Why don the classic PC Doom games run well on my Windows (XP) machine?
PC Doom, Ultimate Doom, Doom II, and Final Doom (TNT/Evilution and Plutonia) are all DOS-based games. DOS is an old operating system predating Windows. Microsoft had supported DOS and Windows for years, but support for DOS-based applications has steadily declined. Windows XP and other modern versions of Windows are less backward-compatible with DOS applications than previous versions. This can cause problems with sound, music, graphics and input devices when running the original, classic Doom/Doom II game engines. Today there are third-party Doom engines, “source ports”, which allow these old games to run well under Windows XP and other modern operating systems. Most source ports fix various bugs or limitations in the original games, and provide other enhancements or expanded capabilities as well. Some source ports, such as Chocolate Doom, are strictly designed to maintain the look and feel of the original games; Others, such as JDoom, allow the use of updated graphics to “modernize” t
