Windows 1.0 was released on November 20, 1985, as the first version of the Microsoft Windows line. It runs as a graphical, 16-bit multi-tasking shell on top of an existing MS-DOS installation. Windows 1.0 was the first of its kind and was a major milestone the way computers work. By being able to do things such as cooperative multitasking and encouraging development from all companies, Windows 1.0 paved the way for many others just like it. It spawned a line of software that are still used to this day, and led Windows to be what they are now.