There is a known problem in Ubuntu connected with high frequency of load/unload cycles on hard disk.
Here are useful links:
https://wiki.ubuntu.com/DanielHahler/Bug59695
http://ubuntuforums.org/showpost.php?p=3675960&postcount=26
http://ubuntuforums.org/showpost.php?p=5031046&postcount=3
I used approach from Ubuntu forums and Load_Cycle_Count stopped increasing. Unfortunately, everytime when I woke up my Asus F3F from suspend to RAM (even it was on AC power), Load_Cycle_Count started dramatically increasing. Read More
You can easily check temperature of your hard drive:
Type in command line:
sudo apt-get install hddtemp