This is a redstone computer. It does exactly what your real life computer does (it runs programs that can be loaded onto it), it's just a lot simpler and slower.
Redstone computers have been built before, but this one's very different in a few ways.

Firstly, this computer has an SDK, and a full high level programming language, allowing you to write programs very easily on your PC. This is the easiest vanilla minecraft computer to program, by far. Other computers are usually programmed by writing in raw binary machine code and manually placing/removing torches in program memory, which is very complicated to do.

Secondly, this computer uses command blocks and takes advantage of scoreboards. This allows the computer to be faster and simultaniously more powerful than anything you can build with standard redstone. This computer is entirely 32 bit, while most redstone computers are 8 bit. Scoreboards and command blocks allow this computer to have compact, high density RAM and ROM, and allow for hardware multiplication and division.

Thirdly, this computer has a 16 colour 32x32 pixel screen, double buffered, using the ANDEX system. There's also a general purpose framebuffer onboard, allowing for collision detection and faster graphics, among other things.




For more information, see the fourm post here: http://www.minecraftforum.net/forums/minecraft-discussion/redstone-discussion-and/redstone-creations/351957-commandore-32-advanced-command-block-based

Download links for both the computer and SDK can be found on the fourm post. Happy coding!