by DOS, and records application programs and the like.

An image file 202 records an image of the hard disk 106 on which DOS is installed (the same recording data as the recording data of the hard disk). From the standard access mechanism of DOS, the image file 202 is a CD in ISO-9660 format.
-Seen as one file in ROM 109. The image file 202 contains a normal hard disk 1
As in 06, data such as the master boot sector 204, the boot sector 205, and the file system 206 are recorded.

The file system 206 stores the FAT (Fi
le Allocation Table), root directory entry, subdirectory entry, and file information. The CD-ROM loader 108 directly refers to the image file 20.
There are only two. Therefore, by accessing the image file 202 via the CD-ROM loader 108, the image file 202 appears as a normal hard disk from the source of the hard disk access request 102.

FIG. 3 shows the internal configuration of the CD-ROM loader 108.

In FIG. 3, reference numeral 301 denotes “int 13
h) is a mechanism for rewriting the vector 103 into an access pointer of a CD-ROM. By executing this, the access to the hard disk 106 is performed on the CD-ROM.
It is converted to access to 109.

Reference numeral 302 denotes an int 13h handler. The int 13h vector rewriting mechanism 301 uses “int
13h "vector 103 is set to have a pointer to this int 13h handler 302. CD-RO
It is int 13h to actually access M109
The handler 302.

Reference numeral 303 denotes a bootability determination mechanism. i
One of the functions of the nt13h handler 302 is CD-
CD-ROM accessed via ROM loader 108
If the BIOS 109 is a bootable device,
Has the role of informing 1

Reference numeral 304 denotes a disk access mechanism.
One of the functions of the int13h handler 302 is that the CD-R
The image file 202 on the OM 109 has a role to appear as a hard disk. Specifically, the BIOS 10
1 issues a hard disk access request 102, the location of the access request is
The position corresponding to the above position is calculated, and the data at that position is returned to the side that issued the access request.

FIG. 4 is a diagram showing a procedure from the CD-ROM 109 to the start of the DOS.

When power is turned on or reset, the BIOS
101 initializes hardware. After that, CD-R
Call the OM loader 108 (step 401 '),
Processing 30 for rewriting "int 13h" vector 103
Execute 1. After this, the hard disk access will be C
Converted to D-ROM access. That is, instead of the normal hard disk access routine 105, a CD
-Int 13h handler 30 in ROM loader 108
2 is executed (step 401).

Next, the BIOS 101 issues a vector interrupt "int 19h". "Int 19h"
Searches for a bootable device using "int 13h" (step 402 '). int 13h The BIO is determined by the bootability determination mechanism 303 in the handler 302.
S101 recognizes that the device that appears to be a hard disk by the CD-ROM loader 108 is bootable. Specifically, the int 13h handler 108
Realizes the boot possibility determination mechanism 303 by making it appear that the master boot sector 204 exists (step 402).

Next, the BIOS 101 finds a bootable partition on a device that appears to be a hard disk by the CD-ROM loader 108.
Master boot sector (cylinder = 0, head = 0,
(Sector existing in sector = 1).
At this time, the hard disk access request 10
2 is converted into an access to the master boot sector 204 on the image file 202 by the operation of the disk access mechanism 304 of the int 13h handler 302 (step 403 ′). Thus, the master boot sector 204 on the image file 202 is loaded on the memory (Step 403).

Next, the BIOS 101 passes control to the loaded master boot sector 204 and starts a master bootstrap loader process (step 405).

The master bootstrap loader refers to the partition table in the master boot sector 204 to check for a bootable partition, and loads the first sector of the partition. The sector loaded here is called a boot sector. The hard disk access request 102 issued at this time is converted into an access to the boot sector 205 on the image file 202 by the operation of the disk access mechanism 304 of the int 13h handler 302 (step 405 '). Thus, the boot sector 205 on the image file 202 is changed to “000
0: 7C00 "(the address of the main memory for loading the boot sector). Thereafter, the master bootstrap loader passes control to the boot sector 205 (step 406).

