Software license

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Diagram of software under various licenses according to the FSF and their The Free Software Definition: on the left side "free software", on the right side "proprietary software". On both sides, and therefore mostly orthogonal, "free download" (Freeware). Software Categories expanded.svg
Diagram of software under various licenses according to the FSF and their The Free Software Definition: on the left side "free software", on the right side "proprietary software". On both sides, and therefore mostly orthogonal, "free download" (Freeware).

A software license is a legal instrument governing the use or redistribution of software.

Contents

Since the 1970s, software copyright has been recognized in the United States. Despite the copyright being recognized, most companies prefer to sell licenses rather than copies of the software because it enables them to enforce stricter terms on redistribution. Very few purchasers read any part of the license, initially shrink-wrap contracts and now most commonly encountered as clickwrap or browsewrap. The enforceability of this kind of license is a matter of controversy and is limited in some jurisdictions. Service-level agreements are another type of software license where the vendor agrees to provide a level of service to the purchaser, often backed by financial penalties.

Copyleft is a type of free license that mandates derivative works to be licensed. The other types of free license lack this requirement: for permissive licenses, attribution is typically the only requirement, and public-domain-equivalent licenses have no restrictions. The proliferation of open-source licenses has compounded license compatibility issues, but all share some features: allowing redistribution and derivative works under the same license, unrestricted access to the source code, and nondiscrimination between different uses—in particular, allowing commercial use.

Free and openNon-free
Public domain [1] and equivalent licenses Permissive license [2] [3] Copyleft [2] [3] Noncommercial license [4] Proprietary license [5] Trade secret [6]
DescriptionWaives copyright protectionGrants use rights, including right to relicense (allows proprietization, license compatibility)Grants use rights, forbids proprietization Grants rights for noncommercial use only.Traditional use of copyright; no rights need be grantedNo information made public
Notable software licensesPD, CC0 [7] MIT, Apache, MPL, BSD GPL, AGPL JRL [8] Proprietary software

The source code (or compiled binaries in the form of object code) [9] of a computer program is protected by copyright law that vests the owner with the exclusive right to copy the code. The underlying ideas or algorithms are not protected by copyright law, but are often treated as a trade secret and concealed by such methods as non-disclosure agreements. [10] Software copyright has been recognized since the mid-1970s and is vested in the company that makes the software, not the employees or contractors who wrote it. [1]

Software licenses and rights granted in context of the copyright according to Mark Webbink. [11] Expanded by freeware and sublicensing.
Rights granted Public domain and equivalent Permissive FOSS license (e.g. BSD license) Copyleft FOSS license (e.g. GPL) Freeware / Shareware / Freemium Proprietary license Trade secret
Copyright retainedNoYesYesYesYesYes
Right to perform YesYesYesYesYesNo
Right to displayYesYesYesYesYesNo
Right to copyYesYesYesOftenNoLawsuits are filed by the owner against copyright infringement the most
Right to modify YesYesYesNoNoNo
Right to distributeYesYes, under same licenseYes, under same licenseOftenNoNo
Right to sublicenseYesYesNoNoNoNo
Example software SQLite, ImageJ Apache web server, ToyBox Linux kernel, GIMP, OBS Irfanview, Winamp Windows, the majority of commercial video games and their DRMs, Spotify, xSplit, TIDAL Server-side
Cloud computing programs and services,
forensic applications, and other line-of-business work.

Proprietary software licenses

A brief, written-out beta test software license issued by Macromedia in 1995 Ohhh, Shockwave (117804940).jpg
A brief, written-out beta test software license issued by Macromedia in 1995

The tendency to license proprietary software, rather than sell it, dates from the time period before the existence, then the scope of software copyright protection was clear. These licenses have continued in use after software copyright was recognized in the courts, and are considered to grant the company extra protection compared to copyright law. [12] According to United States federal law, a company can restrict the parties to which it sells but it cannot prevent a buyer from reselling the product. Software licensing agreements usually prohibit resale, enabling the company to maximize revenue. [13]

Traditionally, software was distributed in the form of binary object code that could not be understood or modified by the user, [9] but could be downloaded and run. The user bought a perpetual license to use a particular version of the software. [14] Software as service (SaaS) vendors—who have the majority market share in application software as of 2023 [15] —rarely offer perpetual licenses. [16] SaaS licenses are usually temporary and charged on a pay-per-usage or subscription basis, [17] although other revenue models such as freemium are also used. [18] For customers, the advantages of temporary licenses include reduced upfront cost, increased flexibility, and lower overall cost compared to a perpetual license. [14] In some cases, the steep one-time cost demanded by sellers of traditional software were out of the reach of smaller businesses, but pay-per-use SaaS models makes the software affordable. [19]

End-user license agreement (EULA)

