So let's move on and talk about the different types of processing.
There really are two different ways that group policy is processed at the client.
The first way is called foreground processing.
What?
This is the processing that occurs at computer startup for computer objects.
So when the computer first boots up, it connects to the network.
It connects to Active Directory and it performs group policy processing for the computer.
And then at user log on for user objects and AD, there's a foreground processing cycle that occurs
and I'll talk about why the group policy engine distinguishes between these kinds of processing cycles
in a bit.
It definitely matters in terms of which client side extensions or policies areas process when.
But let's just suffice it to say that foreground processing happens for computers at startup and users
at log on.
And then there's a background processing cycle that occurs every 90 minutes, plus a 30 minute random
offset.
So essentially every up to a maximum of every 120 minutes on workstations processing, the engine will
wake up and perform some processing work and go back to sleep for another 90 plus 30 offset minutes.
And that's designed to process any changes that might have occurred in your policy.
While the computer has been started and the user has been logged on on servers, that actually happens
every 5 minutes.
So you get a lot more frequent checking of group policy changes.
And I think the idea there is that servers tend to be more critical.
And if you make changes like security changes to servers, you want them to get those pretty quick.
Okay.
So we've got these two types of processing.
Foreground and background.
So let's look at foreground in processing and background processing in a little bit more detail.
So foreground processing, why is it important?
Well, certain policy areas can only run in the foreground.
Policy areas like folder direction, software installation and before Windows 8.1 group policy preferences
drive mappings also would only run in the foreground.
In other words, these three areas would only run at computer startup or user log on.
And of course, during foreground processing, just like during background processing, the engine doesn't
actually do any work unless that list of GPOs that applied to the computer or the user has changed.
For whatever reason, GPO has been deleted or unlinked.
A security group filter has changed.
The user or computer security group membership has changed and therefore the list has changed.
If none of that happens, if the list is the same from one foreground processing cycle to the next,
then the engine wakes up, runs through core processing, and then does no work.
Now, similarly with background processing, it's really, as the name implies, happening in the background.
The user doesn't know what's happening.
It's just running, picking up every 90 plus 30 minutes.
And basically that same logic applies about whether things have changed or not changed.
And then it goes back to sleep.
So these are kind of the ways that foreground and background processing happen.
The next thing we'll do is look at the different modes for processing.