1.2 SEM: What is software? from Wikipedia Computer software, or simply software, is a part of a computer system that consists of data or computer instructions,
in contrast to the physical hardware from which the system is built. In computer science and software engineering, computer
software is all information processed by computer systems, programs and data. Computer software includes computer programs,
libraries and related non-executable data, such as online documentation or digital media. Computer hardware and software
require each other and neither can be realistically used on its own.
At the lowest level, executable code consists of machine language instructions specific to an individual
processor—typically a central processing unit (CPU). A machine language consists of groups of binary values signifying
processor instructions that change the state of the computer from its preceding state. For example, an instruction may change
the value stored in a particular storage location in the computer—an effect that is not directly observable to the user. An
instruction may also (indirectly) cause something to appear on a display of the computer system—a state change which should be
visible to the user. The processor carries out the instructions in the order they are provided, unless it is instructed to
"jump" to a different instruction, or is interrupted (by now multi-core processors are dominant, where each core can run
instructions in order; then, however, each application software runs only on one core by default, but some software has been
made to run on many).
The majority of software is written in high-level programming languages that are easier and more efficient for
programmers to use because they are closer than machine languages to natural languages. High-level languages are translated
into machine language using a compiler or an interpreter or a combination of the two. Software may also be written in a
low-level assembly language, which has strong correspondence to the computer's machine language instructions and is translated
into machine language using an assembler.
The Free Software Foundation (FSF) is a 501(c)(3) non-profit organization founded by Richard Stallman on 4 October 1985
to support the free software movement, which promotes the universal freedom to study, distribute, create, and modify computer
software, with the organization's preference for software being distributed under copyleft ("share alike") terms, such as
with its own GNU General Public License. The FSF was incorporated in Massachusetts, USA, where it is also based.
From its founding until the mid-1990s, FSF's funds were mostly used to employ software developers to write free
software for the GNU Project. Since the mid-1990s, the FSF's employees and volunteers have mostly worked on legal and
structural issues for the free software movement and the free software community.
Consistent with its goals, the FSF aims to use only free software on its own computers.
A great variety of software companies and programmers in the world comprise a software industry.
Software can be quite a profitable industry: Bill Gates, the founder of Microsoft was the richest person in the world in 2009,
largely due to his ownership of a significant number of shares in Microsoft, the company responsible for Microsoft Windows and
Microsoft Office software products.
This is a list of free and open-source software packages, computer software licensed under free software licenses and
open-source licenses. Software that fits the Free Software Definition may be more appropriately called free software; the GNU
project in particular objects to their works being referred to as open-source. For more information about the philosophical
background for open-source software, see free software movement and Open Source Initiative. However, nearly all software
meeting the Free Software Definition also meets the Open Source Definition and vice versa. A small fraction of the software
that meets either definition is listed here.
Open-source software (OSS) is computer software with its source code made available with a license in which the
copyright holder provides the rights to study, change, and distribute the software to anyone and for any purpose.
Open-source software may be developed in a collaborative public manner. Open-source software is the most prominent example of
The open-source model, or collaborative competition development from multiple independent sources, generates an
increasingly more diverse scope of design perspective than any one company is capable of developing and sustaining long term.
A report by the Standish Group (from 2008) states that adoption of open-source software models has resulted in savings of about
$60 billion per year to consumers.
Projects and organizations
Some of the "more prominent organizations" involved in OSS development include the
Apache Software Foundation,
creators of the Apache web server; the
a nonprofit which as of 2012 employed Linus Torvalds, the creator of the Linux operating system kernel; the
home of the Eclipse software development platform; the
creators of the influential Debian GNU/Linux distribution; the
home of the Firefox web browser; and
OW2, European-born community developing open source middleware.
New organizations tend to have a more sophisticated governance model and their membership is often formed by legal
Several open source programs have become defining entries in their space, including the
GIMP image editing system; Sun's Java programming language and environment; the
MySQL database system; the
FreeBSD Unix operating system;
LibreOffice office productivity suite; and the
Wireshark network packet sniffer and protocol analyser.
Open Source development is often performed "live and in public", using services provided for free on the Internet, such as the
GitHub web sites.
Open Source Software Institute is a membership-based,
non-profit 501 (c) organization established in 2001 that promotes the development and
implementation of open source software solutions within US Federal, state and local government agencies.
OSSI's efforts have focused on promoting adoption of open source software programs and policies within Federal Government and
Defense and Homeland Security communities.
Open Source for America is a group created to raise
awareness in the U.S. Federal Government about the benefits of open source software.
Their stated goals are to encourage the government's use of open source software, participation in open source software
projects, and incorporation of open source community dynamics to increase government transparency.
Mil-OSS is a group dedicated to the advancement of OSS use and
creation in the military.
Public-domain software is software that has been placed in the public domain: in other words, there is absolutely no
ownership such as copyright, trademark, or patent. Software in the public domain can be modified, distributed, or sold even
without any attribution by anyone; this is unlike the common case of software under exclusive copyright, where software
licenses grant limited usage rights.
Under the Berne Convention, which most countries have signed, an author automatically obtains the exclusive copyright
to anything they have written, and local law may similarly grant copyright, patent, or trademark rights by default. The Berne
Convention also covers programs. Therefore, a program is automatically subject to a copyright, and if it is to be placed in the
public domain, the author must explicitly disclaim the copyright and other rights on it in some way, e.g. by a waiver
statement. In some Jurisdictions, some rights (in particular moral rights) cannot be disclaimed: for instance, civil law
tradition-based German law's "Urheberrecht" differs here from the Anglo-Saxon common law tradition's "copyright" concept.
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