One advantage of the repetitive form is that the model is easy to extend to more complex cases when the additional effort is justified. In this case, the same title is used for every page. In a longer document, the title might be specific to a chapter or section. Use of a special title is optional. Typically, an aggregate represents material of the same original format that belongs to the same American Memory collection.
Many collections consist of a single aggregate.
In this example, the rpbaasm aggregate will hold the entire collection of page-images of sheet music. For items stored at LC, the combination of aggregate and item names form a unique identifier and provide the American Memory system with enough clues to retrieve the files listed in other columns in the table. At present the files are stored in the UNIX file system following a strict rule. The nesting of directories in this fashion keeps the number of files in any one directory to a manageable number. LC's experience indicates that 300 is a reasonable upper limit for the number or files in one directory.