JP2004287550A - Recording medium data erasing method, data display method, computer program, and recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To completely erase data of a recording medium such as a hard disk to prevent restoration of data and then to give another meaning while facilitating its confirmation. <P>SOLUTION: Random number values are first written in the whole erase object area of the hard disk (S301). Specific information is written in the first and last parts of each sector, and fixed values of "0" or "1" are written in other areas (S302-S304). When writing of one sector part is completed, whether or not writing of the whole erase object area is completed is determined, and if not being completed, the erasure processing is repeatedly performed (S302-S304). When completed, the erasure processing is terminated. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a data erasing method and a data displaying method for a recording medium, and more particularly, to a method for erasing data recorded on a recording medium such as a hard disk while giving it another meaning. The present invention relates to an erasing method, a method for displaying data in a recording medium, a computer program, and a recording medium.
[0002]
[Prior art]
For the purpose of preventing personal information and important data from leaking from the hard disk when returning a leased or rented personal computer (PC) or letting go of an old computer for replacement, etc. There are many means for erasing data, and there are various erasing methods.
[0003]
For example, in the NSA standard (U.S. Department of Defense NSA standard), complete erasure of recorded data is realized by writing a random number the first time and the second time and writing zero (hexadecimal 00) the third time. In the old NSA standard, complete erasure of recording data is realized by writing zero at the first and third times and writing a fixed value (for example, hexadecimal FF) at the second and fourth times. Further, in the DoD standard (U.S. Department of Defense standard), complete erasure of recorded data is realized by writing zero at the first time, fixed value at the second time, and random number at the third time. In the NATO standard (NATO standard), complete erasure is realized by writing zero at the first, third, and fifth times, writing a fixed value at the second, fourth, and sixth times, and writing a random number at the seventh time. ing.
[0004]
In addition, in order to prevent unauthorized use of application software that executes the above-described erasing method, a method of writing specific information of the used application software to a start address or an end address of the hard disk after data erasing processing on the hard disk is also known. (See Patent Document 1). According to this method, it is possible to specify the application software from which the data on the hard disk has been deleted. Further, by including the serial number of each application software in the specific information, each application software can be specified.
[0005]
[Patent Document 1]
JP-A-2002-312128
[Problems to be solved by the invention]
However, in any of the above-mentioned erasing methods, the purpose of the data recorded on the hard disk after the erasing process is performed is simply to prevent the data recorded on the hard disk before the erasing operation from being restored. Do not have. Therefore, there is a problem that it is difficult to determine whether or not the data has been erased. Another problem is that simply recording the specific information of the application software on the hard disk makes it difficult to confirm the specific information.
[0007]
Therefore, an object of the present invention is to completely erase data on a recording medium such as a hard disk, make it impossible to restore the data, give it another meaning, and make it easy to confirm it. An object of the present invention is to provide an improved data erasing method and data displaying method.
[0008]
[Means for Solving the Problems]
An object of the present invention is to provide a first writing step of writing a random value on a recording medium, writing specific information at a predetermined position of each sector of the recording medium, and writing "0" or "1" at other positions. This is achieved by providing a method for erasing data on a recording medium, comprising a second writing step of writing a constant value of.
[0009]
According to the present invention, it is possible to completely erase data on a recording medium such as a hard disk so that the data cannot be restored, give another meaning, and easily confirm the meaning.
[0010]
In a preferred embodiment of the present invention, the predetermined position is a beginning and an end of each sector of the recording medium.
[0011]
According to the preferred embodiment of the present invention, specific information can always be displayed on the dump screen, and it is easy to confirm the proof that the erasure has been performed.
[0012]
In a preferred embodiment of the present invention, the specific information includes information that can specify any one of a date and a time or a date and a time when the erasing process is performed.
[0013]
According to the preferred embodiment of the present invention, it is possible to reliably prove the date and time when the erasing process was executed.
[0014]
In a further preferred embodiment of the present invention, the recording medium is a hard disk.
[0015]
According to a further preferred embodiment of the present invention, when completely erasing data recorded on the hard disk for the purpose of preventing personal information and important data from being leaked when giving up an old computer by replacement etc. In particular, it becomes easy to confirm proof that the erasing process has been performed, which is particularly required.