The boot sector 205 sets the first three sectors of “IBMbio.com”, which is the kernel part of the OS, to “0”.
000: 0700 "(the address of the main memory), and jumps there. At this time, the hard disk access request 102 is also transmitted to the int 13h handler 30.
By the operation of the second disk access mechanism 304, the access is converted to access to the file system 205 on the image file 202 (step 406 '), and the first three sectors of "ibmbio.com" are "0000: 0700" from the file system 205. (Address of main memory)
Is loaded. After that, "ibmdos.com"
Is loaded, and various device drivers are loaded, all of which are stored in the i-side of the CD-ROM loader 108.
The nt 13h handler 302 takes out the image file 202 on the CD-ROM 109 and loads it (step 407).

With the above, the CD-ROM without any change to the DOS
DOS can be started from the ROM 109.

FIG. 5 shows an example of the configuration of the CD-ROM 109.
The application program is recorded according to a format defined in ISO-9660.

Reference numeral 501 denotes a logical drive generated when the image file 202 on the CD-ROM 109 is viewed as a hard disk by the operation of the CD-ROM loader 108. It seems that the DOS system 502 and the configuration file 503 exist in this. CD-R
Since the OM loader 108 functions as a hard disk from the DOS side, the OM loader 108 can be executed without modifying the application program for the CD-ROM.

Reference numeral 504 denotes a logical drive provided by the DOS standard CD-ROM access mechanism. In this, normal application programs such as the main program software 505, the library 506, and the document 507 are recorded.

The logical drive 501 stores a CD-RO in the PC.
Since the logical drive becomes visible only when the M loader 108 is incorporated, it cannot be accessed as a drive by a normal CD-ROM access mechanism.

The logical drive 504 is a DOS standard C
Since it is a logical drive provided by the D-ROM access mechanism, even if the DOS is started from the drive 501, the DOS started from the normal hard disk 106
But you can access it in the same way.

A P with a built-in CD-ROM loader 108
In C, the DOS can be started with one CD-ROM, and the application program can be executed. In this case, there may not be a hard disk. The PC without the CD-ROM loader 108 has the same CD-RO
Even with M, DOS cannot be started from a CD-ROM, but since the logical drive 504 can be read by a normal mechanism, application programs can be executed.

Therefore, the main program software 5
05, the library 506, and a part of the document 507 in the logical drive 501, so that the CD-RO
All functions can be used with a PC incorporating the M loader 108, but a PC without the CD-ROM loader 108 can be used.
C can provide a software providing method such that only limited functions can be used.

FIG. 6 is a schematic diagram showing the data structure of a CD-ROM disk 601 having a copy protection function according to the present invention.

Reference numeral 601 stores digital data in a directory structure in file units. 602 is IS
This is a directory record of a CD-ROM disc specified in O-9660, in which information on a file or directory 604 included in one directory 603 recorded in 601 is recorded according to a format specified in ISO-9660. I have.

Reference numeral 605 denotes extent position information defined in ISO-9660, which is a file included in the directory 603 or a CD-R of the directory 604.
The recording start position on the OM disk is recorded.

Reference numeral 606 denotes data length information defined in ISO-9660, in which the data length of a file or directory 604 included in the directory 603 is recorded. A file 607 is provided with a copy protection function described later. In this embodiment, the description will be given on the assumption that the file 607 is included in the directory 603. Reference numeral 608 denotes a directory record of the file 607 that has been subjected to the copy protection function.

Reference numeral 609 denotes 607 extent position information. 610 realizes a copy protection function to be described later, so that instead of the actual data length of the file 607,
This is erroneous data length information that records an erroneous data length. In the erroneous data length information 610, a value smaller than the actual data length of the file, for example, “0 byte” is recorded.

