JPH05174491A - Information memory - Google Patents

Abstract

PURPOSE:To unenable reading user data by adding a CRC check byte to the ID part of information recording medium corresponding to the user data and optionally setting an initial value of the byte with a user. CONSTITUTION:A host I/F device controller 30 receives the commands such as read or write of the user data from a host computer 1 and controls n-th storing medium driving device 5<1>. Also, a format controller 37 receives data from a buffer memory 39 through a buffer controller 38 or writes the data of the n-th storing medium driving device 5<1> in the buffer memory 39. Before starting to add to the CRC register of the format controller 37, the initial value of the CRC register is optionally set by the user and when an ID part AM is detected at the time of reading, the ID part AM deciding means of the format controller 37 decides whether the AM is coincident with the initial value or not.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to confidential user data in a disk device such as a magneto-optical disk, a removable HDD, a floppy disk, a tape device (streamer), an information storage device capable of storing arbitrary information such as DAT. Regarding the improvement of the holding mechanism, in particular, by simply adding a simple data confidentiality holding means using existing hardware, it becomes impossible to read the user data itself,
The present invention relates to an information storage device that realizes complete protection during reading.

[0002]

2. Description of the Related Art Conventionally, in a disk device or the like,
A user data confidentiality protection method is adopted. For example, various confidentiality protection methods are available, such as encrypting the recorded data itself, changing the sector size in the middle, or providing a password to the data so that it cannot be used by applications. It is used.

However, in the conventional security system,
Generally, the data itself can be read, and in many systems, the contents are dealt with so that the contents cannot be easily understood. That is, the protection method that makes it impossible to read the user data itself is complicated in processing and operation, and thus has not been used so far.

Here, an outline of the configuration of a conventional information storage device for writing and reading user data will be described. FIG. 6 is a functional block diagram showing an example of the main configuration of a conventional information storage device. In the figure, 1 is a host computer, 2 is a host I / F (interface) device, 3 is a storage device controller, 4 is a disk I / F device, 5 is a first storage medium drive device, and 6
Indicates a second storage medium driving device.

The information storage device shown in FIG. 6 includes a storage device controller 3 and a plurality of storage medium drive devices, for example, a first storage medium drive device 5 and a second storage medium drive device 6. Drive device and a disk I / F (interface) device 4 connecting these devices. It should be noted that the number of storage medium driving devices 5 and 6 for the storage device controller 3 can be selected arbitrarily.

The host computer 1 and the storage device controller 3 are connected to each other via a host I / F device 2 such as a SCSI I / F device or an AT / I / F device. The storage device controller 3
The disk I / F device 4 that connects the first and second storage medium drive devices 5 and 6 with each other is composed of a disk interface such as ESDI or a tape drive interface.

A conventional information storage device for writing and reading user data has a structure as shown in FIG. 6, and as described above, various security methods are known. However, in the conventional method of maintaining confidentiality of user data,
It is possible to read the data itself from the information storage device, and the confidentiality of user data cannot always be maintained.
There was an inconvenience.

[0008]

SUMMARY OF THE INVENTION According to the present invention, by solving such a disadvantage in the conventional user data confidentiality protection method of the information storage device and prohibiting the reading of the data itself from the information storage device, It is an object of the present invention to provide an information storage device which enables data to be protected completely and ensures confidentiality.

[0009]

According to the present invention, firstly,
An information storage device capable of storing arbitrary information has an area for adding a CRC check byte to an ID portion of an information storage medium corresponding to user data, and a user arbitrarily sets an initial value of a CRC register of the check byte. This is a configuration including initial value setting means and.

Secondly, in an information storage device capable of storing arbitrary information, it has an area for adding an ECC check byte to the ID part of the information storage medium corresponding to user data, and the initial value of the ECC register of the check byte. And an initial value setting means for the user to arbitrarily set.

