Mac OS X v10.4 Tiger: Developer Overview:

"Now in Tiger, Cocoa can manage your data objects themselves through the power of Core Data, providing automatic undo/redo support, additional user interface synchronization, and data consistency, correctness, and speed enhancements when it's time to write to disk.

Core Data gives you the ability to create a description of your data objects. Once defined, Core Data handles most of the heavy work of managing your data objects, both in-memory and on-disk. This allows you to focus on application logic and avoid the infrastructure work. In short, Core Data is a model-driven object management graph and persistence framework.

In Tiger, Core Data will support three different kinds of files for storage of data:

* A text-based XML file format * A better performing binary file format * A high-performance, SQLite-based database file format"