Accolade achieved a technical victory in one court case against Sega, challenging this control, even though it ultimately yielded and signed the Sega licensing agreement. Several publishers, notably Tengen (Atari), Color Dreams, and Camerica, challenged Nintendo's control system during the 8-bit era by producing unlicensed NES games. The concepts of such a control system remain in use on every major video game console produced today, even with fewer "cartridge-based" consoles on the market than in the 8/16-bit era. Replacing the security chips in most modern consoles are specially encoded optical discs that cannot be copied by most users and can only be read by a particular console under normal circumstances.