Operating Systems

About
An operating system (OS) is a collection of software that manages computer hardware resources and provides common services for computer programs. The operating system is a vital component of the system software in a computer system. Application programs usually require an operating system to function.

Time-sharing operating systems schedule tasks for efficient use of the system and may also include accounting for cost allocation of processor time, mass storage, printing, and other resources.

For hardware functions such as input and output and memory allocation, the operating system acts as an intermediary between programs and the computer hardware, although the application code is usually executed directly by the hardware and will frequently make a system call to an OS function or be interrupted by it. Operating systems can be found on almost any device that contains a computer—from cellular phones and video game consoles to supercomputers and web servers.

Examples of popular modern operating systems include Android, BSD, iOS, Linux, Mac OS X, Microsoft Windows, Windows Phone, and IBM z/OS. All these, except Windows and z/OS, share roots in Unix.

Proprietary
Proprietary software or closed source software is computer software licensed under exclusive legal right of the copyright holder with the intent that the licensee is given the right to use the software only under certain conditions, and restricted from other uses, such as modification, sharing, studying, redistribution, or reverse engineering.

Microsoft
Microsoft Windows is a family of proprietary operating systems designed by Microsoft Corporation and primarily targeted to Intel architecture based computers, with an estimated 88.9 percent total usage share on Web connected computers. The newest version is Windows 8 for workstations and Windows Server 2012 for servers. Windows 7 recently overtook Windows XP as most used OS.

Microsoft Windows originated in 1985 as an operating environment running on top of MS-DOS, which was the standard operating system shipped on most Intel architecture personal computers at the time. In 1995, Windows 95 was released which only used MS-DOS as a bootstrap. For backwards compatibility, Win9x could run real-mode MS-DOS and 16 bits Windows 3.x[20] drivers. Windows ME, released in 2000, was the last version in the Win9x family. Later versions have all been based on the Windows NT kernel. Current versions of Windows run on IA-32 and x86-64 microprocessors, although Windows 8 will support ARM architecture. In the past, Windows NT supported non-Intel architectures.

OS List

 * Windows 1.0 (Windows 1 - Based on Visi On)
 * Windows 2.0 (Windows 2)
 * Windows 3.0 (Windows 3 - Is the first version of Windows to make substantial commercial impact)
 * Windows 3.1x (Windows 3.1)
 * Windows for Workgroups 3.11
 * Windows 95 (Codename Chicago - Windows 4.0)
 * Windows 98 (Codename Memphis - Windows 4.1)
 * Windows Millennium Edition (Windows Me - Windows 4.9)
 * Windows XP (Windows NT 5.1)
 * Windows Server 2003 (Windows NT 5.2)
 * Windows Fundamentals for Legacy PCs (based on Windows XP)
 * Windows Vista (Windows NT 6.0)
 * Windows Azure (based on Windows Vista) 2009
 * Windows Home Server (based on Windows Server 2003)
 * Windows Server 2008 (based on Windows Vista)
 * Windows 7 (Windows NT 6.1)
 * Windows Server 2008 R2 (based on Windows 7)
 * Windows Home Server 2011 (based on Windows Server 2008 R2)
 * Windows Server 2012 (based on Windows 8)
 * Windows 8 (Windows NT 6.2)

Server editions of Windows are widely used. In recent years, Microsoft has expended significant capital in an effort to promote the use of Windows as a server operating system. However, Windows' usage on servers is not as widespread as on personal computers, as Windows competes against Linux and BSD for server market share.

Open Source
Open-source software is software whose source code is published and made available to the public, enabling anyone to copy, modify and redistribute the source code without paying royalties or fees.

Debian
Debian (pron.: /ˈdɛbiən/) is a computer operating system composed of software packages released as free and open source software primarily under the GNU General Public License along with other free software licenses. Debian GNU/Linux, which includes GNU tools and the Linux kernel, is a popular and influential Linux distribution. It is distributed with access to repositories containing thousands of software packages ready for installation and use.

