On Mon, Feb 15, 2010 at 07:55:21PM -0700, Richard wrote:
  Yes, even in 1986 I would expect a memory mapped frame
buffer to a VAX
 to get updated faster than that.  So that does point to a serial line
 terminal. 
An alternative is that the image is loaded from disk into the frame
buffer, they do talk about "load" images from files.
/P
(And yes, Johnny, I should have recognized it as a TU77 :)