Currently, the largest named measure of data is the yottabyte (YB), which is exponentially greater than the zettabyte, exabyte, petabyte, terabyte, and so on. The yottabyte is approximately equal to 5X * 10^6, where X is equal to all printed matter that exists on our planet. More definitively, 1 YB=2^80 Bytes.
The highest-density digital tape (which is the highest-density medium currently in common use) made by one of the world's leading manufacturers stores data at a density of 124,000 bpi (bits-per-inch). Assume zero overhead for error-correction and -detection.
At a tape thickness of 8.9 microns, what must the diameter of a roll of tape be in order to store one YB of data, assuming that it is wrapped around a spool with a diameter of 0.5 inches and assuming that there is no space between the layers of tape?
