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Probably not a plasma screen in the 70s. It looks like a bunch of individual characters. They are probably vacuum fluorescent like what was on calculators and t

by troupe 3y ago

Probably not a plasma screen in the 70s. It looks like a bunch of individual characters. They are probably vacuum fluorescent like what was on calculators and the Speak & Spell educational toy from that period.

balazer 3y ago
It appears to be a Burroughs Self-Scan plasma display. The display in action on a Q1: https://www.1000bit.it/lista/q/q1europe/q1microlite.png https://www.1000bit.it/lista/q/q1europe/q1microlite.png Close-up shot in a Q1: https://www.peel.dk/Q1/img/SN615-05.jpg https://www.peel.dk/Q1/img/SN615-05.jpg Brochure: https://archive.org/details/TNM_Self-Scan_II_panels_for_data_terminals_-_Burr_20170922_0484/mode/2up https://archive.org/details/TNM_Self-Scan_II_panels_for_data... There are videos of the display being demonstrated on YouTube. Search for Burroughs Self-Scan.
actionfromafar 3y ago
https://www.thebyteattic.com/p/q1.html https://www.thebyteattic.com/p/q1.html Looks like it is plasma but with characters, not a pure bitmap display.
- adrian_b 3y ago
  Yes, it is pretty certain that no bitmap plasma displays existed at that time, because the drivers for them would have been more expensive than an entire desktop computer (due to the high number of rows and columns). It is said that the display was an unusual plasma display and not a vacuum fluorescent display, which were much more frequent in the desktop calculators of that time, but it must have been an alphanumeric display with segments, perhaps with 16 segments per character.
  - Turing_Machine 3y ago
    What we think of as "plasma screens" were invented at UIUC for the PLATO project in (checks) 1964, by Donald Bitzer, H. Gene Slottow, and Robert Willson. They had a resolution of 512x512. They started cranking them out in bulk in 1972. These were monochrome orange vector displays. They didn't use segments.
    - adrian_b 3y ago
      Wikipedia says that the 512x512 PLATO plasma display had a cost of $2500 at a time when that was a much greater value than today. Moreover, I doubt that the cost includes the one thousand high voltage transistors that would have been needed to drive the display. As I have already written, such a display would have been too expensive for a desktop computer with an 8-bit CPU. In the early seventies, as an alternative to the red LED displays and green or blue vacuum fluorescent displays, there were the orange Panaplex plasma displays with segments for numeric (7 segments) or alphanumeric (14 or 16 segments) characters. I believe that the Q1 computer must have had such a Panaplex display, which was cheap enough. Vector displays are possible only where there is a drawing spot that can be moved in any programmable direction, i.e. only on CRTs or mechanical plotters. They are not possible with plasma displays.
      - jjtheblunt 3y ago
        Where did you get the 1000 high voltage transistors thing? I used PLATO at UIUC in the late 80s briefly, because they were still around, but everything had been WYSE-50 or Sun already (or contemporaries) and the PLATO terminals weren't some monstrosities....just looked 20 years old.
        adrian_b 3y ago
        In the simplest case you need one transistor per row and one per column for bitmap displays. If any transistor in omitted, than that row or column must have a fixed voltage, which means that the corresponding column or row of pixels would no longer be controllable and they would display the same pixels as whatever other column or row is selected at a given instant. One thousand transistors do not need a huge space (they would fit easily on a PCB of a size compatible with a PLATO terminal, based on the photo from Wikipedia), but they were quite expensive. Suitable high-voltage integrated circuits have appeared later. In 1972, one could have used Nixie decoders like 74141 for the negative voltage, replacing 512 transistors with 64 IC packages, but 512 discrete transistors would still have been needed for the positive voltage. For segmented alphanumeric displays you need only 14 or 16 transistors for the segments plus one transistor per character.
- troupe 3y ago
  Ah ok. So maybe one of the early Panaplex segment displays instead of bitmap displays that came later.
- mortenjorck 3y ago
  From this link posted in another thread, the structure of the display is a little clearer: https://www.peel.dk/Q1/ https://www.peel.dk/Q1/ In the shot of the display frame by itself without the tinted plastic in front of it, it almost looks like a miniature arrival/departure board at a train station.

