The Sega Model 2 is an arcade system board released by Sega in 1993. Like the Model 1, it was developed in cooperation with Martin Marietta, and was essentially a continuation of the Model 1 hardware. One of the most noticeable improvements was the presence of texture mapped polygons, as opposed to the flat shading used in Model 1 games.
The Model 2 was a very successful system; much more so than the Model 1. It featured the highest grossing arcade game of all time, Daytona USA.
Model 2 has four different varieties, commonly referred to as Model 2, Model 2A-CRX, Model 2B-CRX and Model 2C-CRX. While Model 2 and 2A-CRX use a custom DSP with internal code for the geometrizer, 2B-CRX and 2C-CRX use well documented DSPs and upload the geometrizer code at startup to the DSP. This, combined with the fact that some games were available for both 2A-CRX and 2B-CRX, lead to the reverse engineering of the Model 2 and Model 2A-CRX DSPs.