Out of boredom, I spent a considerable amount of time reverse engineering the protocol of my Logitech mouse to see if I could store data in it. I ended up with two bytes via the DPI register.
This open-source article I have written relates to classic graphics (graphics typical of pre-2000 video games for home computers, game consoles, and arcade machines, at a time before "shaders").
The article is intended to encourage the development of—
modern video games that simulate pre-2000 graphics and run with very low resource requirements (say, 64 million bytes of memory or less) and even on very low-end computers (say, those that support Windows 7, XP, and/or 98), and
graphics engines (especially open-source ones) devoted to pre-2000 computer graphics and meant for developing such modern video games.
So far, I have found that pre-2000 computer graphics involve a "frame buffer" of 640 × 480 or smaller, simple 3-D rendering (less than 12,800 triangles per frame for 640 × 480, fewer for smaller resolutions, and well fewer than that in general), and tile- and sprite-based 2-D graphics. For details, see the article.
I stress that the guidelines in the article are based on the graphics capabilities (e.g., triangles per frame) actually achieved by pre-2000 video games, not on the theoretical performance of hardware.
Besides the article linked, there is a companion article suggesting a minimal API for pre-2000 graphics.
