JP4018970B2 - Information destruction system and information destruction program for magnetic recording medium - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an information destruction system and an information destruction program for a magnetic recording medium for substantially destroying information recorded on a magnetic recording medium such as a hard disk.
[0002]
[Prior art]
Generally, in an electronic computer such as a personal computer, an actual data area for recording actual data, a file management area for recording file management information such as a file name of the actual data and a recording position on a disk (magnetic recording medium), The data is stored in a hard disk drive (hereinafter referred to as “HDD”).
[0003]
Usually, the data recorded in the HDD is deleted by a predetermined processing operation on the operating system. However, in such data deletion processing, only part of the file management information is changed, and the actual data remains. Even if the HDD is formatted, only the file management information is deleted, and the actual data remains. For this reason, in such a state, the recording position of the actual data is not known, so the data cannot be viewed. However, for example, if a commercially available application for data restoration is used, the data can be easily viewed. .
[0004]
Here, in the HDD of an electronic computer such as a personal computer, personal information such as an address and a credit card number input at the time of online shopping is stored due to the recent spread of the Internet. Also, confidential information and the like are stored in companies and government offices. For this reason, it is common to delete data or format data at the time of replacement or lease-up of an electronic computer. However, since the actual data remains in the HDD as described above, a malicious third Data may be restored by a person, and important information such as personal information may be leaked.
[0005]
For this reason, in the past, at the time of sale, disposal, lease-up, etc. of an electronic computer, the owner, the seller, etc., or these contractors have deleted the actual data remaining in the HDD so that the data cannot be restored The HDD is physically destroyed. For example, the entire area of the HDD is overwritten with a fixed pattern such as “00”, or the data is destroyed by irradiating the disk with strong magnetism to make the data unrecoverable.
[0006]
[Patent Document 1]
Japanese Patent Laid-Open No. 11-259369
[Problems to be solved by the invention]
However, in the above-described conventional method of erasing actual data, the entire HDD area is overwritten, so that the process takes time. In particular, the processing time has increased remarkably due to the recent increase in capacity of the HDD. There was an inconvenience. This is inconvenient for users, especially for data erasure companies, because a large number of computers are brought in at the same time as the life cycle of recent products shortens. This has also affected the increase in man-hours.
[0008]
As described above, the conventional erasing method requires processing time. However, particularly in an electronic computer used in a company or the like where most of the data is confidential information, the remaining data on the HDD is shorter than the reduction in data erasing processing time. It is more important to prevent the leakage of information. On the other hand, depending on how the computer is used, even if the remaining data is leaked to a third party, there is no problem. In such a case, it is preferable that the processing time is short. However, as described above, since the overwrite process is conventionally performed on the entire area of the HDD, it takes more time than necessary, which is not preferable.
[0009]
In addition, because of the license (license agreement) with the software manufacturer installed on the computer, data such as programs may be erased or destroyed to make it impossible for third parties to use the software. Some want it. In such a case, the software cannot be used if only a part of the data is erased without erasing all of the data. Since all overwriting processes are performed, it takes more time than necessary, which is not preferable.
[0010]
Therefore, the present invention provides an information destruction system and an information destruction program for a magnetic recording medium that improve the disadvantages of the conventional example and enable efficient destruction of substantial data recorded on the HDD. And its purpose.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, the information destruction system according to the present invention has means for writing character characters on the magnetic recording medium in accordance with the specified writing ratio, and recorded on the magnetic recording medium. Information is being destroyed.
[0012]
In order to achieve the above object, the information destruction program according to the present invention has a command for causing the control device to perform a process of writing character characters on the magnetic recording medium in accordance with a specified writing ratio. By this, information recorded on the magnetic recording medium is destroyed.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of an information destruction system for a magnetic recording medium according to the present invention will be described with reference to FIGS.
[0014]
As shown in FIG. 1, the information destruction system according to this embodiment includes an information destruction program 11 for destroying various data in an HDD (magnetic recording device) 3 provided in or connected to an electronic computer 1 such as a personal computer. Have. In this embodiment, the information destruction program 11 is stored in a portable recording medium 10 such as a flexible disk or a CD-ROM. Further, as shown in FIG. A DOS system 12 and an automatic start file 13 for automatically starting on the MS-DOS system when the power is turned on to start the information destruction program 11 are stored. Thus, the information destruction program 11 is automatically started on the MS-DOS system by inserting the recording medium 10 into the reading device 4 of the electronic computer 1 and turning on the power.
