Why Wubi is important for Linux
I have read a few comments of people being concerned about the role of Wubi. I'd like to address those concerns and explain why I think that Wubi is important for Linux and how I think it will affect the installers arena. Caveat: I am Wubi author (see the credits section for a full list of Wubi developers), hence my views on Wubi are heavily biased and highly optimistic.
If you do not know what Wubi is, have a look at http://wubi-installer.org/. In short, Wubi is a Windows installer that tries to make it as simple as possible to install and use Ubuntu. How simple? 1-click simple... No ISO to burn, no change of partitions required, and no change of bootlader, just 1-click.
But there is more...
Wubi is a disruptive technology and as such it does not fit well with traditional schemes (and sometimes people get confused). Wubi fills the gap between a pure demo (LiveCD or VM) and a real installation. Until today, demo mode and real installation have always been two completely separate setups (even if they come on the same medium), Wubi blurs the difference, like a demo it is very easy and safe to try/install/uninstall. Like a real installation it gives you a dual boot setup with full HW access (read 3D desktop), almost full speed and persistent storage. If you like what you see, and find yourself using Ubuntu a lot, you can "upgrade" to a dedicated partition via LVPM (still in early beta). If you do not like what you see, you can uninstall cleanly and revert the system to its previous state.
Wubi promotes an install-then-try approach which is more captivating than the try-then-install approach of the live CD or VM. The partitioning/bootloader hurdle becomes an optional step and it is deferred until the user has accumulated enough goodwill. Without a dedicated partition the user gives up a bit of performance, some robustness and the ability to hibernate, but he still gets a fully usable set-up, and the transition becomes gradual and smooth.
Also some people do not seem to digest too well that Wubi "requires" Windows. They fear that you might end up needing Windows in order to install and use Linux. Not quite. Our "dependency" on Windows is only for the installer front-end. Once installed, you end up with a dual boot installation that is completely independent of the host OS. The installation simply "sits" inside the host filesystem. Do you know what happens to a Wubi installation if you delete C:\WINDOWS? Absolutely nothing. You can still boot and use Ubuntu. So much for dependency...
As for the Windows front-end (Wubi), that happens to be the most popular one for obvious reasons, but we also have a front-end for Linux (Lubi), and we plan to create a Mac front-end called "Mubi". So what does this "dependency" really boils down to? Simple: we aknowledge that most people already have an OS installed, and we try to leverage that to improve the installation experience.
To begin with we do not have to explain how to change BIOS settings to boot from a CD. Nor to explain what to do with an ISO file. With an executable there is absolutely nothing to explain, but if you want to run an executable, you need an OS.
Second, since we run the installer from a working OS we can detect the settings from a live and working system, therefore we can spare the user several pointless questions and make fairly good guesses. Yes you already have migration-assistant to import the settings (and in fact we do use that), but observing an online system is always better than observing an offline system.
Third, since Wubi sits inside another OS, it can also be uninstalled cleanly. There is no ominous message such as "once you press this button, there is no turning back". We just install. If the user has seconds thoughts, s/he can always restore the system to its previous state.
Well, all that puts us in a fairly unique position. What is the result? The result is that Wubi is probably the first 1-click OS installer ever: enter the password, click "install" and reboot. It does not get any easier than that. First impressions are important, and sporting what can possibly be considered one of the easiest OS installer around does help a lot if you have to fight the stigma of being a "difficult" OS.
Will Wubi replace traditional installers? No. If you already know that you want to use Ubuntu and/or are confident about ISO burning and partitioning, there is not much point in using Wubi at all. Wubi helps when you do not know whether you will end up using Ubuntu and/or you are not confident about ISO burning and partitioning. It's a "niche" market, but one that includes the vast majority of users out there.
So will it change things for Linux? I really hope so. Wubi might end up disrupting the Linux installer scenario, like the introduction of LiveCD did a few years ago'. I would not be too surprised (and quite pleased indeed) if we ended up with Wubi clones popping up in other distros (debian-based distros are already supported by the way). In fact Wubi will be incorporated within Ubuntu in the 8.04 release cycle.