Linux Environment- Linux vs Unix

TRINITY INSTITUTE OF PROFESSIONAL STUDIESSector – 9, Dwarka Institutional Area, New

Delhi-75Affiliated Institution of G.G.S.IP.U, Delhi

BCALinux Environment

BCA306

Linux vs UnixKeywords: Linux, Unix, features

TRINITY INSTITUTE OF PROFESSIONAL STUDIESSector – 9, Dwarka Institutional Area, New Delhi-75

LINUX VS UNIX

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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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• 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.

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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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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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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


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.


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.

LinuxInception• 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

UnixInception:• 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

ComparisonLinux• 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


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.


• 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.

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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.

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Linux Environment- Linux vs Unix