rtlfree-sources license file

FSMLabs (text/plain), 11.19 KB, created by John (EBo) David on 2004-09-26 10:07:30 UTC

                    FSMLABS Licensing for RTLinux/Free 

   This document specifies the licensing for this release of
   RTLinux/Free. Individual files in this release are each labeled with
   an identification of the applicable license. FSMLabs copyrighted files
   that are labeled as GPL are licensed by FSMLabs for use under GPL
   version 2.0 which is included with the RTLinux source tree. The entire
   RTLinux release is licensed under the RTLinux Open Patent License
   Version 2 which is also included with the release. Please read and
   make certain you understand both licenses. If you do not agree to the
   terms of both licenses, you may not use, copy, modify, or distribute
   this software.

   The licenses, the source management files from Bitkeeper and the
   documentation are copyright FSMLabs. You may copy them verbatim, but
   you are not permitted to make any changes in those files. RTLinux is a
   registered trademark and FSMLabs is a service mark of Finite State
   Machine Labs Inc. As long as you agree to and do not violate the terms
   of the GPL V2.0 and the Open RTLinux Patent License, you are granted
   permission to label unmodified re-distributed copies of this release
   as "Third Party Distributed FSMLabs Free RTLinux®" and you may also
   label modified re-distributed versions as "Third Party Distributed
   Modified FSMLabs Free RTLinux®". You may not use either mark in any
   other manner without explicit permission of FSMLabs.

   This release of RTLinux/Free is not released as "Open RTLinux Code"
   and does not qualify under paragraph "B" of "Approved use" in the
   Open RTLinux Patent License.

   Trademarks: RTLinux and FSMLabs are registered trademarks of Finite
   State Machine Labs Inc. Linux is a registered trademark of Linus
   Torvalds..

                                   A FAQ

   Disclaimer: This is not legal advice. Laws governing software
   intellectual property are complicated and vary around the world.
   Please consult a lawyer to get legal advice. Descriptions of license
   terms here are in informal language and necessarily imprecise -
   consult the text of the licenses for exact terms.

   Do I need RTLinux/Pro and/or a commercial license or can I use a
   version of RTLinux/Free?

   If you are developing commercial software or making commercial or
   other government use of RTLinux/Free, we request that you buy a
   license or a support contract. Please consider carefully whether you
   get a benefit from our work and would like to see it continue. If you
   are developing GPL V2.0 code only, you don't need a special license -
   although you may want the Pro version for other reasons. If your
   applications include non-GPL code, you may or may not need an
   additional license, but we suggest some care. The GPL requires that
   all work derived from GPL software be released under GPL. The Open
   RTLinux Patent License provides a royalty free use of the patent only
   for GPL code. Contrary to what you might read on the Internet, "using
   an API" or "putting code in modules" or other tricks to make a barrier
   between GPL and non-GPL code don't work. If you have questions, ask us
   by sending email to [e-mail].

   If I start with a version of RTLinux®/Free what parts of my code do I
   have to GPL?

   The GPL is quite definitive on the following condition: If you begin
   with a GPL Program and produce a new program from the original GPL
   Program so that the new program is "derived" from the original, the
   new program must also be released under the GPL. The simple case for
   this is when your new program is produced by a change in the code of
   the original program. In this case, you must license the new program
   including the changes under the GPL. Things are more complex when the
   new program is produced by attaching a plug-in, a module, or a
   discrete component of some sort to the original program.

   Linus Torvalds has attached to the Linux license an explicit note that
   running a program under Linux does not subject that program to the
   GPL. RTLinux/Free does not have such an exception. RTLinux/Free is a
   program that runs Linux as an application. Applications that run under
   Linux are probably protected by Torvalds exception: certainly many big
   companies are relying on this. Applications that run under control of
   the RTLinux/Free kernel are not Linux applications and do not come
   under this exception. We require that any derived work be released
   under the GPL unless you purchase a commercial license from FSMLabs.
   You may be interested in reading a discussion of this issue in:

         http://www.gnu.org/licenses/gpl-faq.html#GPLModuleLicense

   RTLinux/Free and any GPL implementation of the RTLinux dual kernel
   process are also restricted under the terms of the Open RTLinux Patent
   License. This license permits royalty free use of the RTLinux dual
   kernel process by GPL software, and it offers only one, limited
   exception to this requirement. In general, all components of software
   (modules, programs, plugins, code, etc.) that are used with the
   RTLinux dual kernel process under this license must be released under
   the GPL. That is, if an application, as a whole, makes use of the
   RTLinux dual kernel process under the GPL provisions of the Open
   RTLinux Patent License, the software as a whole must be licensed under
   the GPL under the strictest interpretation of the provisions of the
   GPL. You cannot meet the requirements of the license by splitting
   software into separate programs,modules, or other software components
   and only releasing some of them under the GPL. The GPL is a copyright
   license and so the boundaries that might exist between programs,
   modules, or other software components are boundaries of the effect of
   the GPL. The Open Patent License applies to " software" that makes use
   of the patented process even if this software consists of many
   distinct programs, modules, or other software components."

