Datatape

within the Star Wars universe
A Datatape is a recording device that can be read by a Holo-Projector, such as the one standard in R2 units, or a Computer terminal. the plans for the first Death Star were recorded on Datatapes, which were stolen by Princess Leia and downloaded into R2-D2. later, the tapes came into the possession of the Rebellion, and helped in the battle of Yavin.

Speculation
the use of the word "Tapes", in "A New Hope" was in 1977. the downside of science fiction is that, no matter how much imagination one may have, it is always restricted by the limits of modern science. in the 1970s, Tapes were a modern way of recording audio and vidio. the possible conclusion that can be drawn here is that, in the future, tapes will hold information as well.