Adaptive prewrite compensation apparatus

Claim 1

An adaptive prewrite compensation apparatus for writing data on a magnetic medium, the apparatus comprising: data supply means for introducing a serial data pattern into the apparatus; data storage means for storing the data pattern; encoding means for encoding the data pattern; write delay determination means for determining a write delay value; application means for applying the write delay value to the data pattern; and writing means for writing the data pattern with the applied write delay value so that when the data pattern is read back, bits of the read data pattern will have the same temporal spacing as bits of the pattern as received from the data supply means; wherein the writing means employs a code decoder and a disk drive assembly containing at least one disk; wherein the data supply means employs a code encoder, a timing clock, and a disk drive interface suitable for manually entering data patterns into the adaptive prewrite compensation apparatus; wherein the data storage means employs a shift register; wherein the decoding means is a plurality of subpattern recognizers; wherein the write delay determination means employs a plurality of delay selectors, one for each subpattern recognizer; and wherein the write delay determination means further employs a subtractor.