I'm netbooting a VS4000/60.  Because the video console isn't
supported, I'm using a serial cable connected to a PC.  It's
working fine, but why does the kernel crash if I touch the
VAX keyboard (LK402-AM):

panic: ptelen fault in system space: addr 0 pc 800e46ea
syncing disks... Trap: type 2, code 0, pc 80000648, psl 4150000
panic: trap

  83 BOOT SYS