Studies show [PDF] that the amount of data being recorded is increasing at 30 to 40 percent per year. At the same time, the capacity of modern hard drives, which are used to store most of this, is increasing at less than half that rate. Fortunately, much of this information doesn’t need to be accessed instantly. And for such things, magnetic tape is the perfect solution. …
Indeed, much of the world’s data is still kept on tape, including data for basic science, such as particle physics and radio astronomy, human heritage and national archives, major motion pictures, banking, insurance, oil exploration, and more. There is even a cadre of people (including me, trained in materials science, engineering, or physics) whose job it is to keep improving tape storage.
Tape has survived for as long as it has for one fundamental reason: It’s cheap. And it’s getting cheaper all the time. But will that always be the case?
You might expect that if the ability to cram ever more data onto magnetic disks is diminishing, so too must this be true for tape, which uses the same basic technology but is even older. The surprising reality is that for tape, this scaling up in capacity is showing no signs of slowing. Indeed, it should continue for many more years at its historical rate of about 33 percent per year, meaning that you can expect a doubling in capacity roughly every two to three years. Think of it as a Moore’s Law for magnetic tape.
Read more at IEEE Spectrum