Launched in November, the Asus Eee PC is hot on everybody's wish list with Asus struggling to keep up with demand, as it has sold out in almost every country. If you haven't already read a review on the Eee PC and are wondering what the heck we’re talking about, you can see one on our ex-sister site, TrustedReviews
Anyone who wants to use the Eee PC as a portable media device will be sorely disappointed at the size of the internal SSD, ranging from 2-8GB. In my case, I have the 4GB model. The operating system itself takes up a large majority of the drive, leaving 1.4GB of user space. However, use of the UnionFS file system complicates things slightly.
The 2.6GB partition of the drive which the operating system resides on is mounted as read only and is then unified with the 1.4GB secondary “user” partition to give the effect of an entire 4GB drive. Whenever a system file is changed or updated, the new file is stored on the secondary partition. This is known as “copy on write”, as you are adjusting a copy rather than the original.
This method of storing files is why it is incredibly easy to restore the Asus Eee PC back to its factory defaults – you simply press F9 on boot. You'll notice it takes no more than five seconds to do so, as all it has to do is wipe the secondary partition of information.
A way of imagining this is with two sheets of transparent overhead projector paper – the bottom sheet is your read only partition, while the top sheet is your user partition. Using your marker pen, you write something on the top sheet, while everything that is written on the sheet underneath is still visible through it – giving the effect of a single sheet. Simply replacing the top sheet with a fresh one is all that is needed to bring you back to the beginning.
The downside to this method, apart from a slight overhead, is that performing large updates (such as updating OpenOffice) will take up a large amount of space. Replacing 300MB with 300MB of updated files means eating an additional 300MB out of your user space, rather than replacing the originals.
Aside from the fast recovery, another upside to this method is backups. Instead of backing up the entire 4GB of hard drive space, we only need to backup the secondary partition as this contains all the changes. For most people these are little things like preferences, favourites and a few documents. In size, this takes up very little space – but tweaking things to how you want them takes a while, so it’s worth backing up. In my case, on a pretty highly modified install, my secondary partition is still under 500MB which, even by today's standards, is still small.
In this article, we'll be modifying our Eee PC by neatly adding in an extra 32GB of storage space – this is well within the grasp of anyone with even the most basic soldering skills. In part two of this series, we'll be making the most out of the operating system, including how to successfully back up quickly.