[0016]
The object of the present invention also provides a computer having a recording / reproducing means for a recording medium, a first writing step of writing a random value to the recording medium, and specific information at a predetermined position in each sector of the recording medium. This is also achieved by a computer program for executing a second writing step of writing a constant value of “0” or “1” in another position while writing.
[0017]
The above object of the present invention is further characterized in that it has a step of dumping and displaying the data in the recording medium in half-sector units and a step of switching the dump display in one-sector units or half-sector units. This is also achieved by a method for displaying data in a recording medium.
[0018]
According to the present invention, the entire dump screen can be reliably displayed even in the VGA display, and when the specific data is written at the beginning and end of one sector by the above-described data erasing method, the dump screen is displayed. Specific information can always be displayed on the screen, and it is easy to confirm that the erasure has been performed.
[0019]
It is another object of the present invention to provide a method for dumping and displaying data in a recording medium in units of a half sector on a computer provided with a recording / reproducing means for a recording medium. This is also achieved by a computer program for executing the step of switching the dump display.
[0020]
The above object of the present invention is also achieved by a computer-readable recording medium recording the computer program.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[0022]
FIG. 1 is a schematic block diagram showing a configuration of a computer system for realizing a data erasing method for a hard disk according to a preferred embodiment of the present invention.
[0023]
As shown in FIG. 1, the computer system 100 includes a computer main body 101, display means such as a display 102, and data input means such as a keyboard 103 and a mouse 104. These display means and data input means constitute a graphical user interface together with a data erasing program for a hard disk described later. A computer main body (sometimes simply called a computer) 101 is a configuration of a general personal computer, and includes a CPU 105, a memory 106, a hard disk drive (HDD) 107, a flexible disk drive (FDD) 108, and a CD-ROM drive 109. , An input / output interface (I / O) 110 and the like.
[0024]
In the present embodiment, the hard disk drive 107 is a target of data erasure, and the hard disk drive 107 includes a hard disk (HD). Only one hard disk drive 107 may be connected, or a plurality of hard disk drives 107 may be connected as shown. For example, in the case of IDE connection, up to four hard disk drives can be connected. On the other hand, the data erasing program 111 of the hard disk is provided in a state of being recorded on the flexible disk (FD) 108F or the CD-ROM 109C. The data erasing program 111 of the hard disk is read from the FDD or the CD-ROM drive when the computer is started, and is automatically expanded in the memory 106. As a result, the program operates at the BIOS level, and data is erased from the hard disk.
[0025]
FIG. 2 is a screen diagram showing a main screen of the data erasing program of the hard disk displayed on the display 102.
[0026]
As shown in FIG. 2, on the main screen 200, a menu box 201 for selecting any one of the items “data erase” 201a, “dump” 201b, and “end” 201c is displayed. Each item is selected by a predetermined key operation and shifts to each mode. The “data erasing” 201a is a mode for executing an erasing process according to the erasing method according to the present invention, and shifts to the mode when the “1” key is pressed. The "dump" 201b is a mode for checking the contents of the hard disk. When the "2" key is pressed, the mode shifts to that mode. The "end" 201c is a mode for ending the hard disk erasing program. When the “data erase” 201a is selected, it is preferable to execute a process of repeatedly confirming whether the erase process may be executed before actually executing the erase process. Next, the procedure of the data erasing process will be described in detail.
[0027]
FIG. 3 is a flowchart showing the procedure of the data erasing process of the hard disk.
[0028]
As shown in FIG. 3, in this data erasing process, first, a random number value is written in the entire erasure target area of the hard disk (S301). The random number value may not be generated in units of bits, and may be generated in units of several bits or several bytes. Further, a predetermined random number pattern may be repeatedly used.
