Creating disk images

Background

The disk imager component in Klennet Recovery is based on the now-discontinued Klennet Disk Imager. The integrated imager provides the most-used subset of the capabilities of the standalone tool. Additionally, you can use the integrated imager to create images of RAID arrays.

Concept

The disk imager reads the source media and creates a disk image file, which holds the copy of all the readable content from the source media. The imager does it in three passes. The goal of using multiple passes instead of a single pass is to capture all the easily readable data first, then re-do the difficult parts and localize the media damage. To this end, the imager uses a large block size on the first pass, smaller block size for the second pass, and then reads individual sectors on the final pass.

Controls and settings

Pause

The imager opens paused so you can adjust the settings before it starts. Once you have configured the settings as you see fit, uncheck the Pause to start the process. Later, you can pause and resume any time you like.

Stop

The Stop button stops the imaging. The resulting disk image file contains the data read before you stopped the process.

Block sizes and timeouts

This group of settings controls parameters for each pass.

  • The third pass always uses single-sector blocks.
  • On a good disk, set the block size and timeout of the first pass to the maximum to achieve maximum throughput.
  • When imaging a physically damaged disk, you may have to decrease block size and timeout for the first pass. 256KB and 250 ms or 100 ms should be a good starting point.
  • Somewhat surprisingly, the same values work for SSDs.

Bad block fill

This group of settings determines what is written to the image file when the corresponding sector of the source is unreadable. Consider using a text signature - it allows you to find damaged spots later by doing a full-text search for the signature in the recovered files. In any mode, the imager fills the entire bad sector with a pattern you specify by repeating the pattern to the end of the sector.