What caching mechanisms have you used or know about, and what are they used for?

In iOS, the following mechanisms are often used for caching:

• NSCache — a class similar to a dictionary but automatically releases memory when resources are low. Used for temporary storage of objects like images to avoid reloading from the network.
• URLCache — caches responses of network requests, speeding up repeated loads and reducing traffic.
• Core Data with caching — for storing and quick access to app data.
• File caching — saving data to the filesystem, e.g., for offline access.

The main goal of caching is to improve app performance, reduce delays, and decrease load on the network or database.