Function 0Dh (13)        Disk Reset

    Flushes all file buffers.

       On entry:      AH         0Dh

       Returns:       Nothing

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       Notes:         This function flushes all file buffers but does not
                      close files. To ensure that the proper length of a
                      changed file is recorded in the disk directory, use
                      one of the two Close File Functions (10h or 3Eh).