What is magnetic disk storage capacity?

Answer 1

Tape remains a viable alternative to disk in some situations due to its lower cost per bit. This is a large advantage when dealing with large amounts of data. Though the areal density of tape is lower than for disk drives, the available surface area on a tape is far greater. The highest capacity tape media are generally on the same order as the largest available disk drives (about 5 TB in 2011). Tape has historically offered enough advantage in cost over disk storage to make it a viable product, particularly for backup, where media removability is necessary.