   As an example, if you distribute a data acquisition system that
   consists of an implementation of the RTLinux dual kernel process, a
   driver, and a control program, the entire collection of programs must
   be licensed under the GPL in order to make use of the royalty free
   Open RTLinux Patent License. If your program only makes incidental use
   of the RTLinux Patented Process it is not subject to the license - but
   we suggest that you either ask us or get qualified legal advice. Both
   the GPL and the RTLinux Open Patent License are aimed at facilitating
   use of GPL code with GPL code, and you should be careful about other
   uses.

   What is the difference between RTLinux/Free and Open RTLinux?

   Certain releases of RTLinux/Free are designated by FSMLabs as
   OpenRTLinux releases. These releases are intended to provide some
   limited exceptions to the GPL for commercial users of RTLinux/Free by
   allowing for non-GPL modules to be linked - see section "B" of
   "Approved uses". In order to make use of these exceptions, the user or
   distributor must agree to the additional license terms.

   Can I submit patches to RTLinux?

   Yes, of course, We take nearly anything reasonable into the
   "contributions" list. Code that we like and test gets integrated into
   the main body of the code. Like nearly all other open-source projects,
   we require a release before we integrate contributions into the main
   code. Most other projects, such as GCC and ReiserFS, require
   assignment of copyright. We don't ask for copyright, because we do not
   want to restrict your rights to later reuse your code. Instead, we
   require a release so that we retain our rights over RTLinux. See the
   file CONTRIBUTION for details.

   Why is RTLinux/Pro not covered under the GPL?

   The GPL is a license that is offered by the copyright owners of some
   programs. The copyright owners still own the code however, and have
   unchallenged right to license the code under any other terms of their
   choice. Since FSMLabs owns the copyright for RTLinux outright, FSMLabs
   has the right to offer a version of its RTLinux software under a
   commercial license as well. Since RTLinux is not derived from Linux,
   but is an independent program that uses Linux as an optional
   application, RTLinux is not subject to the terms of the Linux GPL.

   The commercial version of RTLinux - RTLinux/Pro -- can be purchased
   with or without source. If you purchase source, you get the right to
   modify the source and to distribute your modifications without GPL
   restrictions. You may distribute changes and RTLinux itself in binary
   form under that license --- as long as you pay the appropriate
   royalties and fees. You may not redistribute our source. Please
   contact us to discuss the specific terms and conditions of FSMLabs
   commercial license.

   Doesn't RTLinux/Pro share address space with Linux?

   It is sometimes argued that programs that run in the same hardware
   memory space with a GPL program must be released under GPL. This is
   not strictly correct. The test is whether the result is a "derived
   work", A little thought shows that this distinction is necessary: BIOS
   programs run in the hardware address space shared with Linux, MS DOS ,
   which has no hardware memory protection, runs GPL programs, uCLinux
   only runs on processors with no hardware memory protection at all and
   so on. The important issue is not whether the hardware enforces
   address space separation, but whether the programs are independent and
   running in their own logical address spaces or whether they are
   components of the same program using a logical single address space.

   When RTLinux starts running, it allocates memory for its own use or
   attaches to pre-allocated memory and this memory space is intended to
   be used by RTLinux and not shared with Linux. In fact, the entire
   real-time capability of RTLinux depends deeply on the very limited and
   highly structured nature of interactions between RTLinux and the
   general purpose operating system base. RTLinux generally does not use
   hardware to enforce this separation of address space, but this is an
   implementation choice to improve efficiency and has nothing to do with
   whether there is the kind of sharing of address space that is seen
   when a program is linked to a library.

   What is the legal situation of RTAI?

   FSMLabs wants to encourage experimentation with the RTLinux process
   and derived programs under the provisions of the RTLinux Open Patent
   License and the GPL. We try very hard to avoid imposing unnecessary
   restrictions, especially on educational and other non-commercial use.
   However, programs derived from RTLinux source, or making use of the
   RTLinux Open Patent license are required to follow the terms of the
   Open Patent License (where applicable) and the GPL. People modifying,
   distributing or using this code have no legal right to grant further
   rights or to re-license under other licenses. Many commercial projects
   need to escape from the GPL restrictions and we are happy to offer
   additional licenses to those projects. If you are using RTAI for a
   product and your product contains non-GPL code, you should contact
   FSMLabs to determine whether you need a commercial license.