3 ms·

>Everything these days is glass and refresh rates The higher the display refresh rate the metaphorically "quieter" the computer. Discrete frames introduce late

by mrob 1mo ago

>Everything these days is glass and refresh rates The higher the display refresh rate the metaphorically "quieter" the computer. Discrete frames introduce latency, phantom array effect, and (on most displays) sample-and-hold blur. These don't exist in real life, so they weaken the illusion of the computer becoming part of your body, like a pencil or a hand tool. A computer that can be operated with minimum cognitive load needs a display refresh rate of at least 1000 Hz.

anilakar 1mo ago
We had CRT displays that could easily do 100 to 120 Hz. Then we regessed to LCD panels that could do 60 Hz and it somehow became the performance target.
- Avicebron 1mo ago
  I mean CRT is inherently bulky, it's hard not to see why LCD panels became popular.
  - krige 1mo ago
    To sellers, yes. The drop of visual quality when the top-down LCD push began was staggering.
    - deleted 1mo ago
      [deleted]
    - LargoLasskhyfv 1mo ago
      Depended very much on the CRTs used, there were very wide gaps in quality. Even a now obsolete HP ZR2240w (24" 1920x1200@60Hz) was a huge upgrade from a 21" Hitachi Superscan Supreme https://crtdatabase.com/crts/hitachi/hitachi-superscan-21-cm2112mu https://crtdatabase.com/crts/hitachi/hitachi-superscan-21-cm... That thing was at least Trinitron equivalent, if not better, because it lacked the thin wires holding the mask from within. Now you are talking about the start of all that, OFC there were bad and cheap ones, but there was also very good stuff from the beginning by Eizo, Sharp, NEC, and many more. Just as with CRTs. I don't miss them.
    - rcxdude 1mo ago
      To buyers as well. I don't recall the switch to LCDs being particularly pushed, though I was admittedly quite young at the time. Especially keep in mind that people today are generally comparing the absolute top-tier of CRTs which were not what the average person had. (Another thing to keep in mind is that the systems of the time generally could not drive the kinds of resolutions and framerates that make those CRTs shine in some of today's comparisons. At the time the difference in quality in practice was lower because of this)
      - aleph_minus_one 1mo ago
        > (Another thing to keep in mind is that the systems of the time generally could not drive the kinds of resolutions and framerates that make those CRTs shine in some of today's comparisons. At the time the difference in quality in practice was lower because of this) For desktop applications, the systems could. For 3D games, keep in mind that CRTs (in opposite to flat screens) could also diplay every other supported resolution sharply. The reason why many people think that CRTs were worse in practice is that many graphics cards of the time simply had a low-quality VGA signal generators built-in.
      - anilakar 1mo ago
        I owned a 17-inch Trinitron and very much preferred it over the early slow and small LCD panels. I did get a 15-inch Samsung VGA LCD panel for free later, but only kept it as a LAN party display as it folded completely flat for storage and transport.
    - tom_ 1mo ago
      Was there a top-down push? In general, people on average never really actually liked CRT displays all that much. They are annoyingly deep; they are heavy; the screen is flickery, or not quite pin sharp, or both; they use up a lot of power; they fail in annoying ways, and they're expensive to fix - and they have magnets in them.
      - thfuran 1mo ago
        And they make a constant shrieking sound.
        mrob 1mo ago
        Only SD CRTs make an audible shrieking sound. LCD computer monitors were replacing VGA or better CRTs with a horizontal refresh rate of >30kHZ. Maybe they could annoy your dog but no human could hear it.
        NathanielK 1mo ago
        I still use a 130kHz CRT monitor sometimes. There's no 15kHz whine, but there's audible harmonics. It depends what you're looking at at and how hard you're pushing it.
    - BigTTYGothGF 1mo ago
      I had multiple mediocre-to-crappy CRTs in the 90s and 00s and was glad to move away from them. I think the last one I owned was even one of the fabled trinitrons, and it was acceptable.
