The IMLAC PDS-4 was an updated version of the PDS-1 which was originally released in 1970. The PDS-1 is a graphical display system that was used in the 1970s. It included A CRT monitor, control panel, and desk pedestal which contained a 16-bit minicomputer, core memory and display processor.
The PDS-1 while low cost for its time compared to other similar computers was hugely expensive by today's standards. The base model would set you back about $8,300. It was used to develop one of the first hypertext systems and was also used as a component in larger systems including a newspaper layout and typesetting system. But it was an early game development and gaming system too. Spacewar! started out as a demo on the PDS-1 and the first online multiplayer computer game, Mazewar, was also first created on a couple of PDS-1s. Perhaps most interestingly, Frogger started life as a game called Freeway that was developed on a PDS-1 as a psychology experiment related to the study of short-term memory.
The PDS-4 was very similar to the PDS-1 but it was twice as fast and able to display twice as many lines of text without flicker.
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