GPL and What You Need to Know

Open Source. General Public License. Linux.

Maybe you’ve read about them, or maybe know somebody running something with these in the title. But maybe you haven’t actually taken any more time to understand the origins of Open Source.

You’ve heard the buzz and know that it’s transforming the IT landscape and making inroads around the globe. But maybe you need some background on what Free and Open Source Software (FOSS) is really about. And what should you know about open source licenses, such as the General Public License?

In this edition of In Focus, you’ll get a brief overview of the origins of open source, some related topics to know about, and how to start making sense of the GPL .

1. An Overview of FOSS

The roots of the modern Free and Open Source movement are somewhat
debatable, and their provenance is lengthy. So we’ll go with an executive
summary instead. The BSD (Berkeley Software Distribution) project and its
later derivatives are perhaps the first
examples of a Free or Open Source operating system, tracing their genesis to
1977.

In and around 1984, Richard Stallman (usually referred to by his initials
RMS) founded the GNU project (GNU’s not Unix) as an effort to create a
free alternative to Unix , the widely used operating system
for workstations that once belonged to AT&T. As part of his effort to create
a free version of Unix, Stallman created the GNU General Public License in
1989.

By 1991, we were up to version 2. Essentially, the GPL
enshrines and defines the nature of free software and is usually held up as
the standard against which all other licenses are measured. (But we’ll have more on that
later.)

Free software has nothing to do with price; it’s about software freedom.
The quote “Free as in Freedom not Beer” is oft-repeated in the free software
community. Free software is a philosophy and a movement that pre-dates the
term “open source” by almost 14 years.

Open Source

The term open source was coined in 1998, partially in response to a
community-driven initiative led by Bruce Perens and Eric Raymond after
Netscape released the source code for its browser (which is the roots of the
Mozilla browser and project ). The Netscape source code was released
under what was to become known as the Mozilla Public License. Perens and
Raymond were looking to make “free software” as defined by the Free Software Foundation (FSF) and its
GPL more palatable to commercial interests. The Open Source Initiative
(OSI) currently lists over 50 licenses that are considered by it to be “OSI
approved.”

External links to philosophy of free software and FSF:

Open Source Definition
OSI Approved Licenses
Free Software Foundation
Richard Stallman: Why Software Should Be Free
The GNU Project

Free vs. Open Source

There are numerous differences between “free” and “open source” software.
For the free software community, a free software-compatible application is one
that offers a license that is either the GPL or is compatible with the GPL.
For the open source community, open source is software that is compatible with the open source
definition.

But in a more philosophical sense, there is a much deeper division between the
two groups.

“The fundamental difference between the two movements is in their values,
their ways of looking at the world,” Richard Stallman wrote in his paper
“Free vs. Open Source Software.”

“For the open source movement, the issue of
whether software should be open source is a practical question, not an
ethical one. As one person put it, ‘Open source is a development methodology; free
software is a social movement.’

“For the open source movement, non-free
software is a suboptimal solution. For the free software movement, non-free
software is a social problem and free software is the solution.”

The Linux Kernel

One of the things that the GNU project was missing was a kernel. A
kernel is the core of an operating system and contains much of the root
functions, such as virtual memory, multitasking, shared libraries, demand
loading, shared copy-on-write executables and TCP/IP networking.

In 1991, Linus Torvalds wrote and first published the Linux kernel. It has been
licensed under the GPL since its 0.12 release while Torvalds holds the copyright to
the Linux name. The Linux kernel is the core of the Linux operating systems and is currently at
version 2.6, though many popular distributions are running version 2.4.

One issue that has been raised in relation to the interaction of the 2.6
kernel with the 2.4 kernel is the practice of
“backporting” features of 2.6 into 2.4. Torvalds
supports the practice, saying
“it makes sense from a company standpoint to basically ‘cherry-pick’ stuff from the development
version that they feel is important to their customers.”

Linux Kernel Issues

The origins of Linux and whether any copyrighted code was taken from Unix is
one of the issues at the root of the SCO vs. Linux controversy. (See our Special Report on the SCO/Linux controversy.)
. In response, the community , third parties Linux distributions and companies like HP have all moved to indemnify their users
against any potential liability that may be involved.