Thirdly, in an information storage device capable of storing arbitrary information, it has an area for adding a CRC check byte to the ID part of the information storage medium corresponding to user data, and the initial value of the CRC register of the check byte. Is set by the user arbitrarily, and when any user data is read, the initial value of the CRC register at the time of writing the CRC of the user data is different from the initial value of the CRC register at the time of reading. After the ID CRC error occurs, the number of times limiting means for limiting the number of times the initial value of the CRC register can be changed is provided.

Fourthly, in an information storage device capable of storing arbitrary information, it has an area for adding an ECC check byte to the ID part of the information storage medium corresponding to user data, and the initial value of the ECC register of the check byte. The initial value setting means for the user to arbitrarily set is different from the initial value of the ECC register at the time of reading the user data when the user data is read, and the initial value of the ECC register at the time of reading the user data is different. After the ID ECC error, the number of times limiting means for limiting the number of times the initial value of the ECC register can be changed is provided.

Fifth, in an information storage device capable of storing arbitrary information, it has an area for adding a CRC check byte to the ID portion of the information storage medium corresponding to user data, and the initial value of the CRC register of the check byte. Is set by the user arbitrarily, and when any user data is read, the initial value of the CRC register at the time of writing the CRC of the user data is different from the initial value of the CRC register at the time of reading. After the ID CRC error occurs, the number of times limiting means for limiting the number of times that the initial value of the CRC register can be changed, and, when the number of times the ID CRC error is repeated reaches a predetermined limit number, A prohibition flag recording means for setting a read prohibition flag is provided on the information storage medium, and after the read prohibition flag is recorded, the It is configured so as to prohibit reading of Zadeta.

Sixth, an information storage device capable of storing arbitrary information has an area for adding an ECC check byte to the ID part of the information storage medium corresponding to user data, and the initial value of the ECC register of the check byte. The initial value setting means for the user to arbitrarily set is different from the initial value of the ECC register at the time of reading the user data when the user data is read, and the initial value of the ECC register at the time of reading the user data is different. A number limiting means for limiting the number of times that the initial value of the ECC register can be changed after an ID ECC error occurs; and when the number of times the ID ECC error is repeated reaches a predetermined limit number, A prohibition flag recording means for setting a read prohibition flag is provided on the information storage medium, and after the read prohibition flag is recorded, the It is configured so as to prohibit reading of Zadeta.

[0015]

In the information storage device of the present invention, attention is paid to the CRC (error detection / error correction code) area of the ID part of the user data and the ECC (error detection code) area of the data part, and these areas are CRC check byte and EC
A C check byte is added, and CRC or EC is added when writing.
Allow the user to arbitrarily set the initial value of the C check byte. Then, at the time of arbitrary reading, the user data can be read only when the initial values of the CRC and ECC check bytes match, so that C
A password function is given to the initial values of the RC and ECC check bytes (common to the inventions of claims 1 to 6).

As described above, according to the present invention, in the format of the user data, the CRC area of the ID part and the EC
Focusing on the C area, if the initial values match and do not match,
The user data itself cannot be read. Therefore, the format of user data conventionally used in a disc will be described.

FIG. 2 is a conceptual diagram showing an example of the main part of the format of user data on the disc. In the figure, is VFO, is AM, is ID,
Indicates CRC, GAP, VFO, AM, DATA, and ECC areas.

As shown in FIG. 2, the sector formats are VFO, AM, ID, CRC and GAP.
, VFO, AM, DATA, ECC. The user data of such a sector format is roughly divided into an ID part and a data part.

The ID section is composed of the first half VFO and AM of FIG. 2, the ID data of the ID, and the CRC (or one or both of the last ECC) corresponding to the ID data. The ID part of the first half,
The latter half of the data section is separated by GAP existing in the middle.

The data part is composed of VFO and AM.
And DATA and ECC. The contents of each sector are as follows.

First, VFO is a recording area of a pattern for achieving bit synchronization by using a PLL, which is "PLL".
It is also called "SYNC". This VFO is necessary pattern data that is always used for synchronizing the data, and the same pattern as the VFO described later is recorded.

