/COLUMNS=n

    Lists the files, using the specified number of columns on each
    line of the display. This qualifier is used in conjunction with
    the /BRIEF qualifier (either explicitly or by default). The
    default number of columns is dependent on the volume format and
    the information requested. The DIRECTORY command attempts to use
    as many columns as possible. If you request too many columns,
    DIRECTORY displays a message and reduces the number of columns to
    the number that fit on the listing.