Free software 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.
GNU is an extensive collection of free software, which can be used as an operating system or can be used in parts with other operating systems. The use of the completed GNU tools led to the family of operating systems popularly known as Linux. Most of GNU is licensed under the GNU Project's own General Public License (GPL).
A Linux distribution is an operating system made from a software collection that is based upon the Linux kernel and, often, a package management system. Linux users usually obtain their operating system by downloading one of the Linux distributions, which are available for a wide variety of systems ranging from embedded devices and personal computers to powerful supercomputers.
Info-ZIP is a set of open-source software to handle ZIP archives. It has been in circulation since 1989. It consists of 4 separately-installable packages: the Zip and UnZip command-line utilities; and WiZ and MacZip, which are graphical user interfaces for archiving programs in Microsoft Windows and classic Mac OS, respectively.
The GNU C Library, commonly known as glibc, is the GNU Project's implementation of the C standard library. Despite its name, it now also directly supports C++. It was started in the 1980s by the Free Software Foundation (FSF) for the GNU operating system.
Within the free software and the open-source software communities there is controversy over whether to refer to computer operating systems that use a combination of GNU software and the Linux kernel as "GNU/Linux" or "Linux" systems.
This is a list of operating systems specifically focused on security. General-purpose operating systems may be secure in practice, without being specifically "security-focused."
Exec Shield is a project started at Red Hat, Inc in late 2002 with the aim of reducing the risk of worm or other automated remote attacks on Linux systems. The first result of the project was a security patch for the Linux kernel that emulates an NX bit on x86 CPUs that lack a native NX implementation in hardware. While the Exec Shield project has had many other components, some people refer to this first patch as Exec Shield.
Free and open-source software (FOSS) is software that is both free software and open-source software where anyone is freely licensed to use, copy, study, and change the software in any way, and the source code is openly shared so that people are encouraged to voluntarily improve the design of the software. This is in contrast to proprietary software, where the software is under restrictive copyright licensing and the source code is usually hidden from the users.
Free/open-source software – the source availability model used by free and open-source software (FOSS) – and closed source are two approaches to the distribution of software.
These tables compare free software / open-source operating systems. Where not all of the versions support a feature, the first version which supports it is listed.
A proprietary device driver is a closed-source device driver published only in binary code. In the context of free and open-source software, a closed-source device driver is referred to as a blob or binary blob. The term usually refers to a closed-source kernel module loaded into the kernel of an open-source operating system, and is sometimes also applied to code running outside the kernel, such as system firmware images, microcode updates, or userland programs. The term blob was first used in database management systems to describe a collection of binary data stored as a single entity.
Linux is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged in a Linux distribution.
FreeBSD is a free and open-source Unix-like operating system descended from the Berkeley Software Distribution (BSD), which was based on Research Unix. The first version of FreeBSD was released in 1993. In 2005, FreeBSD was the most popular open-source BSD operating system, accounting for more than three-quarters of all installed simply, permissively licensed BSD systems.
GNU variants are operating systems based upon the GNU operating system. According to the GNU project and others, these also include most operating systems using the Linux kernel and a few others using BSD-based kernels.
In the 1950s and 1960s, computer operating software and compilers were delivered as a part of hardware purchases without separate fees. At the time, source code, the human-readable form of software, was generally distributed with the software providing the ability to fix bugs or add new functions. Universities were early adopters of computing technology. Many of the modifications developed by universities were openly shared, in keeping with the academic principles of sharing knowledge, and organizations sprung up to facilitate sharing. As large-scale operating systems matured, fewer organizations allowed modifications to the operating software, and eventually such operating systems were closed to modification. However, utilities and other added-function applications are still shared and new organizations have been formed to promote the sharing of software.
Ksplice is an open-source extension of the Linux kernel that allows security patches to be applied to a running kernel without the need for reboots, avoiding downtimes and improving availability. Ksplice supports only the patches that do not make significant semantic changes to kernel's data structures.
OpenSMTPD is a Unix daemon implementing the Simple Mail Transfer Protocol to deliver messages on a local machine or to relay them to other SMTP servers. It was publicly released on 17 March 2013 with version number 5.3, after being in development since late 2008.
Hyperbola GNU/Linux-libre is an operating system for the i686 and x86-64 architectures. It is based on Arch snapshots and Debian development. It includes the GNU operating system components and the Linux-libre kernel instead of the generic Linux kernel. Hyperbola GNU/Linux-libre is listed by the Free Software Foundation as a completely free operating system, true to their Free System Distribution Guidelines.