      - AnotherGoodName 1mo ago
        Yeah i had a trinitron and i still had bloodshot eyes after a few hours that i never got with LCD screens. Everyone was aware that CRTs sucked terribly for eye strain. The tradeoffs moving to even the early LCDs was well worth it. I remember people spending effectively double on LCDs at the time over higher specced and larger CRTs and being delighted with the result. eg. early LCDs were just 14inch, low res, low refresh rates when you could get a 17inch CRT higher specced in every way. People were still opting for the early LCDs. Your eyes are important!
  - TacticalCoder 1mo ago
    > I mean CRT is inherently bulky, it's hard not to see why LCD panels became popular. But going from, say, a Sony Trinitron CRT [1] to one the first LCD was a huge step backwards, which is what GP is saying. I did wait for the first LCD with DVI support before switching: for the difference in crispyness between an analog video cable and a DVI one was night and day (I also won many points when I helped friend set up a startup in southern california and we realized one person out of two had picked the VGA cable instead of the DVI one when setting up its desk / computer: so with the CTO late at night we went through every PC and changed all those with VGA cables to the DVI ones). We're not saying modern days flat monitors aren't better than old CRTs: we're saying the first flat screens were complete suckage. [1] even though on a Trinitron you could see two faint horizontal lines (Trinitron were still amazing)
    - LargoLasskhyfv 1mo ago
      DVI or not didn't matter that much when your VGA had a good RAMDAC, and you had a good cable. https://en.wikipedia.org/wiki/RAMDAC https://en.wikipedia.org/wiki/RAMDAC Which of course you could only see in direct comparison. Which most ppl didn't have the opportunity to do, so you needed experience instead to judge that. Which most ppl also didn't have, because they've been exposed to cheap stuff only.
      - jaffa2 1mo ago
        Matrox used to have the best back in the day. Ai were ok and Nvidia were the worst. Even a lay person could see that difference between the tnt out put vs a millenium. It was so great that i used to use an older matrox card think it was the g450 since it worked great under Linux and the pq was amazing.
        LargoLasskhyfv 1mo ago
        Yes. Matrox was very good. But so were later Voodoo3. I know, because I've driven a https://crtdatabase.com/crts/hitachi/hitachi-superscan-21-cm2112mu https://crtdatabase.com/crts/hitachi/hitachi-superscan-21-cm... with it. At 1600x1200@75Hz. Crystal clear and sharp. I also had something by ELSA with a S3 and a translucent blue RAMDAC by IBM. Same thing. But only 2MB VRAM, and PCI. So only useful for testing purposes. Regarding the usability under Linux, or rather support by XFree86, Matrox accelerated some graphics primitives in the DDX-layer, or whatever that was called then. So did the Voodoo3's! Independently of that Glide stuff for 3D. Really nice to have.
- aitchnyu 1mo ago
  Had a Samtron 15" and the LCD that replaced it was very washed out. Commercial users in India kept them for 15+ years.
- TiredOfLife 1mo ago
  After 15 minutes at crt my eyes were watering, not so for lcd
- inigyou 1mo ago
  Now that you mention it, 60Hz was considered poor on a CRT. 85 was the target. But that was because of flicker. AFAIK, 60Hz video frame rate was considered acceptable, but on a CRT the video frame rate was also the flicker rate and 60Hz was too low for flicker.
  - AnotherGoodName 1mo ago
    A slow motion capture of CRT show's the issue https://www.reddit.com/r/crtgaming/comments/7w0v02/video_by_the_slowmo_guys_showing_how_tvs_work/ https://www.reddit.com/r/crtgaming/comments/7w0v02/video_by_... Almost laser pointer brightness at one point on the screen which you don't consciously see because the your eyes and the hold the image for a few milliseconds but do you really want to be looking at a extremely bright point of light all day. Higher refresh rates on CRTs lowered eye strain since that point could be effectively lower brightness, just refreshing twice as fast. I honestly don't get eye strain on LCDs nearly as bad under any circumstance. 60hz LCD was a massive improvement over the 120hz CRTs.
