Method of writing addresses on a magnetic recording medium

Claim 1

A magnetic recording medium for address information to position a magnetic head and data, comprising a plurality of binary coded tracks, a sub-group of information items needed to position the head, the information items being recorded in sets of reference zones, each track being associated with at least one zone, each of said zones containing a plurality of individual cells, each of said cells containing an item of head-positioning information defined by a first change in magnetization polarity sense followed by a second change in magnetization polarity sense, the magnetization sense of a first elementary magnetic area in all cells of each zone always being of the same polarity, the magnetization sense of the first elementary magnetic area of different zones susceptible of being different, the first elementary magnetic area of each cell preceding the first magnetization sense change of the cell, the track addresses being written within each zone, the number of individual cells in each zone being the same as the number of bits in the address, each set of zones including an indexing magnetic region to allow the beginning of the set to be found, one of the magnetization sense changes in each cell occupying one of only two predetermined positions in each cell, the value of each address bit being indicated by the position occupied by the one magnetization sense change in each cell.

Claim 7

A method of recording binary coded information on at least one track of a recording medium comprising recording bilevel physical flux states at spaced positions along the track in response to the value of a binary bit and desired position for a readout head for the track, said flux states spatially alternating between the two levels, three adjacent regions of said alternating flux states forming a cell representing a binary bit value and the desired head position, a predetermined plurality of said cells together forming a binary word, always recording the flux state at the beginning of each cell with the same bilevel value, controlling the position of a first transition between a first pair of adjacent regions of each cell in response to the desired head position, and controlling the position of a second transition between a second pair of adjacent regions of each cell in response to the binary value associated with the cell.

Claim 8

A method of recording binary coded information on at least one track of a recording medium comprising recording bilevel physical flux states at spaced positions along the track in response to the value of a binary bit and desired position for a readout head for the track, said flux states spatially alternating between the two levels, three adjacent regions of said alternating flux states forming a cell representing a binary bit value and the desired head position, a predetermined plurality of said cells together forming a binary word, always recording the flux state at the beginning of each cell with the same bilevel value, controlling the position of a first transition between a first pair of adjacent regions of each cell in response to the desired head position, and controlling the position of a second transition between a second pair of adjacent regions of each cell in response to the binary value associated with the cell.