Libraries contain objects. Objects come in many types, depending on their function. For example, there are files, programs, commands, job queues, message queues, data areas, and panel groups. Each type of object has an object type identifier; files, for example, have an object type identifier of *FILE.
All identifiers begin with an asterisk and have a standard abbreviation following the asterisk, such as PGM for program. You will learn more about object types in the section about working with objects.