Working for Ryker
Mainframe was a contractor working for Cybertek industries, who invented a type of remote servo technology that allowed him to coordinate and override Cybertek technology. Harlan Ryker hired Mainframe to capture the rogue Deathlok, Michael Collins. Mainframe led a team of Roxxon commandos using Cybertek battlesuits to Coney Island and attacked Deathlok, taking direct control over some of the suits when his remote leadership wasn't enough.
When Deathlok evaded capture, Ryker ordered Mainframe to pull out, but Mainframe promised he could finish the job with his air support. Mainframe used his aerial "Dragonflies" and his aquatic drones to swarm Deathlok and almost drowned the cyborg, but Deathlok escaped and Mainframe was arrested by the police.
The Ultimate War Machine
Mainframe soon broke out of prison and formed an alliance with Ben Jacobs. The two upgraded Mainframe's technology, allowing him to take over machinery remotely without relying on preexisting receivers. Mainframe hacked into Deathlok and made him attack A.I.M. as a demonstration of his abilities, but Deathlok broke his hold over him when he tried to make him kill. Jacobs then tried to kill Deathlok, injuring Mainframe; Mainframe took remote control of Jacobs's cybernetics and forced him to abandon the fight and help him escape.
Mainframe continued to work with Ben Jacobs, despite their volatile partnership. The two joined with their former employer Harlan Ryker, and created a group of state of the art cyborg mercenaries called Cyberwarriors.
The plan worked well initially, but Deathlok, joined by Siege and the Wild Pack dismantled their base of operations, forcing Mainframe to flee along with Ryker and Jacobs.
When Deathlok once again tracked down Ryker, Mainframe used the Cyberwarriors to attack him. Deathlok's ally Coldblood knocked Mainframe out in order to cripple the Cyberwarriors. Mainframe was then presumably taken into custody.
The Power of Terror