What is Operating System<br />An Operating System (OS) is <br /> a set of programs that manages computer hardware resources, and provides common services for application software.<br />Operating systems are found on almost any device that contains a computer from <br />cellular phones and video game consoles <br />to supercomputers and web servers<br />
Examples of popular Operating Systems<br />DOS <br />UNIX<br />Windows<br />Android<br />GNU/ Linux<br />
What is Linux?<br />Common Definition<br />A Unix Operating System and Applications that run on multiple machines from PDAs to Mainframes<br />
What is Linux?<br />Technical Definition<br />Collection of programs distributed with the "Linux Kernel", and most often with several additional applications. Often programs and tools included are from GNU, BSD and many other contributors<br />
Linux Kernel<br />It's the core of Linux OS .<br />It acts as intermediary , between the computer hardware and various programs. <br />It contains the driver support for the PC hardware. <br />It contains advanced memory management features support for many different types of file systems. <br />Features :<br />Linux kernel is monolithic <br />Multilevel application support. <br />LINUX is a non-pre emptive kernel.<br />Multiprocessor support.<br />
The Linux kernel can be further divided into three gross levels. <br /><ul><li>At the top is the system call interface, which implements the basic functions such as read and write.
The Kernel code, which can be more accurately defined as the architecture-independent kernel code. This code is common to all of the processor architectures supported by Linux.
Architecture-dependent code serves as the processor and platform-specific code for the given architecture.</li></li></ul><li>Kernel Structure<br />
What is GNU?<br />The GNU Project was launched in 1984 to develop the GNU operating system, a complete Unix-like operating system which is free software—software which respects your freedom.<br />Unix-like operating systems are built from a software collection of applications, libraries, and developer tools—plus a program to allocate resources and talk to the hardware, known as a kernel.<br />GNU is often used with a kernel called Linux. The Hurd, GNU's kernel, is actively developed, but is still some way from being ready for daily use.<br />
GNU = Gnu’s Not Unix<br />Ensures 4 freedoms<br />0 Use for any purpose<br />1 Study and adapt(modify)<br />2 Distribute either free or gratis<br />3 Distribute the modified source<br />
GNU GPL<br />The GNU General Public License (GNU GPL or simply GPL) is the most widely used free software license, originally written by Richard Stallman for the GNU Project.<br />The GNU General Public License, was the first copyleft license to see extensive use, and continues to dominate the licensing of copylefted software. <br />
Open Source Software (OSS) <br />Open Source Software (OSS) generally refers to software for which the source code is available and which the licensing scheme permits the user to modify it and redistribute it in modified or unmodified form.<br />GNU copyleft1<br />Nobody should be restricted by the software they use. There are four freedoms that every user should have:<br />the freedom to use the software for any purpose, <br />the freedom to change the software to suit your needs, <br />the freedom to share the software with your friends and neighbors, and <br />the freedom to share the changes you make. <br />When a program offers users all of these freedoms, we call it free software.<br />FOSS can and has been commercialized by companies such as Red Hat, IBM, Novell, Oracle, Mozilla Foundation, VMware and others.<br />
TIMELINE<br /><ul><li> 1971 : First edition of UNIX comes out
1972 : Dennis Richie re-writes B and calls it C
12/2003 : 2.6.0</li></li></ul><li>Two types of Interfaces between a computer application and the user. <br />GUI (Graphical User Interface), where the user clicks on a visual screen that has icons, windows and menus, by using a pointing device, such as a mouse. GUI is pronounced like "gooey".<br />CLI (Command Line Interface), where the user types a text command and the computer responds accrording to that command.<br />
GUI (Graphical User Interface)<br />Four of the most popular desktops <br /><ul><li>GNOME
LXDE. </li></li></ul><li>KDE by default (this can be changed) favors blue and grey, has one toolbar at the bottom of the screen, and has one main menu.<br />
Gnome by default (this can also be changed) favors dark grey and purple, has two toolbars (one at the top, one at the bottom), and splits its menu into three submenus—Applications, Places, and System.<br />
Menu Navigation - KDE<br />In KDE, there is a KMenu through which you access all programs. By default in Kubuntu (Ubuntu's implementation of KDE), there is a quick-navigation button that looks like a folder.<br />If you want to go to your Documents folder, you would go to the quick navigation button and then select Documents. Then you would click Open to open it. <br />
Menu Navigation- Gnome<br />In Gnome in Ubuntu's default layout (though you can change it to a one-button format if you'd like), you have separate buttons for applications, for folder navigation, and for system preferences.<br />To go to your Home Folder or Documents folder, you click on Places and then select the location you want to go to.<br />
Renaming Files<br /> In newer versions of KDE, the renaming process focuses on only the main filename and leaves out the extension. The renaming happens in a pop-up window, which you can confirm or cancel when you're done.<br />
In Gnome, renaming a file also focuses on the main file name, but it does so inline and not with a pop-up window. <br />
Exiting<br />In KDE, if you want to exit, you click on the KMenu and select Leave and then the next option. I can't tell whether it's Kubuntu (Ubuntu's implementation of KDE) or all implementations of KDE 4, but after you decide to shutdown, you'll be asked if you want to close all the virtual terminals, too. <br />
In Gnome, the exit option recently moved from being in the System menu to being its own applet. You click it and the options come down.<br />
GNOME and KDE differences in terms of appearance and performance:<br />KDE is more dominant and prioritize so that the view from the KDE look more beautiful and flexible compared to GNOME. Plus KDE, we can freely edit the display according to what we want. Although, GNOME is also interesting in terms of appearance.<br />GNOME is more dominant and prioritize the performance of memory (RAM) than KDE. So, the performance of relatively faster than KDE.<br />If you do not believe you can install GUI GNOME (Ubuntu) and KDE (Kubuntu, Mandriva), and then you feel the difference.<br />
Why use GNOME? The following are a few reasons:<br /><ul><li>FREE. GNOME is the first project to provide a working environment based graphical completely to free software.
