Why the line between an app and the operating system once landed in court
Is a web browser part of the operating system or a separate program? That sounds like pedantry, yet it was one of the central questions in the United States antitrust case against Microsoft over Internet Explorer. Deciding what counts as application software, as opposed to system software, is surprisingly slippery.
Roughly, application software is what people use to get tasks done: word processors, browsers, media players, phone apps. System software, by contrast, runs the machine, handling the hardware and sharing out its resources. The boundary is a judgment call rather than a law of nature. Besides the Microsoft trial, the long-running argument over whether to say Linux or GNU/Linux turns partly on where the kernel stops and the operating system built on it begins.
The short word app has a recent history. It caught on with the iOS App Store in 2008 as a term for smartphone and tablet programs, and spread to desktop software in general once Apple opened a Mac App Store in 2010 and Microsoft launched the Windows Store in 2011.
Some programs matter because they sell hardware. The phrase killer app, coined in the late 1980s, describes software so popular that people buy a platform just to run it. VisiCalc, the first modern spreadsheet, did that for the Apple II, helping to carry personal computers into offices, and email played the same role for the BlackBerry.
There are many ways to sort applications. Suites such as Microsoft Office, LibreOffice and iWork bundle related programs that can open each other's files. Horizontal software like a word processor serves almost everyone, while vertical software targets one industry, such as banking or manufacturing. Licences range from proprietary, where copyright is kept and usage rights are limited, to free and open-source, to public-domain code anyone may reuse without attribution. And a long debate continues over whether browser-based web apps will replace native ones; for now they tend to coexist, and sometimes merge.
Source: Application software
