[Trisquel-users] Ask for help: how to hide hard disk?

[freeuniverse]

I am new to GNU/Linux. Recently I installed a full Trisquel on a USB flash  
drive. Now I can boot Trisquel from the USB flash drive. I don't use any file  
from the hard disk. But when I open the GUI file manager (Nautilus), the hard  
disk is still there under the Devices section on the left column.

Because I don't use any file from hard disk. I hope there is a way to hide  
hard disk automatically when I boot Trisquel.

Anyone has any idea?

Thanks!