[0029]
Next, specific information is written in a predetermined position of each sector, and a constant value of "0" or "1" is written in other positions (S302 to S304). Specifically, in this example, specific information is written as binary data from the beginning of the sector (S302). Next, a constant value of "0" or "1" is written until just before leaving an area for recording specific information (S303). Then, by writing specific information again as binary data at the end of the sector (S304), writing for one sector is completed. That is, in this example, specific information is written at the first and last positions of each sector, and a constant value of "0" or "1" is written at other positions. A sector is a unit for reading / writing data from / to a magnetic disk such as a flexible disk or a hard disk, and one sector is 512 bytes. When the writing of one sector is completed, it is determined whether or not the writing of the entire erasure target area has been completed (S305). When the processing is completed (S304Y), the erasing process is terminated. According to this erasing method, the number of times of writing to the hard disk is two.
[0030]
Since the specific information is the only proof that the erasure has been performed, the name of the program provider or the name of the program (application software) that certifies that the data erasure program has been executed without fail, It is preferable to write the date and time when the erasing is executed, but the present invention is not limited to these. For example, different information such as a serial number may be written for each sector, and arbitrary information specified by the user may be recorded. Therefore, a character code such as an ASCII code is used for the specific information.
[0031]
FIG. 4 is a data map showing an example of the recorded contents of the hard disk erased by the above-mentioned erasing method.
[0032]
As shown in FIG. 4, in the present embodiment, character information 402 of "TDK200330311930001" is recorded at the beginning and end of each sector 401 of the hard disk, and a constant value is recorded in other areas. In FIG. 4, the area where the constant value is recorded is shown as blank. The actual character information is recorded as binary data. Here, the portion of “200303019” in the character information 402 is the date (March 19, 2003) at which the erasing process was executed, and the portion of “123001” is the time (12:30:30). Yes, it is set according to the time information in the computer. As described above, if specific information is recorded in each sector, it can be confirmed in all sectors.
[0033]
FIG. 5 is a diagram showing a dump screen displayed when a dump is selected on the main screen 200 shown in FIG.
[0034]
As shown in FIG. 5, on the dump screen 500, a hard disk (HD) number 501, a capacity (size) 502, and a sector number 503 that are currently being dumped are displayed. When a plurality of hard disks are connected to the computer, each can be distinguished by the HD number 501. The hard disk to be dumped can be switched by key operation. The sector number 503 is the number of the sector currently being dumped, and will be referred to when changing the sector to be dumped, as will be described later in detail.
[0035]
Further, an address display unit 504, a binary display unit 505, and a text display unit 506 are displayed on the dump screen 500. The address display section 504 displays the address of the area currently being dumped. The binary display unit 505 displays binary data recorded at each address in hexadecimal (HEX). In the text display unit 506, binary data recorded at each address is displayed as text according to a character code such as ASCII. Therefore, when the data on the hard disk is erased by the erasing method shown in FIG. 2, specific information is displayed on the text display unit 506 as text. In this specification, a hexadecimal number may be represented by (xx) _h (x is any one of 0 to 9 and A to F).
[0036]
On the dump screen 500, data for one half sector is displayed. That is, 256 bytes of data can be displayed in one screen. The dump range can be moved in sector units or half-sector units by a predetermined key operation, or can be dumped by designating a sector number. As described above, this data erasing program operates at the BIOS level, but the VGA mode (640 dots × 480 dots) is adopted for the display at the BIOS level. Therefore, in the case of the VGA mode, it is difficult to display all data of one sector (512 bytes). However, if the data is 256 bytes, it can be displayed reliably. In the present embodiment, since the first half of the sector in the hard disk erased by the erasing method shown in FIG. 2 is displayed as a dump, specific information is recorded at the head of the sector. For this reason, specific information is shown in the text display unit 506 as text data (TDK20033031293001).
[0037]
As described above, according to the present embodiment, when erasing data from the hard disk, specific information is recorded at the beginning and end of each sector of the hard disk. Can be easily confirmed.
[0038]
Further, according to the present embodiment, since the dump is displayed in units of one-half sector, the entire dump screen can be reliably displayed even in the VGA display. In addition, since the dump is displayed in units of one-half sector and the dump is switched in units of one sector or one-half sector, specific information is written at the beginning and end of one sector. In the case of the deletion, the specific information can be always displayed on the dump screen, and it is easy to confirm the proof that the deletion has been performed.
[0039]
The present invention is not limited to the above embodiments, and various changes can be made within the scope of the invention described in the claims, and these are also included in the scope of the present invention. Needless to say, there is.