[0015]
The processing condition table 14 shown in FIG. 2 is stored in the recording medium 10. The processing condition table 14 is a table for acquiring processing conditions for performing information destruction (character character writing described later), and information destruction based on an average access speed TAT and character character writing ratio described later. This is for determining the character character writing ratio based on the estimated required time required for the processing or the average access speed TAT and the estimated required time required for the information destruction processing desired by the user.
[0016]
In this embodiment, the character character writing ratio and the estimated time required for information destruction processing are used as processing conditions, which are indicated to the user as will be described later. Here, the writing rate indicates the interval at which character characters are written. For example, if the writing rate is 0.01%, 1 KB of character characters are written for every 10 MB sector. In the present embodiment, 1 KB character characters are written at any writing ratio, but the present invention is not necessarily limited to this.
[0017]
Here, the information destruction program 11 of the present embodiment searches the average access speed measurement command 11 a for measuring the average access speed TAT (turn around time) to the HDD 3 and the processing condition table 14. A table search command 11b for obtaining information destruction processing conditions, and a write command 11c for generating character characters for a predetermined number of bytes as random numbers and writing the character characters to the HDD 3 are provided.
[0018]
The average access speed measurement command 11a is a command for causing the control device 2a of the computer main body 2 to access the disk (magnetic recording medium) of the HDD 3 and measuring the average access speed TAT.
[0019]
Further, the table search command 11b is a parameter specified by the user (write ratio or estimated required time until the information destruction process is completed) and an average access speed TAT obtained by the process of the average access speed measurement command 11a. This is a command that causes the control device 2a to search the processing condition table 14 and acquire a search parameter as a search result. Here, the search parameter means an estimated required time until the information destruction process is completed when the designated parameter is a write ratio, and a write ratio when the designated parameter is the estimated required time. For example, when the specified parameter is the write ratio “0.1 (%)” and the average access speed TAT is “a (ms) <TAT ≦ 2 a (ms)”, the estimated required time “20x (s)” is read. Therefore, the writing ratio “0.1 (%)” and the estimated required time “20x (s)” are displayed as the processing conditions. When the designated parameter is the estimated required time “20x (s)” and the average access speed TAT is “a (ms) <TAT ≦ 2 a (ms)”, the write ratio “0.1 (%)” is read. Therefore, the writing ratio “0.1 (%)” and the estimated required time “20x (s)” are displayed as the processing conditions.
[0020]
Next, the write command 11c is a command for generating a random number of characters character fraction (1KB in the present embodiment) predetermined number of bytes to the control unit 2a, a predetermined track from the leading sector S _h shown in FIG. 3 (where In accordance with the command for operating the control device 2a so that the character is written in all sectors of 5 tracks) and the writing rate of the above processing conditions for all the remaining sectors up to the final sector Sl shown in FIG. And a command for operating the control device 2a so that a character is written. Here, the character characters corresponding to the predetermined number of bytes are, for example, a column composed of a plurality of characters such as numbers or alphabets, or a column in which these are mixed.
[0021]
Next, the operation of the information destruction system as described above will be described with reference to the flowcharts of FIGS.
[0022]
First, the user inserts the recording medium 10 in which the information destruction program 11 is stored into the reading device 4 of the electronic computer main body 2, and turns on the electronic computer main body 2 (step ST1). As a result, the system is automatically activated with the reading device 4 as a boot drive, and the control device 2a displays a parameter request prompt on the display device 5 based on the information destruction program 11 (step ST2).
[0023]
Here, when the user designates a desired parameter (write ratio or estimated required time until the information destruction process is completed) from the input device 6 (step ST3), the control is performed by the average access speed measurement command 11a of the information destruction program 11. The device 2a causes the HDD 3 to access the disk and measures the average access speed TAT to the HDD 3 (step ST4).
[0024]
Subsequently, the control device 2a searches the processing condition table 12 by the table search command 11b, reads the search parameter based on the specified parameter in step ST3 and the average access speed TAT obtained in step S4, and specifies the specified parameter. At the same time, it is displayed on the display device 5 (step ST5). The user re-specifies the parameter if he / she wishes to change the processing conditions.
