5 ms·

I think I got XFree86 brought up on like, Slackware or something in the early 90s, I want to say like 1994 but I’m not sure. IIRC there was some terrifying ste

I think I got XFree86 brought up on like, Slackware or something in the early 90s, I want to say like 1994 but I’m not sure. IIRC there was some terrifying step involved around setting scan frequencies or modelines or something that was advertised as making it possible to set a CRT on fire (which could have been the maintainers being cheeky). Does anyone remember that era well enough to know the details?

jedberg 2y ago
It probably wouldn’t set the monitor on fire, but this was before they added confirm/revert for resolution changes, so if you put it in an unsupported mode, you couldn’t get it back without booting from the install media. And it could damage the monitor in the process.
- ssl-3 2y ago
  That's what ctrl-alt-backspace was for: To exit X and get back to a BIOS-based text terminal (ideally, one set to some absurd tinytext mode with SVGATextMode), so the modeline could be adjusted.
- immibis 2y ago
  Some displays piggybacked the high voltage generator's oscillation on the horizontal sync signal because it was about the right frequency. Stopping horizontal sync in the right phase could lead to the high voltage generator acting as a short circuit. If you've got the kind of really cheap display that does this, maybe it also doesn't have a fuse...
antod 2y ago
I remembered the warnings, but was lucky enough to always have common predefined monitors that already had settings. Until probably about 2005 when dealing with an unusual monitor when I had to do my own modelines because nothing was working out of the box. Searched the web as much as possible to try and get horizontal scan rates etc, not quite feeling completely comfortable, then biting the bullet with my best guesses. Luckily it worked - to much relief that I hadn't burnt out one of the offices more expensive monitors.
shirro 2y ago
I had to configure modelines on my first PC, bought so I could run a *nix at home, specifically Linux. The video card was a Tseng ET4000W32 and that is about all I can remember about the hardware in that PC. PC monitors seemed to rejected frequencies that were out of spec and shut off so I think the hardware damage thing was an urban legend or it might have been a thing with screens that weren't designed for the consumer mass market. I didn't use X much initially because my version of the card wasn't properly supported in Xfree86 and had some colour/palette problem. Also the resolution and quality and size of cheap CRTs at the time made Xterminals less readable than the console IMO. The SVGA support in console for things like image viewers just worked. It was only when Mosaic came out that I started to run X more often and it wasn't my default for a few years I think. Before PCI, PlugnPlay and Windows 95 everything was configured with dip switches and port numbers and interrupts went into configs even on the DOS side. Partitioning a disk wasn't a trivial thing. Even so modelines seemed kind of silly even back then. When people say Arch is complicated I just chuckle to myself at how far things have come.
- ssl-3 2y ago
  Arch is complicated. It doesn't even come with man pages or documentation. "Hi! Here's a Linux box with a getty and a shell, and you're lucky we even included that much. Good luck!" At least when configuring XFree86 on Slackware in nineteen-ninety-something, I had local man pages and documentation to refer to out-of-the-box.
  - tiberious726 2y ago
    The install medium had documentation loaded, and installing which forms of documentation you want to the persistent system is right in the installation guide
    - ssl-3 2y ago
      TIL. And that's great for people who know this, and who also know in advance what documentation they'll want in the future. It's less-great for people who have booted their new installation without knowing one or both of these things. I mean: I get it. I do realize that a line must be drawn somewhere on what to include or not include by default. I just don't like where that line is drawn in this particular instance. My feeling is that storage is cheap and plentiful... unless it isn't. It seems to me that the people who would benefit from superfluously-available documentation the most are the ones who are likely to have plenty of space available: They're newbs -- newbs who are not building something to fit into less than 2GB of flash, and who are not making a template that will be used for a thousand instances. They're just trying to get their feet wet. And it also seems that the people who would benefit most from a system that is a wee bit leaner due to a lack of auto-installed documentation are the same ones who would have the least amount of difficulty removing that documentation.
ssl-3 2y ago
I used to use custom modelines to overclock CRT monitors. Monitors had a spec, of course -- and it was easy-enough to stay within that spec. They were bandwidth-constrained, but as analog devices that bandwidth was always somewhat flexible. So why have settle for 1024x768 at 75Hz that the book says will work, when that same 15" monitor would do 1360x1020 or more at a similar refresh rate and still have readable tiny text? Why not run a 19" monitor at 2130x1598? "You can fit so many xterms in this baby!" And why not shrink down the vertical blanking interval and front and back porches as far as possible before geometry got too bad, to maximize the number of pixels that could be pushed down the wire within a given bandwidth? And why not tweak the trimpots inside to put the monitor's front panel controls into a better range for this kind of service? Fun times, those. The quality of the VGA cable made a substantial difference in smear when pushing things hard enough (literally bandwidth-throttled video), and getting a better DAC to drive the kit with (for even more literal bandwidth) was a primary motivation for periodically finding a better video card. (No fires to report even after a decade and a half or so of these games. Sorry. I guess if any of this stuff ever caught on fire I'd have found a different approach.)
- ForOldHack 2y ago
  640x480 became 704x512. "You are going to hurt your eyes. 800x600 = 875x660, and 1024x768 = 1152x830. Never blew up a monitor, but never ran over scan without the real documentation.

