The document provides an overview of the organization NIIT. It states that NIIT is a global talent development corporation that offers learning solutions in areas such as IT, banking, finance, outsourcing, and communication skills. It has trained over 35 million learners since inception. NIIT introduced India's first cloud campus to provide online training programs in fields such as IT, banking, and management to make students industry-ready. It partners with colleges and universities to deliver in-campus training through its NIIT Careers@Campus program.

1. ACKNOWLEDGEMENT
I have taken efforts in this training. However, it would not have been possible without the
kind support and help of many individuals and organizations. I would like to extend my
sincere thanks to all of them.
I am highly indebted to Technology Uncorked staff for their guidance and constant
supervision as well as for providing necessary information regarding the topics & also for
their support in completing the training.
I would like to express my gratitude towards my parents & member of NIIT for their kind co-operation
and encouragement which help me in completion of this project.
I would like to express my special gratitude and thanks to industry persons for giving me such
attention and time.
My thanks and appreciations also go to my colleague in completing the training and people
who have willingly helped me out with their abilities.
Mithlesh kumar
11111223
7th Semester 4th year

2. PREFACE
What is Linux?
Linux or, less frequently used, is a Unix-like and mostly POSIX-compliant computer
operating system assembled under the model of free and open-source software development
and distribution. The defining component of Linux is the Linux kernel, an operating system
kernel first released on 5 October 1991 by Linus Torvalds.
Linux was originally developed as a free operating system for Intel x86-based personal
computers. It has since been ported to more computer hardware platforms than any other
operating system. It is a leading operating system on servers and other big iron systems such
as mainframe computers and supercomputers. As of June 2013, more than 95% of the
world's 500 fastest supercomputers run some variant of Linux, including all the 44
fastest. Linux also runs on embedded systems, which are devices whose operating system is
typically built into the firmware and is highly tailored to the system; this includes mobile
phones, tablet computers, network routers, facility automation controls, televisions and video
game consoles. Android, which is a widely used operating system for mobile devices, is built
on top of the Linux kernel.
The development of Linux is one of the most prominent examples of free and open-source
software collaboration. The underlying source code may be used, modified, and distributed—
commercially or non-commercially—by anyone under licenses such as the GNU General
Public License. Typically, Linux is packaged in a format known as a Linux distribution for
desktop and server use. Some popular mainstream Linux distributions
include Debian, Ubuntu, Linux Mint, Fedora, opensUSE, Arch Linux, and the
commercial Red Hat Enterprise Linux and SUSE Linux Enterprise Server. Linux distributions
include the Linux kernel, supporting utilities and libraries and usually a large amount of
application software to fulfill the distribution's intended use.
A distribution oriented toward desktop use will typically include X11, Wayland or Mir as
the windowing system, and an accompanying desktop environment such as GNOME or
the KDE Software Compilation. Some such distributions may include a less resource
intensive desktop such as LXDE or Xfce, for use on older or less powerful computers. A
distribution intended to run as a server may omit all graphical environments from the standard
install, and instead include other software to set up and operate a solution stack such
as LAMP. Because Linux is freely redistributable, anyone may create a distribution for any
intended use.

3. What is “C”?
“C” is a general-purpose programming language initially developed by Dennis
Ritchie between 1969 and 1973 at AT&T Bell Labs. Like most imperative languages in
the ALGOL tradition, C has facilities for structured programming and allows lexical variable
scope and recursion, while a static type system prevents many unintended operations. Its
design provides constructs that map efficiently to typical machine instructions, and therefore
it has found lasting use in applications that had formerly been coded in assembly language,
most notably system software like the Unix computer operating system.
C is one of the most widely used programming languages of all time, and C compilers are
available for the majority of available computer architectures and operating systems.
Many later languages have borrowed directly or indirectly from C,
including D, Go, Rust, Java, JavaScript, Limbo, LPC, C#,ObjectiveC, Perl, PHP, Python, Ver
ilog (hardware description language), and UNIX’s C shell. These languages have drawn many
of their control structures and other basic features from C. Most of them (with Python being
the most dramatic exception) are also very syntactically similar to C in general, and they tend
to combine the recognizable expression and statement syntax of C with underlying type
systems, data models, and semantics that can be radically different. C++ and Objective-C
started as compilers that generated C code; C++ is currently nearly a superset of
C, while Objective-C is a strict superset of C.
Before there was an official standard for C, many users and implementers relied on an
informal specification contained in a book by Dennis Ritchie and Brian Kernighan; that
version is generally referred to as "K&R" C. In 1989 the American National Standards
Institute published a standard for C (generally called "ANSI C" or "C89"). The next year, the
same specification was approved by the International Organization for Standardization as an
international standard (generally called "C90"). ISO later released an extension to
the internationalization support of the standard in 1995, and a revised standard (known as
"C99") in 1999. The current version of the standard (now known as "C11") was approved in
December 2011.
What is Embedded C?
Embedded C is a set of language extensions for the C Programming language by the C
Standards committee to address commonality issues that exist between C extensions for
different embedded systems. Historically, embedded C programming requires nonstandard
extensions to the C language in order to support exotic features such as fixed-point arithmetic,
multiple distinct memory banks, and basic I/O operations.