[0025]
The user confirms the parameters of the processing conditions, and gives an instruction for information destruction processing if the processing conditions are acceptable (step ST6). As an instruction method, for example, it is conceivable to input the “Y” key in accordance with the input instruction “Y (YES) / N (NO)” displayed on the display device 5 based on the information destruction program 11. When such an information destruction processing instruction is given, the control device 2a sets the sector position and the number of tracks of the HDD 3 to the initial value “0” in accordance with the write command 11c of the information destruction program 11 (step ST7), and a predetermined number of bytes. Character characters (1 KB in this case) are generated by random numbers and acquired (step ST8).
[0026]
Next, the control unit 2a moves the magnetic head to the first track of the HDD 3, as shown in FIG. 3, the first sector S predetermined tracks from _h step in all sectors (here five tracks are) ST8 The character characters acquired in step 1 are written (steps ST9 to ST11).
[0027]
Subsequently, in response to the write command 11c, the control device 2a starts from the sector next to the last sector written in steps ST9 to ST11 (step ST12), and in step ST8 according to the write ratio of the above processing conditions. The acquired character characters are written in the remaining sectors (steps ST13 to ST16).
[0028]
Specifically, first, it is determined whether or not the sector set as the starting point in step ST12 is the last sector Sl (step ST13). If the sector is not the last sector S1, whether the sector is the sector to be written next. Is determined (step ST14).
[0029]
Here, in the present embodiment, the determination in step ST14 is performed in accordance with the writing ratio of the processing conditions that has been determined in advance. More specifically, the number of bytes writable in one sector is determined in advance by the format of the HDD 3, and the number of character characters to be written in the information destruction processing in this embodiment is also determined in advance. Based on this, the number of sectors required to write the character character of that number of bytes is inevitably determined by the format of the HDD 3. Similarly, the number of sectors corresponding to the number of bytes of the write interval determined by the write rate under the above processing conditions is determined from the format of the HDD 3. Thus, when the number of sectors to be written and the number of sectors having a write interval including this sector are clarified, the number of sectors not to be written in the write interval is determined. Here, in the information destruction program 11, if it is set that character characters are written from the first sector of one writing interval and writing is not performed for the remaining sectors, a predetermined number is written from the first sector. Since this is the target sector and the other sectors are non-written sectors, in the present embodiment, such information is used in the determination of step ST14.
[0030]
More specifically, for example, in the case of the processing conditions described above (writing ratio “0.1 (%)” and estimated required time “20x (s)”), 1 KB character character is written per 1 MB. Here, if the HDD 3 has a format in which 512 B can be written in one sector, two sectors are required to write a 1 KB character, and “1 MB / 512 B = 1953.125”. Therefore, a writing interval of 1 MB requires 1954 sectors. For this reason, the first sector to the second sector from the starting point in step ST12 are determined as write target sectors, and the remaining 1952 (= 1954-2) sectors are determined as non-write sectors.
[0031]
If it is determined in step ST14 that the sector is a write target sector, the control device 2a causes the magnetic head to write a character character in the sector based on the write command 11c (step ST15). When the writing to this sector is completed, the sector position is updated to the next sector (step ST16), and processing for this sector is performed. If it is determined in step ST14 that the sector is a non-write sector, the control device 2a proceeds to step ST16 and causes the next sector to be processed. The above steps ST13 to ST16 are repeated up to the last sector Sl, and if it is determined in step ST13 that it is the last sector Sl, an end message is output to the display device 5 and the process returns to the prompt. Terminate the process. When a write error occurs, a message to that effect is output and the process returns to the prompt and ends.
[0032]
As described above, by using this information destruction system, it is possible to efficiently write character characters to the disk at a writing rate according to the needs of the user, so that the processing time required for information destruction can be shortened. It becomes. Specifically, the user can know the estimated required time when the desired write ratio is specified, and the write ratio before the writing starts when the desired estimated required time is specified. According to the importance of the information recorded in the HDD 3, it is possible to perform the information destruction process giving priority to either the writing ratio or the required time. For example, if confidential information has been recorded, it can be reliably destroyed by increasing the writing ratio even if processing time is long. If information that is not so important is recorded, the processing time can be reduced. Priority processing in a short time becomes possible.
