Tedium - Saving One Screen At A Time 🖥️

Today in Tedium: Having seen a lot of pipes, wavy lines, and flying toasters in my day, there was a real novelty to the art of screen savers, which became another way to put your visual mark on the devices you own. The animated screen saver is still out there, of course, but its cultural relevance has faded considerably. In fact, GNOME, one of the two dominant window managers in the FOSS world (particularly on Linux), straight-up doesn’t support graphical screen savers in modern versions, unless you’re willing to get hacky. And it’s not like people kick up colorful screen savers on their smartphones or tablets. But maybe we’re thinking about screen savers all wrong in terms of their cultural role. When it comes to screen savers, what if GNOME has it right? Today’s Tedium ponders the screen saver, including how we got it and what it represents today. The toasters are flying. — Ernie @ Tedium

The article that introduced regular computer users to the screen saver laid it on a little thick. (Softalk/via Internet Archive)

The roots of the screen saver are in the automatic dimmer

If you’re a long-time reader of Tedium, you probably have heard this line before: When trying to dig into the history of something, look past the accepted answer, lest you run into the “Windex problem,” where a misinformed result from Wikipedia turns into the public record. The reason is simple: The accepted answer is often the easy answer, and when doing a little research, you can bust past that to the point of truth.

And that is true with the screen saver, a technique for preventing burn-in on television sets and computer monitors, particularly CRTs. The commonly accepted root of this object is SCRNSAVE, a program developed by John Socha, a computer magazine writer and software developer who later created Norton Commander. His invention, included in a regular magazine feature he wrote for Softalk, spoke of the need to protect displays from themselves:

The simplest preventive is to turn down the intensity before you walk away from your computer. If you don’t see an image on the screen, it'll be safe from burn damage. But although simple, this method is unreliable. It's too easy to leave the display on for “just a few minutes,” only to return several hours later to find the screen still brightly lit.

(In other words: Screen saving is an anti-forgetfulness technique.)

Socha’s idea was to create a program in machine language called Scrnsave.com, which effectively did this brightness-minimizing task automatically, without the user having to think about it. (He made it more accessible to the masses by creating a program in BASIC that wrote the machine-code program. Clearly thinking ahead.)

The secret to its functionality, added Socha, was by building a program that hung out in resident memory and utilized the computer’s internal clock, while comparing it to the input from the keyboard. He continued:

How does Sernsave do all this? The clock inside your PC ticks 18.2 times per second. Scrnsave contains a three-minute counter that starts at 3276—the number of clock ticks for three minutes. On each tick of the clock, Scrnsave subtracts one from this count, and it turns off the screen when it reaches zero. We need some way to reset this counter while we are using the PC, so Scrnsave also intercepts two interrupts in addition to the interrupts generated by the clock.

Each time you push or release a key, the keyboard sends an interrupt signal to the PC. Scrnsave intercepts this interrupt; each time you push or release a key, Scrnsave resets its counter to 3276 (three minutes) before passing control to the ROM BIOS routines that read keystrokes. Scrnsave also resets its counter to 3276 every time a program sends characters to the screen. By intercepting these last two interrupts, Scrnsave can tell when you need to have the screen active, so it won't shut out the lights unless you sit back or walk away for three minutes or more.

This was a very clever program at the time. Many operating systems do this today without asking. And to be clear, while Socha deserves credit for popularizing the technique with a broad audience, the idea wasn’t totally new.

See, during the 1970s and early 1980s, numerous hardware and software developers attempted to build things in the same wheelhouse as Socha’s early screen saver. The difference was, they weren’t for the IBM PC or even for a computer at all. Rather, they were for dumb terminals or video game systems.

A Micro-Tec Model 70, which recently appeared on eBay. If you have like $1,200 to spend on a monitor that was state of the art the year Chris Martin of Coldplay was born, this is your ticket. (via eBay)

The first example I found, from 1977, was the Micro-Tec Model 70 CRT display, intended for dumb terminals. It included a feature that sounds suspiciously like a screen saver. As Computerworld wrote in 1977:

Optional features or capabilities include polling and paging. The optional CRT Saver reduces screen intensity when the unit has not been operated in a preset amount of time to eliminate wear of the screen phosphor, the spokesman noted.

