Can someone give me an explaination of the graphics (not text) modes available
on the Atari ST? I'm reading through some file format specs for the Atari ST
(NEO, PI, PC, TNY, etc.) and I see mention of low, medium, and high resolutions,
but nothing on the size and pixel depth of these resolutions. The standard
screenshot size seems to be 320x200, but the Atari FAQ lists 320x192 as a
standard graphics resolution. The FAQ also does not explain "overscanned" and
"underscanned" modes. I assume this is how Atari achieves 640x200x4 resolution?

Somebody care to enlighten me? Thanks much.