[0033]
Here, in this information destruction system, not only writing at intervals, but also writing of character characters to all sectors from the leading sector _Sh to a predetermined number of tracks. This is because the file management information is generally recorded on the head sector _Sh side, and by writing character characters to all sectors from the head sector _Sh to a predetermined number of tracks as in this system, The file management information is securely deleted, and the actual data area can be accessed.
[0034]
Further, the HDD 3 in which information is destroyed by this system does not destroy the data by irradiating the disk with strong magnetism as in the conventional example, so that it can be reused by formatting again.
[0035]
In the above-described embodiment, an example in which the MS-DOS system 12 and the automatic startup file 13 are stored in the recording medium 10 illustrated in FIG. 1 is illustrated, but the present invention is not necessarily limited thereto. You may have in advance,
[0036]
Further, although the HDD 3 is exemplified as the destruction target, the present system can also be used when destroying information recorded on a magnetic recording medium such as a flexible disk.
[0037]
【The invention's effect】
According to the information destruction system and information destruction program for a magnetic recording medium according to the present invention, character characters are written at a specified writing rate, so that the processing time required for information destruction can be shortened, thereby enabling efficient information. Destruction is possible. In addition, prioritize either the writing rate or the required time according to the needs of the user, that is, considering whether the recorded information is important information such as confidential information or not so important information. Therefore, it is possible to efficiently destroy information according to the importance of information.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing an embodiment of an information destruction system and an information destruction program according to the present invention.
FIG. 2 is a diagram showing an example of a processing condition table used in the present embodiment.
FIG. 3 is a conceptual diagram exemplifying a sector to which a character character is written in the HDD according to the embodiment.
FIG. 4 is a flowchart illustrating a flow of information destruction processing in the present embodiment.
FIG. 5 is a flowchart for explaining the continuation of the information destruction process shown in FIG. 4;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Electronic computer 2 Electronic computer main body 2a Control apparatus 3 HDD
4 Reading device 5 Display device 6 Input device 10 Recording medium 11 Information destruction program 11a Average access speed measurement command 11b Table search command 11c Write command 12 MS-DOS system 13 Automatic startup file 14 Processing condition table Sh First sector Sl Last sector TAT Average Access speed

Claims (4)

A processing condition table storing an estimated required time required for information destruction processing based on an average access speed for a magnetic recording medium having a plurality of sectors and a character character writing ratio indicating an interval at which character characters are written; An information destruction system for a magnetic recording medium that destroys recorded information,
A first step of measuring an average access speed to the magnetic recording medium, and determining a writing ratio of character characters per sector corresponding to the measured average access speed with reference to the processing condition table ;
A second step of writing character characters for a predetermined number of bytes generated from random numbers in all recording areas of all sectors for a predetermined track from the first sector of the magnetic recording medium;
A magnetic recording medium comprising means for executing a third step of writing character characters in the proportion determined in the first step in the recording areas of all remaining sectors following the predetermined track. Information destruction system. Said means is
A fourth step for displaying the time required for the information destruction process according to the write ratio determined in the first step; and when the required time is specified, the write ratio according to the specified required time is displayed. 5. The information destruction system for a magnetic recording medium according to claim 1, wherein the fifth step is performed. Including a processing condition table storing an estimated required time required for information destruction processing based on an average access speed and a writing ratio of character characters to a magnetic recording medium having a plurality of sectors, An information destruction program for a recording medium information destruction system,
On the computer,
A first function of measuring an average access speed to the magnetic recording medium and determining a writing rate of character characters per sector corresponding to the measured average access speed with reference to the processing condition table;
A second function for writing character characters for a predetermined number of bytes generated from random numbers in all recording areas of all sectors for a predetermined track from the first sector of the magnetic recording medium;
An information destruction program for a magnetic recording medium for executing a third function of writing character characters at a ratio determined by the first function in a recording area of all remaining sectors following the predetermined track. A fourth function for displaying a time required for the information destruction process according to the writing ratio determined in the first function;
4. The program for destroying information on a magnetic recording medium according to claim 3, wherein when the required time is designated, a computer is caused to execute a fifth function for displaying the writing ratio according to the designated required time.

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