The next AM is a recording area of a timing pattern for starting a byte delimitation by determining where each bit is a break in byte units after bit synchronization is achieved. The ID is an area for writing information indicating which sector this sector is, and is usually composed of a head number, a cylinder number, and a sector number. The head, cylinder, and sector numbers are called ID data.

CRC is a check byte for checking whether or not the ID data has an error.
This is a code for error detection of a part. In this invention, this CR
The data of C is used (the inventions of claim 1, claim 3 and claim 5).

GAP is an area between the trailing edge of the CRC of the previous ID and the leading edge of the VFO of the data section.
For example, it is a gap part where there is no data of 3 bytes length. This GAP is an area provided for switching from read to write, and a space for this GAP is secured corresponding to the time required to switch from read to write, and is called a write splice or PAD. ..

That is, in order to write to the data part, the ID part and the CRC of the ID are read, and after confirming that the IDs match, writing to the VFO of the data part is performed. The VFO, like the VFO of the ID section, is an area in which pattern data necessary for synchronizing the data is recorded.

AM, like the AM of the ID section,
This is a recording area of a timing pattern for starting byte delimitation. DATA is an area for recording user data.

The ECC is an area for recording check bytes for error detection and error correction of the user data part. In this invention, this ECC data is also used (inventions of claim 2, claim 4 and claim 6).

The above is an example of the format of the conventional user data. In the present invention, in the format shown in FIG. 2, CRC of the ID part (error detection code of the ID part) and ECC (data of the data part) Error detection / correction code) and set an arbitrary initial value as a password at the time of formatting to prohibit the reading of the user data itself and enable complete protection. ..

[0029]

Embodiments of the information storage device of the present invention will now be described in detail with reference to the drawings. This embodiment is common to the inventions of claims 1 to 6.
In the present invention, the storage device controller 3 provided in the conventional information storage device shown in FIG. 6 has a main function. Therefore, the configuration and operation of the storage device controller 3 will be mainly described.

FIG. 1 is a functional block diagram showing an embodiment of the detailed configuration of the storage device controller in the information storage device of the present invention. Reference numerals in the figure are the same as those in FIG. 6, 5'is an nth storage medium drive device, 30 is a host I / F device controller, and 31 is a CP.
U, 32 is ROM, 33 is RAM, 34 is a sequencer,
Reference numeral 35 is drive control means, 36 is a drive status controller, 37 is a format controller, 38 is a buffer controller, and 39 is a buffer memory.

Storage device controller 3 shown in FIG.
Then, the host I / F device controller 30, for example, S
Host computer 1 consisting of CSI controller etc.
It receives commands such as read and write of user data from and sends them to the CPU 31. The CPU 31 interprets the content of the command and controls the nth storage medium driving device 5 '.

Firmware preprogrammed for the operation of the CPU 31 is written in the ROM 32, and the CPU 31 operates in accordance with this firmware. Further, the RAM 33 is used as a work area when the CPU 31 operates and holds variables, tables and the like.

The drive control means 35 is a control means for controlling a read gate, a write gate and the like. The sequencer 34 commands the drive control means 35 and the drive status controller 36 according to the format of the user data shown in FIG. 2 to control the corresponding read gate, write gate, etc. in time series.

Further, the format controller 37
Receives data from the buffer memory 39 via the buffer controller 38, or writes data read from the nth storage medium driving device 5'into the buffer memory 39. Here, the format controller 37 will be described in detail.

FIG. 3 shows the format controller 37 in the storage device controller 3 shown in FIG.
It is a functional block diagram which shows one Example of the detailed structure. Reference numerals in the figure are the same as those in FIG. 1, 71 is an ID data register, 72 is a CRC (ECC) register, 73 is an ID section AM determination means, 74 is a data latch circuit for serial / parallel conversion means 76, and 75 is Data latch circuit for parallel / serial conversion means 77, 76 serial / parallel conversion means, 77 parallel / serial conversion means, 78 read buffer circuit, 79
Is a read data buffer circuit, and 80 is a write data buffer circuit.

