National archives mass storage requirements--1975 to 1980

The Federal Government is the largest buyer of magnetic tape in the world. Current procurement is approximately one million reels annually. Of these tapes, slightly ever 1 percent are destined to contain data of permanent value. The problems the National Archives and Records Service (NARS) is encountering in preserving machine-readable records for long periods of time, particularly periods in excess of either the shelf life or technological life of the medium, are described. The economics of magnetic tape storage and NARS long-range storage requirements are discussed. Performance parameters for both a device and medium for the 1975-1980 time frame are given. These are basically 1) a medium lifetime of 50 years, equivalent to archival microfilm; 2) transfer rates equivalent to magnetic tape drives for the next 20 years; and 3) an annual capacity to transcribe 10¹²bit/year. Removable media are acceptable, as access time and bulk are not critical parameters.