Disk imaging

The extracted raw image can be used to reconstruct usable data after any logical damage has been repaired. Once that is complete, the files may be in usable form although recovery is often incomplete.
Open source tools such as DCFLdd or DOS tools such as HDClone can usually recover data from all but the physically-damaged sectors. Studies^[1][2] have shown that DCFLdd v1.3.4-1 installed on a Linux 2.4 kernel system produces extra "bad sectors" when executed with certain parameters^[3], resulting in the loss of information that is actually available. These studies state that when installed on a FreeBSD kernel system, only the bad sectors are lost. DC3dd, a tool that has superseded DCFLdd, and ddrescue resolve this issue by accessing the hardware directly^[3]. Another tool that can correctly image damaged media is ILook IXImager.
Typically, hard disk drive data recovery imaging has the following abilities^[4]: (1) communicating with the hard drive by bypassing the BIOS and operating system which are very limited in their abilities to deal with drives that have "bad sectors" or take a long time to read. (2) reading data from “bad sectors” rather than skipping them (by using various read commands and ECC to recreate damaged data). (3) handling issues caused by unstable drives, such as resetting/repowering the drive when it stops responding or skipping sectors that take too long to read (read instability can be caused by minute mechanical wear and other issues). and (4) preconfiguring drives by disabling certain features, such as SMART and G-List remapping, to minimize imaging time and the possibility of further drive degradation.