In FIG. 3, the read clock input to the read clock buffer circuit 78 is the read reference clock when the disk interface is ESDI as described above. Also, CRC (EC
C) In the register 72, the CRC data of the ID part is set at the time of reading, and the ECC data of the data part is set at the time of writing.

Next, with reference to FIGS. 1 and 3, the operations of the information storage device of the present invention at the time of reading, writing and formatting will be sequentially described. First, the operation during the first read is as follows.

Using the read clock from the read clock buffer circuit 78, the user data from the read data buffer circuit 79 is taken into the serial / parallel conversion means 76, and the data latch circuit for the serial / parallel conversion means 76. ID section AM determination means 7 via 74
Transfer the data to 3. The sequencer 34 of FIG. 1 determines the arrival of the ID portion of the sector (or the ID portion of the record) by the ID portion AM determination means 73 of FIG.
By comparing the predetermined pattern with the data sent from the data latch circuit 74 for the serial / parallel conversion means 76, and when both match, the ID part AM
It is determined that (of FIG. 2) has been detected.

When the ID section AM is detected, the ID section AM determination means 73 causes the ID data register 71 and the CRC (E
CC) register 72 sends an activation signal to I
The D data register 71 starts fetching ID data (head, track, sector number, etc.) into the register in order,
Further, the CRC (ECC) register 72 starts addition of ID data. In the CRC (ECC) register 72, the CRC of the ID part or the ECC of the data part shown in FIG. 2 is set and addition is performed.

Specifically, the ID section AM determination means 73
When the ID data has been taken into the ID data register 71, the CRC data following the ID data (see FIG.
CRC) and the ID data that is the addition result added by the CRC (ECC) register 72 are compared, and when both comparison data match, it is determined that the fetched ID data is valid. When the two data do not match, it is determined that some error has occurred. This judgment result is
For example, by a flag or an interrupt signal, the CPU of FIG.
31 is notified.

When it is determined by the above operation that the fetched ID data is valid, then the fetched ID data is changed to the target sector (or record).
The sequencer 34 of FIG. 1 determines whether or not it is, and if it is the target sector, the read operation of the data portion is started. The above is the operation during the first read.

Next, the operation during the second write will be described. Even during this writing, the operation related to the ID section is
As in the case of reading, if the fetched ID data is valid and it is determined that the fetched ID data is the target sector, then the write operation is started.
That is, if it is determined that the fetched ID data is valid and the fetched ID data is the target sector, the data written in the buffer memory 39 of FIG. , Or write data sent from the host computer 1 via the host I / F device controller 30.

At the time of writing this user data (at the time of ratoi)
, The data flow is the opposite of the previous read. Therefore, the data written in the buffer memory 39 of FIG. 1 is taken into the data latch circuit 75 for the parallel / serial conversion means 77 of FIG. 3, serialized by the parallel / serial conversion means 77, and written. The data is transferred to the nth storage medium driving device 5'through the data buffer circuit 80, and the data is written. The above is the operation during the second write.

Finally, the operation of the third format will be described. At the time of this format, the ID part is written. First, the head of the sector is detected by the nth storage medium driving device 5 '(or a sector detecting means (not shown) provided in the storage device controller 3).

As for the detected sector, the parallel / serial conversion means 77 has the ID portion data previously written in the ID data register 71 of FIG. 3 by the sequencer 34 of FIG.
The data is transferred to the n-th storage medium driving device 5'through the data latch circuit 75 for writing and written in a predetermined area.

In this case, the CRC (ECC) register 7
2, the data of the ID part is added, and when the data of the ID part is completely transferred to the nth storage medium driving device 5 ', subsequently, the contents of the CRC (ECC) register 72 are parallel. / CR transferred to the ID part by being transferred to the data latch circuit 75
The C data is written in the data latch circuit 75 for the parallel / serial conversion means 77.

