Within the context of the ITIL framework, the Definitive Media Library is a secure repository in which an organisation's definitive, authorised versions of media Configuration Items (CIs) are stored and protected. It should contain master copies of controlled software media that have passed appropriate quality assurance checks, typically including both procured and bespoke application and gold build source code and executables.
In conjunction with the Configuration Management Database (CMDB), it effectively provides the DNA of the data center i.e. all application and build software media connected to the CMDB record of installation and configuration.
The Definitive Media Library (DML) is a primary component of an organisation's release and provisioning framework and service continuity plan.