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Chapter – 14
Programming for “Raw File” Recovery
Raw File Recovery
There are many specific file types which have some specific sequence or combination of characters written in the starting and ending of the file. We can analyze these combinations easily with the help of any disk editing program. We can also use EDIT command of DOS to study the structure of file in ASCII format.
The specific sequence or combination of character which is present in the starting of the file is usually called the header and the sequence or combination of characters which is stored in the ending of the file is called the footer of the file.
If we have lost our data in such type of disk crash that no FAT or Root Directory information is available to recover the data, we can use headers and footers to search these specific file types. The header indicates the starting of the file of that particular type and the footer indicates the end of file of that particular file type.
Here we are using the raw structure of particular file type to recover the data therefore the recovery technique is called Raw File Recovery. The surface of the disk is searched sector be sector to find the header and footer information.
Although the Raw File Recovery may have a wide area of application, but there are some specific cases of recovery where it may help a lot. For example, by mistake if you have run any data wiping program in the disk which had some important files but till you stop the program, all the information of MBR, DBR, FAT, and Root directory including Operating system files are wiped out.
In such case even format recovery programs may not help you to recover the data. Here you can use Raw file Recovery to recover the files of those specific file types by searching the headers and footers.
Not only this, even you can recover data in such cases, where you have got such a hard disk in which you have deleted all the logical partitions of the disk, recreated the partitions of different size then before and even you have installed the operating system.
Now you get remembrance, that you had some important data in the disk before partitioning and formatting it. If you have just installed the operating system, there are a lot of chances for the file to be recovered.
The factors that affect the performance of Raw File Recovery are, Fragmented data and the amount of data overwritten by some another other data. However you can your self find more and more areas of application for raw file recovery.
The procedure or almost the rules to search the files with raw file recovery program consider the following conditions:
- Search the header of the file or multiple file types simultaneously in the sectors of the disk.
- If header of any file type is found, save the data in a file and check the following four conditions to close and save the file
a) The footer of that file type is found
b) The another header of the same file type is found
c) The header of another file type is found
d) No another header or footer for the defined file types in the program is found and the size of the file in which you are storing the data reaches to the maximum size limit, which you defined for the file size, in your program.
The information should be stored in the file including the data of the sectors in which you found the header and footers of the file type.
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