1. Computer organization

2. I / O

12. IO mapped i/o Data valid Address bus i/o bus CPU Status F register IO device interface Data register Data accepted Data bus I/o read I/o write

17. Memory mapped i/o data Address read write Main memory CPU IO port 1 IO port 2 IO port 3 IO device A IO device B

18. IO mapped i/o data Address Read M write Main memory CPU IO port 1 IO port 2 IO port 3 IO device A IO device B Write M Read IO Write IO

27. Modes of data transfer -DMA Processor Main memory Disk/DMA controller DMA controller Printer Keyboard Network interface disk disk System bus