The Unix operating system was conceived and implemented in the 1960s and first released in 1970. Its wide availability and portability meant that it was widely adopted, copied and modified by academic institutions and businesses, with its design being influential on authors of other systems.

The GNU Project, started in 1984, had the goal of creating a "complete Unix-compatible software system"^[5] made entirely of free software. In 1985, Richard Stallman created the Free Software Foundation and developed the GNU General Public License (GNU GPL). Many of the programs required in an OS (such as libraries, compilers, text editors, a Unix shell, and a windowing system) were completed by the early 1990s, although low level elements such as device drivers, daemons, and the kernel were stalled and incomplete.^[6] Linus Torvalds has said that if the GNU kernel had been available at the time (1991), he would not have decided to write his own.^[7]

[edit] MINIX

MINIX, a Unix-like system intended for academic use, was released by Andrew S. Tanenbaum in 1987. While source code for the system was available, modification and redistribution were restricted (that is not the case today). In addition, MINIX's 16-bit design was not well adapted to the 32-bit design of the increasingly cheap and popular Intel 386 architecture for personal computers.

In 1991, Torvalds began to work on a non-commercial replacement for MINIX while he was attending the University of Helsinki.^[8] This eventually became the Linux kernel.

In 1992, Tanenbaum posted an article on Usenet claiming Linux was obsolete. In the article, he criticized the operating system as being monolithic in design and being tied closely to the x86 architecture and thus not portable, as he described "a fundamental error."^[9] Tanenbaum suggested that those who wanted a modern operating system should look into one based on the microkernel model. The posting solicited the response of Torvalds and Ken Thompson, one of the founders of Unix, which resulted in a well known debate over the microkernel and monolithic kernel designs.^[9]

Linux was dependent on the MINIX userspace at first. With code from the GNU system freely available, it was advantageous if this could be used with the fledgling OS. Code licensed under the GNU GPL can be used in other projects, so long as they also are released under the same or a compatible license. In order to make the Linux kernel compatible with the components from the GNU Project, Torvalds initiated a switch from his original license (which prohibited commercial redistribution) to the GNU GPL.^[10] Linux and GNU developers worked to integrate GNU components with Linux to make a fully functional and free operating system.^[6]

[edit] Commercial and popular uptake

Today Linux is used in numerous domains, from embedded systems^[11] to supercomputers,^[12] and has secured a place in server installations with the popular LAMP application stack.^[13] Torvalds continues to direct the development of the kernel. Stallman heads the Free Software Foundation, which in turn supports the GNU components. Finally, individuals and corporations develop third-party non-GNU components. These third-party components comprise a vast body of work and may include both kernel modules and user applications and libraries. Linux vendors and communities combine and distribute the kernel, GNU components, and non-GNU components, with additional package management software in the form of Linux distributions.

[edit] Design

Linux is a modular Unix-like operating system. It derives much of its basic design from principles established in Unix during the 1970s and 1980s. Linux uses a monolithic kernel, the Linux kernel, which handles process control, networking, and peripheral and file system access. Device drivers are integrated directly with the kernel.

Much of Linux's higher-level functionality is provided by separate projects which interface with the kernel. The GNU userland is an important part of most Linux systems, providing the shell and Unix tools which carry out many basic operating system tasks. On top these tools form a Linux system with a graphical user interface that can be used, usually running in the X Window System.

[edit] User interface

See also: User interface

Linux can be controlled by one or more of a text-based command line interface (CLI), graphical user interface (GUI) (usually the default for desktop), through controls on the device itself (common on embedded machines).

On desktop machines, KDE, GNOME and Xfce are the most popular user interfaces,^[14] though a variety of other user interfaces exist. Most popular user interfaces run on top of the X Window System (X), which provides network transparency, enabling a graphical application running on one machine to be displayed and controlled from another.

Other GUIs include X window managers such as FVWM, Enlightenment and Window Maker. The window manager provides a means to control the placement and appearance of individual application windows, and interacts with the X window system.

A Linux system usually provides a CLI of some sort through a shell, which is the traditional way of interacting with a Unix system. A Linux distribution specialized for servers may use the CLI as its only interface. A “headless system” run without even a monitor can be controlled by the command line via a protocol such as SSH or telnet.

