Explain these commands in details.

cat /proc/iomem (what are we looking at?) dmesg Igrep DMA (explain the "DMA zone" statements) git clone https://github.com/Wallacoloo/Raspberry-Pi-DMA-Example.git cd Raspberry-Pi-DMA-Example/ make rpi3 sudo ./dma-example (what is this doing?) less dma-example.c (or view it with nano/vi, whatever is easiest for you) what is the memfd variable? what is the cb1 variable? what is it used for? o why do we need the sleep(1) statement? dmesg Igrep mmco (explain each line of results) file /dev/mmcblko (what do the results mean?) file /dev/loop0 (what do the results mean? The numbers in the results?) file /dev/kmsg (explain the results) o o O