I'm not fond of throbbers, but I see the reasoning behind the idea here. Something that may be worth considering is moving the visual, "I'm busy" feedback off the screen. After all, the N900 also has a programmable LED.

A "busy" color & blink pattern using the LED may not be as recognizable to new users as an hourglass or whatnot on screen, but users would likely come to recognize a particular LED light show as "busy" without too much trouble. Also, there would no obscuring of on-screen elements, and as I understand it, there would be no additional load on the CPU once it pushes the proper NJoy string across I2C to the LED controller.

... Neat, sjgadsby. Go add that to the brainstorm as a solution!

i agree with sjgadsby here, refreshing the screen multiple times to show the throbber will require cpu and gpu power that is currently being used (the whole screen needs compositing)

cycling a disco light maybe a better way of handling the update.

even more so if it was flashing like computer hard drive lights, a quickly flashing light indicates something is happening (its what I watch when shutting down old pc)

There already is something like that which pops up every so often, most often for the web browser... a dialog box pops up asking if you want to kill the window.

*grumble* *grumble* Okay, done.

The idea wasn't to fade just the offending app (which would also require monitoring individual CPU usage and continuous fading/unfading => big consumption), but to fade the whole desktop when there's too much to handle. This would have the same function as the fullscreen throbber (showing the system won't respond too soon), but would leave the screen readable and would allow giving some more commands (like pressing already visible buttons on screen) for the system to process when it can

Also, the LED idea is pretty good. Maybe it can be made to blink with speed proportional to processing load?

I don't like something that covers what I'm trying to read (ref. zerojay's posting, which I agree with), and I wouldn't like the screen to dim, for the same reason. Even if the device is busy there might be something I'm trying to read there. This is even a problem with the older devices, with those little pop-ups (loading, searching, etc) which covers something I'm currently reading.

So, whatever solution anyone comes up with, please don't let it interfer with/cover up other useful stuff/info on the screen.

I agree with zerojay that a fullscreen throbber would be annoying if you wanted to read the screen. The problem with fading is that it might be confused with just the backlight level changing.

Maybe the OS could put a throbber in the title bar? I know that individual apps can do this at the moment, but if an app isn't responding, then I imagine the OS could also draw up in that area. I realise that this would then be ambiguous between whether it's just the individual app that is busy or the whole OS.

Maybe put the busy throbber in the task button area in the top-left, to show that this is a systemwide thing. Clicking on it could cause more information to pop up.

I was also thinking along with the LED light maybe some sort of icon indicator could pop up on the icon tray that blinks ( much like the indicator on the n810 letting you know of an available update) but maybe instead of a exclamation point in it, a question mark could be in it or something. then once you click on it it "simply tells you whats slowing the device down" as far as which app and even gives you choices to close those apps or wait. I guess in a lot of ways it would be like the cpu/load icon for maemo 4 but this one would be a more new user friendly way to know how to identify and handle issues before it slows to much or crashes. it would only complement the LED letting the user know what that certain color pattern indicates, that is flashing.