Linux Startup process

Here's a quick no nonsense guide to how linux boots up.

• When a linux system is started, Linux Loader (GRUB or LILO usually) loads the kernel.
• Initially, when LILO or GRUB calls kernel, the kernel is uncompressed and kernel starts checking hardware attached, loads the required modules.
• When all hardware modules or drivers are appropriately loaded, Kernel opens root volume (/) in read only mode.
• Kernel checks if root volume has any problems. If no problems are detected, the root volume is mounted as read-write.
• Once the above step is done, kernel executes a process called init.
• When init is done, the linux is up and running.
• init is highly configurable with various customizations.