Microsoft Windows is a family of operating systems by Microsoft. They can run on several types of platforms such as servers, embedded devices and, most typically, on personal computers. Microsoft first introduced an operating environment named Windows in November 1985 as an add-on to MS-DOS in response to the growing trend of graphical user interfaces (GUI) popularized by the Macintosh. Microsoft Windows eventually came to dominate the world's personal computer market. At the 2004 IDC Directions conference, IDC Vice President Avneesh Saxena stated that Windows had approximately 90% of the client operating system market.

The Application System/400 (also known as AS/400), now System i (also known as iSeries), is a type of computer produced by IBM. It was first produced in 1988. It was then renamed to the eServer iSeries in 2000 as part of IBM's e-Server branding initiative. Now with the global move of the server and storage brands to the System brand with the Systems Agenda, the family has been renamed to System i in 2006, with the POWER5-based members of the series being called the System i5.