...Running head: Linux Systems Exploring Linux Operating Systems Student College Exploring Linux Operating Systems Much like Windows OS and the OS X for the Mac, Linux is an operating system that was created by Linus Torvalds in 1991. Linux is traditionally a command line system as opposed to the GUI that many home computer users are more accustomed to. Linux uses a prompt where various commands and arguments are used to navigate the system and directories. One cannot point and click an icon in order to execute a program, in Linux the command line is like typing out the directions for your computer so it knows exactly where to look. Linux is being utilized in many different applications from business databases, cell phones, and even the New York stock exchange. Linux, however, is hardly considered a “personal computer” OS because of its limitations in personal computing. Although a Linux GUI desktop does exist, the command line interface is considered an advanced program and not for the faint of heart. Linux however holds many advantages in database software, server maintenance, code development and computer programming. The Linux “language” is close to coding language and the kernel is more secure than, say, the Windows Kernel. This advantage is encouraging to businesses and anyone else looking to keep or store sensitive data. Linux is a solid OS to use when handling such information when confidentiality is key. Like the other OS there are different means for file editing...
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...NOS 120 Linux/UNIX Single User Compiling Linux Software from Source Code Objectives After reading this chapter and completing the exercises, you will be able to: * Understand basic elements of C programming * Debug C programs * Create, compile, and test C programs Text Reference: Chapter 10 – Developing UNIX/Linux Applications in C and C++ Programming Overview A computer program is a list of instructions given to a computer to make it perform a specific task or series of tasks. A programmer communicates these instructions to the computer in a language the computer understands. Computers, however, can only operate using binary code (1’s and 0’s), which makes a computer’s language very difficult for humans to understand. The solution to this problem is to create an intermediate language that both humans and computers can understand. These are called programming languages. Programmers create a list of instructions for the computer in a programming language such as C, C++, or Java. The C Programming Language The C programming language was released in 1973. C was created by Brian Kernighan, Dennis Ritchie and Ken Thompson working at Bell Labs. Both the UNIX and Linux operating systems are written in C. The C programming language is a high-level language because the code itself is written in relatively English-like statements. In 1978, Kernighan and Ritchie wrote "The C Programming Language," still one of the best C programming books available...
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...Having access to the source code is probably the single most significant difference between Linux and Windows. The fact that Linux belongs to the GNU Public License ensures that users (of all sorts) can access (and alter) the code to the very kernel that serves as the foundation of the Linux operating system. You want to peer at the Windows code? Good luck. Unless you are a member of a very select (and elite, to many) group, you will never lay eyes on code making up the Windows operating system. You can look at this from both sides of the fence. Some say giving the public access to the code opens the operating system (and the software that runs on top of it) to malicious developers who will take advantage of any weakness they find. Others say that having full access to the code helps bring about faster improvements and bug fixes to keep those malicious developers from being able to bring the system down. I have, on occasion, dipped into the code of one Linux application or another, and when all was said and done, was happy with the results. Could I have done that with a closed-source Windows application? No. #2: Licensing freedom vs. licensing restrictions Along with access comes the difference between the licenses. I’m sure that every IT professional could go on and on about licensing of PC software. But let’s just look at the key aspect of the licenses (without getting into legalese). With a Linux GPL-licensed operating system, you are free to modify that software and...
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...Chapter 1 Introduction to Linux At a Glance Class Notes Table of Contents • Overview • Objectives • Teaching Tips • Quick Quizzes • Class Discussion Topics • Additional Projects • Additional Resources • Key Terms • Technical Notes for Hands-On Projects Lecture Notes Overview Linux technical expertise is essential in today’s computer workplace as more and more companies switch to Linux to meet their computing needs. Thus, it is important to understand how Linux can be used, what benefits Linux offers to a company, and how Linux has developed and continues to develop. In the first half of this chapter, you will learn about operating system terminology and features of the Linux operating system, as well as the history and development of Linux. Later in this chapter, you will learn about the various types of Linux and situations in which Linux is used. Chapter Objectives In this chapter, you will learn to: • Understand the purpose of an operating system • Outline the key features of the Linux operating system • Describe the origins of the Linux operating system • Identify the characteristics of various Linux distributions and where to find them • Explain the common uses of Linux in industry today Quick Quiz 1 1. What term is used to describe a running program on Linux? a. Application b. Process c. Runtime d. Project 2. What is represented...
