Library /sys$common/syshlp/sysgen.hlb SHOW, /CONFIGURATION, Qualifiers, /ADAPTER  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /ADAPTER=nexus

    Specifies the number of MASSBUS or UNIBUS adapters to be
    displayed. The nexus value can be expressed as an integer or
    with one of the generic names listed by the SYSGEN command
    SHOW/ADAPTER.