USER FRIENDLY. Every moment, GNOME always endeavored to keep it easy to use, even by beginners. GNOME
USABILITY PROJECT aims to increase the level of ease of use GNOME.
CUTTING EDGE. GNOME always use the latest technologies. Call it CORBA for network transparency, the use of XML, and everything is implemented using C language for speed and portability.
DEVELOPER FRIENDLY. Not just enough to ease of use, GNOME also comes with an intuitive programming environment.
INTERNATIONAL. The GNOME developers are spread widely throughout the world. You can also contribute. With the new GNOME I18N features, you can work with any type of popular language, complete with documentation.
ACCESSIBLE. For those who are not able to use standard features of GNOME, a project under the name of the GNOME Accessibility Project was developed to actively support the GNOME usage by anyone.</li></li></ul><li>A Linux distribution is a member of the family of Unix-like operating systems built on top of the Linux kernel. Such distributions (often called distros for short) are Operating systems including a large collection of software applications such as word processors, spreadsheets, media players, and database applications. <br />
Pros: Fixed release cycle and support period; novice-friendly; wealth of documentation, both official and user-contributed<br />Cons: Lacks compatibility with Debian; frequent major changes tend to drive some users away<br />Software package management: Advanced Package Tool (APT) using DEB packages<br />Available editions: Ubuntu, Kubuntu, Xubuntu, Lubuntu (desktop with LXDE), Edubuntu, Ubuntu Studio and Mythbuntu for 32-bit (i386) and 64-bit (x86_64) processors;<br />
<ul><li>Pros: Superb collection of "minty" tools developed in-house, hundreds of user-friendly enhancements, inclusion of multimedia codecs, open to users' suggestions
Cons: The alternative "community" editions don't always include the latest features, the project does not issue security advisories
Software package management: APT with mintInstall using DEB packages (compatible with Ubuntu repositories)
Available editions: A "main" edition (with GNOME), a variety of "secondary" editions (with KDE, Xfce and Fluxbox), Linux Mint "Debian" edition (rolling-release with GNOME or Xfce)</li></li></ul><li>Pros: Highly innovative; outstanding security features; large number of supported packages; strict adherence to the free software philosophy; availability of live CDs featuring many popular desktop environments<br />Cons: Fedora's priorities tend to lean towards enterprise features, rather than desktop usability; some bleeding edge features, such as early switch to KDE 4 and GNOME 3, occasionally alienate some desktop users<br />Software package management: YUM graphical and command line utility using RPM packages<br />Available editions: Fedora for 32-bit (i386) and 64-bit (x86_64) processors; Red Hat Enterprise Linux for i386, IA64, PowerPC, s390x and x86_64 architectures; also live CD editions with GNOME, KDE, LXDE or Xfce desktops<br />
Pros: Very stable; remarkable quality control; includes over 20,000 software packages; supports more processor architectures than any other Linux distribution<br />Cons: Conservative - due to its support for many processor architectures, newest technologies are not always included; slow release cycle ; discussions on developer mailing lists and blogs can be uncultured at times<br />Software package management: Advanced Package Tool (APT) using DEB packages<br />Available editions: Installation CD/DVD and live CD images for 11 processor architectures, including all 32-bit and 64-bit processors from Intel, AMD, Power and others<br />
Pros: Comprehensive and intuitive configuration tool; large repository of software packages, excellent web site infrastructure and printed documentation<br />Cons: Novell's patent deal with Microsoft in November 2006 seemingly legitimised Microsoft's intellectual property claims over Linux; its resource-heavy desktop setup and graphical utilities are sometimes seen as "bloated and slow"<br />Software package management: YaST graphical and command-line utility using RPM packages<br />Available editions: openSUSE for 32-bit (i386), 64-bit (x86_64) processors (also installable live CD edition); SUSE Linux Enterprise Desktop/Server for i586, IA64, PowerPC, s390, s390x and x86_64 architectures<br />
