VMS Help INITIALIZE, Qualifiers, /SYSTEM  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Requires a system UIC or SYSPRV (system privilege) privilege.

    Defines a system volume. The owner UIC defaults to [1,1].
    Protection defaults to complete access by all ownership
    categories, except that only system processes can create top-
    level directories.