VMS Help Sys Parameters, LONGWAIT  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    LONGWAIT defines how much real time (in seconds) must elapse
    before the swapper considers a process to be temporarily idle.
    This parameter is applied to local event flag (LEF) and hibernate
    (HIB) waits to detect such conditions as an inactive terminal or
    ACP.

    LONGWAIT has the DYNAMIC, GEN, and MAJOR attributes. On Alpha
    systems, LONGWAIT is also an AUTOGEN-altered parameter.