  - mrob 1mo ago
    CRT flicker is equally visible when frame rate is the same as refresh rate as when it differs. 60Hz CRTs were never good. 60Hz was only considered "acceptable" because people didn't know any better at the time. At least you didn't suffer with 50Hz CRTs using the same fast phosphors like the PAL regions did.
DonHopkins 1mo ago
We don't need faster refresh rates, we need slower phosphor. https://youtu.be/1EWQYAfuMYw?t=832 https://youtu.be/1EWQYAfuMYw?t=832
- mrob 1mo ago
  We need faster refresh rates. Slow phosphors also cause unnatural visual artifacts. 1000Hz is roughly the point where you get motion quality that, except for a rare few test signals (e.g. multiplexed displays), is easily mistaken for reality.
  - DonHopkins 1mo ago
    Naw, we just need better software and slower computers, like the PDP-1, that don't require such fast refresh rates, just slow phosphor. But slow computers still need fast and reliable user interfaces, like radial pie menus. Flight of the PIXIE - Yuja Wang: https://www.youtube.com/watch?v=jDrqR9XssJI https://www.youtube.com/watch?v=jDrqR9XssJI PIXIE: A New Approach to Graphical Man-Machine Communication: https://www.donhopkins.com/home/documents/PIXIE%20a%20new%20approach%20to%20man-machine%20communication.pdf https://www.donhopkins.com/home/documents/PIXIE%20a%20new%20... The computer shown in that video is a much more advanced and faster PDP-7, talking to an even bigger and faster Titan mainframe over a custom network! https://en.wikipedia.org/wiki/Titan_(1963_computer) https://en.wikipedia.org/wiki/Titan_(1963_computer) It proves that slow computers can still be usable with better software, and that today's unusable computers are pissing away enourmous amounts of power, but still suck. Edit: I just showed you a video of a computer with a light pen. Did you check that out? It's only two minutes, and I made it to musically highlight PIXIE, because most people don't want to sit through silent hours of the original digitized films from Cambridge. PIXIE is not one box. It is a network distributed CAD workstation (1967–1972) -- like AJAX, but with P7 two-layer cascade phosphor on a 16ADP7A radar tube instead of HTML: Interactive front end: DEC PDP-7 + Type 340 CRT. Real-time drawing, light pen, radial "control lightbuttons", graph model in core. Compute / storage host: Titan (Cambridge’s Ferranti/ICT Atlas 2 prototype). RAINBOW apps: CONN, COMPACT, PLOT, LADAN circuit analysis, file store. Wire between them: Wiseman link (Cambridge custom) + Lang's supervisor software. Move typed ring-structure models blocklet-by-blocklet. Word size: 18 bits. Core (PIXIE design target): 8K words — "only 8K of 18 bit words ... no auxiliary storage". Core (likely installed): 8K–16K (GUIDE: "here likely 16K"). Cycle time: ~1.75 µs. ~571K cycles/s. Addressing: 13-bit + indirect bit. Registers: One accumulator + link bit. DEC made lots of "instruction sets in a chassie" extension boxes, and Wiseman at Cambridge rolled his own network with its own custom instructions. Extended Arithmetic Element: Type 177 EAE. Multiply, divide, shifts, normalize (64xxxx op family in listing). Precision incremental display: Type 340. Required — second processor + DMA display file. Light pen: Type 370. Pen flag IOTs; diagnostic 7-78-M in pdp-7 reference. Symbol generator: Type 342. 