The above is the operation in the third format. In this format, the information storage device of the present invention uses the CRC of the ID part and the ECC of the data part in the format shown in FIG. 2 above to set an arbitrary initial value to form a password. Of the three operations described above, the first read operation and
The operation at the time of the second write is an operation common to the inventions of claims 1 to 6, and the operation at the time of the third format is different.

The inventions of claim 1, claim 3 and claim 5 utilize CRC data (of FIG. 2), whereas the inventions of claim 2, claim 4 and claim 6 are used. Then EC
The difference is that the C data (of FIG. 2) is used.
Next, each invention of claims 1 to 6 will be specifically described.

First, in the invention of claim 1, at the time of formatting, the CRC data (of FIG. 2) is converted into the CRC (EC of FIG. 3).
C) CRC before starting addition in register 72
The user arbitrarily sets the initial value of the register 72,
The CRC data (data of the ID part) similar to the conventional one is added to the initial value and written in the CRC data part on the information storage medium. After that, the user data is written by the usual operation similar to the conventional one.

Therefore, when the user data written in this information storage medium is read, this user data cannot be read unless it matches the initial value of the CRC register 72 set at the time of formatting. Therefore,
At the time of writing, the initial value set by the user in the CRC register 72 becomes a password, and the confidentiality of data is improved.

According to the invention of claim 2, CRC data (see FIG.
The ECC data (of FIG. 2) is used in place of the () of FIG. 2), and the user arbitrarily sets the initial value of the ECC register 72 before starting the addition in the CRC (ECC) register 72 of FIG. The ECC data (data of the ID part) is added to the initial value and written in the ECC data part on the information storage medium. Other configurations and effects
This is the same as the invention of claim 1 above.

According to the third aspect of the present invention, the initial value set by the user in the CRC register 72 used in the first aspect of the invention is used as a password not only to enhance the confidentiality of data, but also to the CRC register 72. The number of initial values that can be set (the number of changes) is limited. The value of the changeable number (control number) is also written as a part of the CRC data (or ECC data). That is, when the initial value set in the CRC register 72 at the time of writing and the initial value set at the CRC register 72 at the time of reading do not match, “ID CRC error” is given.
To occur.

Therefore, the user is required to use this "ID CRC
Corresponding to "Error", before reading by retry, C
The initial value set in the RC register 72 must be changed. Thus, when the initial values set at the time of reading do not match, the retries are repeated until they match, but the initial values that can be set in the CRC register 72 for the retries corresponding to the "ID CRC error". In order to limit the number of times (changeable number), a number of times setting means for arbitrarily setting the number of times of reading by retry, a number of times counting means for counting the number of times of reading by retry, the number of times setting means and the number of times counting means And a comparison means for comparing the contents of

Therefore, according to the invention of claim 3, I
When a D CRC error occurs, the number of times of retrying is limited, so that the confidentiality of data is further enhanced as compared with the invention of claim 1 above.

The invention of claim 4 uses the initial value of the CRC register 72 in the invention of claim 3, while the ECC register 72 is the same as the invention of claim 2.
The only difference is that it uses the initial value of. That is, the initial value set in the CRC (ECC) register 72 at the time of writing does not match the initial value set in the CRC (ECC) register 72 at the time of reading, and the "ID E
When a "CC error" occurs, the number of re-try cycles is limited, so that the confidentiality of data is further enhanced as compared with the invention of claim 2 (the same as the invention of claim 3). effect).

In the invention of claim 5, the function of the means for limiting the number of initial values (changeable number) that can be set in the CRC register 72 added in the invention of claim 3 is further strengthened and can be set arbitrarily. When the number of retry cycles is reached, a means for recording a read prohibition flag is added to the information storage medium. This read prohibition flag is also written as part of the CRC data (or ECC data). Therefore, if a person who does not know the initial value of the CRC register 72 arbitrarily set at the time of writing attempts to read it forcibly and the number of changes of the initial value is reached,
Immediately reading is prohibited, and compared with the invention of claim 3 above,
Further, the confidentiality of data is further enhanced.

