What is WindowServer?

[debo]

In the activity monitor under proccesses running there is WindowServer. What is this? And while I'm on it, what is kernal_task?

 

[MoparShaha]

Don't touch either of them, otherwiser you're going to have a very unhappy Mac!

I have a rough idea of what they do, but I'm going to let someone who can really explain them do so.

 

[bankshot]

I'll attempt to answer, though someone else may be able to provide more detail.

kernel_task is the first process that is run by the kernel (core of the OS) during system startup. It is responsible for system initialization and starting up further process in the system init process. I'm not sure if it does anything after system startup - it may well be what controls basic operations such as disk / file access, etc, which make the computer do its thing. I'm not really sure if that stuff is in kernel_task or if it's buried deeper within the kernel itself. But rest assured that this process is vital to your machine being able to do anything at all!

WindowServer draws everything you see on the screen. It acts as a mediator between applications that want to draw on the screen and the graphics hardware. When an application wants to draw something, it establishes a connection with WindowServer, tells WindowServer what to draw, and WindowServer handles the drawing / compositing / Quartz Extreme hardware acceleration to finally produce what's seen on the entire screen.

That's basically at a high level, and about the extent of how much I know about this stuff. Like MoparShaha said, don't touch either one, or you'll be in big trouble...

If anyone wants to add anything or correct anything I've said, feel free.

 

[janey]

Originally posted by bankshot
WindowServer draws everything you see on the screen. It acts as a mediator between applications that want to draw on the screen and the graphics hardware. When an application wants to draw something, it establishes a connection with WindowServer, tells WindowServer what to draw, and WindowServer handles the drawing / compositing / Quartz Extreme hardware acceleration to finally produce what's seen on the entire screen.

*claps* excellent description...when i first saw this thread i was wondering how hard it would be to explain, but it seems like you've already done a good job

btw debo, try not to touch anything (you dont know) while using Activity Monitor, because most of the processes are necessary for the computer to function.

 

[Scenicroadways]

kernal_task eating up memory

for some reason, kernal_task uses more memory than any other process, including any apps that I am running. Is this normal?>

 

[Counterfit]

Also, don't touch login_window, I've had it crash on me a few times (Under jag though) and it logs you right out.

 

[Makosuke]

for some reason, kernal_task uses more memory than any other process, including any apps that I am running. Is this normal?>

It only uses more *virtual* memory than everything else, and yes, that's normal. Being the core of the OS, it probably needs it.

Incidentally, the loginwindow that Counterfit mentioned *is* your login, which is why you're instantly logged out if it crashes. I don't recommend it, but if your user session dies for some reason, killing that is one way to get yourself back to the login window for a "soft" restart.

As a rule of thumb, unless you know what you're doing, just don't mess with things in Activity Monitor or think too hard about what it tells you--it can be interesting to look, but there are all kinds of things in there that look weird (inactive vs. free memory, background tasks, etc) but are perfectly normal, and people seem to have a tendency to dig around then panic when something doesn't look right.

There's a reason Apple gives you the "force quit" window, which only shows high-level user processes.