6-bit character codes → stroke sequences in display file. Subroutine option: Type 347. DJS / DJP — display jump-to-subroutine (subpictures as display subroutines) Titan link interface: Cambridge custom (Wiseman) Undocumented IOTs: LCF, LSF, LKE, LLB6, LLB18, LRB18, LLAM, LSA, LKD — networking as instructions. The 340 display was an amazing ensembel of hardware, and could plug into a PDP-1 as well. The SIMH emulator supports it well. Model: DEC Type 340 Precision Incremental CRT System (H-340, Nov 1964). Tube lineage: Type 30E → 16ADP7A radar tube, P7 phosphor, 1024×1024 address grid. CPU coupling: Cycle steal / data break — 340 fetches display words from PDP-7 core while CPU runs. Vector timing: ~1.5 µs incremental vectors (vs Type 30 ~50 µs per CPU-plotted dot). Display word types: Parameter, point, vector, vector-continue, increment, character; with 347: DJS/DJP subroutines. Light pen: Per-word pen-enable bits; tracking uses cross + recovery spiral (~2× cross size) — spec in Ch. 5. The 340 executes its own instruction set in memory (display file = program). PIXIE’s subpictures are literally display subroutines — Myer & Sutherland’s "wheel of reincarnation". The Titan mainframe it communicated woth was another story, a big deal at the time! It ran RAINBOW: BCPL + FORTRAN analysis (e.g. LADAN), file store, COMPACT/PLOT/CONN/CONNMAP pipeline. Identity: Ferranti/ICT Atlas 2 prototype; Cambridge name Titan (1964–Oct 1973). Word size: 48 bits (8×6-bit chars or 2×24-bit halfwords). Core growth: 32K → 64K → 128K words. Addressing: Base/limit registers; user address ORed with base (not added). “Cache”: Tunnel-diode operand slave store — Cambridge claims first cache. Software “instructions”: Up to 512 extracodes (supervisor code in main store). OS: Titan Supervisor / Cambridge Multiple-Access System — public 22 Mar 1967. Storage: Two Data Products 16M-word discs; tape; card/punch. Terminals: Cambridge 64-line multiplexor — 73 registered, 26 simultaneous; modems from 1967. I've been able to gather together and shared all this information about it, thanks to an ongoing discussion with Heinz Lemke, the guy operating the lightpen in the video. He has recently unearthed 128 pages of PIXIE source code in PDP-7 assembly source and octal machine language, and we're scanning it in, and working on reincarnating it with SIMH and a virtual lightpen!
maccard 1mo ago
I disagree. There’s absolutely diminishing returns above 120 or so, and at 120hz you’d do as well to remove input latency rather than output latency. On a non full screen app you’re pretty much guaranteed to have a full frame from the OS/compositor, and more if your application has an event loop that is in any way abstracted from the OS. Any meaningful amount of work is either going to be done “immediately” (see pretty much every spreadsheet in existence except for that one on the network drive) or it will take a perceptible amount of time. Giving progress in 4ms increments instead of 8ms isn’t really going to affect the perception of the task. There are definitely real world tools that take time - pumping petrol/gas isn’t an instant action, neither is cooking. Also - the device that I would consider quietist in my life has a sub 1hz refresh rate, and an 800MHz cpu with a 3 week battery life.
- californical 1mo ago
  I agree that input latency matters a LOT but disagree about 120hz being some sort of sweet spot. On the input side, yeah even a few 10’s of ms is very noticeable when typing or doing something quick. But also I use 240hz monitors for everything, and when I had a config bug on my Mac that degraded my connection to 180hz, my computer felt slow and laggy, and I only realized when it drove me crazy enough to check the settings again. I’m sure the same would happen if I was on a 480hz monitor and it got degraded to the 240hz that I’m used to now. And I agree there are diminishing returns, but there are still very perceptible returns.
