Library /sys$common/syshlp/sysmanhelp.hlb IO, SHOW, PREFIX, Example  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  SYSMAN> IO SHOW PREFIX
  %SYSMAN-I-IOPREFIX, the current prefix list is: SYS$,PSI$,VME_

      This example shows the prefixes used by IO AUTOCONFIGURE to
      build ICBM names.