According to the invention of claim 6, the invention of claim 5 is C
While the initial value of the RC (ECC) register 72 is used, the difference is that the initial value of the ECC register 72 is used as in the case of the above-mentioned invention of claim 4. That is, the function of the means for limiting the number of initial values (changeable number) that can be set in the CRC register 72 added in the invention of claim 5 is further strengthened to reach the number of retry cycles that can be arbitrarily set. At that time, a means for recording a read prohibition flag is added to the information storage medium.

Therefore, even if a person who does not know the initial value of the CRC (ECC) register 72 arbitrarily set at the time of writing tries to read it forcibly, as soon as the number of changes of the initial value is reached, the reading is immediately prohibited and the previous As compared with the invention of claim 4, the confidentiality of data is further enhanced. As described above, in each of the inventions of claims 1 to 6, FIG.
Before the addition is started in the CRC (ECC) register 72, the user arbitrarily sets an initial value of the CRC (ECC) register 72, and the CRC (or ECC) data (data of the ID part) is set to the initial value. Is added and written in the CRC (or ECC) data section on the information storage medium.

By using the initial value arbitrarily set by this user as a password at the time of arbitrary reading of the user data, the confidentiality of the data is enhanced. In addition, in order to improve confidentiality, when an ID CRC (ECC) error occurs,
It is configured to limit the number of cycles to retry again or to prohibit subsequent reading (record a prohibition flag and the like) when the number of times of changing the initial value is reached.

Here, with respect to the information storage device of the present invention shown in FIGS. 1 and 3, a format forming and writing operation,
A flowchart of the read operation will be described.

FIG. 4 is a flow chart showing the main processing flow in formatting the information storage medium under the control of the CPU 31 in the information storage device of the present invention.
In the figure, # 1 and # 2 indicate steps.

In step # 1, the user selects CRC (EC
C) Set the initial value of register 72. When the formatting process is completed, the process proceeds to the next step # 2. In step # 2, the user data is written.

When the writing operation is completed, the flow of FIG. 4 is completed. By the processes of steps # 1 and # 2 described above, the creation of the format of the information storage medium and the writing operation of arbitrary user data are completed.

FIG. 5 is a flow chart showing the main processing flow during the read operation from the information storage medium under the control of the CPU 31 in the information storage device of the present invention. In the figure, # 11 to # 20 indicate steps.

At step # 11, the contents of the CRC (ECC) register (72 in FIG. 3), the limit number setting counter and the error number counter are cleared. In step # 12, the limit number set in advance by the user is loaded into the limit number setting counter.

At step # 13, the user selects CRC (E
CC) Set the initial value of register 72. Step #
At 14, the reading of user data is started.

At the next step # 15, it is checked whether an error has occurred. If an error occurs, proceed to step # 16 and set the error counter to "+
1 ”.

Next, in step # 17, the contents of the error number counter and the limit number setting counter are compared. If the content of the error number counter is smaller than the content of the limit number setting counter, the process proceeds to step # 19, an error occurrence process is performed, and the flow of FIG. 5 ends.

As a result of the comparison in step # 17, if the contents of the error number counter and the contents of the limit number setting counter match, the process proceeds to step # 18, the read prohibition flag is recorded in the information storage medium, and The flow of FIG. 5 ends.

As a result of the judgment in the previous step # 15, if no error occurs, the process proceeds to step # 20, and the read user data is stored in the host computer 1
Transfer to. When the read operation ends, the flow of FIG. 5 ends.

By the processing of the above steps # 11 to # 20, the read operation from the information storage medium is performed, and the CRC
When the initial value set in the (ECC) register 72 is different from the initial value set at the time of writing, an error occurs and the user data cannot be read (the inventions of claims 1 to 6). ). Further, when a CRC (ECC) error occurs, the number of cycles for changing the initial value of CRC (ECC) and retrying is limited (inventions 3 to 6).

If the number of retries reaches a predetermined number set in advance, a read prohibition flag is set for the user data, and subsequent reading becomes impossible (claims 5 and 6). invention). Therefore, when writing,
The initial value arbitrarily set by the user in the CRC (ECC) register 72 functions as a password, and the confidentiality of user data is maintained.

