The document provides an introduction to operating systems, kernels, shells, Linux, and the differences between Linux and Windows. It discusses that an operating system consists of system software that acts as an intermediary between the user and computer hardware. The kernel is the core of the operating system and constantly runs, while the shell provides an interface between the user and kernel. It then covers Linux features such as being open source, modular, offering choices of desktop environments, and being portable. It also compares Linux and Windows in areas such as licensing, market share, filesystems, installation, and configuration.

1. UNIT 1
● Introduction to operating sytem , kernel and shell
● FLOSS/FOSS
● Linux features & Different Distros
● Linux v/s Windows

2. OPERATING SYSTEM
● To do anything useful with a computer, we need to run
software, or programs, on the hardware. Two types of
software exists --
● APPLICATION SOFTWARE -- for each different application
we need different application program like for word-
processing we need the MS-Word etc.
● SYSTEM SOFTWARE – is a program or collection of
programs that acts as an intermediary between a user of a
computer and the computer hardware. It makes the
hardware and software work together and different
hardware to communicate with each other . Different types
of OS --
● Windows , Unix , Linux , Sun Solaris , Multics ,MacOS etc

3. ABSTRACT VIEW OF OF COMPUTER SYSTEM

4. Kernel and Shell
● Operating system can be further subdivided into 2 parts.
While the system is operational a program is constantly
running known as KERNEL. It forms the core of any
operating system
● The other part of operating system is shell which is the
interface between user and system itself. It allows the user
to instruct the machine and to run programs. A shell
communicates with the kernel, but keeps the user at arm’s
length from it. A shell only active when somebody is using
the system while kernel is always active. Todays different
type of shell exists depending on the ideas of different
developers who created them .
● Sh --Bourne shell (first shell named after its creator)
bash – Bourne again shell

5. ● Ksh (korn shell)
● Csh ( c shell)
● Zsh and tcsh (pronounced – teesh)
HARDWARE
KERNEL
SHELL

6. FLOSS – FREE/LIBRE OPEN SOURCE SOFTWARE
● OPEN SOURCE : software and source code available to all
● The freedom to distribute software and source code
● The ability to modify and create derived works
● Integrity of author's code
● GNU : In 1984, Richard M. Stallman started the GNU project
(www.gnu.org), recursively named by the phrase GNU is Not
UNIX.The GNU project aimed at creating a UNIX-like open
source operating system free from regulations preventing it
from being modified and redistributed.GNU worked on GNU
Hurd OS and also build several open source compilers and
libraries but Its aim of Open source Operating system was
achieved in 1991 with the birth of LINUX KERNEL
● LINUX :Linus Torvalds , a student at the University of Helsinki,
created the first version of “Linux” in August 1991. Released
as an open-source software under the Free Software
Foundation's GNU General Public License (GPL)

7. ● A company can charge money for products that include
Linux, as long as the source code is made available. The
GPL allows people to distribute (and charge for) their own
versions of free software.
● According to the Free Software Foundation, the "free" in
free software refers to freedom or liberty, not price.
● Linux refers to the “ kernel or core ” of the operating
system. Combining Linux with a set of open-source GNU
programs from the Free Software Foundation turns it into
what most people know as Linux ”forming both the full
operating system and the core of most Linux distributions”.
● Linux Distributions are built on the versions of Linux kernel,
GNU programs, and other tools that are offered by different
companies, organizations, or individuals. There are over
600 Distro available today. (www.distrowatch.com)
Categorise as the commercial-backed distro like –
Fedora(Redhat) ,openSUSE(novell),Ubuntu(Canonical Ltd)

8. ● And entirely community-driven distributions, such as
Debian , Centos and Gentoo.
● While different Linux systems will add different logos,
choose some different soft-ware components to include,
and have different ways of installing and configuring, one
can easily move from one distro to another because --
● include the same open source projects , like apache ,
samba or mail servers etc
● Linux Standard Base Specification (www.linuxbase.com)
has as one of its primary goals to ensure that applications
written for one Linux system will work on other systems.
● A shell is a shell on all the different distros.
TUX IS LINUX OFFICIAL MASCOT->

