(b) For the DMA (Direct Memory Address) shown in Figure Q5(b) answer the following questions: (i) Explain why are the read and write controller lines bidirectional? [2 marks] (ii) Under what conditions and for what purpose are they used as inputs? [2 marks] Address bus- Data bus - Data bus buffers DMA select- DS Register select RS Read RD Write WR Control logic Bus request BR Bus granted BG Interrupt Internal bus Address bus buffers Address register Word-count register Control register DMA request DMA acknowledge to I/O device Figure Q5(b)