A documentação é escassa, mas ambas Wikipedia , bem como O site do Aser menciona que o software é necessário para emitir comandos para o disco rígido.
Usually the system consists of accelerometers that alert the system when excess acceleration or vibration is detected. The software then tells the hard disk to unload its heads to prevent them coming in contact with the platter, thus potentially preventing head crash
Acer GraviSense is an innovative utility designed to further protect your data by automatically moving the read/write heads of your Acer notebook's hard disk away from the storage disk (this is known as "parking" the heads) in the event that sudden motion is detected. Acer GraviSense can also be set to activate an alarm in case your notebook is moved by an unauthorized person.