[0040]
For example, in the above-described embodiment, the case where the hard disk is erased has been described as an example. However, the present invention is not limited to this. For example, various types such as a flexible disk, a magneto-optical disk (MO), a flash memory card, a USB memory, etc. It is applicable to any recording media. However, for a recording medium without the concept of a sector, 512 bytes correspond to one sector.
[0041]
Further, in the above-described embodiment, the case where the above-described data erasing function and dump display function are realized by one program (application software) is described as an example. However, the present invention is not limited to this. And the dump display program may be provided independently as separate programs.
[0042]
Further, in the above-described embodiment, an example has been described in which the data erasing process according to the present invention is immediately executed when “data erasing” is selected on the main screen. For example, the erasing process may be executed after an erasing target is selected from a plurality of hard disks or partitions thereof, or one of a plurality of erasing methods is selected.
[0043]
Further, in the above-described embodiment, the case where specific character information is recorded at the beginning and end of each sector of the hard disk and a constant value is recorded in other areas is described as an example. However, the present invention is not limited to this. Instead, it is sufficient that specific information is recorded once per half sector. Further, if specific information is recorded at a predetermined position of each sector of the hard disk, where in the sector the specific information is recorded It does not matter.
[0044]
【The invention's effect】
As described above, according to the present invention, data on a recording medium such as a hard disk is completely erased so that the data cannot be restored, the data is given another meaning, and the data can be easily reproduced. An improved data erasing method and data displaying method that can be confirmed can be provided.
[Brief description of the drawings]
FIG. 1 is a schematic block diagram showing a configuration of a computer system for realizing a data erasing method for a hard disk according to a preferred embodiment of the present invention.
FIG. 2 is a screen diagram showing a main screen of a data erasing program of a hard disk displayed on a display 102;
FIG. 3 is a flowchart illustrating a procedure of a data erasing process of a hard disk;
FIG. 4 is a data map showing an example of recorded contents of a hard disk erased by the above-mentioned erasing method.
FIG. 5 is a diagram showing a dump screen displayed when a dump is selected on the main screen 200 shown in FIG. 2;
[Explanation of symbols]
REFERENCE SIGNS LIST 100 computer system 101 computer main body 102 display 103 keyboard 104 mouse 106 memory 107 hard disk drive (HDD)
108 Flexible Disk Drive (FDD)
108F Flexible disk (FD)
109 CD-ROM drive 109C CD-ROM
110 input / output interface (I / O)
111 Data Erase Program 200 Main Screen 201 Menu Box 201a "Erase Data" Item 201b "Dump" Item 201c "End" Item 401 Each Sector 402 Character Information (TDK200303319123001)
500 Dump screen 501 Hard disk (HD) number 502 HD capacity (size)
503 Sector number 504 Address display section 505 Binary display section 506 Text display section

Claims (10)

A first writing step of writing a random value to a recording medium;
A second writing step of writing specific information at a predetermined position of each sector of the recording medium and writing a constant value of "0" or "1" at another position. Erase method. The method according to claim 1, wherein the predetermined position is a beginning and an end of each sector of the recording medium. 2. The method according to claim 1, wherein the specific information includes information that can specify any one of a date, a time, or a date and a time when the erasing process is performed. 4. The data erasing method of a recording medium according to claim 1, wherein the recording medium is a hard disk. A computer equipped with a recording / reproducing means for recording media,
A first writing step of writing a random value to the recording medium;
A computer program for executing a second writing step of writing specific information at a predetermined position of each sector of the recording medium and writing a constant value of “0” or “1” at another position. A step of dumping and displaying data in the recording medium in units of a half sector;
A method of displaying data in a recording medium, comprising a step of switching the dump display in units of one sector or one half sector. A computer equipped with a recording / reproducing means for recording media,
A step of dumping and displaying data in the recording medium in units of a half sector;
A computer program for executing the step of switching the dump display in one-sector units or half-sector units. A computer-readable recording medium on which the computer program according to claim 5 is recorded. A computer-readable recording medium recording the computer program according to claim 7. A computer-readable recording medium recording the computer program according to claim 5.

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