Proprietary software or closed source software is computer software licensed under exclusive
legal right of the copyright holder with the intent that the licensee is given the right
to use the software only under certain conditions, and restricted from other uses, such as modification,
sharing, studying, redistribution, or reverse engineering.
Usually the source code of proprietary software is not made available.
Complementary terms include free software, licensed by the owner under more permissive
terms, and public domain software, which is not subject to copyright and can be used for
any purpose.
Proponents of free and open source software use proprietary or non-free to describe software
that is not free or open source.
A related but distinct categorization in the software industry is commercial software,
which refers to software produced for sale but not necessarily closed source.
Software becoming proprietary Until the late 1960s computers—huge and
expensive mainframe machines in specially air-conditioned computer rooms—were usually
supplied on a lease rather than purchase basis.
Service and all software available were usually supplied by manufacturers without separate
charge until 1969.
Software source code was usually provided.
Users who developed software often made it available, without charge.
Customers who purchased expensive mainframe hardware did not pay separately for software.
In 1969, IBM, under threat of Antitrust litigation, led an industry change by starting to charge
separately for software and services, and ceasing to supply source code.
Legal basis
Most software is covered by copyright which, along with contract law, patents, and trade
secrets, provides legal basis for its owner to establish exclusive rights.
A software vendor delineates the specific terms of use in an end-user license agreement.
The user may agree to this contract in writing, interactively, called clickwrap licensing,
or by opening the box containing the software, called shrink wrap licensing.
License agreements are usually not negotiable.
Software patents grant exclusive rights to algorithms, software features, or other patentable
subject matter.
Laws on software patents vary by jurisdiction and are a matter of ongoing debate.
Vendors sometimes grant patent rights to the user in the license agreement.
Proprietary software vendors usually regard source code as a trade secret.
Free software licenses and open-source licenses use the same legal basis as proprietary software.
Free software companies and projects are also joining into patent pools like the Patent
Commons and the Open Invention Network.
Limitations License agreements do not override applicable
copyright law or contract law.
Provisions that conflict may not be enforceable.
Some vendors say that software licensing is not a sale, and that limitations of copyright
like the first-sale doctrine do not apply.
The EULA for Microsoft Windows states that the software is licensed, not sold.
Exclusive rights The owner of proprietary software exercises
certain exclusive rights over the software.
The owner can restrict use, inspection of source code, modification of source code,
and redistribution.
Use of the software
Vendors typically limit the number of computers on which software can be used, and prohibit
the user from installing the software on extra computers.
Restricted use is sometimes enforced through a technical measure, such as product activation,
a product key or serial number, a hardware key, or copy protection.
Vendors may also distribute versions that remove particular features, or versions which
allow only certain fields of endeavor, such as non-commercial, educational, or non-profit
use.
Use restrictions vary by license: Windows Vista Starter is restricted to running
a maximum of three concurrent applications.
The retail edition of Microsoft Office Home and Student 2007 is limited to non-commercial
use on up to three devices in one household.
Windows XP can be installed on one computer, and limits the number of network file sharing
connections to 10.
The Home Edition disables features present in Windows XP Professional.
Many Adobe licenses are limited to one user, but allow the user to install a second copy
on a home computer or laptop.
iWork '09, Apple's productivity suite, is available in a five-user family pack, for
use on up to five computers in a household.
Inspection and modification of source code
Vendors typically distribute proprietary software in compiled form, usually the machine language
understood by the computer's central processing unit.
They typically retain the source code, or human-readable version of the software, written
in a higher level programming language.
This scheme is often referred to as closed source.
By withholding source code, the software producer prevents the user from understanding how the
software works and from changing how it works.
This practice is denounced by some critics, who argue that users should be able to study
and change the software they use, for example, to remove secret or malicious features, or
look for security vulnerabilities.
Richard Stallman, founder of the Free Software Foundation, says that proprietary software
commonly contains "malicious features, such as spying on the users, restricting the users,
back doors, and imposed upgrades."
Some proprietary software vendors say that retaining the source code makes their software
more secure, because the widely available code for open-source software makes it easier
to identify security vulnerabilities.
Open source proponents pejoratively call this security through obscurity, and say that wide
availability results in increased scrutiny of the source code, making open source software
more secure.
While most proprietary software is closed-source, some vendors distribute the source code or
otherwise make it available to customers.
For example, users who have purchased a license for the Internet forum software vBulletin
can modify the source for his or her own site but cannot redistribute it.
This is true for many web applications, which must be in source code form when being run
by a web server.
The source code is covered by a non-disclosure agreement or a license that allows, for example,
study and modification, but not redistribution.
The text-based email client Pine and certain implementations of Secure Shell are distributed
with proprietary licenses that make the source code available.
Some governments fear that proprietary software may include defects or malicious features
which would compromise sensitive information.
In 2003 Microsoft established a Government Security Program to allow governments to view
source code and Microsoft security documentation, of which the Chinese government was an early
participant.
The program is part of Microsoft's broader Shared Source Initiative which provides source
code access for some products.
The Reference Source License and Limited Public License are proprietary software licenses
where the source code is made available.
Governments have also been accused of adding such malware to software themselves.
According to documents released by Edward Snowden, the NSA has used covert partnerships
with software companies to make commercial encryption software exploitable to eavesdropping,
or to insert backdoors.
Software vendors sometimes use obfuscated code to impede users who would reverse engineer
the software.
This is particularly common with certain programming languages.
For example, the bytecode for programs written in Java can be easily decompiled to somewhat
usable code, and the source code for programs written in scripting languages such as PHP
or JavaScript is available at run time.