2. What you need to know about Linux and the GPL

We asked OSDL’s Open Source Architecture Specialist Bill Weinberg for a quick summary of what enterprise
users need to know about Linux and the GPL. Here are some of the highlights:

  • The Linux kernel, GNU software and other FOSS components that comprise
    the Linux operating system represent the work of thousands of developers
    over the last decade. Despite the size of that community, the origin of
    code in Linux is tightly controlled and well-documented. And unlike
    proprietary software content (with its often-obscure
    origins) any user, corporation or individual can confirm the pedigree,
    quality and safety of any part of Linux at any time.
  • There is no “one right way” to deploy Linux. Companies around the
    world leverage Linux with a mixture of open and proprietary
    software stacks, building on COTS and custom components that meet their
    application needs.
  • Using Linux is IP-safe. Running your applications on Linux and
    storing and distributing your corporate data over Linux in no way
    impacts the status of your IP or your company’s claims to it.
  • Using Linux is secure. The fact that Linux source code is open
    doesn’t make it any less safe from crackers, viruses or other digital
    malfeasance. The developers of Linux do not believe in security through
    obscurity, but rather that community oversight and community-based exploit
    discovery and repair result in a vastly more secure computing environment.
  • You and your company can participate in Linux development and in the
    open source community at any level you desire. You can contribute to the
    code base; you can improve the code; you can share your opinions about
    it; or you can just use Linux to support your IT needs.
  • (Next: Even More Things Enterprise Users Need to Know about the GPL:)

    (Continued from Page 1)

    3. Things Enterprise Users Need to Know about Linux:

  • Linux is not necessarily free.

    Though many Linux distributions are available entirely for free (via an ISO
    download or otherwise), that’s obviously not always the case. Enterprise
    grade distributions with support and enterprise management tools almost
    always have an associated cost. Some call it a subscription; others call it
    support. The bottom line is it’s money.

  • The nature of Linux is such that it is not “owned” by any one vendor or
    entity per say. No one really owns the Linux operating system. Linus
    Torvalds owns the copyright to the name “Linux” but that’s
    about it.
  • The Linux kernel is not always the same.
    The Linux kernel varies somewhat from distribution to distribution as
    vendors include different versions and, in some cases, add additional
    functionality. This is certainly not a bad thing, but it’s
    important to note when trying to make apples-to-apples comparisons.
  • Every year, some new study, vendor or pundit appears on the stage and
    claims that this is the year of the Linux desktop. The reality is that
    the Linux desktop has existed for years, and it continues to improve and
    evolve just like the Microsoft desktop continues to evolve.

  • Linux is not specific to i386. It’ll run on just about anything.
  • 4. More Things Enterprise Users Need to Know about the GPL

    1) Anyone can use GPL licensed code

    2) Anyone can re-use GPL licensed code

    3) GPL doesn’t protect against trademark, copyright or patent
    infringement

    4) The GPL text must be included in every copy of software distributed
    under its license

    5) The GPL is not the only free or open source software license
    Though the GPL is one of the most common licenses, it is not the only
    free/open source software license.

    (Next page: The Kernel, Distros)

    Continued from page 2

    The Kernel, Distros

    The Linux kernel itself is not a complete operating system. It needs to
    be packaged or distributed with a host of other tools and applications in
    order to constitute a modern operating system. Thus, a full Linux operating
    system is commonly referred to as a Linux Distribution.

    A Linux distribution is essentially a “snapshot” of the Linux kernel and various
    applications at a certain release that are packaged together in the
    distribution by its package maintainers. It is entirely possible for users
    to freely download a Linux kernel and the various applications and package
    their own distribution, though the complexity of interaction and
    dependencies, as well as technical support and quality assurance,
    are among the issues that usually lead most users to make use of a
    “mainstream” Linux distribution.

    Linux Distributors


    There are a number of popular Linux distributions. Arguably, the most
    popular commercial Linux distribution is Red Hat Linux, which was
    first created in 1994 and made waves with its IPO in 1999 (at the time it was the
    8th biggest, first-day gain in Wall Street history). SUSE Linux, which was
    acquired by Novell
    in November 2003, is Red Hat’s principal rival in the
    commercial Linux distribution market and benefits from the tremendous
    resources that Novell is putting behind it Red Hat and Novell/SUSE benefit from sales/channel
    agreements with
    IBM and HP that significantly expand their reach and scope.

