Marine Corps Information Assurance Operational Standard (IAOS) a reissued by the Marine Corps Enterprise Network (MCEN) Designated Approval Authority (DAA). The IAOS Series provides modules that guide the implementation of policy direction established in MCO 5239.2. The modules provide procedural, technical, administrative, and supplemental guidance for all information systems used in the automatic acquisition, storage, manipulation, management, movement, control, display, switching, interchange, transmission, or receipt of data within the MCEN as well as other USMC informntion systems.