Red Hat Linux and the GPL

You will find out more about the origins of Linux later on in the course. For now, we will discuss how Red Hat came to be, and why the role of the Free Software Foundation, OSS (Open Source Software), and the GNU GPL are so important to the Linux community.

• Open Source Software: Open Source Software (OSS) means that the source code as well as the binary (the actual program you run) is accessible and distributed freely. Free software may cost money and may be covered under a public license, the most common of which is the GNU Public License (GPL). Open source describes practices in production and development that promote access to the end product's source materials. Some consider open source a philosophy, others consider it a pragmatic methodology. Before the term open source became widely adopted, developers and producers used a variety of phrases to describe the concept. Opening the source code enabled a self-enhancing diversity of production models, communication paths, and interactive communities. Subsequently, a new, three-word phrase "open source software" was born to describe the environment that the new copyright, licensing, domain, and consumer issues created.
  The license for Red Hat Linux is the GPL. If you want binaries from Red Hat, you will need to subscribe to their distribution service, Red Hat Network, also known as RHN. That said if you know someone who has Red Hat binaries, they can redistribute them to you for free. Red Hat simply chooses not to distribute binaries for no cost. This is permissible under the GPL. If you want a binary distro that you do not have to pay for, then as others have said above, try CentOS or Fedora. You can download the src at ftp.redhat.com e.g.:
  

  https://developers.redhat.com/products/rhel/download
  

As you may know, Linux was first introduced by Linus Torvalds in 1991 as a "free" operating system. Torvalds began development of the Linux kernel while he was a student at Helsinki University, and he continues to maintain it today. Red Hat Software distributes Torvalds' version of the Linux kernel.

• GNU General Public License: OSS can be freely seen, modified, and improved by anyone who uses it. Linux was created this way. So was the Internet a technology owned by no one, and to which everyone can contribute. Linux is considered free software, but it is not in the public domain. It adheres to the GNU General Public License (GPL), which says that it can be freely distributed or even sold, but it must always be accompanied by its source code as well as the GNU GPL.

Yes, the GNU General Public License (GPL) is still in existence and is widely used in the open-source software community. The GPL is a free software license that allows users to use, modify, and distribute software under certain conditions, such as requiring that any modified versions of the software be made available under the same license. The GPL was first introduced by Richard Stallman in 1989 as part of the GNU Project, which aimed to create a completely free and open-source operating system. Since then, it has been revised several times, with the current version being GPL version 3, which was released in 2007.
Many popular open-source software projects, such as the Linux kernel, the GNU Compiler Collection, and the GNOME desktop environment, are licensed under the GPL. The GPL has also influenced the development of other open-source licenses, such as the Mozilla Public License and the Affero General Public License. Overall, the GPL continues to be an important and widely used license in the open-source software community, and plays a key role in promoting the principles of free and open-source software.
The GNU ("GNU's Not UNIX") General Public License (GPL) was developed in the 1980s by Richard Stallman, an advocate of free software who eventually founded the Free Software Foundation (FSF). Stallman used the concept of "copyleft" to protect the freedom of GNU project software, effectively reversing the use of copyright law to ensure that source code was never closed off. This early effort to secure freedom in distributing and viewing the source code has led to the popular Open Source Software initiative.
The GNU General Public License is a free license for software and other kinds of works. The licenses for most software and other practical works take away your freedom to share and change the works. The GNU General Public License is intended to guarantee your freedom to share and change all versions of a program and to make sure it remains free software for all its users. The GNU General Public License applies also to any other work released this way by its authors.
You can apply it to your programs, too. The General Public Licenses are designed to make sure that you have the freedom to distribute copies of free software (and charge for them if you wish), that you receive source code or can get it if you want it, that you can change the software or use pieces of it in new free programs, and that you know you can do these things.
To protect your rights, we need to prevent others from denying you these rights or asking you to surrender the rights. Therefore, you have certain responsibilities if you distribute copies of the software, or if you modify it: responsibilities to respect the freedom of others. For example, if you distribute copies of such a program, whether gratis or for a fee, you must pass on to the recipients the same freedoms that you received. You must make sure that they, too, receive or can get the source code. And you must show them these terms so they know their rights.

Developers that use the GNU GPL protect your rights with two steps:

1. assert copyright on the software, and
2. offer you this License giving you legal permission to copy, distribute and/or modify it.

