Imlac PDS-1

The IMLAC PDS-1 and PDS-4 were popular graphical display systems in the 1970s. They were made by IMLAC Corporation, a small company in Needham, Massachusetts. IMLAC is not an acronym, but is the name of a poet from Samuel Johnson's novel, The History of Rasselas, Prince of Abissinia. The PDS-1 debuted in 1970. It was the first low-cost commercial realization of Ivan Sutherland's Sketchpad system of a highly interactive computer graphics display with motion. Only $8300 before options, the cost of four Volkswagen Beetles. The PDS-1 was functionally similar to the huge IBM 2250 costing 30 times more. It was a significant step towards computer workstations and modern displays.

The PDS-1 consisted of a CRT monitor, keyboard, light pen, and control panel on a small desk with most electronic logic in the desk pedestal. The electronics included a simple 16-bit minicomputer, and 8-16 kilobytes of magnetic core memory, and a display processor for driving CRT beam movements.

The monitor was a 14-inch monochrome vector display, continually refreshed from local memory. Its normal resolution was 1024 by 1024 addressable points, and 2K x 2K in small-font scaling mode. The CRT electron beam moved freely in X and Y position and angle under program control to draw individual sloped lines and letter forms, much like the pen-on-paper motions of a pen plotter. The beam skipped blank areas of the screen. Things could be drawn in arbitrary order.

Vector displays are a now-obsolete alternative to raster scan displays. In raster scan displays, like in TV sets, the image is a grid of pixel spots and the CRT beam repeatedly sweeps the entire screen in a fixed horizontal pattern, regardless of which dots are turned on. Bitmap raster graphics requires much more memory than vector graphics. XGA-level 1024x768 black/white resolution requires 96 kilobytes of video refresh memory, 12 times more than a basic PDS-1. In 1970, that much core memory cost about $8000. (It now costs only 0.05 cents of shared DRAM.)

...
Wikipedia