kernel code test: misc device

in this example, the device is named /dev/my_misc/misc by the "nodename".
kernel code test: misc dev name

By comment out the nodename field, the device is named /dev/misc_dev, the same
in the name field.

And there is no entry /dev/my_misc/misc as it did with nodename.
kernel code reading: virtio/virtio-pci
kernel code reading: scheduler core
kernel code reading: pci hotplug
kernel code reading: scheduler core
userspace code test: ftp project
userspace code test: ftp(add display debug function)

when screen is init with 1, we allocate the bottom two lines to display the
cursor position and command content for debug purpose.