Most low-level Linux components, including the GNU Userland, use the CLI exclusively. The CLI is particularly suited for automation of repetitive or delayed tasks, and provides very simple inter-process communication. A graphical terminal emulator program is often used to access the CLI from a Linux desktop.

[edit] Development

Main article: Linux distribution

The primary difference between Linux and many other popular contemporary operating systems is that the Linux kernel and other components are free and open source software. Linux is not the only such operating system, although it is the best-known and most widely used. Some free and open source software licences are based on the principle of copyleft, a kind of reciprocity: any work derived from a copyleft piece of software must also be copyleft itself. The most common free software license, the GNU GPL, is used for the Linux kernel and many of the components from the GNU project.

As an operating system underdog competing with mainstream operating systems, Linux cannot rely on a monopoly advantage; in order for Linux to be convenient for users, Linux aims for interoperability with other operating systems and established computing standards. Linux systems adhere to POSIX,^[15] SUS,^[16] ISO, and ANSI standards where possible, although to date only one Linux distribution has been POSIX.1 certified, Linux-FT.^[17]

Free software projects, although developed in a collaborative fashion, are often produced independently of each other. However, given that the software licenses explicitly permit redistribution, this provides a basis for larger scale projects that collect the software produced by stand-alone projects and make it available all at once in the form of a Linux distribution.

A Linux distribution, commonly called a “distro”, is a project that manages a remote collection of Linux-based software, and facilitates installation of a Linux operating system. Distributions are maintained by individuals, loose-knit teams, volunteer organizations, and commercial entities. They include system software and application software in the form of packages, and distribution-specific software for initial system installation and configuration as well as later package upgrades and installs. A distribution is responsible for the default configuration of installed Linux systems, system security, and more generally integration of the different software packages into a coherent whole.

[edit] Community

Linux is largely driven by its developer and user communities. Some vendors develop and fund their distributions on a volunteer basis, Debian being a well-known example. Others maintain a community version of their commercial distributions, as Red Hat does with Fedora.

In many cities and regions, local associations known as Linux Users Groups (LUGs) seek to promote Linux and by extension free software. They hold meetings and provide free demonstrations, training, technical support, and operating system installation to new users. There are also many Internet communities that seek to provide support to Linux users and developers. Most distributions and open source projects have IRC chatrooms or newsgroups. Online forums are another means for support, with notable examples being LinuxQuestions.org and the Gentoo forums. Linux distributions host mailing lists; commonly there will be a specific topic such as usage or development for a given list.

There are several technology websites with a Linux focus. Linux Weekly News is a weekly digest of Linux-related news; the Linux Journal is an online magazine of Linux articles published monthly; Slashdot is a technology-related news website with many stories on Linux and open source software; Groklaw has written in depth about Linux-related legal proceedings and there are many articles relevant to the Linux kernel and its relationship with GNU on the GNU project's website. Print magazines on Linux often include cover disks including software or even complete Linux distributions.^[18][19]

Although Linux is generally available free of charge, several large corporations have established business models that involve selling, supporting, and contributing to Linux and free software. These include Dell, IBM, HP, Sun Microsystems, Novell, and Red Hat. The free software licenses on which Linux is based explicitly accommodate and encourage commercialization; the relationship between Linux as a whole and individual vendors may be seen as symbiotic. One common business model of commercial suppliers is charging for support, especially for business users. A number of companies also offer a specialized business version of their distribution, which adds proprietary support packages and tools to administer higher numbers of installations or to simplify administrative tasks. Another business model is to give away the software in order to sell hardware.

Desktop

Main article: Desktop Linux

Although in specialized application domains such as desktop publishing and professional audio there may be a lack of high quality software, users migrating from Mac OS X and Windows can find equivalent applications for most tasks.^[23]

Many free software titles that are popular on Windows are also available, such as Pidgin, Mozilla Firefox, Openoffice.org, and GIMP, amongst others. A growing amount of proprietary desktop software is also supported under Linux,^[24] examples being Adobe Flash Player, Acrobat Reader, Matlab, Nero Burning ROM, Opera, RealPlayer, and Skype. In the field of animation and visual effects, most high end software, such as AutoDesk Maya, Softimage XSI and Apple Shake are available both for Linux, Windows and/or MacOS X. Additionally, CrossOver is a proprietary solution based on the open source Wine project that supports running older, superseded Windows versions of Microsoft Office and Adobe Photoshop. (Microsoft Office 2007 and Adobe Photoshop CS are known not to work,^[25][26] while Adobe Photoshop CS2 and CS3 are untested and unsupported.^[27][28])

Linux's open nature offers the ability for distributed teams to localize Linux distributions for use in locales where doing so to proprietary systems would not be cost-effective. For example, the Sinhalese language version of the Knoppix distribution was available for a long time before the initiation of translation of Microsoft Windows XP to Sinhalese. In this case, The Lanka Linux User Group played a major part in developing the localized system by combining the knowledge of university professors, linguists and local developers.