For the protection of developers and authors , the GPL clearly explains that there is no warranty for this free software. For the sake of both users and authors, the GPL requires that modified versions be marked as changed, so that their problems will not be attributed erroneously to authors of previous versions. Some devices are designed to deny users access to install or run modified versions of the software inside them, although the manufacturer can do so. This is fundamentally incompatible with the aim of protecting the freedom of users to change the software. The systematic pattern of such abuse occurs in the area of products for individuals to use, which is precisely where it is most unacceptable. Therefore, we have designed this version of the GPL to prohibit the practice for those products. If such problems arise substantially in other domains, we stand ready to extend this provision to those domains in future versions of the GPL, as needed to protect the freedom of users. Finally, every program is threatened constantly by software patents. States should not allow patents to restrict development and use of software on general-purpose computers, but in those that do, we wish to avoid the special danger that patents applied to a free program could make it effectively proprietary. To prevent this, the GPL assures that patents cannot be used to render the program non-free. The precise terms and conditions for copying, distribution and modification follow.

The concepts of free software that costs nothing and free software whose source code everyone can view are often confused. OSS is a more recent phenomenon than free software. As it is currently defined by the GNU GPL, "free" software does not mean it costs nothing. On the contrary, if you sell software covered by this license, you have to make the source code available to the buyer for free (or for the cost of the materials it is shipped on).

• How the GPL works: The GPL allows anyone to modify the source code covered by the license, and to distribute derived products as long as the original source is made available. OSS gives users the ability to modify the code to suit their own needs, which is not possible with proprietary software code.
  OSS is the reason behind the amazing speed at which Linux development occurs. OSS is extremely flexible. Depending on how it is used, there are zero licensing costs, it has fast bug fixes, and it is rich with feature enhancements.

Linux consists of a worldwide community of developers who have written drivers, features, and new functions all working under the GNU GPL. Since 1991, Linux has developed into a full-blown computing environment with a worldwide installed base of millions of users.
The purpose of this document is to help developers (and their managers) work with the development community with a minimum of frustration. It is an attempt to document how this community works in a way which is accessible to those who are not intimately familiar with Linux kernel development (or, indeed, free software development in general). While there is some technical material here, this is very much a process-oriented discussion which does not require a deep knowledge of kernel programming to understand.

As you begin writing modules for the Linux kernel, you become part of a larger community of developers. Within that community, you can find not only people engaged in similar work, but also a group of highly committed engineers working toward making Linux a better system. These people can be a source of help, ideas, and critical review as welthey will be the first people you will likely turn to when you are looking for testers for a new driver. The central gathering point for Linux kernel developers is the linux-kernel mailing list. All major kernel developers, from Linus Torvalds on down, subscribe to this list. Please note that the list is not for the faint of heart: traffic as of this writing can run up to 200 messages per day or more. Nonetheless, following this list is essential for those who are interested in kernel development; it also can be a top-quality resource for those in need of kernel development help.

Red Hat is the largest Open Source company in the world. It believes that the free discourse of ideas holds the greatest potential for business and human development. Red Hat introduced its comprehensive Package Based distribution of Linux and Linux resources in 1994. Since then, Red Hat Linux has grown to be the most popular and widely used Linux distribution. Red Hat Linux and the Apache Web server are especially popular with Internet Service Providers and for other network resources and roles.

The current Red Hat distribution includes installation and configuration software, the latest version of the Linux kernel, and common utilities and applications. The Red Hat distribution adds tremendous value to the base Linux components and offers good technical support. Also, because of the large install base of Red Hat Linux systems around the world, Red Hat acts as a standardizing force in the diverse Linux community. The Red Hat Linux package is available on CD-ROM, and comes with a free copy of the Red Hat Installation Guide. Although Red Hat distributes the same software free via FTP from mirror sites around the globe, the download is extremely time consuming, so most people elect to purchase the CD-ROM.

• Linux for the desktop: Recently, there has been a focus on making Linux more functional for non-technical users. This has been accomplished with desktop environment efforts for GNOME and KDE, two easy-to-configure graphical environments available in Linux. These projects make the Linux desktop more accessible, allowing someone who has little experience outside of the Microsoft Windows setting to be comfortable in the Linux environment.
  In the next lesson, the prerequisites will be discussed.