The new REALbasic 3 file format has a number of advantages over the older REALbasic 2 format. The main advantages are:
1. Improved forwards-compatibility: in the future, we'll be able to add new features to REALbasic and extend the file format as needed, without losing the ability to open those newer files in older versions of REALbasic. For example, REALbasic 3.0 should be able to open a project file made with REALbasic 4.0, and it will simply ignore any new features it doesn't understand. With the old format, every time we added a feature we had to change the file format in a way that was not backwards compatible.
2. Improved robustness: the new format relies much less on sequential ordering of information. This gives it much greater structural integrity, which means that damaged files will be more likely to load (at least partially). It's like the difference between a tower of stacked bricks, and a tower with a solid steel frame set in a firm foundation.
3. Random access: the old format could only be read by starting at the beginning, and reading the entire file straight through to the end. The new format is more like a database, allowing us to jump directly to the code for a particular class, for example.
4. Advanced features: the new format has been designed with some advanced uses in mind, including indexing and version control. We are not yet using all these features in REALbasic 3.0, but we've laid the foundation for cool things to come.