Reference numeral 611 denotes a copy protection area that cannot be read by a copy protection mechanism described later except from a dedicated reading mechanism. Reference numeral 612 denotes index information describing the internal data structure of the file 607. For example, when the MS-DOS file format is used as the internal data format of the file 607, an MS-DOS partition table is stored.

FIG. 7 shows the configuration of the files 604 and 607 of FIG.

FIG. 8 is a flowchart in the case where the copy protected file 607 of the CD-ROM disk 601 shown in FIG. 6 is read by a reading means other than a normal reading mechanism, that is, a dedicated reading mechanism.

First, the reading mechanism reads the directory record 608 corresponding to the file 607 (step 701). The directory record 608 includes the extent position information 109 and the erroneous data length information 610 of the file 607.

Next, the reading mechanism reads digital data from the CD-ROM disk 601 by the data length indicated by the erroneous data length information 610 from the recording start position of the file 607 indicated by the extent position information 609 read in step 701. (Step 702). Here, as described above, the erroneous data length information 610 contains the file 607.
A value smaller than the actual data length of the file, for example, “0 byte” is described. Therefore, reading is not performed on the copy protection area 611 existing after the data length.

As a result, it becomes impossible to correctly read the copy-protected file 607 (step 703).

FIG. 9 shows a state of FIG.
6 is a flowchart for reading a copy-protected file 607 of the CD-ROM disk 601 shown in FIG.

First, the dedicated reading mechanism reads the directory record 608 corresponding to the file 607 in the same manner as in the step 701 (step 801). The directory record 608 includes extent position information 609 and erroneous data length information 610 of the file 607.

Next, the dedicated reading mechanism performs step 8
01, a file 60 having a specific size located at a specific distance away from the recording start position of the file 607 indicated by the extent position information 609 read in
The index information 612 describing the internal data structure of No. 7 is read (step 802).

The specific portion where the index information 612 is located is fixed and determined in advance, for example, as “a region having a data length of 1024 bytes” located at the head of the information 612. Also, data for designating a specific portion is recorded in a data area that can be read by a normal reading mechanism in a format that can be determined by a dedicated reading mechanism without being fixed in advance.
Can be recorded at an arbitrary start position with an arbitrary data length.

As an example, there is a method of encrypting data for designating a specific portion and recording the data in a data area that can be read by an ordinary reading device.

Next, index information 612, for example, M
The S-DOS partition table is analyzed to obtain the actual data length of the file 607 (step 803).

Finally, a dedicated reading mechanism is provided in step 8
From the recording start position of the file 607 indicated by the extent position information 609 read in 01, digital data is read from the CD-ROM 601 by the data length obtained in step 803 (step 804).

In this case, the data length of the digital data read by the dedicated reading mechanism is not the erroneous data length 610 recorded in the directory record 608 but the actual data length recorded in the index information 612. Therefore, the copy protected file 607 including the copy protection area 611 can be correctly read (step 805).

FIG. 10 is a diagram showing an example of a file structure of the trial version CD-ROM. Reference numeral 901 denotes a main program software file which can be read by a normal reading mechanism, and provides a basic function of the software. Reference numerals 902 and 903 denote software support libraries, each of which is a set of software library files for providing the 901 with various peripheral functions. 902 is readable by a normal reading mechanism, while 903 is readable only by a dedicated reading mechanism. 9
04 and 905 are document data;
903 is a set of document data files provided to the user through the software 903. 904 is readable by a normal reading mechanism, while 905 is readable only by a dedicated reading mechanism. In the present invention, reading can be restricted in file units, not in disk units. Therefore, even when a normal reading mechanism is used, files 901, 902, and 904 can be read. That is, even when a dedicated reading mechanism is not used, the functions provided by 901, 902, and 904 can be used. Using this, a trial version CD-ROM can be realized.

For example, referring to FIG. 10, reference numeral 901 denotes moving image reproduction software; 902, a library required for normal reproduction of moving images; 903, fast forward / rewind / slow reproduction /
A library required for special playback of moving images such as frame-by-frame playback. When the first half of the moving image is recorded in 904 and the second half of the moving image is recorded in 905, this CD is read by a normal reading mechanism.
-By reading the ROM, it is possible to provide trial software with limited functions such that only the first half of a moving image can be played back only in normal playback.

