It turns out that IBM Corp’s much-trumpeted Giant Magnetoresistive Effect disk heads, which it says will enable enormously higher disk capacities in three or four years, borrowed from patented work done in Germany – and it looks as if others such as Read-Rite Corp that are also working on Giant Magnetoresistive Effect, will likely have to license the patent too. IBM has made some refinements of its own and patented them, but it can’t take the work any further without infringing the German patent. The US patent on Magnetic Field Sensor with Ferromagnetic Thin Layers Having Magnetically Antiparallel Polarised Components was granted to Peter Grunberg in 1989 and is based on work completed at the Forschungszentrum Jlich GmbH, one of the 16 national research centres in the Federal Republic. IBM has persuaded the Germans to keep quiet about how much it is paying, but a spokesman cheerfully described the sum to be paid for non-exclusive use is not bad.
