The orange and black display

Jun 6th, 2010 | Posted by Stone

Plato V terminals, Computer History Museum

Back when I was in college, I had the good fortune to become involved in the Plato IV computer-aided instruction project. The Plato IV system consisted of up to a 1000 terminals connected to a CDC mainframe computer. Each terminal had a black and orange plasma display, using the same basic technology now in plasma televisions. The 512 x 512 randomly addressable display, touch panel and typewriter-like keyboard created one of the first graphics workstations. (The Plato V terminals shown in the picture have the same technology. The Plato IV terminal wasn’t working when I was there)

The Plato system was used to teach courses during the day. At night, developers created courseware and expanded the system. The first computer chat, shared notes, and multi-player games were created for the Plato IV system.

My work involved connecting a plasma display, keyboard and touch panel to a PDP/11 mini-computer to create an “intelligent terminal.”   My thesis was on character encoding, to improve performance over the 1200bps communication line. I may have sent the first embedded graphics via email by writing software that packed an image into ASCII bytes that were then decoded in the terminal.

The plasma panel’s bright orange dots are created by neon gas discharge, revealing the fundamental mechanism of plasma displays. Plasma televisions use xenon to energize colored phosphors, but the Plato IV displays predate their development by a decade or more. While initially startling, both developers and users quickly adapted, focusing on the concepts presented, not the color.

At the Plato reunion, the question was asked whether having the orange and black displays was limiting. Would color displays have been significantly better?  As in all new media, creative minds work around and with the limitations of the medium. Creativity and innovation flowed in orange and black in the Plato project. Applications that required color were not explored, but there were plenty of other choices.

Would color have been better? This can’t be asked independently of the available technology. Given that there were no affordable color displays, it was clearly better not to wait for color. As display technologies evolve, adding color generally means lowering resolution. For text and illustration, higher resolution is the better choice.  Similarly, lower price and higher reliability are often more important than color.

All imaging technologies progress from a limited proof-of-concept (usually black and white), through grayscale to full color. Once the color versions achieve quality and reliability at a sufficiently low price, they will replace their achromatic  predecessors except for specialized applications. The history of  photography, printing, television and displays all show this evolution. The orange and black plasma panels of the Plato project of the 7o’s were the first step on the path towards the color plasma televisions available today. But more importantly, they enabled a world-changing burst of creativity and innovation whose impact can still be seen today.

Links: Plato History, Plasma Displays

  1. Marina LaPalma
    Aug 27th, 2010 at 17:50
    Reply | Quote | #1

    Hi Maureen — I really enjoyed reading your posts about color, maps, monitors … what got me into it was the piece about the Russian photographer and his glass plates.


  2. Mithril@group Dragon FSU
    Sep 11th, 2010 at 16:12
    Reply | Quote | #2

    Hoenstly, I remember working so diligentlly and being so engrossed in what we could do on PLATO that I don’t think the idea of a color display ever crossed my mind back then.

  3. Bill Geimer
    Jul 7th, 2011 at 13:44
    Reply | Quote | #3

    I doubt many thought much of color displays. IBM Green on black was rare back then, and being a CRT, you could neither draw on it nor project through it (as long as the air pressure held out.) I agree everybody so was amazed by it that it probably only came up for the more graphically inclined.

  4. Bill Geimer
    Jul 7th, 2011 at 13:48
    Reply | Quote | #4

    The only other orange on black display I remember was a Burroughs’ terminal, which had four virtual pages that you could rotate back and forth, but my recollection was that you could not see all 24 lines of a 24×80 display. I think it was only text, and it was circa 1977-1980.