distribution. There are many different Linux distributions from different
vendors, but many derive from or closely mimic the Debian Linux
distribution, on which Ubuntu is based.
NOTE
Debian lists several dozen other Linux distributions as being based on
Debian Linux (see www.debian.org/misc/children-distros).While it is really the kernel itself that is most appropriately referred to as
“Linux,” colloquial language uses the term to refer to more than just the
kernel. Most people who say they “use Linux” are referring to, at a minimum,
a suite of software that includes several things. We have listed some of the
more necessary ones here, in the order in which they are loaded into your
computer’s memory during the boot cycle, after your computer’s BIOS or
UEFI firmware (which was included by the manufacturer of the motherboard
and which runs from where it is stored on the motherboard) has run to get
things started:
A boot loader, like GRUB2, which is described in Chapter 1, “Installing
Ubuntu and Post-Installation Configuration”
The Linux kernel, which is described in Chapter 22, “Kernel and Module
Management”
Daemons, which are background processes that the system itself runs to
perform tasks like logging or listening for attempted network
connections and so on; daemons may be more easily understood as
programs that are not run or invoked directly by a user but that lie
dormant until any of a specific set of conditions occurs
The shell, which is a command processor that most people know best
because it is what they see when they log in to the terminal; the shell is
described in Chapter 14, “Automating Tasks and Shell Scripting”
Shell utilities, such as most of the commands in Chapter 10, “Command-
Line Beginner’s Class,” Chapter 11, “Command-Line Master Class, Part
1,” and Chapter 12, “Command-Line Master Class, Part 2”
A graphical server, such as the X server, which is described in Chapter 3,
“Working with GNOME”
A desktop environment, such as GNOME, which is also described in
Chapter 3, “Working with GNOME,” and others such as those discussed
in Chapter 7, “Other Ubuntu Interfaces”
Desktop software, such as web browsers, office suites, media players,
games, and so on