So, in this module, let's talk about some important components of your system. In particular, we want to talk about system initialization, we want to talk about memory, and we want to talk about network interfaces. When the system starts, it goes through a number of phases. The first one is your early boot phase, which is rather hardware-dependent, and involves getting your Linux kernel started. This, on most Linux systems, involves using so-called GRUB, which lets you choose alternative operating systems, kernel options, et cetera, when you start. And on embedded systems, you'll do something else, such as Das U-Boot. The next phase has to do with actual initialization of various system services, and that's really a question of system administration, rather than early boot. The second thing we want to talk about is memory. We want to talk about how your system uses memory and what it does when it runs out of memory and has to use so-called swap space. At this point, you may find your OOM killer, Out of Memory killer, invoked, which decides how to deal with things when you've run out of memory. The third thing we want to talk about is network and network devices. We want to talk about how you can enable network devices, make sure they go up or go down as needed, and how they are named. So, let's begin talking about these three topics.