The original King's Quest (King's Quest: Quest for the Crown) was written for the IBM PC Jr. with Sierra's AGI game engine, which was used for all the King's Quest games until King's Quest 4. During the development of KQ4, Sierra finished their new engine, SCI which allowed for higher resolutions greater color depths and full MIDI (music) support. Shortly after Sierra released the new KQ4 in AGI, they replaced it with the new SCI version. All of these games were made for DOS, Microsoft's first operating system, though they were also ported to other platforms, such as the Apple ][ and later for the Mac.
With the release of King's Quest 5, Windows 3.1 was available, so there were two versions of KQ5, one for DOS and one for Windows. Windows 3.1 was just another program running out of 16 bit DOS, so the two versions weren't that different. King's Quest 6 and 7 were written for DOS/Windows 3.1 as well.
Shortly after the release of King's Quest 7, Microsoft released their revolutionary 32 bit Windows 95. Though 95 had protected memory (key areas of memory such as where main system files reside in memory), giving it greater stability than DOS, programs still could have direct access to the hardware, making it still less stabile than it could be. King's Quest Mask of Eternity was written solely for 32 bit Windows (Win32). It was released around the same time as Windows 98, which was still sitting on top of DOS.
In the early 90s Microsoft was developing Windows NT, a true 32 bit non legacy OS. It had protected memory and handled all of the calls that programs made to the hardware (programs no longer had direct access to the hardware.) Though it could still run some 16 bit programs, DOS programs running in NT's DOS emulator couldn't address the audio hardware, so no sound in DOS games, and NT 3.5, which had a Win 3.1 type interface, didn't handle 16 bit code very well. NT 4 (which had a Win 95 interface) handled 16 bits better, but was still not very compatible with older programs.
NT 4 was replaced with Windows 2000 which has a compatibility tool to help run old code. It is an improvement over NT 4's backwards compatibility. Windows XP has its compatibility mode built into it and is better yet at DOS emulation, but it is still not perfect. Windows 2000/XP trades some backwards compatibility for a great deal more stability.
So, what does this mean for our old classics such as the King's Quest games? The good news is that they will run, but the down side is that we sometimes have to do a little work to get them to work. How? Just click on the links below for help with your game.
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