Looking at the following article:
..: I find my self thinking that hard drives wouldn’t be obsolete, but OS installations might be. Already there are many LiveCD installations of Linux and Windows, which don’t require a Hard Drive at all, but simply boot to the CD/DVD… With more sophisitication and personalization options (there are already setups where you can store personalizations on a USB flash drive or something) I think the idea of a static state OS would be very appealing. Think about never having to reinstall windows – ever! Never being worried about a virus which could damage the OS… sure, your profile data might be in jeapordy, installed programs… but the OS could be 100% seperate. Given that seperation, backing up personal data would become easier and hopefully more common (how many people mean to do so, but never do?).