an apparatus for providing sector location pulses to a controller of a rotating disk data storage device having a counter clocked in proportion to the disk rotation rate and an accumulator for accumulating times to sectors on the disk . a comparator connected to the counter and the accumulator enables an accumulator clock for repetitive clocking of the accumulator at such times the contents of the accumulator do not exceed the contents of the counter . a sector location pulse generator connected to the comparator generates the controller pulses , when enabled , concurrently with the accumulator clock signals . a master reset generator resets the first counter and the accumulator each time an index location on the disk passes a transducer head used to read and write data to and from the disk and a partial reset generator resets the accumulator each time the transducer head is moved between tracks on the disk . the sector location pulse generator includes a flip - flop that is set following a partial reset signal to prevent sector location pulses from being generated following partial reset until the accumulator has accumulated the count in the counter . an apparatus for determining a sector location in a disk . a location circuit is configured to determine an angular location of a transducer head according to a selected index location on the disk . a memory is used to store a first value that corresponds to a selected angular distance along a selected track on the disk . an accumulator is configured to add the first value to the value of the content of the accumulator in response to an accumulator clock signal . a comparator is coupled to the location circuit and the accumulator to compare data related to the angular location and the content of the accumulator to generate a result . a generator is coupled to the comparator to provide a sector location signal in response to the result .