PIM considers not only the methods used to store and organize information, but also is concerned with how people retrieve information from their collections for re-use. For example, the office worker might re-locate a physical document by remembering the name of the project and then finding the appropriate folder by an alphabetical search. On a computer system with a hierarchical file system, a person might need to remember the top-level folder in which a document is located, and then browse through the folder contents to navigate to the desired document.