Described is a technology by which a virtual hard disk is migrated from a source storage location to a target storage location without needing any shared physical storage, in which a machine may continue to use the virtual hard disk during migration. In one embodiment, the apparatus includes a near endpoint analysis filter bank operable to divide a near endpoint signal into a plurality of near endpoint subband signals, a far endpoint analysis filter bank operable to divide a far endpoint signal into a plurality of far endpoint subband signals, and a background signal power estimator operable to determine background noise at the near end. Electricity is conducted to the tell-tale strips by foil conductors that are embedded within adhesive backed plastic strips which adhere to the sail. The end of the optical line may be attached to the side of the phase modulator with the end of the optical line being non-parallel to the side of the phase modulator.