It’s 1985. You have an IBM PC with a monochrome monitor; the color, or CGA, monitor is just too expensive. You work on VisiCalc. It’s up there, on the screen for about 8 hours a day. It even shows up when you turn off the monitor.
The problem was called phosphor burn-in. It’s a latent image that appeared primarily on monochrome monitors, even when the monitor was turned off.
For me, the image wasn’t VisiCalc, it was WordPerfect. There, in the lower right corner of my monochrome monitor, I’d see the page number, line number, and other persistent information from that program, even when the monitor was turned off.
To combat the perils of phosphor burn-in, intrepid programmers developed the screen saver.
Early screen savers were memory resident or TSR programs. They monitored the keyboard and started a timeout after a key was pressed. When the timeout value was hit, the screen was blanked. They were really that simple; I remember one I coded that was only a few dozen bytes in size.
Because the early monitors weren’t energy efficient, the program simply displayed a blank screen; all spaces. That was it. When you tapped a key on the keyboard, the old screen was restored. (Remember, this time was before computers used a mouse.)
When Windows appeared, the screen savers became graphical in nature. One of the most popular was After Dark, which started on the Macintosh. It featured the famous Flying Toaster screen saver, shown in Figure 1.
Figure 1. The original Flying Toasters screen saver animation from After Dark.
After Dark offered other creative screen savers as well. In fact, at the time (late 1980s/early 1990s), screen savers became more of a hobby — a toy — than anything the monitor’s hardware really needed. That’s because the monitors became better, especially the color monitors. Phosphor burn-in was a thing of the past. Today’s LCD monitors don’t even use phosphor!
Screen savers exist today, but mostly as a diversion or to lock the computer. Nothing is truly being saved any longer. That’s too bad, because back when the screen saver was truly needed, they were wildly creative. Compared with then, today’s screen savers are kind of boring and plain. It makes me miss After Dark and all it’s clever animated screen savers.
