Alan JoWe need to know I/O execution path
Since there is so many i/o device, so we need i/o bus
I/o address
predefined address between CPU and I/O address
DMA (direct memory access)
Bypass CPU to transfer data directly between I/O device and memory. – Used to avoid programmed I/O for large data movement. – Require DMA controller
– Cycle stealing
•. – Burst mode •
Addressing in DMA
memory region should be pinne during dma
Typical PC Architecture
