Open Source software Licensing Computer science department third year cs Lecturer : yasmin maki

What is a license? Grants permission to use a copyrighted work Can grant any or all of the rights associated with copyright Can impose other restrictions, such as type or place or usage, or duration of the license Does not transfer ownership of the copyright Source: David Drooz, Open Source Licenses – Basic Information and Examples (2002)

A software license is the contract between the software owner and the licensee defining terms of use of software

Contracts العقود Must have three things: - Offer - Acceptance - Consideration : information that should be kept in mind when making a decision

Open Source Software Licenses - Source Code Source code to original product always provided; Licensee can modify or enhance source code (create “derivative works”) or include source code with other license types (create “larger works”); Licensee may be required to share modifications with the world (in source and/or binary form), but not necessarily;

An open source licensor must give the licensee certain rights to be considered open source Basically, the licensee has the right to use, modify or distribute the software, and the right to access the source code.

Prominent Open Source Vendors IBM Red Hat Sun Microsystems Source: Rosen at 38

Examples of Popular licenses [The following licenses are popular, widely used, or have strong communities: Apache License 2.0 BSD 3-Clause "New" or "Revised" license BSD 2-Clause "Simplified" or "FreeBSD" license GNU General Public License (GPL) The GPL, or “copyleft” family of licenses GNU Library or "Lesser" General Public License (LGPL) MIT license Mozilla Public License 2.0 Common Development and Distribution License

Other open source licenses Traditional proprietary licenses Shareware/freeware Public domain (not a license, but a way of accessing software)

"Copyleft" refers to licenses that allow derivative works but require them to use the same license as the original work. For example, if you write some software and release it under the GNU General Public License (a widely- used copyleft license), and then someone else modifies that software and distributes their modified version, the modified version must be licensed under the GNU GPL too — including any new code written specifically to go into the modified version.

The GPL family of licenses Basic rights under the GPL – access to source code, right to make derivative works “Copyleft” The Library or Lesser General Public License

The BSD family of licenses Same basic rights as GPL No copyleft provisions, i.e. licensees can take software licensed under the BSD private Can re-release software under a different license

Shareware/Freeware May be free or may not Licensor does not provide the right to make derivative works or give access to source code

Public Domain Author retains no copyright rights if software is in the public domain Open source software authors retain copyright rights Open source licenses contain restrictions, just different ones than licensees may be used to The restrictions in open source licenses are based on copyright law and depend on it for their effectiveness.

Problems with the GPL Linking to GPL programs No explicit patent grant Does no discuss trademark rights Does not discuss duration Silent on sub licensing Relies exclusively on license law, not contract

GNU Library or "Lesser" General Public License (LGPL) a Lesser GPL, which applies to libraries to be used in “nonfree” software, that is to say that you don’t have to re-license the software under the GPL.

The Berkeley Software Distribution License (BSD)   There are two types here as well, 2-clause and 3-clause. The 2-clause form is newer, even though the 3-clause license is called the “New” one. 2-clause is referred to as “simplified” or “FreeBSD”. Like the GPL, it was not written by lawyers and hence is incomplete, failing to discuss patents, sublicensing, scope and duration, etc. No copyleft/reciprocity provision Does not mention patents

BSD-style license Key terms: License grant: unlimited use, modification, distribution No warranties; disclaimer of consequential damages No endorsement

The Mozilla Public License (MPL) Professionally written Includes an explicit patent grant, including a reciprocal grant for contributors Includes many specific provisions that are absent in the GPL and BSD but which are often in licenses.

The Common Public License (CPL) Developed and owned by IBM Includes a limited patent license Contains a reciprocity provision Contains a patent defense provision Indemnity provisionتقديم تعويض

Multiple Licensing and other strategies Microsoft’s Shared Source License Public Source Multiple Licensing Licensing in phases

How do licensors make money with open source software? Usually by providing other services, such as: Support Training Customization Integration Certification Offering warranties

Other open content licenses include: GNU Free Documentation License Open Content License Free Art License Open Game License October Open Game License

Considerations before licensing with Creative Commons or other open content license Make sure you understand what rights you are retaining and which ones you are giving up Make sure you own the copyright Make sure your work is subject to copyright law “Be specific about what you are licensing”