RingEdge 2 (RE2 henceforth) is the main computer used by Sega in a number of their arcade games. In their cronology it exists as the successor to the RingEdge (no huge surprise there), which itself was the successor to the Lindbergh, and is the predecessor of Nu. There also exists the RingWide, a slightly less powerful variant of the Ring* computers. These pages focus on the RE2. I have no reason to believe the RE2 software stack is especially differnet to that of the RE, but I haven't confirmed this. Nu, however, uses different systems in many places, and most of the deep-dive pages will not be applicable.