An optical disc is a flat, usually circular disc which encodes binary data in the form of pits and lands on a special material on one of its flat surfaces.
- Main article: Shadow Moses Incident
Metal Gear REX's combat exercise data, concerning the stealth nuclear warhead, was originally stored on a hard disk at Shadow Moses Island, but it was damaged by gunfire during FOXHOUND's revolt in 2005. The only remaining data was stored on a magneto-optical disc, which ArmsTech president Kenneth Baker entrusted to Solid Snake to give to the U.S. Secretary of Defense Jim Houseman. Revolver Ocelot took the disc from Snake prior to torturing him. Following the incident, Ocelot supplied the data to Solidus Snake, and later sold the information on the black market, resulting in the development of countless Metal Gear derivatives all over the world.
At the conclusion of the Shadow Moses Incident, Nastasha Romanenko was given two optical discs by her ex-husband, DIA Major Richard Ames as a means to protect her from his employers, the Patriots. One contained the entire record of events of the incident, while the other held details on the Pentagon's FOXDIE project. Nastasha later used this information to write a book called In the Darkness of Shadow Moses: The Unofficial Truth.
Gary McGolden, a journalist, received an optical disc from an unknown party. He believed it was from his friend Max Smithson, chief editor of the magazine MEGASURPRISE, though Max would later deny this. The disc contained Nastasha's book, In the Darkness of Shadow Moses: The Unofficial Truth. After reading the book, he decided to conduct an investigation to see if the contents of the book were true. He disappeared soon after publishing his story.
During the Big Shell Incident in 2009, Emma Emmerich used a disc containing a worm cluster to disable the GW AI, which had been modeled after the FOXDIE assassination virus. She managed to install the virus, but the upload stopped at ninety percent, severely impairing GW, but failing to destroy it entirely. It was also intended to destroy the Patriots identities, but Philanthropy managed to utilize the copy inside the disc to find the parameter code that would allow them to locate what was believed to be the Patriots identities and their main base of operations. A dummy disc was also supplied to Raiden by Solid Snake shortly before the former's capture.
Behind the scenes
The MO Disc is an item acquired by the player in both Metal Gear Solid and Metal Gear Solid 2: Sons of Liberty, after the player's character rescues Kenneth Baker and President Johnson, respectively. It has no use during gameplay, and is removed from the inventory around the time that the player's character is captured by enemy forces.
- "Optical disc given by the President. Contains computer virus to destroy control function of GW / Arsenal Gear."
- ―MO Disc description in Metal Gear Solid 2: Sons of Liberty