VMS Help LINK, Qualifiers, /P0IMAGE  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Directs the linker to place an executable image entirely in P0
    address space. When the /P0IMAGE qualifier is specified, the user
    stack and OpenVMS RMS buffers, which usually reside in P1 space,
    are placed in P0 space by the image activator.