Forward compatibility
Forward compatibility is a design concept where a system is designed to gracefully accept input from unknown future versions. This is different from extensibility which occurs when a specification is set before future versions are made which they must conform to. In its truest form, forward compatibility describes a system which is designed to be so general it will work with specifications that have not yet been designed. Forward compatibility is also often applied to the older version of anything that is backward-compatible, but there is an important distinction to be made; in these cases, the original designers didn't try to make their product work with the future version, but rather the later designers conformed their new design to the older specifications.
An example of forward compatibility as a result of backward compatibility is color television. Rather than create a competing incompatible system, the signal for color TV was designed to work within the confines of the existing black and white television signal in order to be backward-compatible with existing TVs. Black and white televisions are able to process a color TV signal, without the color, so they are forward-compatible with color TV signals, but the designers of black and white TV had not considered color in their initial specification, so this is not true forward-compatible thinking.
An example of a true forward-compatible system is the HTML standard. HTML was originally designed to process a specific set of tags with the expectation that new tags would be created in future versions. Since designers obviously couldn't predict what those tags might be, the HTML standard specified that all HTML viewers simply ignore any tags not yet recognized. This is forward compatibility because, although an older HTML viewer may not be able to load the new aspects of a later HTML document, it won't crash, and will still load all everything it does understand.
In regard to computers and video games, most platforms are designed to be extensible, and some are forward-compatible as a result of backward compatibility, but almost none are designed to be truly forward-compatible. This is a result of economics; as they are based on rapidly-changing technology, consumer computers and video game consoles are typically obsolete after only a couple years, so it's a better business practice to ignore future compatibility and keep the design more targeted and cheap than generalized and expensive.
Examples
- Game Boy can play some Game Boy Color games, just without color.
- Leapster can play Leapster L-Max games.
- Leapster L-Max can play Leapster 2 games.
- Neo Geo Pocket can play most Neo Geo Pocket Color games.
- WonderSwan can play some WonderSwan Color games.
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