Boot File System (BFS) is a file system used under SCO UnixWare to
allow the bootloader access to the kernel image and other important
files during the boot process. It is usually mounted under /stand
and corresponds to the slice marked as "STAND" in the UnixWare
partition. You should say Y if you want to read or write the files
on your /stand slice from within Linux. You then also need to say Y
to "UnixWare slices support", below. More information about the BFS
file system is contained in the file
Documentation/filesystems/bfs.txt.

If you don't know what this is about, say N.

To compile this as a module, choose M here: the module will be called
bfs. Note that the file system of your root partition (the one
containing the directory /) cannot be compiled as a module.

source code:

fs/bfs/