The Atari 2600 is an example of a system where games didn't have headers and a checksum/database or other heuristic has to be used to account for the occasional hardware extension.
Z26 implements a heuristic to determine PAL or NTSC mode, which is done by monitoring how long the software takes to begin outputting lines (PAL's vblank is longer than NTSC's).
But this article makes me think of the problem of determining the boundary between emulation and simulation. The reason why the original Atari Pong of 1972 is not in MAME is because Pong doesn't have a CPU, it's all implemented as discrete hardware (and has no ROM). But you can't play any games on any emulator if some hardware isn't simulated, like the video.
There is some project that will take a description of the Pong schematic and render a playable game, but it's very slow. I can't recall the name of it. I also find it interesting that the NES's video chip has been reverse engineered to the point of accounting for every change in waveform it outputs to composite video--even the bad ones; meaning the flickerly color fringes and unsmooth vertical lines of real NES video are now documented and implementible by anyone who cares.
Z26 implements a heuristic to determine PAL or NTSC mode, which is done by monitoring how long the software takes to begin outputting lines (PAL's vblank is longer than NTSC's).
But this article makes me think of the problem of determining the boundary between emulation and simulation. The reason why the original Atari Pong of 1972 is not in MAME is because Pong doesn't have a CPU, it's all implemented as discrete hardware (and has no ROM). But you can't play any games on any emulator if some hardware isn't simulated, like the video.
There is some project that will take a description of the Pong schematic and render a playable game, but it's very slow. I can't recall the name of it. I also find it interesting that the NES's video chip has been reverse engineered to the point of accounting for every change in waveform it outputs to composite video--even the bad ones; meaning the flickerly color fringes and unsmooth vertical lines of real NES video are now documented and implementible by anyone who cares.