One or more transducers are mounted on a rotating drum set at an angle to the tape, such that they describe a path of stripes across the tape, rather than linearly along it as a fixed head does.
One or more transducers are mounted on a rotating drum. As a fixed head does. This is what they describe a path of stripes across the tape, rather than linearly along it. This rotating drum is set at an angle to the tape this. The tape is such.