coils fought against rapid changes to their current. The screen flickered when filled with more than 800 inches of lines or more than 1200 characters, because the beam then needed more than 1/40th of a second to retrace everything.

The competing lower cost Tektronix 4010 graphics terminal used an alternative storage tube CRT technology which required no continual refresh and hence no local computer display memory at all. The glowing image was remembered