CN100423002C - Method for deleting files in FAT roll - Google Patents
Method for deleting files in FAT roll Download PDFInfo
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- CN100423002C CN100423002C CNB2006101222495A CN200610122249A CN100423002C CN 100423002 C CN100423002 C CN 100423002C CN B2006101222495 A CNB2006101222495 A CN B2006101222495A CN 200610122249 A CN200610122249 A CN 200610122249A CN 100423002 C CN100423002 C CN 100423002C
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Abstract
The related canceling method for FAT file comprises: a. positioning the file directory; b. modifying the first character of short filename directory into hexadecimal '0xE5', and storing; c. modifying the first character of long filename directory into hexadecimal '0xE5', and storing; d. positioning all FAT items according to file initial cluster information to obtain the cluster chain; e. filling all FAT items of the file with hexadecimal '0x00'. This invention can cancel file even the file is used.
Description
Technical field
The present invention relates to computer application field, relate in particular to the method for file in a kind of FAT of deletion volume.
Background technology
The method of file is a lot of in the deletion disk, also there is the delet method of self in the Windows system, but, after definite certain file is rogue programs such as virus or wooden horse, rogue software, when needing this rogue program file of deletion, often, bring certain difficulty to virus sweep like this in internal memory, also can't delete for user's file just in use in addition because this document is just carried out and the refusal deletion action.On the other hand, some rogue program can be protected some files, allows the user can not delete these files, and in this case, the method for existing deleted file just can't reach the deleted file purpose.
Summary of the invention
The present invention has overcome shortcoming of the prior art, and the method for using file in a kind of FAT of deletion volume is provided.
In order to solve the problems of the technologies described above, be achieved through the following technical solutions:
The method of file in the deletion FAT volume, it comprises the steps:
A, according to the directory entry of file path location this document of user input;
B, change first character of the short-and-medium file name list item of this document directory entry into 16 hex value " 0xE5 " and deposit;
C, change first characters of all long filenames directory entries in this document directory entry into 16 hex value " 0xE5 " and deposit;
D, locate corresponding FAT item in all FAT table, obtain bunch chain of this file according to file starting cluster information in the directory entry of this document;
E, according to the FAT chain information of this document, fill the FAT item that all this document take bunch space with 16 hex value 0x00.
File in use the inventive method deletion FAT volume is not subjected to the influence of file user mode, both made file be in user mode, can delete this document equally, this method mainly is that first character that will treat the file name list item in the deleted file directory entry changes deleted marker into, in addition, the FAT chain information of this document is filled with 16 hex value 0x00, so just can delete the file in the FAT volume.
Description of drawings
Fig. 1 is the inventive method process flow diagram.
Embodiment
Introduce the process and the principle of work of the inventive method below with reference to Fig. 1.
The method of file in the deletion FAT volume, it comprises the steps:
1, locatees the directory entry of this document according to the file path of user's input; File (file) is the format management with directory entry in the FAT volume, and each file (file) all has directory entry separately, comprises project information such as file (catalogue) name, file starting cluster information, file size and creation-time in the directory entry.Suppose to treat the deleted file path be D: food milk.doc, promptly find the directory entry of milk.doc file.
2, first character with the short-and-medium file name list item of this document directory entry changes 16 hex value " 0xE5 " and deposit into; Because some operating system is not supported the filename of length greater than 8 bytes, for with these system compatibles, for the file of filename length greater than 8 bytes, one short filename (length is 8 bytes) and a long filenames (length is greater than 8 bytes) are arranged, and for the file of length less than 8 bytes, it has only a short filename.Change first character of filename file name list item into 16 hex value " 0xE5 ", just first character of this document name is changed into deleted marker "? ", show that this document is deleted.
3, first character with all long filenames directory entries in this document directory entry changes 16 hex value " 0xE5 " and deposit into; Then do not have this step for the file that does not have long filenames, its principle is the same.
4, locate corresponding FAT item in all FAT table according to file starting cluster information in the directory entry of this document, obtain bunch chain of this file; Described in step 1, comprise file starting cluster information in the directory entry, the starting cluster of supposing this milk.doc file is 3, can navigate to the 3rd in the FAT table, suppose that this middle content is 5, the 5th in navigating to FAT table then, the rest may be inferred, up to finding the FAT of end mark item is arranged, also just obtain bunch chain of this document.
5, according to the FAT chain information of this document, fill the FAT item that all this document take bunch space with 16 hex value 0x00.This step is exactly with the whole zero clearings of each FAT item in the above-mentioned bunch of chain, also promptly can't find the correspondence position of this document data in disk, realizes the purpose of deleted file.
Above step is the unrestricted technical scheme of the present invention in order to explanation only.Any modification or partial replacement that does not break away from spirit and scope of the invention all should be encompassed in the middle of the claim scope of the present invention.
Claims (2)
1. the method for file in the deletion FAT volume is characterized in that it comprises the steps:
A. locate the directory entry of this document according to the file path of user's input;
B. first character with the short-and-medium file name list item of this document directory entry changes 16 hex value " 0xE5 " and deposit into;
C. first character with all long filenames directory entries in this document directory entry changes 16 hex value " 0xE5 " and deposit into;
D. locate corresponding FAT item in all FAT table according to file starting cluster information in the directory entry of this document, obtain bunch chain of this file;
E. according to the FAT chain information of this document, fill the FAT item that all this document take bunch space with 16 hex value 0x00.