4. In 2008, the C Standards Committee extended the C language to address these issues by
providing a common standard for all implementations to adhere to. It includes a number of
features not available in normal C, such as, fixed-point arithmetic, named address spaces, and
basic I/O hardware addressing.
Embedded C uses most of the syntax and semantics of standard C, e.g., main() function,
variable definition, data type declaration, conditional statements (if, switch, case), loops
(while, for), functions, arrays and strings, structures and union, bit operations, macros, etc.
A Technical Report was published in 2004] and a second revision in 2006.
Difference between C and Embedded C
Though C and embedded C appear different and are used in different contexts, they have
more similarities than the differences. Most of the constructs are same; the difference lies in
their applications.
 C is used for desktop computers, while embedded C is for microcontroller based
applications.
 C takes more resources of a desktop PC like memory, OS, etc. while programming on
desktop systems what embedded C cannot. Embedded C has to use the limited resources
(RAM, ROM, I/O) on an embedded processor. Thus, program code must fit into the
available program memory. If code exceeds the limit, the system is likely to crash.
 Compilers for C (ANSI C) typically generate OS dependent executable files. Embedded
C requires compilers to create files to be downloaded to the
microcontrollers/microprocessors where it needs to run. Embedded compilers give access
to all resources which is not provided in compilers for desktop computer applications.
 Embedded systems often have the real-time constraints, which is usually not there with
desktop computer applications.
 Embedded systems often do not have a console, which is available in case of desktop
applications.

5. INTRODUCTION OF THE ORGANIZATION
NIIT is a leading Global Talent Development Corporation, building skilled manpower pool
for global industry requirements. The company which was set up in 1981, to help the nascent
IT industry overcome its human resource challenges, has today grown to be amongst world’s
leading talent development companies offering learning solutions to Individuals, Enterprises
and Institutions across 40 countries. Leading IT journal Dataquest has conferred upon NIIT
the ‘Top IT Training Company’ award successively for the past 20 years, since the inception
of this category.
NIIT’s training solutions in IT, Banking, Finance and Insurance, Knowledge Process
Outsourcing (KPO), Business Process Management (BPM), Executive Management
Education, Vocational Skills, School Learning Solutions and Communication and
Professional Life Skills has impacted over 35 million learners since inception. NIIT’s
expertise in learning content development, training delivery and education process
management make it the most preferred training partner, worldwide.
NIIT has introduced “India's first Cloud Campus” , through its new-age GNIIT program. NIIT
offers training programs in IT, Banking, Global Finance, Management, Digital & Social
Media Marketing, through its NIIT Cloud Campus with innovative learning features, to make
students first day-first hour industry ready professionals. Cloud Campus offers students
higher mobility as they can access their courseware using Netbooks and connect seamlessly to
NIIT’s Cloud Campus network. NIIT Careers@Campus, the company’s Institutional
Alliances Business for colleges and Universities, delivers in-campus training through
Synchronous Learning Technology.
NIIT Careers@Campus Advantage:
 Enhanced employability through results driven training
 Cost-effective learning inside campus
 Opportunity to learn from expert trainers
 Placement services upon graduation
 Online Assessments and Certification
 Benefits from tech alliances partners
 Web services for student engagement

6. LIST OF TABLES
 Linux vs. Windows 3 - 6
 Linux Commands 12 - 17
 Numerical Permissions 18 – 19
 Symbolic Modes 19 – 20
 Symbolic Examples 21 – 22
 System Call 23
 C Library Functions 48
LIST OF FIGURES
 OS Layers 6
 Need of Network 58
 Linear bus topology 61
 Star topology 62
 Tree topology 63

7. CONTENTS
Chapter – 1
Linux
 Operating System 1 - 3
 Linux vs. Windows 3 - 6
 OS Layers 7 - 9
 Linux Commands 10 - 17
 File Permissions – “chmod” 17 - 23
 Shell Scripting 23 - 27
 Process Management 27 - 28
Chapter – 2
C Language
 Compilation and Execution 29 - 30
 Data Types 30 - 39
 Constants and Variables 39 – 42
 Arrays in C 42 - 46
Chapter – 3
Embedded C
 Functions 47 - 48
 Unions 48 - 51
 Structures 51 - 54
 C Preprocessor 54 - 58
 Microcontroller 58 - 59
 Embedded Design 59 – 61
Chapter – 4
Communication And Network Concepts

8.  Network 58-59
 Switching Techniques 59-60
 Transmission media 60-61
 Different topologies 61-64
Conclusion 62
Bibliography 63