9. LINUX FEATURES
● It's free
● It's Open Source
● It's Modular --Commercial Operating Systems normally get
installed as a complete unit. One cannot, for example,
install them without their Graphical User Interface, or
without its printing support -- install everything or nothing
● It’s got More Choices – Kde, GNOME ,lxde,xfce
● It's portable – we can run on atmiga , arm arch , embedded
systems, Machintosh, Sun Sparc, HP, Silicon Graphics ,
Motorola etc.
● Its comes loaded with softwares like web , ftp , samba and
office suite etc on the distro CD.
● Its stable -- Linux is rock-solid. Every application runs
independently of all others – if one crashes, it crashes
alone

10. ● Multiple OS’ s on a PC -- Linux can read Windows' files - it
supports the FAT and FAT32 file system’s, and NTFS. The
opposite, however, is not possible.
● Linux is Multi User -- several users can log-on
simultaneously. This means you can share the same
program installation among various users.
● Linux is Multi Vendo -- means that by choosing Linux, you
choose to depend on a set of (more than 600) Linux
distributors in the world, plus the open source community.
Not dependent on a unique vendor. It is also safer, prices-if
any are driven by the market, not by monopoly.

11. Red Hat Distributions
● Red Hat Enterprise Linux---
● Stable, thoroughly tested software
● Professional support services with 24x7 coverage plans.
● Centralized management tools for large networks
● Version available started from 2.1, 3.0, 4.0, 5.0 now 6.0
● Support many processor architectures – Intel x86
compatible, Intel Titanium 2, AMD64, IBM PowerPC
● The Fedora Project---
● More, newer applications
● Community supported (no official Red Hat support)
● For personal systems

12. LINUX VS WINDOWS
● Open source Closed Source
● Can modify & Redistribute Cant modify & Redistribute
● Covers the 70 % share of Covers the 23% share webservers
webservers
● 91 % of supercomputer run 1% of supercompter share run on
linux (top 14 runs linux only) windows
● Filesystem – ext2,ext3,ext4 Filesystem - NTFS, FAT, ISO 9660
reiserfs ,FAT, NTFS, NFS, UDF UDF ,HFS
ISO 9660 , JFS,XFS
● Linux installers will automatically Windows installers will overwrite the
detect and set up other operating MBR , thus rendering non-Windows
systems for dual/multiple boot partition unusable
with Linux
● Linux Kernel is modular , drivers Windows Kernel is Monolithic and all
are loaded dynamically whenever drivers are loaded at boot time thus
required thus, reducing boot time boot time is more

13. ● Linux doesnt require defrag- Windows partition require
mentation. Defragmentation.
● Linux application are installed Windows rely on windows installer
with package manager such as to install third party applications.
apt or yum etc which ensure all
dependencies are met.
● As of 2006 more than 800 pieces As of 2009 more than 2 million of
malware had been detected malware have been detected for
windows
● Linux stores configuration in plain Windows Database of configuration
text file is Registry
● “/” is the head of system file “c:” is generally where we get
storage system files
● “/home” stores the user files and “Document & Settings” stores the
/root stores the admin files user files and admin files also
● “/bin” stores the normal binaries “Program files” stores the binaries
“/sbin” --system binaries
“/usr/bin” -- user binaries

14. ● “/etc” stores the config files “windows/system32” stores the
config files
● “/tmp” stores the temporary files “%temp%” stores temporary files
● “SWAP –memory overcommit “ Virutal Memory”
upto 4 GB --> 2XRAM 1.5 Of RAM
6 GB --> 1X RAM
8 GB --> .5X RAM

15. ?

16. EXERCISE
● What is GPL /GNU Licensing ?
● What are differences b/w linux and unix
● Study Linux Distro family
● Study ext3 , ext4 and other linux filesystem

17. ● References --
● http://en.wikipedia.org
● http://www.nrcfoss.au-kbc.org.in
● http://www.distrowatch.com
● http://encyclopedia.thefreedictionary.com
● RHCE Red Hat Certified Engineer Linux Study
Guide by Michael Jang