    France-based Mandrake Linux is also considered a mainstream distribution.
    In the Asian market, TurboLinux has made some inroads, with the emerging
    story appears to be the homegrown Linux effort known as
    Asianux,
    which was officially created in January 2004.

    Community-Based Distributions

    Not all Linux distributions are “commercial” distributions. In fact, there
    are many who would argue that the most popular distributions in use today
    are in fact “community-based” distributions. Here’s a sampling:

    Debian


    This is a popular distribution with a large user base. It is
    definitively a strong proponent of free software and its Social Contract,
    which is the basis of the Open Source Definition.

    Gentoo Linux


    This distribution gained some
    momentum
    in 2004, both in terms of statistical growth and its emerging enterprise platform.

    Fedora Project

    This was created by Red Hat after it terminated its Red Hat
    Linux line (as opposed to its current mainstay Red Hat Enterprise Linux).
    This is a Red Hat-sponsored community distribution that serves as
    proving ground for the next generation of its Enterprise line. It is an
    extremely popular and trend-setting distribution in its own right, with the
    adoption of such innovative technologies as
    SELinux (Security Enhanced
    Linux) and NX security for the Linux Kernel.

    Other Distributions

    There are many other distributions but, for the most
    part, they are based on one of the mainstream distributions.

    Desktop Linux

    This refers to a Linux operating system environment that has a GUI and is intended for general users on their desktops (just like a regular version of
    Microsoft Windows). There are two essential
    technical components that comprise a Linux desktop, an X Windows System
    implementation and a desktop environment. Until recently XFree86 was the
    most common X Windows System implementation, but, due to licensing issues, it
    has been supplanted by X.org.

    KDE

    This and GNOME
    are two main desktop environments that are both actively developed.
    Most mainstream Linux distributions will allow users to use
    either of them depending on a user’s personal preference.

    BSD

    The FreeBSD Project is one of the earliest open source operating system
    projects, and is a direct descendent of the original open source BSD work
    performed at the University of California at Berkeley. There are currently
    three mainstream open source BSD variants, NetBSD, OpenBSD and FreeBSD.

    The GPL and FOSS Licenses


    The GNU GPL (General Public License) is one of the most common and popular
    FOSS licenses. It is the license under which the Linux kernel
    itself is licensed and is at the heart of the SCO controversy. SCO
    claimed
    at one point that the GPL is unconstitutional, but its dispute really started with IBM over a contract. It has now evolved to include claims that select parts of the Linux kernel were pilfered from Unix System V code, to which SCO claims copyright. The case is slated for trial in 2005.

    The GPL essentially encourages and enshrines Freedom for the software
    code. The code is open. If you would like, you can read the
    text of the GPL itself.
    Software that is GPL-licensed is free to be distributed and modified, providing a number of crucial stipulations are met: that it remain free (remember “free” as in freedom not necessarily cost) and that the license is always included.

    In some respects, the stipulation that code must always remain free makes
    the GPL a restrictive license as opposed to a BSD-type license, which has no such restriction.

    FOSS applications run the gamut of virtually everything that exists in
    enterprise IT software today. They are either produced as a project by a
    developer or foundation or are donated/freed/liberated by a corporate
    entity to the community. The ongoing discussion by SUN Microsystmes over whether
    to open source Java is part of the latter discussion. Even Microsoft has
    gotten into the game with its
    WiX toolset, one of three projects it has donated to the open source community.

    One of the most popular open source repositories is SourceForge, which claims the largest number of projects and
    developers (currently over 800,000 developers).


    The Apache Software Foundation (ASF) contains a number of very influential
    and popular FOSS applications, including its namesake Apache Web Server,
    which is the dominant Web server on the Internet today. ASF projects are
    typically licensed under the
    Apache Software License.

    The Mozilla Foundation is known for the Mozilla and Firefox Web
    browsers, which are cross-platform and, in light of recent security
    issues with Microsoft’s Internet Explorer, are seen as alternatives to the IE browser.

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