Linux is an operating system that was designed to provide PC users a free or very low-cost operating system comparable to traditional and usually more expensive Unix systems. Linux was developed by Linus Torvalds at the University of Helsinki in Finland. It is sometimes suggested as a possible publicly developed alternative to the desktop predominance of Microsoft Windows. Although Linux is popular among users already familiar with Unix, it remains far behind Windows in numbers of users. Linux has an estimated desktop operating system market share of 4 percent.