The first development of computers in the 1950s and the 1980s used a different type of vector graphics system display. In these systems, the electron beam of the CRT display directly generates the required graphics piece by piece, and the rest of the screen remains black. In order to achieve the effect of no flicker or close to no flicker, this process is repeated many times per second. This display system can generate line art with very high resolution, and does not require the grid system to generate the same resolution. The memory space was very huge at the time. This vector-based display is called an X-Y display.