Redistribution
Proprietary software vendors can prohibit users from sharing the software with others.
Another unique license is required for another party to use the software.
In the case of proprietary software with source code available, the vendor may also prohibit
customers from distributing their modifications to the source code.
Shareware is closed-source software whose owner encourages redistribution at no cost,
but which the user sometimes must pay to use after a trial period.
The fee usually allows use by a single user or computer.
In some cases, software features are restricted during or after the trial period, a practice
sometimes called crippleware.
Interoperability with software and hardware
Proprietary file formats and protocols
Proprietary software often stores some of its data in file formats which are incompatible
with other software, and may also communicate using protocols which are incompatible.
Such formats and protocols may be restricted as trade secrets or subject to patents.
Proprietary APIs A proprietary application programming interface
is a software library interface "specific to one device or, more likely to a number
of devices within a particular manufacturer's product range."
The motivation for using a proprietary API can be vendor lock-in or because standard
APIs do not support the device's functionality.
The European Commission, in its March 24, 2004 decision on Microsoft's business practices,
quotes, in paragraph 463, Microsoft general manager for C++ development Aaron Contorer
as stating in a February 21, 1997 internal Microsoft memo drafted for Bill Gates:
The Windows API is so broad, so deep, and so functional that most ISVs would be crazy
not to use it.
And it is so deeply embedded in the source code of many Windows apps that there is a
huge switching cost to using a different operating system instead.
Early versions of the iPhone SDK were covered by a non-disclosure agreement.
The agreement forbade independent developers from discussing the content of the interfaces.
Apple discontinued the NDA in October 2008.
Vendor lock-in
A dependency on the future versions and upgrades for a proprietary software package can create
vendor lock-in, entrenching a monopoly position.
Software limited to certain hardware configurations Proprietary software may also have licensing
terms that limit the usage of that software to a specific set of hardware.
Apple has such a licensing model for Mac OS X, an operating system which is limited to
Apple hardware, both by licensing and various design decisions.
This licensing model has been affirmed by the United States Court of Appeals.
Abandonment by owners
Proprietary software which is no longer marketed by its owner and is used without permission
by users is called abandonware and may include source code.
Some abandonware have the source code released to the public domain either by its author
or copyright holder and is therefore free software, and no longer proprietary software.
If the proprietor of a software package should cease to exist, or decide to cease or limit
production or support for a proprietary software package, recipients and users of the package
may have no recourse if problems are found with the software.
Proprietors can fail to improve and support software because of business problems.
When no other vendor can provide support for the software, the ending of support for older
or existing versions of a software package may be done to force users to upgrade and
pay for newer versions; or migrate to either competing systems with longer support life
cycles or to FOSS-based systems.
Pricing and economics
Proprietary software is not synonymous with commercial software, though the industry commonly
confuses the term, as does the free software community.
Proprietary software can be distributed at no cost or for a fee, and free software can
be distributed at no cost or for a fee.
The difference is that whether or not proprietary software can be distributed, and what the
fee would be, is at the proprietor's discretion.
With free software, anyone who has a copy can decide whether, and how much, to charge
for a copy or related services.
Proprietary software that comes for no cost is called freeware.
Proponents of commercial proprietary software argue that requiring users to pay for software
as a product increases funding or time available for the research and development of software.
For example, Microsoft says that per-copy fees maximise the profitability of software
development.
Proprietary software generally creates greater commercial activity over free software, especially
in regard to market revenues.
Similar terms The founder of free software movement, Richard
Stallman, sometimes uses the term "user-subjugating software" to describe proprietary software.
Eben Moglen sometimes talks of "unfree software".
The term "non-free" is often used by Debian developers to describe any software whose
license does not comply with Debian Free Software Guidelines, and they use "proprietary software"
specifically for non-free software that provides no source code.
The Open Source Initiative uses the terms "proprietary software" and "closed source
software" interchangeably.
A related concept is closed platform or "walled garden".
The term "silo" is used to describe the even broader notion of "closed habitats that serve
as private marketplaces that lock customers in and competitors out".
Examples Well known examples of proprietary software
include Microsoft Windows, Adobe Flash Player, PS3 OS, iTunes, Adobe Photoshop, Google Earth,
Mac OS X, Skype, WinRAR, Java and some versions of Unix.
Software distributions considered as proprietary may in fact incorporate a "mixed source" model
including both free and non-free software in the same distribution.
Most if not all so-called proprietary UNIX distributions are mixed source software, bundling
open source components like BIND, Sendmail, X Window System, DHCP, and others along with
a purely proprietary kernel and system utilities.
Some free software packages are also simultaneously available under proprietary terms.
Examples include MySQL, Sendmail and ssh.
The original copyright holders for a work of free software, even copyleft free software,
can use dual-licensing to allow themselves or others to redistribute proprietary versions.
Non-copyleft free software allows anyone to make proprietary redistributions.
Free software that depends on proprietary software is considered "trapped" by the Free
Software Foundation.
This includes software written only for Microsoft Windows, or software that could only run on
Java, before it became free software.
In India, one and a half million laptops were pre-loaded with screen savers of political
minister Mulayam Singh Yadav.
The author of software developed for these laptops included a malicious feature that
would "crash" the device if the laptop's owner attempted to change, remove, or modify this
feature.
Formerly open source Some closed-source software was formerly open-source,
but most of those kinds are usually still free-of-charge to download.
A famous example of such is the Doom source port ZDaemon which was prone to aimbot cheaters.
See also
References