Primary data aquisition aquired during the 1980s is still stored as "original" on various optical formats .. although secondary copies have been made.
Exploration | geophysical | seismic surveys that "can never be repeated" ( the atmosphere | climate | ground has changed since ) and cost thousands to millions per day to acquire have troves of original copies - SEG-9 (SEG-21) track tapes, DAT tape, optical discs, that tend to be preserved "for reference" despite much of the data having migrated media-wise forward.
Exploration | geophysical | seismic surveys that "can never be repeated" ( the atmosphere | climate | ground has changed since ) and cost thousands to millions per day to acquire have troves of original copies - SEG-9 (SEG-21) track tapes, DAT tape, optical discs, that tend to be preserved "for reference" despite much of the data having migrated media-wise forward.