What are these strange horizontal black lines or scanlines?
Scanlines are the thin horizontal lines which form the image on your monitor screen. On modern monitors at the modern high resolutions, you can’t even notice them. But on a low resolution arcade monitor you can see them very well! In MAME, “scanline modes” are the video modes which display a visible black line between scanlines. Since these modes are the ones which resemble more closely the original machines, they are enabled by default. You can disable them by editing MAME.CFG and finding the line scanlines = yes and just change the yes to no.
