Introduction and Features of Linux

Introduction to Linux

 Introduction to Linux

The History of Linux

 Linus Torvalds, a student at the University of Helsinki Finland, introduced Linux in 1991. Towards work on the Linux project and wrote the source code of Linux kernel. Linux is a free operating system. Awards made Linux available on the internet. Many programmers added to the code, change it, and built it support for all kinds of hardware. He released the system to a community of “hackers” on the internet and asked them to work with it, fix it and enhance it. In fact, today there are thousands of software developers around the world who have worked on it will stop the source code for the software is freely available, anyone can work on it. Developers are encouraged to feed their fixes and improvements back into the community so that planets can continue to grow and improve.

Linux is like a clone of Unix and has been written from scratch by Linus Torvalds. Torvalds, mainly used Minix, a miniature version of Unix as a teaching aid in Universities and colleges. He was very much impressed with the feature of the Unix operating system. He wanted to create his own version of the Unix operating system and distribute it free for use to everybody. There is a vast amount of software that can be used with Linux, all of which include features that can compete with or surpass doze off any other operating system in the world.

Linux is very similar to Unix. Unique started off as a single-user operating system. In 1969, Ken Thompson, by taking ideas and help from Dennis Ritchie and others, wrote a small, general-purpose operating system for small machines. In 1973, Thompson and Ritchie rewrote the Unix operating system in C in ways of writing an operating system in assembly language. In 1974, Unix was licensed to universities for educational purposes and later on, was made commercially available.

Torvalds has made the source code of the Linux kernel available for study and charges over the internet. This means that the current development version of Linux is always open to everybody. Torvalds also accepts modification to the kernel code. In order to maintain stability, Torvalds exercised strict quality control and must all the new code into the kernel. The internet has played a major role in the development of the Linux operating systems. Today, many companies provide support for Linux over the internet.

Features of Linux

Linux has lots of interesting features. Some important features are as follows :

• Linux is a multi-user operating system. Here, more than one user can connect to the system and work concurrently at any point in time. Each user can have more than one program running simultaneously. Users can also have their own environments arranged, the way they want, their own directory for storing files, and their own desktop interface with icons, menus, and applications arranged to suit them.

• Linux supports multiprogramming, which allows many programs to executed simultaneously by different users. Multiprogramming is made possible on the Linux system by the concept of time-sharing. The operating system has to manage the different programs to be executed.

• A program in Linux is broken into tasks, each task being something like reading from or writing to the disk or waiting for input from a user. The operating system which has the ability to handle the exclusion of multiple tasks is known as multi-tasking.

• Linux is Posix-compliant and supports most of the standard sets for UNIX systems.

• Linux is a powerful framework for working with graphical applications and it's referred to as the x-windows system.

• Linux has a program called DOSEMV. It creates a DOS emulator that can execute many DOS applications. DOSEMV users image files of a hard disc to emulate a dost hard disc so that you need not have a DOS partition.

• Linux comes with the Apache Web Server that service web pages full stop it is the most popular web server in use today.

• Linux also comes with a lot of other useful and free software such as text editors, Browsers, and scientific applications.

• Linux can be installed in several machine profiles without the need to configure the software.

• No virus can attack Linux since common users don't have access to the system’s main Kernel.

!!!!   Thanks for reading. !!!!

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Introduction of C

-: Introduction of  C :-

C - LANGUAGE :-

• Introduction in C
• What is c language?
• Features of C
• Operators in C
• Variables in C
• Constants of C
• Expressions in C
• Conditional Statement
• Jumping

1.    If
2.    If-Else
3.    Nested If
4.    Nested If-Else

• Branching
• Looping

1.    Do
2.    Do While
3.    For

• Nested Loop
• Array
• String
• Pointer

-: What is C Language ? :-

          C is a programming language developed at AT and T's Bell Laboratories of USA in 1972. It was developed and written by a man named Dennis Ritchie  . In the late seventies C began to to replace the more familiar languages of that time like PL/|,ALGOL,etc.No one pushed C.It wasn't made 'official' Bell Labs language.Thus,without any advertisement,C's reputation spread and its pool of users grew.

          Why C seems so popular is because it is reliable ,simple and easy to use.Moreover in industry where newer languages,tools and technologies emerge and vanish day in and day out,a language that has survived for more than three decades has to be really good.

          There are several reasons to why we should learn C Programming language, all are given below :-

1. I believe that nobody can learn C++ or java directly .This is because while learning these languages you have things like classes,objects,inheritance,polymorphism,templates,exception handling etc. do deal with apart from knowing the actual language elements.Learning these complecated concepts when you are not comfortable with the basic language elements is like putting the cart before the horse.Hence one should learn all the language thoroughly using C language before migrating to C++,Java,.Net.Though this two steps learning process may take more time ,but at the end of it you will definetely find it worth the trouble.

2. Major parts of popular operating systems like Windows,UNIX,Linux are still written in C.This is because even today when it comes to perfomance(speed of execution) nothing beats C.Device Driver programmes are also written in C.

3. Mobile devices like cellular phones and palmtops have become rage of today.Also,common consumer devices like microwaves ovens,washing machines and digital cameras are getting smarter by the day .This smartness comes from a microprocessor,an operating system and a program embedded in these devices.These programs not only have to run fast and also have to work in limited amount of memory.No wonder that such programs are written in C.When memory and speed of execution comes C always preceded by all languages.

4. You must have seen several professional 3D computer games where the user navigates some objects,like say a spaceshipe and fires bulletes at the invaders. The essence of all such games is speed.Needless to say,such games would not become popular if they takes a long time to move the spaceship or to a fire a bullet.To match the expectations of player game has to react fast to the user inputs.This is where C scores over other languages.Many popular gaming frameworkshave been built using C language.

5. At times one is required very closely interact with hardware devices.Since C provides several language elements that make this interaction feasible without compromising the perfomance it is the preferred choice of the programmer.

-: C-LEARNING :-

An inventory has been made with a number of partners to find out how a training program with today's possibilities better matches the wishes of entrepreneurs and trainers. We see a tendency in which entrepreneurs are reluctant to invest in the traditional way of training (someone in front of the class), partly because of the difficult to estimate effect of this type of education. In addition, there are all kinds of additional costs: location rent, lunch, continued payment of wages, not to mention the high costs associated with coaching processes and training itself.

We have been looking for a more practical training form with lower costs. Of course you will quickly arrive at an 'internet-like' application such as eLearning. However, we find this form of education too one-sided and not in line with the wishes of the target group. The interaction between teacher, professional and employee is crucial in a coaching process and eLearning does not sufficiently meet this need.

C-Learning is the new innovative way of coaching and training your employees. With our internet application you can make video, audio or photo fragments and have them assessed by professionals. The professionals provide feedback on the fragments based on predefined criteria and draw up advice. The employees then make a second fragment, which is again assessed by the professionals and placed next to the first fragment.

The self-assessment, assessment of the manager and assessment of the professional form the basis for the continuation of the training and are stored as a reference work. In this way, it can always be added later as a basis for later assessments.

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