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

1 - /ALL

    Selects all remaining processors in the system's available set to
    join the multiprocessing system.

2 - /DEFAULT_CAPABILITIES

    Eliminates all previous capability (user and system)
    modifications for the specified CPU and reinitializes them with
    the values in the global initialization variable SCH$GL_DEFAULT_
    CPU_CAP.

    Normally, user capabilities survive CPU shutdowns and restarts
    (not reboots), making the downtime as transparent to the user as
    possible. The CPU user capability bits are only initialized from
    SCH$GL_DEFAULT_CPU_CAP at the first boot of the CPU. (The system
    capability bits, however, are reinitialized to their defaults
    taken from SCH$GL_DEFAULT_CPU_CAP.)

    However, there may be times when the CPU needs to be returned to
    a known, consistent state. The /DEFAULT_CAPABILITIES qualifier
    mimics the behavior of the initial bootstrap of the CPU.