  - firen777 1mo ago
    > But also I use 240hz monitors for everything, and when I had a config bug on my Mac that degraded my connection to 180hz, my computer felt slow and laggy, and I only realized when it drove me crazy enough to check the settings again. Not trying to dismiss your perception, but are you sure the feeling of lag wasn't caused by some other bugs related to the bad config, say, some kind of interval mismatch? The difference between 240hz and 180hz is less than 1.5ms (if my calculation is correct) and I've seen OSU! player demand less precision than this.
    - 1mo ago

by mrob 1mo ago

anilakar 1mo ago

We had CRT displays that could easily do 100 to 120 Hz. Then we regessed to LCD panels that could do 60 Hz and it somehow became the performance target.

Avicebron 1mo ago
I mean CRT is inherently bulky, it's hard not to see why LCD panels became popular.
- krige 1mo ago
  To sellers, yes. The drop of visual quality when the top-down LCD push began was staggering.
  - deleted 1mo ago
    [deleted]
  - LargoLasskhyfv 1mo ago
    Depended very much on the CRTs used, there were very wide gaps in quality. Even a now obsolete HP ZR2240w (24" 1920x1200@60Hz) was a huge upgrade from a 21" Hitachi Superscan Supreme https://crtdatabase.com/crts/hitachi/hitachi-superscan-21-cm2112mu https://crtdatabase.com/crts/hitachi/hitachi-superscan-21-cm... That thing was at least Trinitron equivalent, if not better, because it lacked the thin wires holding the mask from within. Now you are talking about the start of all that, OFC there were bad and cheap ones, but there was also very good stuff from the beginning by Eizo, Sharp, NEC, and many more. Just as with CRTs. I don't miss them.
  - rcxdude 1mo ago
    To buyers as well. I don't recall the switch to LCDs being particularly pushed, though I was admittedly quite young at the time. Especially keep in mind that people today are generally comparing the absolute top-tier of CRTs which were not what the average person had. (Another thing to keep in mind is that the systems of the time generally could not drive the kinds of resolutions and framerates that make those CRTs shine in some of today's comparisons. At the time the difference in quality in practice was lower because of this)
    - aleph_minus_one 1mo ago
      > (Another thing to keep in mind is that the systems of the time generally could not drive the kinds of resolutions and framerates that make those CRTs shine in some of today's comparisons. At the time the difference in quality in practice was lower because of this) For desktop applications, the systems could. For 3D games, keep in mind that CRTs (in opposite to flat screens) could also diplay every other supported resolution sharply. The reason why many people think that CRTs were worse in practice is that many graphics cards of the time simply had a low-quality VGA signal generators built-in.
    - anilakar 1mo ago
      I owned a 17-inch Trinitron and very much preferred it over the early slow and small LCD panels. I did get a 15-inch Samsung VGA LCD panel for free later, but only kept it as a LAN party display as it folded completely flat for storage and transport.
  - tom_ 1mo ago
    Was there a top-down push? In general, people on average never really actually liked CRT displays all that much. They are annoyingly deep; they are heavy; the screen is flickery, or not quite pin sharp, or both; they use up a lot of power; they fail in annoying ways, and they're expensive to fix - and they have magnets in them.
    - thfuran 1mo ago
      And they make a constant shrieking sound.
      - mrob 1mo ago
        Only SD CRTs make an audible shrieking sound. LCD computer monitors were replacing VGA or better CRTs with a horizontal refresh rate of >30kHZ. Maybe they could annoy your dog but no human could hear it.
        NathanielK 1mo ago
        I still use a 130kHz CRT monitor sometimes. There's no 15kHz whine, but there's audible harmonics. It depends what you're looking at at and how hard you're pushing it.
  - BigTTYGothGF 1mo ago
    I had multiple mediocre-to-crappy CRTs in the 90s and 00s and was glad to move away from them. I think the last one I owned was even one of the fabled trinitrons, and it was acceptable.