That product feature comes a full six years before Scrnsave, and it wasn’t the only one. Doing a patent search, I found that Termiflex, a company that specialized in developing handheld interactive terminals, actually discussed the concept of an “auto dim mode” in a patent application initially filed in 1974.

“This mode causes the automatic dimming of the display if no information is received or generated on the display for approximately five minutes,” the filing stated, while disappointingly noting that “in the present version of the invention, this feature has been eliminated.”

In the early 1980s, companies like Memorex and Decision Data were promoting “an automatic dimming feature to preserve the quality of the display” in their terminals, which could be seen as a predecessor to the ambient light sensor used on many modern computers.

The self-dimming computer screen makes sense in the context of our improving understanding of how to control light or input. If you look up information about “automatic dimming,” you will likely start to find references to cars and planes. Some of the earliest I found date to the 1930s, when an unnamed French inventor created a way for headlights to automatically dim at the sight of oncoming traffic. It didn’t hit the market in a big way until the 1950s, when Oldsmobile began offering it as an optional accessory.

And while it wasn’t automatic until later, the solid-state home dimming switch, which controlled the amount of light coming into a home by using a type of semiconductor called a thyristor, came to being in 1959. While the specifics matter here (and a cathode ray tube is not exactly the same as a light bulb), the general concept of dimming or turning off the screen by limiting the amount of energy delivered to the light source is pretty consistent.

And to be clear, the display wasn’t the only part of the machine that needed this kind of wear-and-tear element added. For example, the PerCom Data LFD-400 minifloppy system included an “inactivity time-out circuit to increase drive motor life.”

At its root, any attempt to dim or darken a screen is an attempt to make it work more efficiently. It is at the root of any device with a screen, especially if it uses a battery. The fun graphics, which didn’t come until later, kind of do the opposite.

Why video games needed attract screens, exhibit A. (via Reddit)

The first “screen saver” most people saw was likely a video game attract mode in an arcade

But even getting past the idea of dumb terminals here, it’s worth pointing out that most people’s first interaction with computerized text or graphics likely didn’t start with a dumb terminal or even a home computer. Odds are, it was a video game, either in the home or an arcade. As Claude C. Jones noted in Compute in 1987, the realization that static images could damage CRTs became a known problem thanks to home consoles.

The effect was noticed when home video games first became popular in the late 1970s. Someone would leave a video game on the TV all day, only to discover a shadow image of the game remaining when the channel was changed. Video game manufacturers soon modified their machines to cycle through a series of colors whenever the screen displayed a static playfield.

Developers had fixes for this issue, but what they did wasn’t called a “screen saver.” The term they used was “attract mode.”

Thanks to those attract modes, you could argue that many arcade machines, like Space Invaders and Galaga, operated not unlike screen savers. The goal was more to convince people to drop coins into the machines—which meant that, unlike many modern screen savers, they weren’t noisy—but they also, in effect, ensured the machine would remain dynamic, with pixels constantly moving on the CRT.

Home systems, including computers and video games, did this as well. Atari 2600 games, such as Pitfall, would change colors while idling, another move designed to discourage burn-in.

By focusing on games, you can actually find some prior art for Socha’s idea in BASIC programming guides in magazines. For example, a 1980 issue of Interface Age featured a game called Galactic Giggle that effectively included its own internal screen saver, similar to the Pitfall example above:

Memory location 77 is the screen saver timer. Every four seconds 1 is added to the location. When it reaches a value of 128, then the screen starts changing colors. This is done to prevent burning an image onto the TV screen. By constantly resetting location 77 to 0 in line 30, the screen saver is kept from ruining the colors of the galaxy.

Put in context, it is not hard to compare this to what a bouncing DVD logo does.