Initially, end-user license agreement (EULAs) were printed on either the shrinkwrap packaging encasing the product (see shrink-wrap contract) or a piece of paper. The license often stipulated that a customer agreed if they did not return the product within a specified interval. [20] More recently, EULAs are most commonly found as clickwrap or browsewrap where the user's clicks or continued browsing are taken as a sign of agreement. As a result of the end of physical constraints, length increased. [21] Most EULAs have been designed so that it is very difficult to read and understand them, but easy to agree to the licensing terms without reading them. [12] [20] Regardless of how easy it is to access, very few consumers read any part of the license agreement. [22] [23] Most assume the terms are unobjectionable or barely notice agreeing while installing the software. [24] Companies take advantage of consumers' inattention to insert provisions into EULAs. [25]

Proprietary software is usually offered under a restrictive license that bans copying and reuse and often limits the purchaser to using the software on one computer. [5] [26] Source code is rarely available. Derivative software works and reverse engineering are usually explicitly prohibited. [26] Many EULAs allow the vendor to collect information about the user and use it in unrestricted ways. [27] Some EULAs restrict the ability of users to exercise copyright over derivative work made using the software, such as creative creations in the virtual worlds of video games. [28] [29]

Most disclaim any liability for harms caused by the product, [30] and prevent the purchaser from accessing the court system to seek a remedy. [31] Furthermore, many EULAs allow the vendor to change the terms at any time and the customer must choose between agreeing or ceasing use of the product, without getting a refund. [32] It is common for EULAs to allow unilateral termination by the vendor for any number of vague reasons or none at all. [33]

EULAs, almost always offered on a take-it-or-leave-it basis as a non-negotiable condition for using the software, [34] are very far from the prototypical contract where both parties fully understand the terms and agree of their own free will. [35] There has been substantial debate on to what extent the agreements can be considered binding. Before 1996 in the United States, clickwrap or browsewrap licenses were not held to be binding, but since then they often have been. [36] [21] Under the New Digital Content Directive effective in the European Union, EULAs are only enforceable to the extent that they do not breach reasonable consumer expectations. The gap between expectations and the content of EULAs is especially wide when it comes to restrictions on copying and transferring ownership of digital content. [37] Many EULAs contain stipulations that are likely unenforceable depending on the jurisdiction. Software vendors keep these unenforceable provisions in the agreements, perhaps because users rarely resort to the legal system to challenge them. [38]

Service-level agreement (SLA)

Service-level agreements are often used for enterprise software and guarantee a level of service, such as software performance or time to respond to issue raised by the customer. Many stipulate financial penalties if the service falls short of the agreed standard. [39] SLAs often cover such aspects as availability, reliability, price, and security using quantifiable metrics. [40] Multi-tier SLAs are common in cloud computing because of the use of different computing services that may be managed by different companies. [41] SLAs in cloud computing are an area under active research as of 2024. [42]

Free and open-source software licenses

Before the open-source movement in the 1980s, almost all software was proprietary and did not disclose its source code. [43] Open-source licensing is intended to maximize openness and minimize barriers to software use, dissemination, and follow-on innovation. [4]

Open-source licenses share a number of key characteristics: [44]

The Open Source Initiative vets and approves new open-source licenses that comply with its Open Source Definition. [44]

Types of open-source licenses

The most popular open source licenses as of 2022 are the Apache License (permissive), the MIT License (permissive), and the GPL (copyleft). Open-source-license-chart.svg
The most popular open source licenses as of 2022 are the Apache License (permissive), the MIT License (permissive), and the GPL (copyleft).

Outside of software, noncommercial-only Creative Commons licenses have become popular among some artists who wish to prevent others from profiting excessively from their work. [51] However, software that is made available for noncommercial use only is not considered open source. [8] Sun Microsystems' noncommercial-only Java Research License was rejected by the open-source community, and in 2006 the company released most of Java under the GPL. [8]

Compatibility

Compatibility chart for some open-source software licenses GPL-Compatible.svg
Compatibility chart for some open-source software licenses

Since 1989, [43] a variety of open-source licenses for software have been created. [53] Choosing an open-source software license has grown increasingly difficult due to the proliferation of licenses, [54] [55] many of which are only trivially distinct. [56] Many licenses are incompatible with each other, hampering the goals of the free software movement. [57] Translation issues, ambiguity in licensing terms, and incompatibility of some licenses with the law in certain jurisdictions compounds the problem. [58]

Although downloading an open-source module is quick and easy, complying with the licensing terms can be more difficult. [59] The amount of software dependencies means that engineers working on complex projects must often rely on software license management software in order to help them achieve compliance with the licensing terms of open-source components. [60] Many open-source software files do not unambiguously state the license, increasing the difficulties of compliance. [59] When combining code bases, the original licenses can be maintained for separate components, and the larger work released under a compatible license. [61] This compatibility is often one-way. Public domain content can be used anywhere as there is no copyright claim, but code acquired under any almost any set of terms cannot be waved to the public domain. Permissive licenses can be used within copyleft works, but copyleft material cannot be released under a permissive license. Some weak copyleft licenses can be used under the GPL and are said to be GPL-compatible. GPL software can only be used under the GPL or AGPL. [62]