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...Why is Linux popular? Why is it popular in academia? Because of it portability and it is free as Free Expression easy to manipulate and transport. Because of its portability and easy to manipulate. 3. What are multiuser systems? Why are they successful? Multi-user are the several individual user that can access one system that being physical machine or VM. They are popular because it help to centralize resources and energies and minimize security concerns. 4. What is the Free Software Foundation/GNU? What is Linux? Which parts of the Linux operating system did each provide? Who else has helped build and refine this operating system? The Free Software Foundation (www.fsf.org) is the principal organizational sponsor of the GNU Project. GNU developed many of the tools, including the C compiler, that are part of the NU/Linux Operating System. Linux is the name of an operating system kernel developed by Linus Torvalds and expanded and improved by thousands of people on the Internet. Torvalds’s kernel and GNU’s tools work Together as the GNU/Linux Operating System. 5. In which language is Linux written? What does the language have to do with the success of Linux? Linux was written in C language. C can be used to write machine-independent programs. A programmer who designs a program to be portable can easily move it to any computer that has a C compiler. 6. What is a utility program? A utility (program), sometimes referred to as a command, is a...
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...Extract the Linux-3.6.9 to location /usr/src/ or extract it on the Desktop and by typing the command on Terminal cd Desktop mv linux-3.6.9 /usr/src/ Create a NewFolder In /usr/src/Linux-3.6.9/ #include <linux/linkage.h> //for linking a system call #include <linux/kernel.h> //for the printk asmlinkage long sys_myservice (int arg1) { printk(KERN_EMERG “My Service is Running”); return 1; } Create a Makefile and add following code in it in Newfolder. #####Makefile Start##### obj-y += myservice.o #####Makefile End####### In /usr/src/linux-3.6.9/include/asm-generic/unistd.h, define an index for system call. #define __NR_myservice 273 Increment the system call count in same file of step 8. #define NR_syscalls 274 as pointed by an arrow in the previous screenshot. /usr/src/linux-3.6.9/arch/x86/syscalls/syscall_64.tbl, define a pointer to hold a reference to your system call routine. In /usr/src/linux-3.6.9/include/linux/syscalls.h contain the declarations for system calls. Add the following line at the end of the file: asmlinkage long sys_myservice (int arg1); Add directory path of the NewFolder to the Makefile (/usr/src/Linux-3.6.9/Makefile) core-y += kernel/ mm/ fs/ ipc/ security/ crypto/ block/ NewFolder/ Now on Terminal type these commands to be have root access to compile the privileged commands. Compile Kernel cd usr/src/linux-3.6.9 * Enter (make oldconfig) * Start compiling...
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...applications. Memory is one of the most essential components of any computer system. No matter which operating system is being used, whether it is Windows, Linux or Mac’s OS X, the same basic requirements of memory management exist. The main requirements of memory management are protection, sharing, relocation and organization. Memory protection is necessary because it stops unauthorized programs, which may contain harmful threats, from accessing the computer’s memory. Memory sharing is when multiple programs need to access the same portion of memory. Proper management of memory ensures that this happens without hindering the performance of the system. Relocation involves moving programs between virtual memory and physical memory 2. Compare two common operating systems—Windows 8 and Fedora 20—on the difference in the memory management features. * Full access vs. No access * Linux Fedora 20: Linux has the most significant access to the source code, allowing the users to alter the code that serves as the foundation of the Linux operating system. * Windows 8: Windows 8 allows no users to the code, which is a good idea once you think about it, as some people has used that access to take advantage to make bugs and viruses. * Licensing freedom vs. licensing restrictions * Linux Fedora 20: With a Linux GPL-licensed operating system, you are free to modify that software and use and even republish or sell it. Also, with the GPL, you can...