Debian is known for relatively strict adherence to the philosophies of free software as well as using collaborative software development and testing processes. Debian can be used on a variety of hardware, from laptops and desktops to NAS devices, phones, and servers. It focuses on stability and security and is used as a base for many other distributions.

Fedora
Fedora (pron.: /fɨˈdɒr.ə/), formerly Fedora Core, is an RPM-based, general purpose collection of software, including an operating system based on the Linux kernel, developed by the community-supported Fedora Project and owned by Red Hat. The Fedora Project's mission is to lead the advancement of free and open source software and content as a collaborative community.

One of Fedora's main objectives is not only to contain software distributed under a free and open source license, but also to be on the leading edge of such technologies. Fedora developers prefer to make upstream changes instead of applying fixes specifically for Fedora—this ensures that their updates are available to all Linux distributions.

A version of Fedora has a relatively short life cycle—the maintenance period is only 13 months: there are 6 months between releases, and version X is supported only until 1 month after version X+2. This promotes leading-edge software because it frees developers from some backward compatibility restraints, but it also makes Fedora a poor choice for product development (e.g., embedded systems), which usually requires long-term vendor-support, unavailable with any version of Fedora.

In 2008, Linus Torvalds, author of the Linux kernel, stated that he used Fedora because it had fairly good support for the PowerPC processor architecture, which he had favoured at the time.

According to DistroWatch, Fedora is the fourth most visited Linux-based operating system on their site as of January 2013, behind Mint, Mageia and Ubuntu, and it is the second most visited RPM-based Linux distribution.

Linux
Linux (or GNU/Linux) is a Unix-like operating system that was developed without any actual Unix code, unlike BSD and its variants. Linux can be used on a wide range of devices from supercomputers to wristwatches. The Linux kernel is released under an open source license, so anyone can read and modify its code. It has been modified to run on a large variety of electronics. Although estimates suggest that Linux is used on 1.82% of all personal computers, it has been widely adopted for use in servers and embedded systems (such as cell phones). Linux has superseded Unix in most places, and is used on the 10 most powerful supercomputers in the world.The Linux kernel is used in some popular distributions, such as Red Hat, Debian, Ubuntu, Linux Mint and Google's Android.

The GNU project is a mass collaboration of programmers who seek to create a completely free and open operating system that was similar to Unix but with completely original code. It was started in 1983 by Richard Stallman, and is responsible for many of the parts of most Linux variants. Thousands of pieces of software for virtually every operating system are licensed under the GNU General Public License. Meanwhile, the Linux kernel began as a side project of Linus Torvalds, a university student from Finland. In 1991, Torvalds began work on it, and posted information about his project on a newsgroup for computer students and programmers. He received a wave of support and volunteers who ended up creating a full-fledged kernel. Programmers from GNU took notice, and members of both projects worked to integrate the finished GNU parts with the Linux kernel in order to create a full-fledged operating system.

Linux Mint
Linux Mint is a computer operating system based on the Linux distribution Ubuntu. Linux Mint adds many features that Ubuntu does not have such as providing a more complete out-of-the-box experience by including proprietary software including Java and the Adobe Flash web browser plugin, which are not installed by default in most Linux distributions. Due to issues with licensing, proprietary drivers for hardware such as wireless cards are not included by default, though they can be downloaded for free after installation.[citation needed]

Linux Mint introduced its first release, named "Ada", in 2006. Its latest and 14th release is "Nadia". The names of the releases are in alphabetical order (1 is Ada, 2 is Barbara, 3 is Cassandra, etc.)

Lubuntu
Lubuntu (pronounced /luːˈbuːntuː/ "loo-BOON-too") is a lightweight Linux operating system based on Ubuntu but using the LXDE desktop environment in place of Ubuntu's Unity shell and GNOME desktop. LXDE is touted as being "lighter, less resource hungry and more energy-efficient".

Lubuntu received official recognition as a formal member of the Ubuntu family on 11 May 2011, commencing with Lubuntu 11.10, which was released on 13 October 2011.

Like Xubuntu, Lubuntu is intended to be a low-system-requirement, low-RAM environment for netbooks, mobile devices and older PCs. Tests show it can use half as much RAM as Xubuntu, making it an attractive choice for installing on older hardware being refurbished for charitable distribution.