Enforceability

Free and open-source software licenses have been successfully enforced in civil court since the mid-2000s. [63] Courts have found that distributing software indicates acceptance of the license's terms. [64] However, developers typically achieve compliance without lawsuits. Social pressures, like the potential for community backlash, are often sufficient. [65] Cease and desist letters are a common method to bring companies back into compliance, especially in Germany. [66]

A long-debated subject within the FOSS community is whether open-source licenses are "bare licenses" or contracts. [67] A bare license is a set of conditions under which actions otherwise restricted by intellectual property laws are permitted. [63] Under the bare license interpretation, advocated by the Free Software Foundation (FSF), a case is brought to court by the copyright holder as copyright infringement. [63] Under the contract interpretation, a case can be brought to court by an involved party as a breach of contract. [68] United States and French courts have tried cases under both interpretations. [69]

Value

More than 90 percent of companies use open-source software as a component of their proprietary software. [70] The decision to use open-source software, or even engage with open-source projects to improve existing open-source software, is typically a pragmatic business decision. [71] [72] When proprietary software is in direct competition with an open-source alternative, research has found conflicting results on the effect of the competition on the proprietary product's price and quality. [73]

For decades, some companies have made servicing of an open-source software product for enterprise users as their business model. These companies control an open-source software product, and instead of charging for licensing or use, charge for improvements, integration, and other servicing. [74] Software as a service (SaaS) products based on open-source components are increasingly common. [75]

Open-source software is preferred for scientific applications, because it increases transparency and aids in the validation and acceptance of scientific results. [56]

See also

Related Research Articles

<span class="mw-page-title-main">Software</span> Non-tangible executable component of a computer

Software consists of computer programs that instruct the execution of a computer.

<span class="mw-page-title-main">Free software</span> Software licensed to be freely used, modified and distributed

Free software, libre software, or libreware is computer software distributed under terms that allow users to run the software for any purpose as well as to study, change, and distribute it and any adapted versions. Free software is a matter of liberty, not price; all users are legally free to do what they want with their copies of a free software regardless of how much is paid to obtain the program. Computer programs are deemed "free" if they give end-users ultimate control over the software and, subsequently, over their devices.

The free software movement is a social movement with the goal of obtaining and guaranteeing certain freedoms for software users, namely the freedoms to run, study, modify, and share copies of software. Software which meets these requirements, The Four Essential Freedoms of Free Software, is termed free software.

<span class="mw-page-title-main">GNU Lesser General Public License</span> Free-software license

The GNU Lesser General Public License (LGPL) is a free-software license published by the Free Software Foundation (FSF). The license allows developers and companies to use and integrate a software component released under the LGPL into their own software without being required by the terms of a strong copyleft license to release the source code of their own components. However, any developer who modifies an LGPL-covered component is required to make their modified version available under the same LGPL license. For proprietary software, code under the LGPL is usually used in the form of a shared library, so that there is a clear separation between the proprietary and LGPL components. The LGPL is primarily used for software libraries, although it is also used by some stand-alone applications.

<span class="mw-page-title-main">Open-source license</span> Software license allowing source code to be used, modified, and shared

Open-source licenses are software licenses that allow content to be used, modified, and shared. They facilitate free and open-source software (FOSS) development. Intellectual property (IP) laws restrict the modification and sharing of creative works. Free and open-source licenses use these existing legal structures for an inverse purpose. They grant the recipient the rights to use the software, examine the source code, modify it, and distribute the modifications. These criteria are outlined in the Open Source Definition.

An end-user license agreement or EULA is a legal contract between a software supplier and a customer or end-user, generally made available to the customer via a retailer acting as an intermediary. An EULA specifies in detail the rights and restrictions which apply to the use of the software.

<span class="mw-page-title-main">Apache License</span> Free software license

The Apache License is a permissive free software license written by the Apache Software Foundation (ASF). It allows users to use the software for any purpose, to distribute it, to modify it, and to distribute modified versions of the software under the terms of the license, without concern for royalties. The ASF and its projects release their software products under the Apache License. The license is also used by many non-ASF projects.

Beerware is a tongue-in-cheek software license with permissive terms. It provides the end user with the right to use a particular program.

<span class="mw-page-title-main">Free and open-source software</span> Software whose source code is available and which is permissively licensed

Free and open-source software (FOSS) is software that is available under a license that grants the right to use, modify, and distribute the software, modified or not, to everyone free of charge. The public availability of the source code is, therefore, a necessary but not sufficient condition. FOSS is an inclusive umbrella term for free software and open-source software. FOSS is in contrast to proprietary software, where the software is under restrictive copyright or licensing and the source code is hidden from the users.

