Seagate estimates that it has shipped 79 million terabytes of storage in its 29-year history.
"Digital content proliferation is a long-term phenomenon," said John Rydning, research director for hard drives at IDC.
"This phenomenon is pushing demand for hard drives to more than 600 million units a year by 2010, and will continue to fuel demand in the decade ahead."
As volumes have risen in the industry so prices have fallen. The first Seagate drives cost US$300 per megabyte, compared to one fiftieth of a cent today.
Bill Watkins, chief executive at Seagate, said: "Al Shugart and a few others started the company behind a convenience store in 1979 and enabled the birth of the first PCs."