Linux Environment- Linux vs Unix Linux Features The POSIX Standard GNU is Not Unix! Comparison Advantages of Linux

1. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Affiliated Institution of G.G.S.IP.U, Delhi
BCA
Linux Environment
BCA306
Linux vs Unix
Keywords: Linux, Unix, features

2. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
LINUX VS UNIX
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3. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
What is Linux
• Linux is an operating system that was initially created as a hobby by
a young student, Linus Torvalds, at the University of Helsinki in
Finland.
• Linus had an interest in Minix, a small UNIX system, and decided
to develop a system that exceeded the Minix standards.
• He began his work in 1991 when he released version 0.02 and
worked steadily until 1994 when version 1.0 of the Linux Kernel
was released. The kernel, at the heart of all Linux systems, is
developed and released. It is this kernel that forms the base around
which a Linux operating system is developed.
• There are now literally hundreds of companies and organizations
and an equal number of individuals that have released their own
versions of operating systems based on the Linux kernel.
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4. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
• Apart from the fact that it's freely distributed, Linux's
functionality, adaptability and robustness, has made it the
main alternative for proprietary Unix and Microsoft
operating systems. IBM, Hewlett-Packard and other giants
of the computing world have embraced Linux and support
its ongoing development.
• Well into its second decade of existence, Linux has been
adopted worldwide primarily as a server platform. Its use as
a home and office desktop operating system is also on the
rise. The operating system can also be incorporated directly
into microchips in a process called "embedding" and is
increasingly being used this way in appliances and devices.
Contd..

5. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Linux Features
• multithreading: has native kernel support for multiple
independent threads of control within a single process memory
space.
• has memory protection between processes, so that one
program can't bring the whole system down.
• demand loads executables: Linux only reads from disk those
parts of a program that are actually used.
• virtual memory using paging (not swapping whole
processes) to disk: to a separate partition or a file in the
filesystem, or both, with the this if necessary, by changing a
few lines of source code.
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6. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Linux Features Contd…
• support for many national or customized keyboards,
• Supports several common filesystems, including
minix, Xenix, and all the common system V
filesystems, and has an advanced filesystem of its
own, which offers filesystems of up to 4 TB, and
names up to 255 characters long.
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7. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Linux
• Linux is a free Unix-like operating system that has become popular
with PC users around the world. An independent POSIX
implementation, Linux does true multitasking and includes virtual
memory, shared libraries, demand loading, memory management,
TCP/IP networking and other features that are available with current
full featured commercial operating
• systems . A feature of the Linux operating system that
distinguishes it from other operating systems is that it is one of
the few operating systems whose source code is also available as
free software under the GNU General Public License (GPL).
The GNU GPL is intended to safeguard and guarantee the
freedom of any user of free software to share, modify and also
share the modified software. This is in contrast to the licenses
• given for proprietary software that prohibits its users to share or
modify software

8. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
The POSIX Standard
• POSIX stands for Portable Operating System Interface for
Computer Environments. POSIX was first adopted by the
United States Federal Information Processing Standard (FIPS)
in 1988 and revised in 1990. POSIX, adopts the Institute of
Electrical and Electronics Engineers (IEEE) Standard The
IEEE Standard defines an interface to an operating system
environment.
• The main aim of the, POSIX standard was to permit Federal
Agencies in the United States of America to exercise control
over the production, management and use of information
resources by promoting the portability of applications at the
source code level. This in turn is expected to reduce the cost of
maintaining & transferring information technology
application.

9. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
GNU is Not Unix!
• Conceived in 1983 to make cooperative development and use of software
possible without the constraints imposed by the usage of proprietary
software, the GNU project has developed a ‘free software’ system name
‘GNU’. GNU is upwardly compatible with Unix. The term free software
here stands for fact that users of the software have the freedom to 1)
copy and give it away 2) change the program in any manner the user
wishes, by having full access to the source code and 3) distribute an
improved version of the sources or programs.
• To use a computer system an user needs an operating system that can run
on it. Having free software for the operating system helps further the cause
of cooperative
• use of software. GNU achieved the initial goal of a free Unix like operating
system by the early 1990s except for the kernel. When Linux was
developed and combined with other parts of the operating system already
developed, a complete GNU operating system resulted.

