IMU3000 FIFO Footer

Hi,

I wish to use the IMU-3000 to read raw sensor data. My intention is to average samples read from the FIFO, the more the merrier. However, I am having difficulty understanding how the FIFO works. Is the only way to guarantee that data order is preserved to never let the FIFO overflow by resetting it after every read, and reading after less than 512*(sample period)? Does the footer cause the FIFO to stop receiving data?

The data sheet claims the FIFO operates as a circular buffer when it overflows. Does that mean that at every sample period a full 16 bytes of the oldest data (if so configured) are popped off the top, or do individual bytes pop off the top? Or is old data not discarded at all (circular?) ?