I'm thinking to make a game console. I mean from scratch, not using emulators. I want something built by myself. Here are my ideas: Use an existing OS (for example DOS) and customize it, then design the hardware and start developing games. Make my own OS and file format, think of the way of developing games. This will be hard. Use ATMega microcontroller, write games and run them directly without OS. What do you think? Which is the best? Any other suggestions? Thanks!