    - AnotherGoodName 1mo ago
      Yeah i had a trinitron and i still had bloodshot eyes after a few hours that i never got with LCD screens. Everyone was aware that CRTs sucked terribly for eye strain. The tradeoffs moving to even the early LCDs was well worth it. I remember people spending effectively double on LCDs at the time over higher specced and larger CRTs and being delighted with the result. eg. early LCDs were just 14inch, low res, low refresh rates when you could get a 17inch CRT higher specced in every way. People were still opting for the early LCDs. Your eyes are important!
- TacticalCoder 1mo ago
  > I mean CRT is inherently bulky, it's hard not to see why LCD panels became popular. But going from, say, a Sony Trinitron CRT [1] to one the first LCD was a huge step backwards, which is what GP is saying. I did wait for the first LCD with DVI support before switching: for the difference in crispyness between an analog video cable and a DVI one was night and day (I also won many points when I helped friend set up a startup in southern california and we realized one person out of two had picked the VGA cable instead of the DVI one when setting up its desk / computer: so with the CTO late at night we went through every PC and changed all those with VGA cables to the DVI ones). We're not saying modern days flat monitors aren't better than old CRTs: we're saying the first flat screens were complete suckage. [1] even though on a Trinitron you could see two faint horizontal lines (Trinitron were still amazing)
  - LargoLasskhyfv 1mo ago
    DVI or not didn't matter that much when your VGA had a good RAMDAC, and you had a good cable. https://en.wikipedia.org/wiki/RAMDAC https://en.wikipedia.org/wiki/RAMDAC Which of course you could only see in direct comparison. Which most ppl didn't have the opportunity to do, so you needed experience instead to judge that. Which most ppl also didn't have, because they've been exposed to cheap stuff only.
    - jaffa2 1mo ago
      Matrox used to have the best back in the day. Ai were ok and Nvidia were the worst. Even a lay person could see that difference between the tnt out put vs a millenium. It was so great that i used to use an older matrox card think it was the g450 since it worked great under Linux and the pq was amazing.
      - LargoLasskhyfv 1mo ago
        Yes. Matrox was very good. But so were later Voodoo3. I know, because I've driven a https://crtdatabase.com/crts/hitachi/hitachi-superscan-21-cm2112mu https://crtdatabase.com/crts/hitachi/hitachi-superscan-21-cm... with it. At 1600x1200@75Hz. Crystal clear and sharp. I also had something by ELSA with a S3 and a translucent blue RAMDAC by IBM. Same thing. But only 2MB VRAM, and PCI. So only useful for testing purposes. Regarding the usability under Linux, or rather support by XFree86, Matrox accelerated some graphics primitives in the DDX-layer, or whatever that was called then. So did the Voodoo3's! Independently of that Glide stuff for 3D. Really nice to have.
aitchnyu 1mo ago
Had a Samtron 15" and the LCD that replaced it was very washed out. Commercial users in India kept them for 15+ years.
TiredOfLife 1mo ago
After 15 minutes at crt my eyes were watering, not so for lcd
inigyou 1mo ago
Now that you mention it, 60Hz was considered poor on a CRT. 85 was the target. But that was because of flicker. AFAIK, 60Hz video frame rate was considered acceptable, but on a CRT the video frame rate was also the flicker rate and 60Hz was too low for flicker.
- AnotherGoodName 1mo ago
  A slow motion capture of CRT show's the issue https://www.reddit.com/r/crtgaming/comments/7w0v02/video_by_the_slowmo_guys_showing_how_tvs_work/ https://www.reddit.com/r/crtgaming/comments/7w0v02/video_by_... Almost laser pointer brightness at one point on the screen which you don't consciously see because the your eyes and the hold the image for a few milliseconds but do you really want to be looking at a extremely bright point of light all day. Higher refresh rates on CRTs lowered eye strain since that point could be effectively lower brightness, just refreshing twice as fast. I honestly don't get eye strain on LCDs nearly as bad under any circumstance. 60hz LCD was a massive improvement over the 120hz CRTs.