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...Narayan Patel 11008945 K2R21 (05) Q1: List various Commands used to perform following operations a) Make your Home Directory your current directory. b) To display who is logged in your system. c) To change password for the current user. d) To move the directory /usr/local to /opt/pgms. e) To list various files and directories in current working directory. Ans:- a) Make your Home Directory your current directory. Use the 'cd' command without any target; that always puts you in the home directory which becomes by default the working directory. b) To display who is logged in your system. who command is used to get the list of the usernames who are currently logged in. Output of the who command contains the following columns: user name, tty number, date and time, machine address. $ who ramesh pts/0 2009-03-28 22:57 (dev-db-server) jason pts/1 2009-03-28 23:01 (dev-db-server) john pts/2 2009-03-28 23:04 (dev-db-server) To get a list of all usernames that are currently logged in, use the following: $ who | cut -d' ' -f1 | sort | uniq john jason ramesh c) To change password for the current user. Almost all Linux and Unix and variants have access to the passwd command. Enter this command at the prompt to change your password. You'll need to know the current password before being able to change the password to a new...
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...Narayan Patel 11008945 K2R21 (05) Q1: List various Commands used to perform following operations a) Make your Home Directory your current directory. b) To display who is logged in your system. c) To change password for the current user. d) To move the directory /usr/local to /opt/pgms. e) To list various files and directories in current working directory. Ans:- a) Make your Home Directory your current directory. Use the 'cd' command without any target; that always puts you in the home directory which becomes by default the working directory. b) To display who is logged in your system. who command is used to get the list of the usernames who are currently logged in. Output of the who command contains the following columns: user name, tty number, date and time, machine address. $ who ramesh pts/0 2009-03-28 22:57 (dev-db-server) jason pts/1 2009-03-28 23:01 (dev-db-server) john pts/2 2009-03-28 23:04 (dev-db-server) To get a list of all usernames that are currently logged in, use the following: $ who | cut -d' ' -f1 | sort | uniq john jason ramesh c) To change password for the current user. Almost all Linux and Unix and variants have access to the passwd command. Enter this command at the prompt to change your password. You'll need to know the current password before being able to change the password to a new...
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...UNIX • Originally developed at AT&T Bell Labs – Late 1960s and early 1970s – Distributed in source code form • Two standard versions evolved: – AT&T Bell Labs produced SystemV (SysV) – UC Berkeley developed BSD • Linux might be considered a more integrated version of UNIX than its predecessors • POSIX: effort of experts from industry, academia, and government to standardize UNIX 15 5 UNIX Concepts 16 Linux and UNIX • Linux is a UNIX-like operating system – Not written from the traditional UNIX code – Kernel created to look and act like UNIX • Enhancements include the POSIX standards • Linus Torvalds released it free of charge in 1991 – Many distributions are available: • • • • • Debian GNU/Linux Fedora Red Hat Enterprise Linux openSUSE Linux Ubuntu 17 Introducing UNIX/Linux Shells • Shell: program that interprets commands you enter from keyboard – Bourne shell, developed by S. Bourne (AT&T Bell Labs), was the first UNIX command processor – Another Bell employee developed the Korn shell • History feature – C shell is designed for C programmers’ use – Linux uses Bash shell as its default shell • Graphical user interface (GUI) desktop can open a terminal window 18 6 Introducing UNIX/Linux Shells (continued) 19 Choosing your Shell • Shells do much more than interpret commands – Extensive built-in commands turn shells into firstclass programming languages • A default shell is associated with your account ...
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...LINUX PROGRAMMING FINAL NOTES UNIT 1ST THESE NOTES ARE AS PER SYLLABUS & WILL HELP YOU TO ACHIEVE SUCCESS IN FINAL EXAM OF MCA 5TH SEMESTER. LETS START: UNIT 1ST Linux – The Operating System: Linux is one of popular version of UNIX operating System. It is open source as its source code is freely available. It is free to use. Linux was designed considering UNIX compatibility. It's functionality list is quite similar to that of UNIX. Linux is a free distributed implementation of a Unix-like Kernel Developed by Linus Torvalds at the University of Helsinki with the help of programmers across the Internet. Linux history: * Linux features: Following are some of the important features of Linux Operating System. * Portable - Portability means softwares can works on different types of hardwares in same way.Linux kernel and application programs supports their installation on any kind of hardware platform. * Open Source - Linux source code is freely available and it is community based development project. Multiple teams works in collaboration to enhance the capability of Linux operating system and it is continuously evolving. * Multi-User - Linux is a multiuser system means multiple users can access system resources like memory/ ram/ application programs at same time. * Multiprogramming - Linux is a multiprogramming system means multiple applications can run...