by troupe 3y ago

balazer 3y ago

It appears to be a Burroughs Self-Scan plasma display. The display in action on a Q1: https://www.1000bit.it/lista/q/q1europe/q1microlite.png https://www.1000bit.it/lista/q/q1europe/q1microlite.png Close-up shot in a Q1: https://www.peel.dk/Q1/img/SN615-05.jpg https://www.peel.dk/Q1/img/SN615-05.jpg Brochure: https://archive.org/details/TNM_Self-Scan_II_panels_for_data_terminals_-_Burr_20170922_0484/mode/2up https://archive.org/details/TNM_Self-Scan_II_panels_for_data... There are videos of the display being demonstrated on YouTube. Search for Burroughs Self-Scan.

actionfromafar 3y ago

https://www.thebyteattic.com/p/q1.html https://www.thebyteattic.com/p/q1.html Looks like it is plasma but with characters, not a pure bitmap display.

adrian_b 3y ago
Yes, it is pretty certain that no bitmap plasma displays existed at that time, because the drivers for them would have been more expensive than an entire desktop computer (due to the high number of rows and columns). It is said that the display was an unusual plasma display and not a vacuum fluorescent display, which were much more frequent in the desktop calculators of that time, but it must have been an alphanumeric display with segments, perhaps with 16 segments per character.
- Turing_Machine 3y ago
  What we think of as "plasma screens" were invented at UIUC for the PLATO project in (checks) 1964, by Donald Bitzer, H. Gene Slottow, and Robert Willson. They had a resolution of 512x512. They started cranking them out in bulk in 1972. These were monochrome orange vector displays. They didn't use segments.
  - adrian_b 3y ago
    Wikipedia says that the 512x512 PLATO plasma display had a cost of $2500 at a time when that was a much greater value than today. Moreover, I doubt that the cost includes the one thousand high voltage transistors that would have been needed to drive the display. As I have already written, such a display would have been too expensive for a desktop computer with an 8-bit CPU. In the early seventies, as an alternative to the red LED displays and green or blue vacuum fluorescent displays, there were the orange Panaplex plasma displays with segments for numeric (7 segments) or alphanumeric (14 or 16 segments) characters. I believe that the Q1 computer must have had such a Panaplex display, which was cheap enough. Vector displays are possible only where there is a drawing spot that can be moved in any programmable direction, i.e. only on CRTs or mechanical plotters. They are not possible with plasma displays.
    - jjtheblunt 3y ago
      Where did you get the 1000 high voltage transistors thing? I used PLATO at UIUC in the late 80s briefly, because they were still around, but everything had been WYSE-50 or Sun already (or contemporaries) and the PLATO terminals weren't some monstrosities....just looked 20 years old.
      - adrian_b 3y ago
        In the simplest case you need one transistor per row and one per column for bitmap displays. If any transistor in omitted, than that row or column must have a fixed voltage, which means that the corresponding column or row of pixels would no longer be controllable and they would display the same pixels as whatever other column or row is selected at a given instant. One thousand transistors do not need a huge space (they would fit easily on a PCB of a size compatible with a PLATO terminal, based on the photo from Wikipedia), but they were quite expensive. Suitable high-voltage integrated circuits have appeared later. In 1972, one could have used Nixie decoders like 74141 for the negative voltage, replacing 512 transistors with 64 IC packages, but 512 discrete transistors would still have been needed for the positive voltage. For segmented alphanumeric displays you need only 14 or 16 transistors for the segments plus one transistor per character.
troupe 3y ago
Ah ok. So maybe one of the early Panaplex segment displays instead of bitmap displays that came later.
mortenjorck 3y ago
From this link posted in another thread, the structure of the display is a little clearer: https://www.peel.dk/Q1/ https://www.peel.dk/Q1/ In the shot of the display frame by itself without the tinted plastic in front of it, it almost looks like a miniature arrival/departure board at a train station.