What is a dynamic configuration overlay (DCO)?

An additional hidden area on many of today’s HDDs is the Device Configuration Overlay (DCO). The DCO allows system vendors to purchase HDDs from different manufacturers with potentially different sizes, and then configure all HDDs to have the same number of sectors. An example of this would be using DCO to make an 80 Gigabyte HDD appear as a 60 Gigabyte HDD to both the OS and the BIOS. 

Some data sanitization standards include the DCO as a "user accessible" area that needs to be be removed/erased in order to comply with the standard. The thought process behind this requirement is that the DCO could potentially contain some kind of remnant data, and therefore should be removed in order to ensure that all of the potentially "user accessible areas" are available for erasure. 

The Verity Eradication Software is designed to detect and restore the DCO, but in the rare instance that it is unable to do so, the software will document the condition in the log files and reporting generated as a result of the eradication session.

Versions: v1.0.1