A Digital Resource Identifier a a D D I

How much can you change a document before it is a different document? Why do we never change an automobile’s vehicle identification number? Why do we talk of each human being as having a single identity from before birth until after she has decayed in the grave, even though we would not recognize the 60-year old from her baby picture? Why do we have proper names for some entities, but not for most entities? When do we decide that a name is not enough, and that adding an identifier is worthwhile? In a project to show how to preserve digital documents for 100 years and longer, we found it worthwhile to revisit the seemingly simple topic of identifiers. For business control, a digital work may need to be traced during its production. Furthermore, scholars, archivists, and attorneys often want to study multiple editions of a work. Dante’s Inferno, for instance, has an existence beyond that of any particular edition of the work and transcends the existence of any printed instance held by a library. The work itself, each edition and translation, and each print instance may merit unique identification.