This should only be used as a temporary workaround
And has been tested to work on a Acer Aspire 5601AWLMi laptop with a 80GB IDE hard drive, but this work around may not work for everyone.
sudo nano /etc/rc0.d/S00hdd-shutdown-workaround
which includes this two lines:
echo 1 > /sys/class/scsi_disk/0\:0\:0\:0/stop_on_shutdown
Then make it executable:
sudo chmod +x /etc/rc0.d/S00hdd-shutdown-workaround
On the next shutdown it should park the hdd heads correctly.
If you have more than one directory at “/sys/class/scsi_disk/“, add another line for each of them in the S00hdd-shutdown-workaround file.