[0073]

According to the first aspect of the present invention, the CRC data is C
Before starting the addition in the RC register (72 in FIG. 3), C
The user arbitrarily sets the initial value of the RC register,
The data of the ID part is added to the initial value and written in the CRC part (of FIG. 2) on the information storage medium.

In order to read the information storage medium, data cannot be read unless the initial value of the CRC register matches the formatted value. Therefore, the initial value of the CRC register (72 in FIG. 3), which can be known only by the person who performed the formatting, becomes the password, and the confidentiality of the data is improved.

According to the second aspect of the invention, the ECC data is EC
Before the addition is started in the C register (72 in FIG. 3), the user arbitrarily sets the initial value of the ECC register, and the data of the ID part is added to the initial value to add the ECC part on the information storage medium. I try to write it in (Fig. 2).

In order to read the information storage medium, it cannot be read unless the initial value of the ECC register matches the value at the time of formatting. Therefore, the initial value of the ECC register, which can be known only by the person who performed the formatting, becomes the password, and the confidentiality of the data is improved.

In the third aspect of the invention, the CRC data is CR.
CR before starting the addition in the C register (72 in FIG. 3)
The user arbitrarily sets the initial value of the C register, adds the data of the ID section to the initial value, and writes it in the CRC section (of FIG. 2) on the information storage medium. To read the information storage medium, the initial value of the CRC register cannot be read unless the initial value of the CRC register matches the value at the time of formatting. Therefore, the initial value of the CRC register that only the person who performed the formatting can know. Is the password.

At this time, a retry causes a CRC error, and the number of cycles for changing the initial value of the CRC and retrying is limited (for example, a command for changing the initial value of the CRC register is terminated with an error). Etc. are executed). Therefore, the confidentiality of the data can be further enhanced.

According to the fourth aspect of the invention, the ECC data is EC
Before the addition is started in the C register (72 in FIG. 3), the user arbitrarily sets the initial value of the ECC register, and the data of the ID part is added to the initial value to add the ECC part on the information storage medium. I try to write it in (Fig. 2). Then, in order to read the information storage medium, the EC
The password cannot be read unless the initial value of the C register matches the value at the time of formatting. Therefore, the initial value of the ECC register that can be known only to the person who performed the formatting becomes the password.

At this time, a retry results in an ECC error, and the number of cycles for changing the initial value of ECC and retrying is limited (for example, a command for changing the initial value of the ECC register is ended with an error). Etc. are executed). Therefore, the confidentiality of the data can be further enhanced.

In the invention of claim 5, the CRC data is CR
CR before starting the addition in the C register (72 in FIG. 3)
The user arbitrarily sets the initial value of the C register, adds the data of the ID part to the initial value, writes it in the CRC part (of FIG. 2) on the information storage medium, and reads arbitrary user data. Sometimes, when the initial value of the CRC register at the time of writing the CRC data of the ID part set for the user data does not match the initial value of the CRC register set at the time of reading, an "ID CRC error" is generated.
Therefore, it is necessary to change the initial value of the CRC register before reading by retry.

However, when a CRC error occurs after retrying, the initial value of CRC is changed to limit the number of cycles for retrying, and a read prohibition flag is recorded in a predetermined area on the information storage medium. Then, subsequent reading is prohibited. Therefore, the confidentiality of the data can be further enhanced.

According to the sixth aspect of the invention, the ECC data is EC
Before the addition is started in the C register (72 in FIG. 3), the user arbitrarily sets the initial value of the ECC register, and the data of the ID part is added to the initial value to add the ECC part on the information storage medium. When writing to (of FIG. 2) and reading arbitrary user data, the ECC register initial value at the time of writing the ECC data of the ID part set for that user data and the initial value of the ECC register set at the time of reading When and do not match, an "IDEC error" is generated. Therefore, it is necessary to change the initial value of the ECC register before reading by retry.

