With Umsdos, Linux can be installed in a standard
DOS partition. Linux is then installed as a second (or
third) OS in the partition. To avoid name collision (there
is maybe a bin or tmp directory in the drive C: already),
Umsdos use
a smart trick: The pseudo-root.
All Linux files are installed in a DOS subdirectory
called linux, generally C: LINUX. The normal
Linux/Unix directory structure goes there. So you
get
C:\LINUX\BIN
C:\LINUX\ETC
C:\LINUX\LIB
C:\LINUX\ROOT
C:\LINUX\SBIN
C:\LINUX\TMP
C:\LINUX\USR
C:\LINUX\VAR
When the Umsdos boot, it probes for the directory linux
and then /linux/etc. If it exist, it activates
the pseudo-root mode.
Mostly, the pseudo-root mode switch the root of the partition
to C:\\LINUX giving the conventional Unix directory
layout
/bin
/etc
/lib
/root
/sbin
/tmp
/usr
/var
To this list, it adds a new one called DOS. This one is
a virtual directory.
This mode can only be triggered
at boot time. There is no way to activate this by
a mount command.
This mechanism is purely a different view of a normal
Umsdos file-system. This means that a partition normally
used as a root partition can be normally mounted. There won't
be any pseudo-root effect.
For example, if you boot linux with a maintenance floppy and
mount your normal root partition in /mnt, you will
find all your linux directory in
/mnt/linux/bin, /mnt/linux/etc and so on.
