operating system question!

[zhongtheman]

how do i know how much of my memory is being used by my OS?

[BigBear]

Which OS?

Windows: Ctrl+Shift+Esc
Linux: in terminal $ free -m

[zhongtheman]

i want to check how much of my memory is occupied by my OS

[DemonWasp]

In Windows, open the task manager and go to the performance tab. In the "Kernel Memory" section, add the values of "Paged" and "Nonpaged". That's what the kernel itself (drivers included) is using.

But an "operating system" also a collection of applications surrounding that kernel, without which it wouldn't be useful. In Windows, you'll see processes like: explorer.exe and dwm.exe, which are Windows-native processes that manage some part of the system. Your drivers probably added a process somewhere to auto-update, especially the graphics card driver.

If you look at the "services" tab, then many of those services are part of the "operating system", like "Spooler" (handles printing), "AudioSrv" (audio subsystem), Dnscache (DNS cache, vital for network access), "hidserv" (manages human interface devices, like keyboards and mice), etc.

If you look back at the performance tab, you can also see that some amount of memory is "cached", meaning that the operating system is keeping a copy of some files from your hard drive in memory because it suspects you might want to read from them again. If it's right, then you get to read that file much faster because it's already in memory; if it's wrong, then there's no real loss because it can just delete the copy and leave the original (on the hard drive) intact.

In short: there's no single answer, because an "operating system" can include a lot of software, and exactly where "OS" ends and "applications" begin isn't well-defined.