A tape drive writes/reads tapes written in a format which stores an increased amount of data because the tracks overlap. The wide write/narrow read heads read a center portion of each track which does not have overlap. The new format is identified by the positions of a reference burst, by encryption...http://www.google.com/patents/US5986843?utm_source=gb-gplus-sharePatent US5986843 - Writing and reading high density magnetic tapes
