Proponents of the digital era recognize that a break-through in mass storage technology may be required to attain a reasonable degree of computerization of the cartographic mapping and data management process. This paper provides the rationale for estimating that about 1014 bits of digital mass storage are needed for developing a digital 1:24 000-scale topographic data base of the US. Also, it will discuss the optical disk as a leading candidate for handling the mass storage dilemma.-from Author