The name Lubuntu is a portmanteau of LXDE and Ubuntu. LXDE stands for Lightweight X11 Desktop Environment, while the word Ubuntu means "humanity towards others" in the Zulu and Xhosa languages.

Red Hat
Red Hat Linux, assembled by the company Red Hat, was a popular Linux based operating system until its discontinuation in 2004.

Red Hat Linux 1.0 was released on November 3, 1994. It was originally called "Red Hat Commercial Linux" It was the first Linux distribution to use the RPM Package Manager as its packaging format, and over time has served as the starting point for several other distributions, such as Mandriva Linux and Yellow Dog Linux.

Since 2003, Red Hat has discontinued the Red Hat Linux line in favor of Red Hat Enterprise Linux (RHEL) for enterprise environments. Fedora, developed by the community-supported Fedora Project and sponsored by Red Hat, is the free version best suited for home use. Red Hat Linux 9, the final release, hit its official end-of-life on 2004-04-30, although updates were published for it through 2006 by the Fedora Legacy project until that shut down in early 2007

Ubuntu
Ubuntu (/ʊˈbʊntuː/ uu-buun-too) is a computer operating system based on the Debian Linux distribution and distributed as free and open source software, using its own desktop environment. It is named after the Southern African philosophy of ubuntu ("humanity towards others") or another translation would be: "the belief in a universal bond of sharing that connects all humanity".

As of 2012, according to online surveys, Ubuntu is the most popular Linux distribution on desktop/laptop personal computers, and most Ubuntu coverage focuses on its use in that market. However, it is also popular on servers and for cloud computing.[citation needed]

Development of Ubuntu is led by Canonical, Ltd., a UK-based company owned by South African entrepreneur Mark Shuttleworth. Canonical generates revenue through the sale of technical support and services related to Ubuntu, and since version 12.10, by displaying advertisements in Unity Dash, the default file manager in desktop Ubuntu. According to Canonical, the Ubuntu project is committed to the principles of free software development; people are encouraged to use free software, improve it, and distribute it.

Unix
Unix was originally written in assembly language. Ken Thompson wrote B, mainly based on BCPL, based on his experience in the MULTICS project. B was replaced by C, and Unix, rewritten in C, developed into a large, complex family of inter-related operating systems which have been influential in every modern operating system (see History).

The UNIX-like family is a diverse group of operating systems, with several major sub-categories including System V, BSD, and Linux. The name "UNIX" is a trademark of The Open Group which licenses it for use with any operating system that has been shown to conform to their definitions. "UNIX-like" is commonly used to refer to the large set of operating systems which resemble the original UNIX.

Unix-like systems run on a wide variety of computer architectures. They are used heavily for servers in business, as well as workstations in academic and engineering environments. Free UNIX variants, such as Linux and BSD, are popular in these areas.

Four operating systems are certified by the The Open Group (holder of the Unix trademark) as Unix. HP's HP-UX and IBM's AIX are both descendants of the original System V Unix and are designed to run only on their respective vendor's hardware. In contrast, Sun Microsystems's Solaris Operating System can run on multiple types of hardware, including x86 and Sparc servers, and PCs. Apple's OS X, a replacement for Apple's earlier (non-Unix) Mac OS, is a hybrid kernel-based BSD variant derived from NeXTSTEP, Mach, and FreeBSD.

Unix interoperability was sought by establishing the POSIX standard. The POSIX standard can be applied to any operating system, although it was originally created for various Unix variants.

Links

 * List of Linux distributions
 * Chris Haney Screenshot Directory - Screenshots of many Linux distributions.
 * Operating-System.org - Lists all known Linux distributions at a glance.
 * The LWN.net Linux Distribution List - Categorized list with information about each entry.
 * Distrowatch - Announcements, information, links and popularity ranking for many Linux distributions.
 * A catalog of operating systems
 * Harold Kaplow Remembrances
 * Large list of operating systems
 * How to configure Windows Server 2008
 * Free .iso