Hardware Reference
In-Depth Information
• The X.Org graphical server
• The desktop environment
The Raspberry Pi bootloader
When your Raspberry Pi is powered on, lot of things happen behind the scene. The
role of the bootloader is to initialize the hardware in the Raspberry Pi to a known state,
and then to start loading the Linux kernel. In the case of the Raspberry Pi, this is done
by the first and second stage bootloaders. The first stage bootloader is programmed
into the ROM of the Raspberry Pi during manufacture and cannot be modified. The
second and third stage bootloaders are stored on the SD card and are automatically
run by the previous stage bootloader.
The Linux kernel
The Linux kernel is one of the most fundamental parts of Raspbian. It manages
every part of the operation of your Raspberry Pi, from displaying text on the
screen to receiving keystrokes when you type on your keyboard.
The Linux kernel was created by Linus Torvalds, who started working on the kernel
in April 1991. Since then, groups of volunteers and organizations have worked
together to continue the development of the kernel and make it what it is today.
Did you know that the cost to rewrite the Linux kernel to where it
was in 2011 would be over $3 billion USD?
The Linux logo is a penguin named Tux:
If you want to use a hardware device by connecting it to your Raspberry Pi, the
kernel needs to know what it is and how to use it. The vast majority of devices on
the market are supported by the Linux kernel, with more being added all the time.
A good example of this is when you plug a USB drive into your Raspberry Pi. In
this case, the kernel automatically detects the USB drive and notifies a daemon
that automatically makes the files available to you.
