Microsoft Windows

Microsoft Windows is a family of Operating Systems developed by Microsoft. It currently uses the Windows Explorer shell.

The first versions of Windows were an operating environment for DOS. Later versions (9x) used DOS as a bootstrapper. Any version of Windows that uses the NT Kernel does not rely on MS-DOS.

Windows for DOS
During this time, Windows was a desktop environment for DOS, an OS inspired by CP/M. There is a dispute whether it can be considered an operating system. One side points on the fact that it did include it's own graphics drivers and program API, which OS's do aswell, however on the other side the argument is that it extensively used the MS-DOS API. Last version of this series is Windows for Workgroups 3.11.

Windows 9x
In 1995, Microsoft released Windows 95, which utilised MS-DOS 7 at it's core. It was a hybrid 16/32bit operating system, which enabled compatibility with almost all existing Win32 applications. Windows 95 used MS-DOS for certain low-level operations, particularly the boot process, however many DOS apps were either entirely replaced with a Windows version (MS-DOS Shell could be considered one of these) or extended with Win32 code (Scandisk). DOS was primarily used as a bootstrapper in Windows 9x-based OS's. Windows ME was the last release belonging to this family.

Windows NT
Windows NT (New Technology) is the current iteration of Windows. It is built on the NT microkernel (hence the name), which was originally intended for use in OS/2 3.0 but was rewritten after the Microsoft - IBM split. The first release based on the new kernel was Windows NT 3.1, the version number of which was chosen so that eventual customers wouldn't consider it inferior to Windows 3.1, its DOS-based counterpart. All NT-based releases up until Windows 2000 were intended primarily for business use. With Windows XP, the NT series merged with Windows 9x, creating a single operating system for consumers and businesses. Windows Phone 8 is the first Windows Phone release to be based on the NT kernel. The most recent version of Windows based on the NT kernel is Windows 10. Following the release of Windows 10, Microsoft have switched to a periodical release system.