An anonymous reader writes: Modern storage methods are designed with longevity in mind. But we haven't always had the scientific knowledge or the foresight to do so. From the late 60s to the late 80s, much of the world's cultural history was recorded on magnetic tapes. Several decades on, those tapes are disintegrating, and we're faced with the permanent loss of that data. "The Cultural Heritage Index estimates that there are 46 million magnetic tapes in museums and archives in the U.S. alone—and about 40 percent of them are of unknown quality. (The remaining 60 percent are known to be either already disintegrated or in good enough condition to be played.)" Fortunately, researchers have worked out a method to determine which copies are recoverable. They "combined a laptop-sized infrared spectrometer with an algorithm that uses multivariate statistics to pick up patterns of all the absorption peaks." Here's the abstract from their research paper. "As the tapes go through the breakdown reaction, the chemical changes give off tiny signals in the form of compounds, which can be seen with infrared light—and when the patterns of reactions are analyzed with the model, it can predict which tapes are playable."