- mrob 1mo ago
  CRT flicker is equally visible when frame rate is the same as refresh rate as when it differs. 60Hz CRTs were never good. 60Hz was only considered "acceptable" because people didn't know any better at the time. At least you didn't suffer with 50Hz CRTs using the same fast phosphors like the PAL regions did.

DonHopkins 1mo ago

We don't need faster refresh rates, we need slower phosphor. https://youtu.be/1EWQYAfuMYw?t=832 https://youtu.be/1EWQYAfuMYw?t=832

mrob 1mo ago
We need faster refresh rates. Slow phosphors also cause unnatural visual artifacts. 1000Hz is roughly the point where you get motion quality that, except for a rare few test signals (e.g. multiplexed displays), is easily mistaken for reality.
- DonHopkins 1mo ago
  Naw, we just need better software and slower computers, like the PDP-1, that don't require such fast refresh rates, just slow phosphor. But slow computers still need fast and reliable user interfaces, like radial pie menus. Flight of the PIXIE - Yuja Wang: https://www.youtube.com/watch?v=jDrqR9XssJI https://www.youtube.com/watch?v=jDrqR9XssJI PIXIE: A New Approach to Graphical Man-Machine Communication: https://www.donhopkins.com/home/documents/PIXIE%20a%20new%20approach%20to%20man-machine%20communication.pdf https://www.donhopkins.com/home/documents/PIXIE%20a%20new%20... The computer shown in that video is a much more advanced and faster PDP-7, talking to an even bigger and faster Titan mainframe over a custom network! https://en.wikipedia.org/wiki/Titan_(1963_computer) https://en.wikipedia.org/wiki/Titan_(1963_computer) It proves that slow computers can still be usable with better software, and that today's unusable computers are pissing away enourmous amounts of power, but still suck. Edit: I just showed you a video of a computer with a light pen. Did you check that out? It's only two minutes, and I made it to musically highlight PIXIE, because most people don't want to sit through silent hours of the original digitized films from Cambridge. PIXIE is not one box. It is a network distributed CAD workstation (1967–1972) -- like AJAX, but with P7 two-layer cascade phosphor on a 16ADP7A radar tube instead of HTML: Interactive front end: DEC PDP-7 + Type 340 CRT. Real-time drawing, light pen, radial "control lightbuttons", graph model in core. Compute / storage host: Titan (Cambridge’s Ferranti/ICT Atlas 2 prototype). RAINBOW apps: CONN, COMPACT, PLOT, LADAN circuit analysis, file store. Wire between them: Wiseman link (Cambridge custom) + Lang's supervisor software. Move typed ring-structure models blocklet-by-blocklet. Word size: 18 bits. Core (PIXIE design target): 8K words — "only 8K of 18 bit words ... no auxiliary storage". Core (likely installed): 8K–16K (GUIDE: "here likely 16K"). Cycle time: ~1.75 µs. ~571K cycles/s. Addressing: 13-bit + indirect bit. Registers: One accumulator + link bit. DEC made lots of "instruction sets in a chassie" extension boxes, and Wiseman at Cambridge rolled his own network with its own custom instructions. Extended Arithmetic Element: Type 177 EAE. Multiply, divide, shifts, normalize (64xxxx op family in listing). Precision incremental display: Type 340. Required — second processor + DMA display file. Light pen: Type 370. Pen flag IOTs; diagnostic 7-78-M in pdp-7 reference. Symbol generator: Type 342. 6-bit character codes → stroke sequences in display file. Subroutine option: Type 347. DJS / DJP — display jump-to-subroutine (subpictures as display subroutines) Titan link interface: Cambridge custom (Wiseman) Undocumented IOTs: LCF, LSF, LKE, LLB6, LLB18, LRB18, LLAM, LSA, LKD — networking as instructions. The 340 display was an amazing ensembel of hardware, and could plug into a PDP-1 as well. The SIMH emulator supports it well. Model: DEC Type 340 Precision Incremental CRT System (H-340, Nov 1964). Tube lineage: Type 30E → 16ADP7A radar tube, P7 phosphor, 1024×1024 address grid. CPU coupling: