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A diagram showing how the user interacts with application software on a typical desktop computer.The application software layer interfaces with the operating system, which in turn communicates with the hardware. The arrows indicate information flow.

Computer software, or simply software, is a collection of data or computer instructions that tell the computer how to work. This is in contrast to physical hardware, from which the system is built and actually performs the work. 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 programming level, executable code consists of machine language instructions supported by an individual processor—typically a central processing unit (CPU) or a graphics processing unit (GPU). 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 invoke one of many input or output operations, for example displaying some text on a computer screen; causing state changes which should be visible to the user. The processor executes the instructions in the order they are provided, unless it is instructed to "jump" to a different instruction, or is interrupted by the operating system. , most personal computers, smartphone devices and servers have processors with multiple execution units or multiple processors performing computation together, and computing has become a much more concurrent activity than in the past.

The majority of software is written in high-level programming languages. They are easier and more efficient for programmers because they are closer to natural languages than machine 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.

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A photo montage
(Pictured right: A photo montage created in Adobe Photoshop from various images and editing)

Adobe Photoshop, or simply Photoshop, is a graphics editor developed and published by Adobe Systems. It is the current market leader for commercial bitmap and image manipulation, and, aside from Adobe Acrobat, is the best-known piece of software produced by Adobe Systems. It is considered the industry standard in most jobs related to the use of visual elements. It has been described as "an industry standard for graphics professionals" and was one of the early "killer apps" on Macintosh.

Photoshop is available for Windows, OS X, and Mac OS; versions up to Photoshop 9.0 can also be used with other operating systems such as Linux using software such as CrossOver. Past versions of the program were ported to the IRIX and Solaris, but official support for this port was dropped after version 3.

The current (12th) version of the program, Photoshop CS5, was released on April 12, 2010. "CS" reflects its integration with other Creative Suite products, and the number "5" represents it as the fifth version released since Adobe re-branded its products under the CS umbrella in 2003. Photoshop CS5 features additions such as three dimensional brushes and warping tools.

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Ubuntu Software Center

Ubuntu Software Center is a computer program for browsing, installing and removing software on the Ubuntu operating system, a computer operating system based on the Debian distribution and distributed as free and open source software.

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Rms ifi large.jpg
Richard Matthew Stallman (born March 16, 1954), often shortened to rms is an American software freedom activist and computer programmer. In September 1983, he launched the GNU Project to create a free Unix-like operating system, and he has been the project's lead architect and organizer. With the launch of the GNU Project, he initiated the free software movement; in October 1985 he founded the Free Software Foundation.

Stallman pioneered the concept of copyleft, and he is the main author of several copyleft licenses including the GNU General Public License, the most widely used free software license. Since the mid-1990s, Stallman has spent most of his time advocating for free software, as well as campaigning against software patents, digital rights management, and what he sees as excessive extension of copyright laws. Stallman has also developed a number of pieces of widely used software, including the original Emacs, the GNU Compiler Collection, the GNU Debugger, and various tools in the GNU coreutils. He co-founded the League for Programming Freedom in 1989.

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Paying isn't wrong, and being paid isn't wrong. Trampling other people's freedom and community is wrong, so the free software movement aims to put an end to it, at least in the area of software.

Richard Stallman, Free Software Magazine interview, January 23, 2008

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...that BIOS software is built into personal computers, and is a type of system software?
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