Remember screen savers? If you're like most people you haven't really used one since the early 2000s. Dig into the settings on your computer, though, and you'll find them.
Apple included a bunch of new screensavers in recent releases, offering 4K videos of cityscapes and nature. They're stunning, but I bet most Mac owners don't realize they're even there. Microsoft, for their part, isn't putting a lot of effort into new screensavers -- the ones available in Windows 11 have been there since Windows Vista, which came out in 2007. The iconic 3D maze and pipes screensavers are gone, sure, but others are still there (including Bubbles, introduced with Vista). And most major Linux distributions also offer a selection of screensavers.
It's kind of weird that a feature most people haven't regularly used in two decades still exists on our computers. Our computers don't have floppy drives or PS/2 ports anymore, after all -- there's no reason. So why do screensavers still exist? And, come to think of it, why were they created t in the first place?
As Popular Science staff writer Andrew Paul explained recently, screen savers were developed because of a now-obsolete technology: the cathode ray tube (CRT) display. If you used a computer in the 1990s you remember these monitors, which were much thicker than the LCD panel displays we all use now. All of that extra space behind the screen was necessary because of the way these displays worked -- an electron "gun" was firing particles at a phosphorescent screen to make pixels glow. The problem: leave the same thing on the screen too long and those pixels would get "stuck", a phenomenon known as "burn-in".
Remember, when you were a kid, how the adults would tell you if you made a funny face for too long it would get stuck that way? With CRT displays this actually happened and was permanent. In mild cases it would be annoying until you decided to replace the display; in other cases it could make the display unusable. With older TVs, which were also CRTs, this usually wasn't an issue because they rarely had the same image on the screen for long. Computers, though, were different. If the user leaves a document or image open, the same content stays on the screen.
That's where screensavers came in. These programs were designed to launch when your computer was idle for a certain amount of time -- ten minutes, for example. They would take up the entire screen and, crucially, make sure that different parts of your screen weren't showing the same thing for very long. Whether it was 3D pipes appearing, toasters flying across the screen, or abstract patterns dancing around, screen savers were designed to never be static. They were fun, yes, but they existed to prevent burn-in by ensuring that every part of the screen was regularly overwritten by a different color.
Modern computer monitors don't really have the screen burn-in problem, for a couple of reasons. First, the flat LCD displays we all use now aren't vulnerable to permanent screen burn-in. In some cases you might see a ghost on your display, sure, but it usually goes away eventually. The other major reason screensavers aren't a thing anymore, though, is that modern computers can put the display to sleep after a certain amount of time. This makes sense when you think about it -- why use energy to show a screensaver when you can turn the display off instead?
The answer, of course, is that screen savers are fun. It's fun to walk away from your computer in the office and come back to a bunch of high-quality nature footage, that green code from The Matrix, or a bunch of bubbles. This, I think, is why tech giants like Microsoft and Apple haven't removed the feature from their operating systems. Sure, most people don't use them, but they don't take up a lot of space and a few people really really like them.
Plus, there are a few useful ways to use screensavers. You can set yours to show a clock, for example, allowing you to see the time from across the room. Or, if you want your computer to contribute in some small way toward scientific progress, there's Folding at Home. This citizen science project uses users' computer's CPU and GPU to simulate folding proteins for medical research, and can optionally be launched as a screensaver -- that way it will only use your resources when you're not.
Most people aren't using screensavers this way, though. That's okay. Screensavers don't need to be practical anymore -- they can just be a fun thing you occasionally play with.