But not everything uses that. Some software simply connects a pin of the port to a motor and another to a sensor, then uses software in the computer to turn t

But not everything uses that. Some software simply connects a pin of the port to a motor and another to a sensor, then uses software in the computer to turn the motor off as soon as it sees the sensor be activated. Devices that do that often have very tight timing requirements - since original 1990's era computers could respond to a change in a pin change in as little as a few clock cycles.