PhotoRec is a free and open-source utility software for data recovery with text-based user interface using data carving techniques, designed to recover lost files from various digital camera memory, hard disk and CD-ROM.

The cluster or block size remains at a constant number of sectors after being initialized during the formatting of the filesystem.

The seek time of mechanical drives is significant for writing and reading data to/from a hard disk, so that is why it is important to keep the fragmentation to a minimum level.

is lost; e.g., in an ext3/ext4 filesystem, the names of deleted files are still present, but the location of the first data block is removed.

To recover these "lost" files, PhotoRec first tries to find the data block (or cluster) size.

Each block is checked against a signature database; which comes with the program and has been growing in the type of files it can recover ever since PhotoRec's first version came out.

In this case, PhotoRec parses the recovered data, then stops the recovery when the stream ends.