Archiving with NSKeyedArchiver

A more flexible approach enables you to save any type of objects to a file, not just strings, arrays, and dictionaries. This is done by creating a keyed archive using the NSKeyedArchiver class.

Mac OX X has supported keyed archives since version 10.2. Before that, sequential archives were created with the NSArchiver class. Sequential archives require that the data in the archive be read back in precisely the same order in which it was written.