Operating systems in the context of Scheduler (computing)

Software consists of computer programs that instruct the execution of a computer. Software also includes design documents and specifications.

The history of software is closely tied to the development of digital computers in the mid-20th century. Early programs were written in the machine language specific to the hardware. The introduction of high-level programming languages in 1958 allowed for more human-readable instructions, making software development easier and more portable across different computer architectures. Software in a programming language is run through a compiler or interpreter to execute on the architecture's hardware. Over time, software has become complex, owing to developments in networking, operating systems, and databases.

A screen reader is a form of assistive technology (AT) that renders text and image content as speech or braille output. Screen readers are essential to blind people, and are also useful to people who are visually impaired, illiterate or learning-disabled. Screen readers are software applications that attempt to convey what people with normal eyesight see on a display to their users via non-visual means, like text-to-speech, sound icons, or a braille device. They do this by applying a wide variety of techniques that include, for example, interacting with dedicated accessibility APIs, using various operating system features (like inter-process communication and querying user interface properties), and employing hooking techniques.

Microsoft Windows operating systems have included the Microsoft Narrator screen reader since Windows 2000, though separate products such as Freedom Scientific's commercially available JAWS screen reader and ZoomText screen magnifier and the free and open source screen reader NVDA by NV Access are more popular for that operating system. Apple Inc.'s macOS, iOS, and tvOS include VoiceOver as a built-in screen reader, while Google's Android provides the Talkback screen reader and its ChromeOS can use ChromeVox. Similarly, Android-based devices from Amazon provide the VoiceView screen reader. There are also free and open source screen readers for Linux and Unix-like systems, such as Speakup and Orca.

An exploit is a method or piece of code that takes advantage of vulnerabilities in software, applications, networks, operating systems, or hardware, typically for malicious purposes.The term "exploit" derives from the English verb "to exploit," meaning "to use something to one’s own advantage."Exploits are designed to identify flaws, bypass security measures, gain unauthorized access to systems, take control of systems, install malware, or steal sensitive data.While an exploit by itself may not be a malware, it serves as a vehicle for delivering malicious software by breaching security controls.

Researchers estimate that malicious exploits cost the global economy over US$450 billion annually.In response to this threat, organizations are increasingly utilizing cyber threat intelligence to identify vulnerabilities and prevent hacks before they occur.

Since the 1990s, there has been ongoing debate over whether operating systems that use the Linux kernel in combination with GNU software should be referred to as Linux or GNU/Linux.

Supporters of the term Linux argue that it is more widely used in the media and by the general public, and that it serves as a practical shorthand for systems that combine the Linux kernel with software from a variety of sources, including the GNU Project.

Bash (short for "Bourne Again SHell") is an interactive command interpreter and scripting language developed for Unix-like operating systems. Created in 1989 by Brian Fox for the GNU Project, it is designed as a completely free software alternative for the Bourne shell, sh, and other proprietary Unix shells, supported by the Free Software Foundation. Having gained widespread adoption, Bash is commonly used as the default login shell for numerous Linux distributions. It also supports the execution of commands from files, known as shell scripts, facilitating automation.

The Bash command syntax is a superset of the Bourne shell's syntax, from which all basic features of the Bash syntax were copied. As a result, Bash can execute the vast majority of Bourne shell scripts without modification. Some other ideas were borrowed from the C shell, its successor tcsh, and the Korn Shell. It is available on nearly all modern operating systems, making it a versatile tool in various computing environments.

In information technology and computer science, especially in the fields of computer programming, operating systems, multiprocessors, and databases, concurrency control ensures that correct results for concurrent operations are generated, while getting those results as quickly as possible.

Computer systems, both software and hardware, consist of modules, or components. Each component is designed to operate correctly, i.e., to obey or to meet certain consistency rules. When components that operate concurrently interact by messaging or by sharing accessed data (in memory or storage), a certain component's consistency may be violated by another component. The general area of concurrency control provides rules, methods, design methodologies, and theories to maintain the consistency of components operating concurrently while interacting, and thus the consistency and correctness of the whole system. Introducing concurrency control into a system means applying operation constraints which typically result in some performance reduction. Operation consistency and correctness should be achieved with as good as possible efficiency, without reducing performance below reasonable levels. Concurrency control can require significant additional complexity and overhead in a concurrent algorithm compared to the simpler sequential algorithm.