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...Exploring Linux Operating Systems Linux is a computer operating system that was created and released by Linux Torvalds in October 1991. Linux was designed and released as a free, open source piece of software. This means that the code that makes up the program is freely available for anyone to copy, study, and modify the code in any way. This design was chosen to encourage the public to voluntarily improve the design and add functionality to the base software. This open source design is anecdotally considered to be a good thing, but has some drawbacks due to splintering, and lack of version control. Due to some of the splintering there are dozens of versions of Linux, most with similar functionality, while there are others that are designed for specific user types and use cases. Each “version” is called a Distribution. There are dozens, if not hundreds of these “distro’s” floating about. One of the most popular distro’s for the entry level user is Canonical’s Ubuntu Linux. This is a Debian based system with a rather simple user interface, and comes standard with a GUI and a host of tools that would make the system useable, and sufficient for most average users. On the other side of the spectrum there are targeted distro’s like KALI whose audience is more on the professional side. This particular distro is pre-loaded with tools that only a professional or an enthusiast would find useful at all. With such a wide range of options, there should be something for everyone...
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...Linux Features of Red Hat Red hat has many different features, I will cover a few of the main features in this section, and Red Hat contains more than 1,200 components covering a broad range of functionality. Red Hat Enterprise Linux provides CIOs and IT managers with the means to reduce costs while improving operational flexibility throughout their computing infrastructure. The following list provides a brief summary of the more important features: * Virtualization is provided in all Red Hat Enterprise Linux server products and is optionally available for desktop products. * Storage and extended server virtualization are provided with Red Hat Enterprise Linux Advanced Platform. * Red Hat Network supports virtualized guest operating systems * Virtual-manager, other management tools are available for single system or scripted virtualization management. * Integration with Red Hat Enterprise Virtualization is available for enterprise virtualization management. Networking & interoperability * Network storage enhancements include Autofs, FS-Cache, and iSCSI support * IPv6 support and conformance enhancements * Improved Microsoft® file/print and Active Directory integration, including support for Windows Security Features * SE Linux enhancements include Multi-Level Security and targeted policies for all services * SE troubleshooter GUI simplifies SE Linux management * Integrated directory and security capabilities * IPSEC enhancements...
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...Linux is one of popular version of UNIX operating System. It is open source as its source code is freely available. It is free to use. Linux was designed considering UNIX compatibility. It's functionality list is quite similar to that of UNIX. Components of Linux System Linux Operating System has primarily three components Kernel - Kernel is the core part of Linux. It is responsible for all major activities of this operating system. It is consists of various modules and it interacts directly with the underlying hardware. Kernel provides the required abstraction to hide low level hardware details to system or application programs. System Library - System libraries are special functions or programs using which application programs or system utilities accesses Kernel's features. These libraries implements most of the functionalities of the operating system and do not requires kernel module's code access rights. System Utility - System Utility programs are responsible to do specialized, individual level tasks. Linux Operating System Kernel Mode vs User Mode Kernel component code executes in a special privileged mode called kernel mode with full access to all resources of the computer. This code represents a single process, executes in single address space and do not require any context switch and hence is very efficient and fast. Kernel runs each processes and provides system services to processes, provides protected access to hardwares to processes. Support code...
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...as booting. A cold boot is when you turn on a computer that has been turned off completely. A warm boot is the process of using the operating system to restart the computer. Performs basic computer tasks The operating system performs basic computer tasks, such as managing the various peripheral devices such as the mouse, keyboard and printers. For example, most operating systems now are plug and play which means a device such as a printer will automatically be detected and configured without any user intervention. Provides a user interface A user interacts with software through the user interface. The two main types of user interfaces are: command line and a graphical user interface (GUI). With a command line interface, the user interacts with the operating system by typing commands to perform specific tasks. An example of a command line interface is DOS (disk operating system). With a graphical user interface, the user interacts with the operating system by using a mouse to access windows, icons, and menus. An example of a graphical user interface is Windows Vista or Windows 7. The operating system is responsible for providing a consistent application program interface (API) which is important as it allows a software developer to write an application on...
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