How is Wubi different from dual-booting or a VM image?

The only difference that I see between regular dual-booting and Wubi is that the latter has a more user-friendly installation process, but otherwise it seems to be the same. Am I missing something here? What makes it so special?

Edit: If the file system is emulated, then how is it different from running it in a virtual machine?

Solution 1:

wubi install doesn't require you to create partitions - that's a major distinction. The filesystem under a wubi install is contained in a single file.

Because of the emulated filesystem-in-a-file, there might be performance differences, and lack of some features such as Hibernate.

Nothing is emulated(except the filesystem, where a file is mounted on a loop device) under wubi. Ubuntu has full native access to all your hardware, in contrast to VM where the entire system is emulated.

What makes it so special?

What makes it so special is that you can install an OS just like any other Windows application, try it out, get to grips with it, experiment with it, and then if you don't want to use it anymore - just uninstall it.

In contrast, if you install via the "normal" way, there's the bootloader management, creating and managing additional partitions, different types of partitions and then trying to remove these can be quite daunting.

Solution 2:

It is different from a virtual machine because you are not wasting resources on running the underlying host OS, and only the filesystem is emulated.

With Wubi, you have to run Linux from the emulated filesystem stored in a flat file, much like a virtual disk (e.g. vmdk). With a virtual machine, you have to run the host OS, The Guest OS, and emulate the filesystem and all virtual devices... not to mention all of the interrupt calls from the Guest OS to the CPU for things like time synchronization and so forth. Wubi is much more efficient.