The package lodlin15.tgz available from sunsite.unc.edu in /pub/Linux/system/Bootutils. This utility is particularly suited to boot a Umsdos system. Generally all you need to do is
Boot DOS C:>loadlinx zimage root=D:
where zimage is a normal kernel image (compressed) simply copied somewhere in the DOS drive. D: is the DOS drive where you have installed Linux.
Booting a Umsdos system from a floppy is not different from booting a Ext2 system. You need a kernel zImage file properly initialize to locate your root Umsdos partition. This is generally achieved using the command rdev. The following sequence will initialize a zImage and put it on a floppy.
rdev zImage /dev/hda1 rdev -R zImage 0 dd if=zImage bs=8192 of=/dev/fd0
If this looks confusing, just format a boot-able DOS floppy and put the following component on it.
and setup the autoexec.bat like this
loadlinx zimage rw root=C:
LILO, the official Linux boot loader can also be used to boot a Umsdos system. I have no experience with it though. Since 1.1.60, it should work. Please email if you know something.
It can be done using any popular DOS tool. There is nothing particular about file produced by Umsdos. And Umsdos do not expect anything particular (directory layout, directory entry sequence, etc...) from the file system under it.
As far as I know, there is no Linux tool to achieve this.
Umsdos rely on the --linux-.--- which rely on the DOS directory. Some users may want to experiment a bit. The utility udosctl part of the umsdos_progs package (containing umssync and umssetup) allows basic directory operation (listing, deletion) independently on the --linux-.--- and the DOS directory.