The first version of Windows, released in 1985, was simply a GUI offered as an extension of Microsoft’s existing disk operating system, or MS-DOS.

What was the first version of Windows called?

Microsoft released Windows 1.0 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, providing an environment which can run graphical programs designed for Windows, as well as existing MS-DOS software.

What is the original PC operating system called?

The first IBM PC, formally known as the IBM Model 5150, was based on a 4.77 MHz Intel 8088 microprocessor and used Microsoft´s MS-DOS operating system.