In general, file format can be divided into two types: an access format and a preservation format.
An access format is “suitable for viewing a document or doing something with it so that users
access the on-the-fly converted access formats.”6 In comparison, a preservation format is “suitable
for storing a document in an electronic archive for a long period”7; it provides “the ability to
capture the material into the archive and render and disseminate the information now and in the
future.”8 While the ability to ensure long-term preservation focuses on the sustainability of
preservation formats, the document in its access format tends to emphasize that it should be
accessible and available by users, presumably all of the time.