However, when an ECC error occurs after retrying, the initial value of ECC is changed to limit the number of cycles for retrying, and a read prohibition flag is recorded in a predetermined area on the information storage medium. Then, subsequent reading is prohibited. Therefore, the confidentiality of the data can be further enhanced.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing an example of a detailed configuration of a storage device controller in an information storage device of the present invention.

FIG. 2 is a conceptual diagram showing an example of a main part of a user data format on a disc.

3 is a functional block diagram showing an example of a detailed configuration of a format controller 37 in the storage device controller 3 shown in FIG.

FIG. 4 shows a CPU 31 in the information storage device of the present invention.
6 is a flowchart showing a main processing flow when formatting an information storage medium under the control of FIG.

FIG. 5 shows a CPU 31 in the information storage device of the present invention.
6 is a flowchart showing a main processing flow during a read operation from the information storage medium under the control of FIG.

FIG. 6 is a functional block diagram showing an example of a main part configuration of a conventional information storage device.

[Explanation of symbols]

 1 host computer 3 storage device controller 30 host I / F device controller 31 CPU 32 ROM 33 RAM 34 sequencer 35 drive control means 36 drive status controller 37 format controller 38 buffer controller 39 buffer memory 5'th storage medium drive device

Claims (6)

[Claims] 1. An information storage device capable of storing arbitrary information, wherein a CRC is provided in an ID portion of an information storage medium corresponding to user data.
An information storage device, comprising: an area to which a check byte is added, and an initial value setting means for arbitrarily setting an initial value of a CRC register of the check byte by a user. 2. An information storage device capable of storing arbitrary information, wherein an ECC is provided in an ID portion of an information storage medium corresponding to user data.
An information storage device, comprising: an area to which a check byte is added, and an initial value setting means for allowing a user to arbitrarily set an initial value of an ECC register of the check byte. 3. An information storage device capable of storing arbitrary information, wherein a CRC is provided in an ID portion of an information storage medium corresponding to user data.
There is an area for adding a check byte, and an initial value setting means for allowing the user to arbitrarily set the initial value of the CRC register of the check byte;
ID due to the difference between the initial value of the CRC register when writing the CRC and the initial value of the CRC register when reading
An information storage device comprising: a number limiter that limits the number of times the initial value of the CRC register can be changed after a CRC error occurs. 4. An information storage device capable of storing arbitrary information, wherein an ECC is provided in an ID portion of an information storage medium corresponding to user data.
There is an area for adding a check byte, and an initial value setting means for the user to arbitrarily set the initial value of the ECC register of the check byte;
ID due to the difference between the initial value of the ECC register when writing the ECC and the initial value of the ECC register when reading
An information storage device, comprising: a number limiter that limits the number of times the initial value of the ECC register can be changed after an ECC error. 5. An information storage device capable of storing arbitrary information, wherein a CRC is provided in an ID portion of an information storage medium corresponding to user data.
There is an area for adding a check byte, and an initial value setting means for allowing the user to arbitrarily set the initial value of the CRC register of the check byte;
ID due to the difference between the initial value of the CRC register when writing the CRC and the initial value of the CRC register when reading
A number limiting means for limiting the number of times that the initial value of the CRC register can be changed after a CRC error occurs; An information storage device comprising: a prohibition flag recording means for setting a read prohibition flag on a storage medium; and prohibiting reading of the user data after the read prohibition flag is recorded. 6. An information storage device capable of storing arbitrary information, wherein an ECC is provided in an ID portion of an information storage medium corresponding to user data.
There is an area for adding a check byte, and an initial value setting means for the user to arbitrarily set the initial value of the ECC register of the check byte;
ID due to the difference between the initial value of the ECC register when writing the ECC and the initial value of the ECC register when reading
A number limiter for limiting the number of times the initial value of the ECC register can be changed after an ECC error occurs; An information storage device comprising: a prohibition flag recording means for setting a read prohibition flag on a storage medium; and prohibiting reading of the user data after the read prohibition flag is recorded.