And it’s clear that many video games did not lean hard enough on screen burn-in being an issue. The two earliest Pac-Man titles, in particular, largely left the maze on the screen, which means that spotting burn-in on an old Pac-Man game is pretty common.

Imagine being a pixel on an old Pac-Man game. For much of your life, you stay in place, completely static. Your existence is literally to turn that one spot into a specific color. That’s what your lot is in life. Nothing changes. You are just a dot, burning in the phosphor of a tube, attached to a machine that isn’t smart enough to realize that you need to change position every once in a while.

You are witnessing the fruit of a Microsoft internal competition.

How screen savers evolved into self-contained art projects—and back

OK, so I just dropped a bunch of concepts that could realistically be called “prior art” when it comes to the screen saver. Maybe there are people out there who might look at attract mode in a new light after all that.

But with that said, how connected are these ideas to the screen saver as we know it today? I would argue they are in the same neighborhood, even if they are not at the same house. The fact is, computers are designed to be much more static in their presentation of data than television-based mediums. A spreadsheet is not a video game, and odds are that spreadsheets, without interaction, could live on the screen for months. And that created burn-in challenges that, at the time spreadsheets first came on the scene, were genuine issues.

With that in mind, the innovation John Socha landed on in his article was to put this in the hands of the computer using a program that remained resident in memory, rather than requiring additional hardware to do the work—and unlike games with screen-saver functions, it needs to work with any program on the machine. This was more complicated in the pre-GUI era, when it often required modifying an autoexec.bat file.

But when the GUI appeared, it created a new context for these screen savers, something that companies like Berkeley Systems exploited through their modular After Dark screen saver tool, first released for the Apple Macintosh in 1989, and Windows a few years later.

For Microsoft, adding native screen saver support to Windows was a branding opportunity, but it unwittingly reflected what was happening in underground computing scenes. In many ways, screen savers leveraged a similar headspace to the demoscenes that emerged around Commodore and Atari computers during the mid-1980s. Those concepts needed a place to go that regular computer users could appreciate. The animated screen saver was it.

While demos like Bad Apple are certainly more ambitious than what you see in your average screen saver, the conceptual threads that bring the two together are very similar.

Last year, Microsoft historian Raymond Chen explained that Windows’ famed 3D Pipes screen saver was part of an attempt to highlight the improved 3D graphics capabilities of Windows NT 3.5, according to an anonymous former employee he knew.

“Windows NT 3.5 was very close to shipping with OpenGL support, but there was nothing in the product that let the user know that this feature even existed,” Chen said of his mole. “He had to find a way to advertise the feature without risking product stability.”

So, essentially, the solution was to create a “demo” competition of screen savers among people on the Windows OpenGL team, which developed visual techniques that promoted the new capabilities, such as 3D Maze and 3D Flying Objects. Rather than choosing just one, though, the company put all of them in, bringing a sense of whimsy to software generally associated with boring business stuff.

The demoscene started from a different place from a crew of high-paid Microsoft engineers, but ultimately, each was building in the same spirit, and that reflected in the final result.

Now, to be clear, a lot has changed since the 1990s. The transition from CRTs to flat-panels dampened the burn-in risk. But it’s still possible, especially if you favor OLEDs over standard LCD panels.

On top of that, putting images on the screen solves only one element of a multi-faceted issue: the screen can’t just stick on a single image in the same spot for hours on end—and it’s wasteful to put images on a screen when it’s not in use. Running an animation, even a fun one, when the screen isn’t in active use is an excellent strategy to kill a battery on a laptop when not in use. And if everyone runs screen savers in an office, it’s an excellent way to tax these energy-sucking computers even when they’re not doing anything.

And the truth is that the novelty has worn off. We have YouTube and memes to fill the niche of wacky things appearing on our screens. And we use computers that are inherently portable now. It doesn’t make sense to run an animated screen saver in many contexts anymore.

But in the early ’90s, I’m sure the flying toasters slayed.