DirectX is the set of application programming interfaces (API) developed by Microsoft to handle all multimedia-related tasks on a Windows operating system. This includes playing music, videos and games. In the days of MS-DOS, game programmers had direct access to a computer's hardware, which they control according to the game's design. But each computer hardware manufacturer comes up with its own configurations. To standardize everything and make the whole process easier, an interface had to be set up between programmer and hardware. Manufacturers would conform to the requirements of this interface so that a wide range of hardware devices could work with the interface. Meanwhile, game programmers no longer needed to understand every configuration on every piece of hardware, they simply needed to learn how to manipulate the interface.
Each component of DirectX handles a particular medium - graphics, audio, user input controllers such as keyboards, mouse, joysticks, etc. These components interact with the computer's hardware through the specific device's drivers. They are also designed to be backward compatible with older versions of device drivers. This means that a game designed to run on a certain version of DirectX can operate on a computer whose currently installed device drivers were written for an earlier version of DirectX. This backward compatibility, however, stopped with DirectX 9. Its succeeding version, DirectX 10 was made for the Windows Vista operating system, which uses a different and more advanced model for application programming interfaces.
Playing older DirectX games on a computer installed with the more recent versions of DirectX (until version 9) shouldn't be a problem. If some issues do arise here are some things you can do to resolve them.
- Check the game's system requirements. A game is always designed within the context of the current technology. That is why each game requires certain software and hardware specifications of a computer before it can be played on it. Some can only run successfully on a particular version of Windows, a minimum amount of RAM and hard disk space is needed, or a specific type of video and audio card is necessary. These requirements should be met by your computer to make sure that at least these factors are not causing your old game to malfunction. This way you can isolate whether the problem is actually a DirectX version incompatibility.
- Use third-party utility software. There is an application called DirectX Changer that can revert your current DirectX to an older version without restarting the operating system. The user interface is easy enough to navigate. It's actually a matter of choosing the appropriate DirectX version from a list, then pressing the 'Patch' button to activate it. DirectX Changer can be downloaded from the Internet and easily installed. This particular software is classified as shareware, which means that it can be initially downloaded for free and will function only within a given trial period. Afterwards, you will need to purchase its license to regain its full functionality.
- Use Compatibility Mode. This is a utility program that comes with Windows XP. It can reconfigure an application's properties to make it 'think' that it is actually running on the older version of Windows it was meant for. Before you install an old game, navigate to the game's setup.exe file (usually located in the game's CD installer). Right-click on this file and choose Properties. In the Properties window pull out the Compatibility tab. Here you will be asked to activate Compatibility Mode and then choose the appropriate previous version of Windows. Once accomplished, you can install the game and it will assume that it is running on the right operating system.
Gamers who prefer dedicated gaming consoles such as the Xbox will rarely or never encounter this kind of compatibility problem. PC gamers, however, might want to learn a little about how games, DirectX and device drivers work together to ensure the quality of their gaming experience.