(8 marks) (b) For the DMA (Direct Memory Address) shown in Figure Q5(b) answer the following questions: (0) 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 Address bus buffers DS Address register DMA select Register select Read RS Internal bus RD Word-count register Write WR Control BR logic Control registet Bus request Bus granted Interrupt BG DMA request DMA acknowledge to lo device