A system software component that is external to the operating system kernel. If the phrase is used to refer to the operating system itself, it is redundant because an operating system "is" software.

What are open-source operating systems? Underpinning an operating system, for example Windows on your PC or Android on your phone, is many, many lines of code. Allowing anyone to inspect the source ...

Your computer has an operating system, or OS. You may be using Microsoft Windows, Apple’s desktop Mac OS X, some variant distribution of Linux such as Ubuntu, Debian or OpenSUSE… or you may be mostly ...