10. Linux
Inception
• It is based on UNIX and eventually after
adding many features of GUI, Drivers etc,
Linus Torvalds developed the framework of the
OS that became LINUX in 1992. The LINUX
kernel was released on 17th September, 1991
• Market share for Desktop PC:The market
share of Linux is about 0.8%
GUI: Linux typically provides two GUIs, KDE
and Gnome. But Linux GUI is optional
• Threat detection and solution: In case of
Linux, threat detection and solution is very
fast, as Linux is mainly community driven and
whenever any Linux user post s any kind of
threat, several developers start working on it
from different parts of the world.
• Cost: Linux can be freely distributed,
downloaded freely, distributed through
magazines, Books etc. There are priced
versions for Linux also, but they are normally
cheaper than Windows
Unix
Inception:
• In 1969, it was developed by a group
of AT&T employees at Bell Labs and
Dennis Ritchie. It was written in “C”
language and was designed to be a
portable, multi-tasking and multi-user
system in a time-sharing
configuration.
• Market share for Desktop PC:Less
than 0.5 percent of the PC market.
•
GUI: Initially Unix was a command
based OS, but later a GUI, popularly
known as X Window was created for
UNIX
• Threat detection and solution: In
case of Unix, user has to wait for a
while, to get the proper bug fixing
patch
• Cost: Different flavors of Unix have
different cost structures

11. Comparison
Linux
• Security: Linux has had about 60-
100 viruses listed till date.
• What is it?: Linux is an example of
Open Source software
development and Free Operating
System (OS).
• Development and Distribution:
Linux is developed by Open Source
development i.e. through sharing
and collaboration of code and
features through forums etc and it
is distributed by various vendors
such as Debian, Red Hat, SUSE,
Ubuntu, GentuX etc.
Unix
• Security: A rough estimate of unix
viruses is between 85 -120 viruses
reported till date.
• What is it?: Unix is an operating
system that is very popular in
universities, companies, big
enterprises etc.
• Development and Distribution:
Unix systems are divided into
various other flavors, mostly
developed by AT&T as well as
various commercial vendors and
non-profit organizations

12. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Advantages of Linux:
• Cost – The most obvious advantage of using Linux is the fact that it is free to
obtain, while Microsoft products are available for a hefty and sometimes recurring
fee. Microsoft licenses typically are only allowed to be installed on a single
computer, whereas a Linux distribution can be installed on any number of
computers, without paying a single dime.
• Security – In line with the costs, the security aspect of Linux is much stronger than
that of Windows. Why should you have to spend extra money for virus protection
software? The Linux operating system has been around since the early nineties and
has managed to stay secure in the realm of widespread viruses, spyware and
adware for all these years. Sure, the argument of the Linux desktop not being as
widely used is a factor as to why there are no viruses. My rebuttle is that the Linux
operating system is open source and if there were a widespread Linux virus
released today, there would be hundreds of patches released tomorrow, either by
ordinary people that use the operating system or by the distribution maintainers.
We wouldn’t need to wait for a patch from a single company like we do with
Windows.

13. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
• Choice (Freedom) – The power of choice is a great Linux advantage. With Linux,
you have the power to control just about every aspect of the operating system.
Two major features you have control of are your desktops look and feel by way
of numerous Window Managers, and the kernel. In Windows, your either stuck
using the boring default desktop theme, or risking corruption or failure by
installing a third-party shell.
• Software - There are so many software choices when it comes to doing any
specific task. Regular users and programmers contribute applications all the
time. Sometimes its a simple modification or feature enhancement of a already
existing piece of software, sometimes its a brand new application. In addition,
software on Linux tends to be packed with more features and greater usability
than software on Windows. Best of all, the vast majority of Linux software is free
and open source. Not only are you getting the software for no charge, but you
have the option to modify the source code and add more features if you
understand the programming language.
• Hardware - Linux is perfect for those old computers with barely any processing
power or memory you have sitting in your garage or basement collecting dust.
Install Linux and use it as a firewall, a file server, or a backup server. There are
endless possibilities.
Contd..

14. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Disadvantages of Linux:
• Understanding – Becoming familiar with the Linux operating system requires
patience as well as a strong learning curve. You must have the desire to read and
figure things out on your own, rather than having everything done for you.
• Compatibility – Because of its free nature, Linux is sometimes behind the curve
when it comes to brand new hardware compatibility. Though the kernel
contributors and maintainers work hard at keeping the kernel up to date, Linux
does not have as much of a corporate backing as alternative operating systems.
Sometimes you can find third party applications, sometimes you can’t.
• Alternative Programs – Though Linux developers have done a great job at
creating alternatives to popular Windows applications, there are still some
applications that exist on Windows that have no equivalent Linux application.