This defense process is for the sole purpose to ensure that risk management is applied on information systems which are otherwise known as IS.
DIACAP comes under the definition of a DoD-wide formal and standard set of actions, general tasks and a basic management infrastructure process in order to certify and accredit the maintenance of the IA, or to give it its full title, the information assurance throughout the system's life cycle.
The first beginnings of the DIACAP actually began back in 2006 where an interim version of the DIACAP was signed, but this was then out-dated and transformed to the DITSCAP. The final copy of this is now entitled the DOD or Department of Defense Instruction and was signed on November 28, 2007.
This is a straight replacement for the interim period where it was under the DIACAP Guidance. It encourages and embraces assurance controls and people who go to college and do a course on the DIACAP will have the opportunity to learn a number of things. These include being knowledgeable in threats, vulnerabilities, adversaries, and risks to information systems.