Cycle steal / data break — 340 fetches display words from PDP-7 core while CPU runs. Vector timing: ~1.5 µs incremental vectors (vs Type 30 ~50 µs per CPU-plotted dot). Display word types: Parameter, point, vector, vector-continue, increment, character; with 347: DJS/DJP subroutines. Light pen: Per-word pen-enable bits; tracking uses cross + recovery spiral (~2× cross size) — spec in Ch. 5. The 340 executes its own instruction set in memory (display file = program). PIXIE’s subpictures are literally display subroutines — Myer & Sutherland’s "wheel of reincarnation". The Titan mainframe it communicated woth was another story, a big deal at the time! It ran RAINBOW: BCPL + FORTRAN analysis (e.g. LADAN), file store, COMPACT/PLOT/CONN/CONNMAP pipeline. Identity: Ferranti/ICT Atlas 2 prototype; Cambridge name Titan (1964–Oct 1973). Word size: 48 bits (8×6-bit chars or 2×24-bit halfwords). Core growth: 32K → 64K → 128K words. Addressing: Base/limit registers; user address ORed with base (not added). “Cache”: Tunnel-diode operand slave store — Cambridge claims first cache. Software “instructions”: Up to 512 extracodes (supervisor code in main store). OS: Titan Supervisor / Cambridge Multiple-Access System — public 22 Mar 1967. Storage: Two Data Products 16M-word discs; tape; card/punch. Terminals: Cambridge 64-line multiplexor — 73 registered, 26 simultaneous; modems from 1967. I've been able to gather together and shared all this information about it, thanks to an ongoing discussion with Heinz Lemke, the guy operating the lightpen in the video. He has recently unearthed 128 pages of PIXIE source code in PDP-7 assembly source and octal machine language, and we're scanning it in, and working on reincarnating it with SIMH and a virtual lightpen!

maccard 1mo ago

I disagree. There’s absolutely diminishing returns above 120 or so, and at 120hz you’d do as well to remove input latency rather than output latency. On a non full screen app you’re pretty much guaranteed to have a full frame from the OS/compositor, and more if your application has an event loop that is in any way abstracted from the OS. Any meaningful amount of work is either going to be done “immediately” (see pretty much every spreadsheet in existence except for that one on the network drive) or it will take a perceptible amount of time. Giving progress in 4ms increments instead of 8ms isn’t really going to affect the perception of the task. There are definitely real world tools that take time - pumping petrol/gas isn’t an instant action, neither is cooking. Also - the device that I would consider quietist in my life has a sub 1hz refresh rate, and an 800MHz cpu with a 3 week battery life.

californical 1mo ago
I agree that input latency matters a LOT but disagree about 120hz being some sort of sweet spot. On the input side, yeah even a few 10’s of ms is very noticeable when typing or doing something quick. But also I use 240hz monitors for everything, and when I had a config bug on my Mac that degraded my connection to 180hz, my computer felt slow and laggy, and I only realized when it drove me crazy enough to check the settings again. I’m sure the same would happen if I was on a 480hz monitor and it got degraded to the 240hz that I’m used to now. And I agree there are diminishing returns, but there are still very perceptible returns.
- firen777 1mo ago
  > But also I use 240hz monitors for everything, and when I had a config bug on my Mac that degraded my connection to 180hz, my computer felt slow and laggy, and I only realized when it drove me crazy enough to check the settings again. Not trying to dismiss your perception, but are you sure the feeling of lag wasn't caused by some other bugs related to the bad config, say, some kind of interval mismatch? The difference between 240hz and 180hz is less than 1.5ms (if my calculation is correct) and I've seen OSU! player demand less precision than this.
  - 1mo ago