Multi-licensing is the practice of distributing software under two or more different sets of terms and conditions. This may mean multiple different software licenses or sets of licenses. Prefixes may be used to indicate the number of licenses used, e.g. dual-licensed for software licensed under two different licenses.

A permissive software license, sometimes also called BSD-like or BSD-style license, is a free-software license which instead of copyleft protections, carries only minimal restrictions on how the software can be used, modified, and redistributed, usually including a warranty disclaimer. Examples include the GNU All-permissive License, MIT License, BSD licenses, Apple Public Source License and Apache license. As of 2016, the most popular free-software license is the permissive MIT license.

License compatibility is a legal framework that allows for pieces of software with different software licenses to be distributed together. The need for such a framework arises because the different licenses can contain contradictory requirements, rendering it impossible to legally combine source code from separately-licensed software in order to create and publish a new program. Proprietary licenses are generally program-specific and incompatible; authors must negotiate to combine code. Copyleft licenses are commonly deliberately incompatible with proprietary licenses, in order to prevent copyleft software from being re-licensed under a proprietary license, turning it into proprietary software. Many copyleft licenses explicitly allow relicensing under some other copyleft licenses. Permissive licenses are compatible with everything, including proprietary licenses; there is thus no guarantee that all derived works will remain under a permissive license.

Companies whose business centers on the development of open-source software employ a variety of business models to solve the challenge of making profits from software that is under an open-source license. Each of these business strategies rest on the premise that users of open-source technologies are willing to purchase additional software features under proprietary licenses, or purchase other services or elements of value that complement the open-source software that is core to the business. This additional value can be, but not limited to, enterprise-grade features and up-time guarantees to satisfy business or compliance requirements, performance and efficiency gains by features not yet available in the open source version, legal protection, or professional support/training/consulting that are typical of proprietary software applications.

<span class="mw-page-title-main">Free-software license</span> License allowing software modification and redistribution

A free-software license is a notice that grants the recipient of a piece of software extensive rights to modify and redistribute that software. These actions are usually prohibited by copyright law, but the rights-holder of a piece of software can remove these restrictions by accompanying the software with a software license which grants the recipient these rights. Software using such a license is free software as conferred by the copyright holder. Free-software licenses are applied to software in source code and also binary object-code form, as the copyright law recognizes both forms.

BSD licenses are a family of permissive free software licenses, imposing minimal restrictions on the use and distribution of covered software. This is in contrast to copyleft licenses, which have share-alike requirements. The original BSD license was used for its namesake, the Berkeley Software Distribution (BSD), a Unix-like operating system. The original version has since been revised, and its descendants are referred to as modified BSD licenses.

<span class="mw-page-title-main">Copyleft</span> Practice of mandating free use in all derivatives of a work

Copyleft is the legal technique of granting certain freedoms over copies of copyrighted works with the requirement that the same rights be preserved in derivative works. In this sense, freedoms refers to the use of the work for any purpose, and the ability to modify, copy, share, and redistribute the work, with or without a fee. Licenses which implement copyleft can be used to maintain copyright conditions for works ranging from computer software, to documents, art, and scientific discoveries, and similar approaches have even been applied to certain patents.

Proprietary software is software that grants its creator, publisher, or other rightsholder or rightsholder partner a legal monopoly by modern copyright and intellectual property law to exclude the recipient from freely sharing the software or modifying it, and—in some cases, as is the case with some patent-encumbered and EULA-bound software—from making use of the software on their own, thereby restricting their freedoms.

<span class="mw-page-title-main">GNU General Public License</span> Series of free software licenses

The GNU General Public License is a series of widely used free software licenses, or copyleft, that guarantee end users the four freedoms to run, study, share, and modify the software. The license was the first copyleft for general use and was originally written by Richard Stallman, the founder of the Free Software Foundation (FSF), for the GNU Project. The license grants the recipients of a computer program the rights of the Free Software Definition. The licenses in the GPL series are all copyleft licenses, which means that any derivative work must be distributed under the same or equivalent license terms. It is more restrictive than the Lesser General Public License and even further distinct from the more widely-used permissive software licenses such as BSD, MIT, and Apache.

<span class="mw-page-title-main">Software categories</span> Groups of software

Software categories are groups of software. They allow software to be understood in terms of those categories, instead of the particularities of each package. Different classification schemes consider different aspects of software.

Open source license litigation involves lawsuits surrounding open-source licensed software. Many of the legal rights of open source software licensors enforceable against users violating licensing agreements are untested by the U.S. legal system. Free and open source software (FOSS) is distributed under a variety of free-software licenses, which are unique among other software licenses. Legal action against open source licenses involves questions about their validity and enforceability.

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Sources

Further reading