VT11 Graphic Display Processor

The VT11 Graphic Display Processor was a vector graphics video terminal from DEC. It was a UNIBUS device, which used DMA to retrieve display programs from main memory. It was intended for use with the VR14 CRT or the VR17 CRT.

It was capable of displaying text (using a built-in hardware character generator), vectors (solid, dashed, and dot-dash), and points (relative and absolute); any displayed item can be set to blink. The resolution was 1024x768 pixels. The VT11 also supported a light pen.

The VT11 consisted of three hex-height boards: A320 (vector and character generators and D-A convertors); M7013 (display processor); and M7014 (UNIBUS interface). They plugged into a custom backplane.

The VT11 used an odd intermediary technique for its character generator; although it was a vector graphics device, for displaying characters, its character generator stored characters as arrays of pixels. To display a character, it did a raster-like scan over a small part of the screen, and displayed the character in much the same way a raster display does, although the raster scan used vertical strokes, not horizontal, as in a normal raster display.