Contiguous, Fragmented, and Damaged files in Klennet Carver

When Klennet Carver recovers files, the files are categorized into three groups - Contiguous, Fragmented, and Damaged.

Category definitions

Contiguous files are just that, files that are stored contiguously on the media. These files are valid and do not require complicated recovery. Non-contiguous files, which are stored in several non-adjacent fragments on media, require complicated reconstruction process to find all the fragments and join them as appropriate. If the recovery algorithm determines that resulting file is valid, the file is placed into Fragmented category. If the recovery algorithm fails to find all fragments of the file, fails to position them properly, or cannot make sure the file is valid, the file is placed into Damaged category.

Understanding results

Contiguous files are good.

Fragmented files are almost always good. File validation algorithms are not perfect, but pretty good, with less than one in thousand average error rate.

Damaged files need to be reviewed by hand.

Image files, such as JPEG, may still be usable, for example after cropping. Image file with has a narrow swath at the bottom damaged may be useful, but is still declared damaged by the algorithm.

Video files (MP4) will be classified as damaged even if there is a single frame missing, which often happens when fragment boundaries cannot be precisely established. I recommend that you review all video files to see if they are badly damaged, can be used in parts, or can be used as a whole. This especially applies to videos coming from dash camera memory, when even several frames can be useful. Also, with damaged videos, always try different players. VLC player and MPC-HC will often work where Windows built-in player does not.

Created Wednesday, May 29, 2019