It makes the useful observation that the first programmable game system (that is, with interchangable cartridges that contained program code), the Fairchile Channel F, contained 2K of RAM to use as a framebuffer, a region of memory the system’s graphics controller referred to in building its display. Using a framebuffer simplifies video creation, but at the time RAM was very expensive.

The Atari VCS/2600, however, only has 128 bytes of on-board RAM. It doesn’t create a framebuffer, it doesn’t have enough memory. Instead the processor, a MOS 6507 (a variation of the 6502), works with the TIA graphics chip to build the signal in real-time. Effectively, the VCS has a one-dimensional display: it focuses on building the video signal by focusing on it one raster line at a time.

There’s a danger when talking about these things, of telling people something they already know. It’s been observed that some game facts that were once obscure are fairly well known among enthusiasts, like that Super Mario Bros. 2 was adapted from an earlier Japanese game called Doki Doki Panic. I feel like the unusual way the VCS constructed its graphics might be one of these things. I’m still fascinated by how it works though. I’ll probably end up bringing it up again someday.

rodneylives