/ALLOCATION=n

    Specifies the initial number of blocks to be allocated to each of
    the specified directories. The default allocation is 1 block.

    This qualifier is useful for creating large directories, for
    example MAIL.DIR;1. It can improve performance by avoiding the
    need for later dynamic expansion of the directory.

    This qualifier does not apply to Files-11 ODS-1, ODS-3, or ODS-4
    volumes.