Enormous improvement in read heads for HDDs has been realized by the introduction of magneto resistive (MR) heads in 1991 by IBM and later many others, and more recently in 1998 by the introduction of GMR heads by IBM followed closely by Hitachi. IBM, for many years, also used multi-track MR sensors in a complex head structure for some tape systems, and recently the quarter inch format adopted multi-track MR thin film heads for advanced products.
Developers of future tape systems will rely primarily on progress in HDD heads for the design and manufacture of GMR heads. At the present time, IBM is the world leader with Hitachi a close second. At the present time, the only independent GMR head supplier is Yamaha, known in the United States primarily for its musical instruments. It has been suggested that Yamaha obtained at least some of the basic technology for GMR from another Japanese company.
There is an enormous effort in GMR both in Japan and the United States with sufficient manufacturing resources in both countries. The capabilities would be rated as equal.