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Watch a screen saver in the background

Another oldie but goodie, and it’s best demonstrated by example:

Yes, that’s a screen saver running in the background, behind whatever work you’re doing. And if nothing else, it’s a great example of the progress of our CPUs and GPUs since 2002. In the original hint, I noted:

On my G4/733 with the GeForce3, this is simply amazing. The new “flurry” screensaver is running right now on the destop at 1600×1200 in thousands, iTunes is playing, the ink recognition floater is open, and yet the CPU utilization is averaging at or below 50% of thereabouts

Today, I’m testing it on a 5K iMac (5120×2880) with a second connected 4K (3840×2160) display—a total of 23,040,000 pixels, or 12 times as many pixels as in 2002—with Flurry running on both screens, and the CPU usage is somewhere around 10% to 15%. (Flurry does send the iMac’s fans into a tizzy, though.) Other screen savers are even less intensive, and don’t send my iMac’s fans into high gear.

I can’t imagine actually working this way for very long, but it is kind of interesting. Here’s how to start (and more importantly, perhaps, stop) a background screen saver.

Copy (and possibly edit) the command below, then open Terminal, paste, and press Return:

Replace Arabesque with the name of the screen saver you’d like to use, exactly as shown in the Desktop & Screen Savers System Preferences panel.

To stop the running screen saver, type fg, press Enter, then press Control-C. A more brute-force approach is to issue killall ScreenSaverEngine. Or you can quit Terminal, which will then warn you that the background task will be terminated if you quit.

While the command to start the screen saver looks a bit intimidating, it’s just four components:

  1. The long string of text at the front is just launching the actual program, named ScreenSaverEngine. However, that app is buried in a framework in the System folder, so the full path is used to reach it.
  2. The -module "Arabesque" is completely optional—it simply specifies which module to use. If you leave it out, then the screen saver chosen in System Preferences will be used. Modules are specified by name, as shown in the Screen Saver tab of the Desktop & Screen Saver System Preferences panel. Case matters, too, so it’s “Word of the Day” not “word of the day.”
  3. The -background command is an option that tells the screen saver engine to run in the background.
  4. Finally, the & tells the shell to run the command in the background, returning control to you—you can press Return a couple times, and you’ll see the shell prompt. Because it’s running in the background, you can use Terminal to do other things, or just ignore it.

Many of the picture screen savers are fun to use—Photo Wall, Photo Mobile, and Ken Burns, for example. And Flurry and Arabesque are both mesmerizing…to the point of making it hard to focus on any work. Configure these (which photos to use, options, etc.) in System Preferences first, and the Terminal command will then use those settings.

As noted, this tip is more for fun than for any real practical use.

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  1. Nice to know it’s still operable. Speaking of oldies but goodies (in this case lost to the Intel migration, however), remember the old PPC screen saver Fluid by ConceptHouse? I don’t think it’s just from a perspective of nostalgia for me to call it my favorite ever. After I loaded it, I don’t think I ever loaded another until after Intel replaced the IBM PPCs. There was a way to run in under Rosetta, I think, but I sure do miss it.

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