5 ms·
Why didn't we do this back in the CRT era, and invented screensaver instead, then? TV is understandable, you don't want a DVD player to show a black screen, oth
by segfaultbuserr 7y ago
Why didn't we do this back in the CRT era, and invented screensaver instead, then? TV is understandable, you don't want a DVD player to show a black screen, otherwise it appears dead. But what about screensavers on computers, why did it come into being? (I know turning a CRT on takes time, but we don't have to turn it off completely to blank the screen either?)
Update: It appears that the original motivation was public terminals/machines.
- dmos62 7y agoSpinning up and down a CRT reduced its life-span, I wager.
- segfaultbuserr 7y agoI don't think it was a major concern. First, you can always display a dummy black image without turning off the CRT. Also, VESA defines two "off" modes in DPMS (1993): blank and fully off. "Blank" allows the monitor to partially suspend without shutting down the CRT completely, which allows an instant recovery.
- dmos62 7y agoMight as well have an animation, as opposed to "black light"?
- segfaultbuserr 7y ago> as opposed to "black light" BTW, the "black" on a CRT is almost a true black. The electron beam is off when the signal voltage is less/equal to the black level, there's no "black light" if the black level is perfectly calibrated. Displaying a black image fullscreen is indistinguishable from an endless vertical/horizontal blanking interval from a practical standpoint. There's a measurable decrease in power consumption, although it's not much (it can be great enough on a large TV, though). On the other hand, VESA blanking mode turns off additional circuitry, and it can save a lot of power while still keeping the CRT heater on, suspending the screen without the disadvantages of a long wakeup time or stressing the tube.
- amelius 7y agoThere is something to say for knowing that the device is on. Saves you from accidentally turning the device off when you wanted to turn it on.