See also: Linux gaming

[edit] Servers and supercomputers

Historically, Linux has mainly been used as a server operating system, and has risen to prominence in that area; Netcraft reported in September 2006 that eight of the ten most reliable internet hosting companies run Linux on their web servers.^[29] This is due to its relative stability and long uptime, and the fact that desktop software with a graphical user interface is often unneeded. Enterprise and non-enterprise Linux distributions may be found running on servers. Linux is the cornerstone of the LAMP server-software combination (Linux, Apache, MySQL, Perl/PHP/Python) which has achieved popularity among developers, and which is one of the more common platforms for website hosting.

Linux is commonly used as an operating system for supercomputers. As of November 2007, out of the top 500 systems, 426 (85.2%) run Linux.^[30]

[edit] Embedded devices

Main article: embedded Linux

Due to its low cost and ability to be easily modified, an embedded Linux is often used in embedded systems. Linux has become a major competitor to the proprietary Symbian OS found in many mobile phones — 16.7% of smartphones sold worldwide during 2006 were using Linux^[31] — and it is an alternative to the dominant Windows CE and Palm OS operating systems on handheld devices. The popular TiVo digital video recorder uses a customized version of Linux.^[32] Several network firewall and router standalone products, including several from Linksys, use Linux internally, using its advanced firewall and routing capabilities. The Korg OASYS and the Yamaha Motif XS music workstations also run Linux.^[33]

[edit] Market share and uptake

Main article: Linux adoption

Many quantitative studies of open source software focus on topics including market share and reliability, with numerous studies specifically examining Linux.^[34] The Linux market is growing rapidly, and the revenue of servers, desktops, and packaged software running Linux is expected to exceed $35.7 billion by 2008.^[35]

IDC's report for Q1 2007 says that Linux now holds 12.7% of the overall server market.^[36] This estimate was based on the number of Linux servers sold by various companies.

About Ubuntu

Ubuntu is a community developed, linux-based operating system that is perfect for laptops, desktops and servers. It contains all the applications you need - a web browser, presentation, document and spreadsheet software, instant messaging and much more.

Learn more about Ubuntu »

Desktop Edition Learn more »

Server Edition Learn more »

The Ubuntu Promise

• Ubuntu will always be free of charge, including enterprise releases and security updates.
• Ubuntu comes with full commercial support from Canonical and hundreds of companies around the world.
• Ubuntu includes the very best translations and accessibility infrastructure that the free software community has to offer.
• Ubuntu CDs contain only free software applications; we encourage you to use free and open source software, improve it and pass it on.

Read more about the Ubuntu philosophy

Check out the "HELP" Section

Click Here

To list your item simply click on the “Sell” link found on the header navigational bar. The listing process is split up into several main sections, notably:-

• Category selection
• Item Details
• Auction Settings
• Shipping and Payment
• Listing preview
• Listing confirmation

The listing process is developed in such a way that you are guided through every step seamlessly.

The first part of the process is to choose the category you wish to list your item in, this can be revised at any time by using the “Previous Step” navigation button.

Step two enables you to enter your item title and description, a full wysiwyg editor is in place to enable you to use HTML descriptions.

If you have a voucher code to redeem this can be entered just below the description field.

Moving on to step three, this is the biggest stage of the listing process. On this step you can set the following:-

· Auction type:-

Standard Auction

This is a single quantity auction

Dutch Auction

Dutch auction enables you to list a multiple quantity auction, for example if you have 100 pens to sell you can list all of these together in a single lot. Bidders will be able to select how many they wish to bid for.

· Currency:-

You can select your preferred auction currency using the drop down menu available

· Quantity:-

This field is only active if listing a Dutch auction, please see above for an explanation of this listing type

· Auction Starts At:-

This requires you to enter the minimum bid you are willing to accept, you can also set a reserve price to ensure you do not sell the item for this amount. Please see below for more information on this.