jedberg 2y ago

It probably wouldn’t set the monitor on fire, but this was before they added confirm/revert for resolution changes, so if you put it in an unsupported mode, you couldn’t get it back without booting from the install media. And it could damage the monitor in the process.

ssl-3 2y ago
That's what ctrl-alt-backspace was for: To exit X and get back to a BIOS-based text terminal (ideally, one set to some absurd tinytext mode with SVGATextMode), so the modeline could be adjusted.
immibis 2y ago
Some displays piggybacked the high voltage generator's oscillation on the horizontal sync signal because it was about the right frequency. Stopping horizontal sync in the right phase could lead to the high voltage generator acting as a short circuit. If you've got the kind of really cheap display that does this, maybe it also doesn't have a fuse...

antod 2y ago

I remembered the warnings, but was lucky enough to always have common predefined monitors that already had settings. Until probably about 2005 when dealing with an unusual monitor when I had to do my own modelines because nothing was working out of the box. Searched the web as much as possible to try and get horizontal scan rates etc, not quite feeling completely comfortable, then biting the bullet with my best guesses. Luckily it worked - to much relief that I hadn't burnt out one of the offices more expensive monitors.

shirro 2y ago

I had to configure modelines on my first PC, bought so I could run a *nix at home, specifically Linux. The video card was a Tseng ET4000W32 and that is about all I can remember about the hardware in that PC. PC monitors seemed to rejected frequencies that were out of spec and shut off so I think the hardware damage thing was an urban legend or it might have been a thing with screens that weren't designed for the consumer mass market. I didn't use X much initially because my version of the card wasn't properly supported in Xfree86 and had some colour/palette problem. Also the resolution and quality and size of cheap CRTs at the time made Xterminals less readable than the console IMO. The SVGA support in console for things like image viewers just worked. It was only when Mosaic came out that I started to run X more often and it wasn't my default for a few years I think. Before PCI, PlugnPlay and Windows 95 everything was configured with dip switches and port numbers and interrupts went into configs even on the DOS side. Partitioning a disk wasn't a trivial thing. Even so modelines seemed kind of silly even back then. When people say Arch is complicated I just chuckle to myself at how far things have come.

ssl-3 2y ago
Arch is complicated. It doesn't even come with man pages or documentation. "Hi! Here's a Linux box with a getty and a shell, and you're lucky we even included that much. Good luck!" At least when configuring XFree86 on Slackware in nineteen-ninety-something, I had local man pages and documentation to refer to out-of-the-box.
- tiberious726 2y ago
  The install medium had documentation loaded, and installing which forms of documentation you want to the persistent system is right in the installation guide
  - ssl-3 2y ago
    TIL. And that's great for people who know this, and who also know in advance what documentation they'll want in the future. It's less-great for people who have booted their new installation without knowing one or both of these things. I mean: I get it. I do realize that a line must be drawn somewhere on what to include or not include by default. I just don't like where that line is drawn in this particular instance. My feeling is that storage is cheap and plentiful... unless it isn't. It seems to me that the people who would benefit from superfluously-available documentation the most are the ones who are likely to have plenty of space available: They're newbs -- newbs who are not building something to fit into less than 2GB of flash, and who are not making a template that will be used for a thousand instances. They're just trying to get their feet wet. And it also seems that the people who would benefit most from a system that is a wee bit leaner due to a lack of auto-installed documentation are the same ones who would have the least amount of difficulty removing that documentation.

ssl-3 2y ago

I used to use custom modelines to overclock CRT monitors. Monitors had a spec, of course -- and it was easy-enough to stay within that spec. They were bandwidth-constrained, but as analog devices that bandwidth was always somewhat flexible. So why have settle for 1024x768 at 75Hz that the book says will work, when that same 15" monitor would do 1360x1020 or more at a similar refresh rate and still have readable tiny text? Why not run a 19" monitor at 2130x1598? "You can fit so many xterms in this baby!" And why not shrink down the vertical blanking interval and front and back porches as far as possible before geometry got too bad, to maximize the number of pixels that could be pushed down the wire within a given bandwidth? And why not tweak the trimpots inside to put the monitor's front panel controls into a better range for this kind of service? Fun times, those. The quality of the VGA cable made a substantial difference in smear when pushing things hard enough (literally bandwidth-throttled video), and getting a better DAC to drive the kit with (for even more literal bandwidth) was a primary motivation for periodically finding a better video card. (No fires to report even after a decade and a half or so of these games. Sorry. I guess if any of this stuff ever caught on fire I'd have found a different approach.)

ForOldHack 2y ago
640x480 became 704x512. "You are going to hurt your eyes. 800x600 = 875x660, and 1024x768 = 1152x830. Never blew up a monitor, but never ran over scan without the real documentation.