U.S. Marine Corps Sergeant Blaine L. Parker was born in Phoenix, Arizona in 1955. Mainframe originally served in the Army Airborne, enlisting when he was seventeen years old. He got to Vietnam for the last year of the war and received his Combat Infantryman's badge. He left the Army and got his degree at MIT on the G.I. Bill, and went on to work in the computer industry. It made him lots of money, but bored him very quickly. When he learned the Marines were looking for computer experts, he signed up and was soon back in uniform.
Mainframe was recruited by the G.I. Joe team in 1986, working as their primary computer expert. A few months after joining the team, Mainframe was sent on a mission into the Middle Eastern nation torn apart by the war between the Royalist rebels and the forces of dictator Colonel Sharif. Spy satellites had detected the infrared signature of a Cobra Terror-Drome launch base hidden in the country, and Mainframe and Dusty were sent in to locate the base. In exchange for helping the Royalists ambush one of Sharif's weapons convoys, the rebels gave the Joes a guide to lead them through the desert. The guide was a teenage rebel named Rashid. As the trio made their way across the desert, Rashid showed Mainframe no respect, seeing him as a weak "fixer of computers", far from the great fighting man Dusty was. Mainframe was mostly amused by the boy, not caring enough about his opinion to explain his past as a soldier. At the end of the mission, Mainframe's skills as a soldier came into play, and he gained Rashid's respect. In fact, Mainframe made such an impression on Rashid, the boy became an expert in computers himself, and was later seen working for Destro. Once the Joes' established the new Pit headquarters in Utah, Mainframe spent much of his time there, working with the team's advanced computer systems. After detecting a shuttle launched from Cobra Island, Mainframe headed into space onboard the space shuttle Defiant to defend U.S. satellites against a Cobra attack. Some time later, Mainframe worked on the U.S.S. Flagg as part of General Hawk's operations team during the Joes' involvement in the Cobra Island civil war. He served in the same capacity on the Flagg later during the Battle of Benzheen.
For the next few years, Mainframe worked at the Pit, occasionally involved in research and development for new weapons systems. After the Joe team was shut down in 1994, Mainframe returned to the computer industry, working as a software developer in Seattle, helping his company give its rivals some stiff competition. When the Joes were reinstated in 2001, computer technology played an even greater role in the military, and Mainframe was happy to return to the team. He headed up a large group of programmers working around the clock to find a way to stop Cobra's nano-mites -- microscopic machines that infected both humans and machines. Working with the Joes' doctor, Lifeline, Mainframe found a way to stop the 'mites. He later helped stop a Cobra BAT wreaking havoc in Chicago. He also used his computer skills to investigate the Jugglers' General Winters and the corrupt congressman Cartwright. On what was to become his final mission, Mainframe joined much of the Joe team in its battle against the forces of a revived Serpentor on Cobra Island. To allow for the start of the invasion, Mainframe and Flash infiltrated a radar station to rig up explosives to destroy the facility. The two Joes were delayed by Serpentor's troops and were unable to get out in time. Flash and Mainframe were both killed in the explosion that followed. Some time later, at Arlington National Cemetary, Mainframe's name was added to a new memorial dedicated to the fallen members of the G.I. Joe team.