The document summarizes raster scan and random scan displays. Raster scan displays use an electron beam that sweeps across the screen from top to bottom to generate pixels based on values stored in a refresh buffer. Random scan displays directly draw images using an electron beam without a fixed pattern, storing only line drawing instructions. The key differences are that raster scan is used for realistic images due to storing intensity values while random scan has higher resolution but is limited to line drawings. Both use a cathode ray tube containing an electron gun, deflection coils, and phosphor screen.