Install Linux… from Windows?

Install Linux from the Web through Windows: What next Microsoft Linux?


Just when Microsoft wants you to forget about alternatives to Vista along comes the Debian based project that allows you to not only install Linux on a Windows system but do it right under its nose.

Linux is renowned for being a compatible operating system catering to all manner of protocols filesystems and co-habitation with other operating systems including Windows.

But usually you need to install it from a clean boot. Now thanks to Debian coder Robert Millan it’s possible to not only install Linux alongside Windows but through it as well.

While the Ubuntu team initially announced exactly this concept earlier this month along with a downloadable prototype Millan appears to have completed a finished version replete with a promotional (if not controversial) website to boot —

By simply clicking the ‘install Debian’ link the installer will download and when run install Debian through your Windows desktop. Aside from the obvious ease of use this sort of install mechanism provides Millan also listed the following benefits in his announcement post to the Debian lists:

– Migrating to Debian on hardware without CD drive (or USB boot
– Migrating to Debian for users who have no idea how to burn an ISO and/or how to configure their BIOS for CD boot.
– Migrating a system to Debian immediately at any time wether
we have a boot CD at hand or not.
– Advocating Debian to Windows users. Rather than give them a CD (expensive) give them a piece of paper with an URL.

It all sounds good but how does it work?

The idea of booting Linux from a Windows partitions isn’t entirely foreign — for a long time we’ve had distributions capable of installing to a FAT16/32 partition and boot directly from it (see loadlin) but we’ve long since moved away from those days.

And in fact this new method isn’t too dissimilar. Here the appropriate Debian images are download and configured and installed as a loopback ext3 filesystem on the NTFS Windows drive — for those unfamiliar this means a self-contained filesystem created as a single large file on the NTFS partition — then mounted as a loopback device within Linux when the kernel boots.

Which is the second part of the magic — the installer finishes by using GRLDR from GRUB4DOS to load the loopback image directly after being booted from the Windows boot manager. So effectively both Windows and Linux are loaded from the NTFS partition although to Linux it’s a world within a world. No partitioning no data moved and aside from updating the boot loader uninstalling would be a matter of deleting the image file.

It’s definitely a nifty trick easy to do and from the average Windows user’s perspective transparent. It should probably explain however that the Windows NTFS partition becomes home to both OSes lest they later decide to update or even remove Windows in favour of Linux and nuke their Debian install in the process.

It’s also not entirely clear how one could extend the disk space for the ext3 container file though of course Linux can read the parent NTFS filesystem (and potentially delete said container file now wouldn’t that be interesting).

On that note it’s probably best to wait until this mechanism has had the pants tested off it before you forward it around to your soon-to-be-converted friends but it is none the less an ingenious use of loopback filesystems and a Linux install that hits Windows users where it matters most — at the simple click of a button.

It also bodes well for future installs of Linux regardless of distribution. The Ubuntu system while still being developed apparently goes a step further and pulls in necessary information from Windows itself streamlining the process for the new Linux user even more.

If you want to give either a try the Debian installer is here and the prototype Ubuntu one here.