To get the user-land going, the kernel, when it has finished
initialization, will create a process with ``pid == 1'' and execute
a program on the root filesystem; this program is normally
``/sbin/init''.
You can substitute any program for /sbin/init, as long as you keep in mind that:
there is no stdin/out/err unless you open it yourself. If you exit,
the machine panics. Signal handling is special for ``pid ==
1''.
An example of this is the ``/stand/sysinstall''
program on the installation floppy.