Examples of valid input syntax are:
    newvmunix     - load newvmunix from the booted device, partition a
    (g)vmunix     - load vmunix from the booted device, partition g
    (3)vmunix.old - load vmunix.old from device unit 3, partition a
    (9,g)vmunix   - load vmunix from device unit 9, partition g
    (4,7)vmunix   - load vmunix from device unit 4, partition h
    NOTE: If specified, the device unit number must be the PHYSICAL
    unit number of a device connected to the SAME CONTROLLER as the
    booted device.