NPAGEVIR defines the maximum size to which NPAGEDYN can be
    increased. If this value is too small, the system can hang.
    If NPAGEVIR is too large, the result is a penalty of 4 bytes
    per extra page on VAX and 8 bytes per extra page on Alpha and
    Integrity servers.

    For the benefit of OpenVMS VAX systems with limited physical
    memory, AUTOGEN logs a warning message in its report if NPAGEDYN
    exceeds 10 percent of physical memory or if NPAGEVIR exceeds 33
    percent of physical memory.

    AUTOGEN also limits its own calculated value for NPAGEDYN to 20
    percent of physical memory, and limits NPAGEVIR to 50 percent
    of physical memory. These calculated values are adequate for
    most workstations and systems with 16 or fewer megabytes of
    physical memory. If your system requires a larger value, you can
    override the AUTOGEN calculated values by setting higher values
    in MODPARAMS.DAT.

    NPAGEVIR has AUTOGEN and GEN attributes.