(Alpha and Integrity servers) If a file is connected to RMS with
    the RMS global buffer DEFAULT option enabled, the number of of
    blocks cached is either a maximum of the GB_CACHEALLMAX parameter
    or a percentage of the file, whichever results in a larger global
    count.

    Note that although a maximum cache size of %x7FFFFFFF is
    supported for an indexed file, sequential and relative file
    organizations are restricted to a maximum cache size of 32767.

    GB_CACHEALLMAX is a DYNAMIC parameter.