Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Why the original Macintosh had a screen resolution of 512×324

512pixels.net

Post reply on HN
Print view View original

131–138 of 138 posts

Re: Why the original Macintosh had a screen resolution of 512×324

#131

Post by p_l »

account42 wrote: post #118
p_l wrote: post #109

Earlier quoted context omitted.

except DVI is essentially VGA without Digital-to-Analog part, and original HDMI is DVI with encryption, some predefined "must have" timings, and extra data stuffed into empty spaces of blasting a signal designed for CRT. I think partial refresh capability only came with some optional extensions to DisplayPort.

DVI is just a connector - it can be either analog or digital or support both.

DVI is an interface, with multiple variants of connectors defined - and the digital portion was essentially the analog portion (which was VGA signals) streamed in digital form

Re: Why the original Macintosh had a screen resolution of 512×324

#132

Post by pezezin »

p_l wrote: post #113
pezezin wrote: post #98

Earlier quoted context omitted.

I have recently been playing with CRTs again, and something that I have noticed is that for fast-paced games running at 60 or 70 Hz* I don't notice the flicker much, but for text anything less than 85 Hz is headache inducing. Luckily the monitor I got can do 1024x768 at 100 Hz :) * The original VGA and thus most MS-DOS games ran at 70 Hz.

I remember when I got my first computer for myself, instead of sharing with others, it was "obvious requirement" that the screen runs at least 72Hz, preferably higher. Which was why 15" CRT had to run at 800x600. Later on, and with graphic card that had more than 2MB of RAM, I remember experimenting a lot with modelines to pull higher refresh rates and higher resolution on the 17" CRT I inherited when my father switc…

Our first PC was a 486 with a crappy 15" monitor, but I was too young to remember the details clearly. I can consider myself lucky, my dad was a big fan of Sony and we soon moved to a nice 17" Trinitron :)

Re: Why the original Macintosh had a screen resolution of 512×324

#133

Post by kragen »

hollerith wrote: post #119
kragen wrote: post #89

Earlier quoted context omitted.

Strobing the backlight seems like it would allow you to not illuminate the new frame of video until the liquid crystals have finished rotating, so you only have to contend with the persistence of vision on your retina instead of additionally the persistence of the liquid crystals.

My "for some strange reason" was the wrong choice of words. I don't wish to imply that I disapprove of the reason that gaming monitors do it, just that I haven't done the work to try to understand.

Yeah, I'm kind of speculating here myself.

Re: Why the original Macintosh had a screen resolution of 512×324

#134

Post by kragen »

nyanpasu64 wrote: post #105
kragen wrote: post #87

Earlier quoted context omitted.

I took film photos of my family's color TV in the 90s with a fast shutter speed. About 20% of the screen was fading at any given time with the (NTSC) 60Hz field rate, the rest being black, so to get a screen that was physically flicker-free with those phosphors, you'd have to refresh it at somewhere around 500Hz. I doubt color CRT monitors had faster-decaying phosphors than my color TV.

I looked up my brightness measurements of a Gateway VX720 VGA monitor (like Diamond Pro 710), and it seems the blue and green phosphors decay to 50% brightness in under 30 microseconds while red stays bright for 300 microseconds. I didn't measure how long it took for them to go to near-black levels. Sadly I never took measurements of my Trinitron TV when I still had it. All in all the results are inconclusive.

That sounds a bit faster than what I remember from my photos of the TV.

Re: Why the original Macintosh had a screen resolution of 512×324

#135

Post by p_l »

pezezin wrote: post #132
p_l wrote: post #113

Earlier quoted context omitted.

I remember when I got my first computer for myself, instead of sharing with others, it was "obvious requirement" that the screen runs at least 72Hz, preferably higher. Which was why 15" CRT had to run at 800x600. Later on, and with graphic card that had more than 2MB of RAM, I remember experimenting a lot with modelines to pull higher refresh rates and higher resolution on the 17" CRT I inherited when my father switc…

Our first PC was a 486 with a crappy 15" monitor, but I was too young to remember the details clearly. I can consider myself lucky, my dad was a big fan of Sony and we soon moved to a nice 17" Trinitron :)

Funnily enough, my first "personal" machine was a 486DX2, with a 15" "multimedia" monitor (meaning it had crappy speakers built-in and pretty much useless microphone).

I don't really count it as "first PC" because by that time PCs have been in house for several years, but it meant I could goof off in games or Logo without asking for a turn ;)

Re: Why the original Macintosh had a screen resolution of 512×324

#136

Post by bzzzt »

monkeyelite wrote: post #83
stefan_ wrote: post #45

Earlier quoted context omitted.

Displays are still bandwidth killers today, we kept scaling them up with everything else. Today you might have a 4k 30bpp 144hz display and just keeping that fed takes 33Gbit/s purely for scanout, not even composing it.

4k jumped the gun. It’s just too many pixels and too many cycles. And unfortunately was introduced when pixel shaders starting doing more work. Consequently almost nothing actually renders at 4k. It’s all upscaling - or even worse your display is wired to double up on inputs. Once we can comfortably get 60 FPS, 1080p, 4x msaa, no upscaling, then let’s revisit this 4k idea.

I didn't have to be '4K', it just should be sharp - Apple was right in 2012 with the 'retina' concept. TV manufacturers doubled the resolution and those panels trickled down to PCs. Games and movies don't need that resolution, but it helps text readability tremendously. And as a bonus you can skip all that 'cleartype' nonsense and other readability hacks that often don't work right.

Re: Why the original Macintosh had a screen resolution of 512×324

#137

Post by monkeyelite »

bzzzt wrote: post #136
monkeyelite wrote: post #83

Earlier quoted context omitted.

4k jumped the gun. It’s just too many pixels and too many cycles. And unfortunately was introduced when pixel shaders starting doing more work. Consequently almost nothing actually renders at 4k. It’s all upscaling - or even worse your display is wired to double up on inputs. Once we can comfortably get 60 FPS, 1080p, 4x msaa, no upscaling, then let’s revisit this 4k idea.

I didn't have to be '4K', it just should be sharp - Apple was right in 2012 with the 'retina' concept. TV manufacturers doubled the resolution and those panels trickled down to PCs. Games and movies don't need that resolution, but it helps text readability tremendously. And as a bonus you can skip all that 'cleartype' nonsense and other readability hacks that often don't work right.

I agree

Re: Why the original Macintosh had a screen resolution of 512×324

#138

Post by s800 »

MBCook wrote: post #66
pragma_x wrote: post #46

Earlier quoted context omitted.

It's also interesting to look at other architectures at the time to get an idea of how fiendish a problem this is. At this time, Commodore, Nintendo, and some others, had dedicated silicon for video rendering. This frees the CPU from having to generate a video signal directly, using a fraction of those cycles to talk to the video subsystem instead. The major drawback with a video chip of some kind is of course cost (…

Plus those weren’t raw bitmaps but tile based to help keep memory and bandwidth costs down.

Not sure we're thinking the same way, but the C64 and Atari had bitmap modes, not just tile or character modes.
Post reply on HN