/sys$common/syshlp/helplib.hlb Sys Parameters, WRITESYSPARAMS  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    On VAX systems, WRITESYSPARAMS indicates that parameters are
    modified during SYSBOOT and are written out to VAXVMSSYS.PAR by
    STARTUP.COM.

    On Alpha systems, WRITESYSPARAMS indicates that parameters are
    modified during SYSBOOT and are written out to ALPHAVMSSYS.PAR by
    STARTUP.COM.

    This special parameter is used by Compaq and is subject to
    change. Do not change this parameter unless Compaq recommends
    that you do so.

    WRITESYSPARAMS is a DYNAMIC parameter.