FAT Filesystem and Linux - Installing Linux On and Booting IT From FAT Volumes Using Umsdos

Installing Linux On and Booting It From FAT Volumes Using Umsdos

As mentioned, umsdos permits installing Linux on, and then bootstrapping and running it from, a FAT format disc volume. The advantage of this is that it permits the use of Linux on a computer where DOS is already installed, without requiring that the hard disc be repartitioned. Linux is not bootstrapped directly from a Volume Boot Record in such a scenario. Instead DOS is first bootstrapped, and loadlin is used to then bootstrap Linux from DOS.

The convention for such an installation is for the Linux root directory to be a subdirectory of the actual root directory of the DOS boot volume, e.g. C:\LINUX . The various Linux top-level directories are thus, to DOS, directories such as C:\LINUX\ETC (for /etc), C:\LINUX\BIN (for /bin), C:\LINUX\LIB (for /lib), and so forth. The umsdos filesystem driver automatically prepends the C:\LINUX\ to all pathnames. The location of the Linux root directory is supplied to the umsdos filesystem driver in the first place via an option to the loadlin command. So, for example, for the aforegiven root directory loadlin would be invoked with a command line such as loadlin c:\linux\boot\vmlinuz rw root=c:\linux .

The installation of Linux into such a directory in the first place simply involves unpacking files from an archive into that directory and its subdirectories. Such an installation also generally requires the use of a swap file rather than a swap partition for Linux, however this is related to the desire not to repartition the hard disc and unrelated to the umsdos filesystem driver per se.