One Gigabit of data was successfully stored on a square inch of disk surface using experimental components, a world record in magnetic data storage, by researchers at IBM’s Almaden Research Center, the company reports; the information was read at 3.5M-bytes-per-second and the measured error rates were one in 1,000m, decreasing to one in 10,000,000m when using standard error correction codes: a thin film recording head was used, with an inductive write element and a magnetoresistive read element and by monitoring the rapid resistance changes that occur as the head passes over recorded magnetic bits it is possible to detect bits too small for a conventional all-inductive head to recognise: the head is similar in principle to the industry’s first magnetoresistive head used in the 3480 Tape Subsystem in 1984; the demonstation also relied on a recording technique known as the Partial Response, Maximum Likelihood channel, which enables significantly greater bit density.
