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

    Requires SYSNAM (system logical name) or SYSPRV (system
    privilege) privilege.

    Places the logical name in the system logical name table. All
    system users can access the logical name. The /SYSTEM qualifier
    is synonymous with the /TABLE=LNM$SYSTEM qualifier.