· Reserve Price:-

Enabling a reserve price affectively means you will not sell the item for less than the amount set, for example you can set the start price at 5.00 but only accept winning bids over 50.00, should a bid be placed for 49.99 the item will close without a winner.

· Buy out (if available):-

Buy out allows you to set an amount you are willing to sell the item for – straight out. For example you can set the start price to 10.00 but offer interested parties the option to buy the item immediately for 100.00.

You can also list buy out only auctions, these auctions remove all bidding options meaning the listing can only be purchased for a set amount. To set a buy out only auction you need to set the buy out value to be exactly equal with the start bid.

· Offer-Range (if available):-

You can set a price bracket in which you are willing to listing to offer, for example if you set the price brackets from 15.00 to 100.00 interested parties will be able to offer you an amount within these brackets, you can opt whether to accept or decline these offers at any time via the members area.

· Bid increment:-

This option can be used to set your own custom bid increment if preferred.

· Item featuring (if available):-

The following options are available to you (fees may apply), these will highlight your item on site to ensure they reach more visitors:-

§ Home page featured

§ Category featured

§ Bold text

§ Highlighted background

· Set start/end time:-

You can either opt to list your item right away and set a defined number of days for it to be live for or you also have the option to define your own custom start/end time.

· Private Auction:-

Private auction will hide the bidders identity on the item details page

· Image upload:-

To accompany your item you can either upload images from your local computer or enter the URL of an image(s) hosted elsewhere

· Media upload:-

In addition to images you can also upload media files, please note only .avi/.mpeg/.mov are supported.

· Auto Re-List

For convenience you can opt to have your items automatically re-listed for you, options are available to allow you to select whether the item should be re-listed if sold and how many re-list attempts should be made.

On the next step you can set your shipping and payment preferences including your shipping rates and available methods of delivery.

Proceeding on, you can then review the listing and make changes if required, please note you can still edit your listing once live via the members area.

The final step provides you with listing confirmation.

The auction watch features notifies you of newly listed auctions which contain keywords you have chosen. For example if you are looking for a new Digital Camera you could enter in those keywords from within your members area area. Each time a new auction is listed containing those keywords you will be notified via email.

The item watch features lets you keep a close eye on any auction without having to place a bid on it. This feature means you can be kept up to date on how an auction is doing and prepares you to place a winning last minute bid. You can watch any auction by clicking on the “Watch this item” link on any auction page.

If the option is available you can use “Buy Out” to purchase the item immediately without having to place a bid. Some sellers offer such an option which can be used at any time until a bid has been placed over any applicable reserve price.

The “Buy Out” option will appear on the item details page, you will be asked to confirm your intention to buy out the item before the sale is concluded. Buy out’s cannot be retracted.

To create your account choose the “Register” link on the header navigational bar or use any of the links available on the home page.

When registering you will be asked to complete a short form which includes standard information such as your contact details, preferred login credentials etc.

Mandatory fields include:-

· Name

· City

· State/Province/county

· Zip/Post Code

· Phone Number

· Birthday

· Username & Password

· E-Mail address

· Confirmation of terms an conditions acceptance

Once registered you will receive E-Mail confirmation.

Should you encounter any registration difficulties please contact us.

Placing a bid on an item you are interested in couldn’t be easier, when viewing the item details page you will have two areas from where you can place your bid, one next to the item details and a second at the bottom of the page.

To place your bid simply enter the amount you wish to bid e.g. 50.00. Please note no currency symbols are required. The bid will be placed in the auction currency.

Once done you will be asked to review your bid and you will also be able to view vital item details such as the shipping conditions before confirming your bid. To submit your bid simply press the “Place Bid” button.

If your bid is high enough to take the lead in the auction a confirmation message will be displayed to you, however if your bid has not taken the lead be it due to a higher proxy bid or not meeting the reserve price you will be invited to make a further bid.

Should you decide to retract your bid this can be done via the “Current Bids” section of the member’s area.

You can also place a proxy bid, proxy bidding allows you to place your “High Bid”. At all times you will only pay the lowest required bid should you win the auction. For example, if the current bid on an auction is 500.00 you can place a proxy bid of 2,000. Should you remain the only bidder you will only pay 500.00. However should the item receive other bids the site will automatically re-bid for you (upto 2,000 in this scenario) to ensure you remain in the lead.