1.2.3. The Kernel

When the kernel is loaded, it immediately initializes and configures the computer's memory and configures the various hardware attached to the system, including all processors, I/O subsystems, and storage devices. It then looks for the compressed initramfs image(s) in a predetermined location in memory, decompresses it directly to /sysroot/, and loads all necessary drivers. Next, it initializes virtual devices related to the file system, such as LVM or software RAID, before completing the initramfs processes and freeing up all the memory the disk image once occupied.

The kernel then creates a root device, mounts the root partition read-only, and frees any unused memory.

At this point, the kernel is loaded into memory and operational. However, since there are no user applications that allow meaningful input to the system, not much can be done with the system.

To set up the user environment, the kernel executes the /sbin/init program.