2. the method for file is characterized in that described 16 hex value " 0xE5 " are the file delete mark in the deletion FAT volume according to claim 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2006101222495A CN100423002C (en) | 2006-09-19 | 2006-09-19 | Method for deleting files in FAT roll |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2006101222495A CN100423002C (en) | 2006-09-19 | 2006-09-19 | Method for deleting files in FAT roll |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1928869A CN1928869A (en) | 2007-03-14 |
| CN100423002C true CN100423002C (en) | 2008-10-01 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2006101222495A Active CN100423002C (en) | 2006-09-19 | 2006-09-19 | Method for deleting files in FAT roll |
Country Status (1)
| Country | Link |
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| CN (1) | CN100423002C (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102567325B (en) * | 2010-12-14 | 2013-11-27 | 无锡华润矽科微电子有限公司 | Method for analyzing file name of FAT(file allocation table)file system |
| CN102280134B (en) * | 2011-06-17 | 2014-04-16 | 苏州国芯科技有限公司 | Method for improving data security in removable storage device |
| CN104331348A (en) * | 2014-11-27 | 2015-02-04 | 四川效率源信息安全技术有限责任公司 | Method for recovering file by reducing initial cluster number of FAT32 directory entry |
| CN104699794B (en) * | 2015-03-18 | 2018-11-13 | 四川秘无痕信息安全技术有限责任公司 | A method of it thoroughly removes and has deleted jpg formatted files in FAT32 file system |
| CN106372080A (en) * | 2015-07-22 | 2017-02-01 | 安恒通（北京）科技有限公司 | File clearing method, apparatus and system |
| CN106326384A (en) * | 2016-08-16 | 2017-01-11 | 中国科学院长春光学精密机械与物理研究所 | File storage method suitable for high-speed mass storage based on FPGA (Field Programmable Gate Array) |
| CN106600750B (en) * | 2016-11-21 | 2019-05-10 | 建荣半导体（深圳）有限公司 | A kind of method of circulation recording, system and automobile data recorder |
| CN113190178B (en) * | 2021-05-21 | 2022-08-02 | 山东省计算中心（国家超级计算济南中心） | Traceless data deletion method and traceless data deletion system in FAT32 file system |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6314437B1 (en) * | 1997-09-30 | 2001-11-06 | Infraworks Corporation | Method and apparatus for real-time secure file deletion |
| CN1359071A (en) * | 2001-11-29 | 2002-07-17 | 上海格尔软件股份有限公司 | Method for completely deleting files on hard disk |
| CN1773462A (en) * | 2005-10-17 | 2006-05-17 | 珠海金山软件股份有限公司 | Method for recovering deleted file of FAT32 partition |
-
2006
- 2006-09-19 CN CNB2006101222495A patent/CN100423002C/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6314437B1 (en) * | 1997-09-30 | 2001-11-06 | Infraworks Corporation | Method and apparatus for real-time secure file deletion |
| CN1359071A (en) * | 2001-11-29 | 2002-07-17 | 上海格尔软件股份有限公司 | Method for completely deleting files on hard disk |
| CN1773462A (en) * | 2005-10-17 | 2006-05-17 | 珠海金山软件股份有限公司 | Method for recovering deleted file of FAT32 partition |
Non-Patent Citations (2)
| Title |
|---|
| 文件删除的原理及应用. 朱蓉，郑建华.电脑学习，第1期. 2006 |
| 文件删除的原理及应用. 朱蓉，郑建华.电脑学习，第1期. 2006 * |
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| Publication number | Publication date |
|---|---|
| CN1928869A (en) | 2007-03-14 |
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Address after: Jinshan computer Building No. 8 Jingshan Hill Road, Lane 519015 Zhuhai Jida Lianshan Guangdong city of Zhuhai Province Patentee after: Zhuhai Kingsoft Software Co.,Ltd. Address before: Jinshan computer Building No. 8 Jingshan Hill Road, Lane 519015 Zhuhai Jida Lianshan Guangdong city of Zhuhai Province Patentee before: Zhuhai Kingsoft Software Co.,Ltd. |
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Effective date of registration: 20140902 Address after: Kingsoft No. 33 building, 100085 Beijing city Haidian District Xiaoying Road Patentee after: BEIJING KINGSOFT INTERNET SECURITY SOFTWARE Co.,Ltd. Address before: Jinshan computer Building No. 8 Jingshan Hill Road, Lane 519015 Zhuhai Jida Lianshan Guangdong city of Zhuhai Province Patentee before: Zhuhai Kingsoft Software Co.,Ltd. |
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Application publication date: 20070314 Assignee: Zhuhai Kingsoft Software Co.,Ltd. Assignor: BEIJING KINGSOFT INTERNET SECURITY SOFTWARE Co.,Ltd. Contract record no.: 2014990000778 Denomination of invention: Method for deleting files in FAT roll Granted publication date: 20081001 License type: Common License Record date: 20140926 |
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