High data rate recording at over 60 Mbytes per second

Abstract

High data rate recording is dependent on the speed of the write driver electronics and the intrinsic head response. The relationship between head response and head design is studied by finite element modeling. The primary parameters studied are head yoke length, head geometry, and number of coil turns. The head designs are tested using an experimental write driver with a 0.9 ns 10-90% risetime. The risetime of the driver is varied from 0.9 to 3.0 ns by adding capacitance at its output. The parametric and BER performance of three different head designs reveal a strong dependence of maximum data rate capability on the head efficiency and response. The best design showed low BER performance for writing to data rates slightly above 60 MB/s while reading at 15 MB/s with a PRML channel using a (0,4,4) run-length-limited code.