Kernel Memory

Question

I was cleaning out files on my laptop and saw this, but I don’t follow what it means. ELI5

In: 1

Answer 1

In people we sometimes say that we have our “animal brain”, that just does the basic things like keep our heart beating, keep us breathing, tell us when we’re hungry or we’re in pain, lets us form and recall memories, make sounds, etc. All animals have this basic animal brain.

But because our brains are complex, humans also have our “rational brain” on top of the animal brain. The rational brain lets us make sense of what we’re seeing and hearing, and gives us the ability to solve problems, communicate using language, etc. Our rational brain needs to use our animal brain to make speech, to hear sounds, and to move around how we decide we want to move.

Computers also have an “animal brain”, and it’s called the kernel. The kernel is how the computer understands and follows instructions, manages its cooling, how to remember information, how it connects to other computers, how to use a display or a keyboard, keeps its battery charged, etc.

The computer’s “rational brain” is represented by the software that runs on top of the kernel. We say this software runs in “user space” rather than “kernel space”. This includes everything from the way your computer draws windows on your screen to the way that your web browser communicates with other web servers to deliver this web page to you. User space programs make a lot of use of the kernel to get its work done.

All software needs memory to run, so when you see something talking about “kernel memory”, it’s talking about the memory used by the kernel to do its basic “animal brain” work. Generally computers don’t use a lot of memory in kernel space since most of it is needed for user space.