Tag Archives: Disk Imaging

Disk Imaging: Image by selective head(s)

Drives presented for recovery sometimes have some heads or surfaces damaged (physical damage). The problem is severe enough for the drive to stop working in its native system. However, with the latest upgraded Data Compass DCEXP utility, it is possible now (before installation of MHA replacement) to create a copy of data using the remaining good surfaces or drive heads; small files can even be recovered directly.

What’s more, this …

Solve Disk Imaging Problems (Part 3)

Customizing Imaging Algorithms

Consider the following conflicting factors involved in disk imaging:

§§ A high number of read operations on a failed drive increase the chances of recovering all the data, and decrease the number of probable errors in that data.

§§ Intensive read operations increase the rate of disk degradation and increase the chance of catastrophic drive failure during the imaging process.

§§ Imaging a drive can take a …

Solve Disk Imaging Problems (Part 2)

Disabling Auto-Relocation and SMART Attribute Processing

While the methods outlined in the previous section go a long way to obtaining an image of the data, other problems remain.

When drive firmware identifies a bad sector, it may remap the sector to a reserved area on the disk that is hidden from the user (Figure 3). This remapping is recorded in the drive defects table (G-list). Since the bad sector could …

Solve Disk Imaging Problems (Part 1)

Imaging tools provide custom hardware and software solutions to the challenges of read instability.

Processing All Bytes in Sectors with Errors

While the system software works well with hard disk drives that are performing correctly, read instability must be dealt with using specialized software that bypasses the BIOS and operating system. This specialized software must be able to use ATA read commands that ignore ECC status. (These commands are only …

Disk Imaging Problems

Disk imaging is not a trivial task. Degraded drives and drives whose physical defects have been repaired often yield a high read error rate, or read instability. Read instability means that multiple readings of the same data tend to yield different results each time. Read instability differs from cases where data originally written in error is read consistently each time, or where a physical scratch makes an entire part of …