Pros: Excellent software management infrastructure; unparalleled customisation and tweaking options; superb online documentation<br />Cons: Occasional instability and risk of breakdown, infrequent install media releases<br />Software package management: "Pacman" using TAR.XZ packages<br />Available editions: Minimal installation CD and network installation CD images for 32-bit (i686) and 64-bit (x86_64) processors<br />
Pros: Out-of-the-box support for graphics drivers, browser plugins and media codecs; rolling-release update mechanism; up-to-date software<br />Cons: no out-of-the-box support for non-English languages; lacks release planning and security advisories, still no stable 64-bit edition in late 2011<br />Software package management: Advanced Package Tool (APT) using RPM packages<br />Available editions: KDE, KDE Full Monty, KDE Minime, LXDE, LXDE Mini, Openbox, Openbox Bonsai, Phinx, Phoenix for 32-bit (i586) processor architectures<br />
Pros: Extremely well-tested, stable and reliable; free to download and use; comes with 5-years of free security updates;<br />Cons: Lacks latest Linux technologies; occasionally the project fails to live up its promise to deliver timely security updates and new stable releases<br />Software package management: YUM graphical and command line utility using RPM packages<br />Available editions: Installation DVDs and installable live CDs (with GNOME) for i386 and x86_64 processors; older versions (3.x and 4.x) also available for Alpha, IA64 and IBM z-series (s390, s390x) processors.<br />
Pros: Beginner-friendly; excellent central configuration utility; very good out-of-the-box support for dozens of languages; installable live media<br />Cons: Lacks reputation and mindshare following its fork from Mandriva, some concern over the developers ability to maintain the distribution long-term on a volunteer basis<br />Software package management: URPMI with Rpmdrake (a graphical front-end for URPMI) using RPM packages<br />Available editions: installation DVDs for 32-bit (i586) and 64-bit (x86_64) processors; installable live CDs for 32-bit (i586) processors<br />
Pros: Considered highly stable, clean and largely bug-free, strong adherence to UNIX principles<br />Cons: Limited number of officially supported applications; conservative in terms of base package selection; complex upgrade procedure<br />Software package management: "pkgtool" using TXZ packages<br />Available editions: Installation CDs and DVD for 32-bit (i486) and 64-bit (x86_64) processors<br />
Pros: Fast and stable; availability of over 21,000 software applications (or "ports") for installation; very good documentation<br />Cons: Tends to lag behind Linux in terms of support for new and exotic hardware, limited availability of commercial applications; lacks graphical configuration tools<br />Software package management: A complete command-line package management infrastructure using either binary packages or source-based "ports" (TBZ)<br />Available editions: Installation CDs for AMD64, ARM/ARMEL, i386, IA64, MIPS/MIPSEL, PC98 PowerPC, SPARC64 and Xbox processors<br />
Other Distributions<br />The following distributions are available for free (without cost): aLinux, Alpine Linux, ALT Linux, Annvix, Arch Linux, Ark Linux, Asianux, BLAG Linux and GNU, Bodhi Linux, Caixa Mágica, CentOS,CRUX, Damn Small Linux, Debian, DeLi Linux, Devil-Linux, dyne:bolic, EasyPeasy, Edubuntu, Elive, EnGarde Secure Linux, Fedora, Finnix, Foresight Linux, Freespire, Frugalware, Gentoo,gNewSense, gnuLinEx, GoboLinux, Gobuntu, Impi Linux, Kanotix, Knoppix, KnoppMyth, Kubuntu, Kurumin, Linux Mint, Lunar Linux, Micro Core Linux, MintPPC, Musix GNU/Linux, Network Security Toolkit, NimbleX, NUbuntu, openSUSE, Pardus, Parsix, PCLinuxOS, Puppy Linux, Sabayon Linux, Scientific Linux, sidux, Slackware, Slax, SliTaz GNU/Linux, Source Mage GNU/Linux, Symphony OS, SYS, Tiny Core Linux, Tor-ramdisk, Trustix, Ubuntu, Ututo, Super OS, Xubuntu, XBMC Live, Yoper, Zenwalk and OpenWrt.<br />The following distributions have several editions, some of which are without cost and some of which do cost money: ClearOS, Mandriva Linux, MEPIS and Red Flag Linux.<br />The following distributions cost money: Novell Open Enterprise Server, Red Hat Enterprise Linux, Rxart, SUSE Linux Enterprise,<br />The following distribution had at least one version that used to cost money: Caixa Mágica (now freely-available), Elive (now freely-available), Xandros (discontinued), Linspire (discontinued)<br />