Put the concept for filelocking here - 06/26/05

Note: The locking for devices is also regulated
by the filelocking. (That's why user-programs
cannot access device directly with the
functions in kernel/dev.c). Other system
resources may also use locking when represented
as files.

As for version 0.0.1 there won't be any more sophisticated
testings whether the attempted file-openmode matches
with the current file-state (e.g. when the file
has been opened previously with OPENEXCLUSIVLY
it should fail).

File open-modes:

- OPENREADONLY	..01
- OPENWRITEONLY ..10
- OPENREADWRITE ..11
- OPENEXCLUSIVLY ..1xx
- ...