History of Linux
Brain behind development
Why GNU ?
Where can you find Linux?
Linux is Best!!
Core components of Linux
Facts about Linux
History of UNIX/Linux
Unix is a command line operating system developed around 1969
in the Bell Labs
Originally written using C
Unix is designed so that users can extend the functionality
• To build new tools easily and efficiently
• To customize the shell and user interface.
• To string together a series of Unix commands to create new
• To create custom commands that do exactly what we want.
Around 1990 Linus Torvalds of Helsinki University started off a
freely available academic version of Unix
Linux is the Antidote to a Microsoft dominated future
Brain Behind Development of
Ken Thompson and Dennis
Richard Matthew Stallman
Developer’s of Unix
Developer of Linux
Developer of GNU Project
: Several programs running at
the same time.
: Several users on the same
machine at the same time (and no two-user licenses!).
: Runs on many different CPUs,
not just Intel.
: SMP support is available on the
Intel and SPARC platforms
Memory Management : Has memory protection
between processes, so that one program can't bring the
whole system down
Open Source : All source code is available, including
the kernel and all drivers, the development tools and all
user programs; also, all of it is freely distributable.
GNU(“GNU’s NOT UNIX”)
GNU is a Unix-like operating system that is free
software—it respects your freedom.
You can install versions of GNU (more precisely,
GNU/Linux systems) which are entirely free software.
What we provide.
The GNU Project was launched in 1984 to develop the
GNU system. The name ―GNU‖ is a recursive acronym
for ―GNU's Not Unix!‖.
―GNU‖ is pronounced g'noo, as one syllable, like saying
"grew" but replacing the r with n.
A Unix-like operating system is a software collection of
applications, libraries, and developer tools, plus a
program to allocate resources and talk to the hardware,
known as a kernel.
The freedom to run the program, for any
The freedom to study how the program
works, and adapt it to your needs Access to
the source code is a precondition for this.
The freedom to redistribute copies so you can
help your neighbour.
The freedom to improve the program, and
release your improvements to the public, so
that the whole community benefits Access to
the source code is a precondition for this.
Where you find Linux ??
Thanks to Google, Linux is a massive success on mobile
phones, and is putting open source software into more
hands than the desktop revolution ever has.
Set-top boxes are another Linux's success. These are
devices that sit next to your television, typically streaming
content from a server, recording digital
browsing the web.
Routers and switches
In the big brave world of the enterprise, networking and
storage is what Linux does best, and some of this technology
has filtered down to the home and small business market
There are several high-profile synthesizers that are using
Linux because of its stability, low latency and development
Desktops , Laptops, Gps , Navigation Systems and many more…..
Linux is best
Works more faster
No external Drivers
No illegal software's when you get it for
Enjoy free and unlimited support
Forget about viruses
No need of external antiviruses/antimalware/firewalls
Flavour’s of Linux
Linux Desktop Distribution
Linux Laptop Distribution
Linux Enterprise Desktop
SUSE Linux Enterprise Desktop (SLED
Linux Enterprise Server
Red Hat Enterprise Linux (RHEL) and SUSE
Linux Enterprise Server (SLES)
Linux Security-Enhanced Distribution
Linux Multimedia Distribution
This is the part of the system that is executed
When you have only one operating system
installed, it simply loads the kernel.
If you happen to have multiple operating
systems or multiple versions of the Linux
kernel installed, it allows you to choose which
one you want to start.
The most popular boot loaders
are GRUB (Grand Unified Boot loader)
and LILO (Linux Loader).
Most users don't need to care about the boot
loader, because it is installed and configured
The kernel is the central component of the system
that communicates directly with the hardware.
In fact, the name "Linux" properly refers to a
particular kind of this piece of software.
It allows programs to ignore the differences between
The kernel allocates system resources like memory,
processor time, hard disk space and external devices
to the programs running on the computer.
It separates each program from the others, so that
when one of them encounters an error, others are
Most users don't need to worry about the kernel in
day-to-day use, but certain software or hardware will
require or perform better with certain kernel
The shell is a textual interface that allows you
to run programs and control the system by
entering commands from the keyboard.
Without a shell (or something that can
replace it, like a desktop environment) it
would be hard to make your system actually
The shell is just a program - there are several
different shells for Linux, each of them
offering different features.
Most Linux systems use the Bourne Again
Linux shells support multitasking (running
several programs at once).
Initramfs, initial ram file system is the successor of
the initial file system that gets loaded into memory
during the Linux start-up process.
The Linux kernel mounts it as root file system and
starts the init process from it. This will complete
certain task before the real root file system is loaded.
Initramfs needs to contain all of the device drivers
and tools needed to mount the real root file system.
The Initramfs is one solution to the chicken-and-egg
problem of some mass storage devices and some file
systems -- especially cryptographic file systems -requiring complex device drivers to read data from
them, when device drivers are normally stored inside
the file system in the mass storage device.
X Window Server
The X window server is a graphical replacement
of the command shell.
It is responsible for drawing graphics and
processing input from the keyboard, mouse,
tablets and other devices.
The X server is network transparent, that is, it
allows you to work in a graphical environment
both on your own computer as well as on a
remote computer that you connect to across a
The X server that is most used today is X.Org.
Most graphical programs will only need the X
server to run, so you can use them under any
window manager and desktop environment.
In general, the letters (fd, sd, hd) refer to the device
type ('SATA, SCSI/SATA, IDE'), the third letter is for
the device order (a the first, b the second, etc) and
the numbers refer to the partitions the device has,
starting by zero.
hd refers to an IDE-type drive
sd refers to a SCSI drive in general, but is mostly
popular for SATA drives and CD/DVD
fd is floppy disk
So for example:
the first (1) partition on your first (a) SATA drive
The third (3) partition on your second (b) SATA drive
the second partition (2) of the second (b) IDE hard
disk is '/dev/hdb2'
The United States National Security Agency (NSA), the original primary developer
of SELinux, released the first version to the open source development community
under the GNU GPL on December 22, 2000
DAC(Discretionary Access Control):
Briefly, Unix DAC allows the owner of an object (such as a file) to set the security
policy for that object—which is why it's called adiscretionary scheme.
RED HAT 6.0
Facts You should know !!!!
Linux is not an OS, but it is the kernel, GNU Linux is the OS and
it comes in several hundred flavours.
Major part of today’s Linux kernel is written in C programming
language and assembly language and only 2% of today’s kernel
contains code written by Torvalds.
A Standard Linux Kernel of today has over 10 Million lines of
code and it grows at the rate of 10% every year. About 4500 lines
of codes are added and 1500 lines of code are changed everyday.
Initially in 1991, Linux kernel version 0.01 was released
with 10239 lines of code.
90% of the world’s most powerful supercomputers are
using GNU/Linux. Top ten of supercomputers use Linux.]
For those who think Linux can’t do Animation – Oscar-winning
visual effects of theTitanic by James Cameron came from
machines with Linux and Avatar was the last movie completely
developed in 3D Applications on Linux platform using Foss
As of January 2010, Linux still only has a 1.02% market share