In the above embodiment, the CD-ROM has been described as an example, but the present invention is not limited to this.

[0072]

As described above, according to the present invention, the CD-R
Making part or all of the digital data recorded on a disk recording medium such as OM unreadable by means other than a dedicated reading mechanism, and making part or all of the digital data recorded on the disk recording medium unusable. Can be.

Further, a disk recording medium in which part or all of digital data cannot be used can be easily created by a commonly used writing mechanism.

As a result, one disk recording medium can be used only as a trial version by a normal personal computer, and all data can be used only by a dedicated machine having a dedicated reading mechanism. This makes it possible to obtain the effect of eliminating the need for specially creating only the trial version.

[Brief description of the drawings]

FIG. 1 shows that an access request to a hard disk is CD-
FIG. 3 is a functional configuration diagram showing a mechanism of conversion into access to a ROM.

FIG. 2 CD-R accessed as a hard disk
It is a block diagram of OM.

FIG. 3 is a functional configuration diagram of a CD-ROM loader.

FIG. 4 is a flowchart showing a procedure from the CD-ROM to the start of the DOS.

FIG. 5 is a diagram illustrating a configuration example of a CD-ROM.

FIG. 6 is a diagram showing a data structure of a CD-ROM having a copy protection function.

FIG. 7 is a diagram showing a data structure of a CD-ROM viewed from a directory.

FIG. 8 is a flowchart showing a reading procedure by a normal reading mechanism.

FIG. 9 is a flowchart showing a reading procedure by a dedicated reading mechanism.

FIG. 10 is a diagram showing a file configuration of a trial version CD-ROM.

[Explanation of symbols]

101: BIOS, 108: CD-ROM loader, 10
9 CD-ROM, 602 directory record, 6
07 ... copy protected file, 610 ... error data length information, 612 ... index information.

Continued on the front page. (72) Inventor Hiroshi Tsuchiyama 6-81 Onoecho, Naka-ku, Yokohama-shi, Kanagawa Prefecture Hitachi Software Engineering Co., Ltd. In-house (72) Inventor Teruo Nakamura 6-81 Onoecho, Naka-ku, Yokohama-shi, Kanagawa Hitachi Software Engineering Co., Ltd. In-house (72) Inventor Naoki Sakaguchi 6-81 Onoecho, Naka-ku, Yokohama-shi, Kanagawa Prefecture Hitachi Software Engineering Co., Ltd. In-house (72) Eiji Suzuki 6-81 Onoecho, Naka-ku, Yokohama-shi, Kanagawa Hitachi Software Engineering Co., Ltd. In-house (72) Inventor Shin Nakano 6-81 Onoecho, Naka-ku, Yokohama-shi, Kanagawa Prefecture Hitachi Software Engineering Co., Ltd.

Claims (3)

[Claims] 1. A copy protection method for a disk recording medium on which digital data is recorded in accordance with a predetermined format, wherein: in a directory record of the disk recording medium, erroneous data of data to be accessed is different from an actual data length. Record long information and at a specific recording location,
A disk copy protection method characterized by recording correct data length information that can be recognized only by a specific reading mechanism. 2. A disk in which erroneous data length information different from an actual data length of data to be accessed is recorded in a directory record of a disk recording medium, and correct data length information is recorded at a specific recording position. A disc reading mechanism for reading a recording medium, comprising: means for recognizing a specific position where the correct data length information is recorded. 3. A disk recording medium on which digital data is recorded according to a predetermined format, wherein erroneous data length information different from an actual data length of data to be accessed is recorded in a directory record of the disk recording medium. A disc recording medium having a recorded record, and a record in which a correct data length information recognizable only by a specific reading mechanism is recorded at a specific recording position.