Other

This page lists other versions and lines of Windows that are/were not part of the main Windows line. These include Windows 10X, which was intended to be a major release of Windows like Windows 10 or 11, Windows CE, the earlier OS for phones, Windows Server, a version of Windows for servers, Windows Phone 8 and 8.1, which was Microsoft's next attempt at a Windows for phones, Windows Mobile 10, the last of Microsoft's efforts in mobile phone operating systems, and MS-DOS, Microsoft's pre-Windows operating systems that led to the development of Windows.

Windows 10X

Windows 10X was an edition of Windows 10, a major release of the Microsoft Windows series of operating systems. Announced by Microsoft on October 2, 2019, it was initially developed as an operating system to support dual-screen devices, such as the unreleased Surface Neo. 10X was expected to be released in 2020, but Microsoft later announced that the project had been cancelled in May 2021. However, some features and design changes from 10X were integrated into the newer Windows 11. While the operating system was originally designed for dual-screen devices, Windows 10X shifted its target to single-screen devices in 2020 due to increasing demand for traditional computers from the COVID-19 pandemic.

IBM licensed and re-released it in 1981 as PC DOS 1.0 for use in its PCs. Although MS-DOS and PC DOS were initially developed in parallel by Microsoft and IBM, the two products diverged after twelve years, in 1993, with recognizable differences in compatibility, syntax and capabilities. Beginning in 1988 with DR-DOS, several competing products were released for the x86 platform.

Initially, MS-DOS was targeted at Intel 8086 processors running on computer hardware using floppy disks to store and access not only the operating system, but application software and user data as well. Progressive version releases delivered support for other mass storage media in ever greater sizes and formats, along with added feature support for newer processors and rapidly evolving computer architectures. Ultimately, it was the key product in Microsoft's development from a programming language company to a diverse software development firm, providing the company with essential revenue and marketing resources. It was also the underlying basic operating system on which early versions of Windows ran as a GUI. MS-DOS went through eight versions, until development ceased in 2000; version 6.22 from 1994 was the final standalone version, with versions 7 and 8 serving mostly in the background for loading Windows 9x.