If JP was recording the position value of each tick of the trading day, the size of the array would quickly exceed the memory limits of most computers in a short amount of time.
It is possible to trade exchange-traded funds both from the long side and the short side and to hedge portfolio positions without the need to track every tick of the market every minute of the day.
On day three, a troop of baboons go about their daily grooming and tick-picking tasks with nonchalance, ignoring both the camera-toting hikers and the dollops of yellow foam blowing off the angry sea.