Windows 1.0

Microsoft Windows 1.0 is a 16-bit graphical interface operating system developed and marketed by Microsoft. It is the first operating system in the Microsoft Windows family of operating systems. Released on November 20, 1985, Windows 1.0 was the first operating system by Microsoft to use a GUI rather than the text interface used in MS-DOS. It was succeeded by Windows 2.0.

History
Windows 1.01 was announced on November 10, 1983 and was originally codenamed "Interface Manager". It was released 2 years later on November 20, 1985 as Windows 1.01. Version 1.01 required a memory of 256 kilobytes or more, MS-DOS version 2.0 support, two double-sided disk drives, and a graphics-adapter card. Version 1.03, released in August 1986, introduced support for MS-DOS 3.2, enhanced keyboard support, Generic/Text-only and PostScript printer drivers support, and required 320 kilobytes of memory or higher. Version 1.04, released in April of 1987, introduced HP soft font support.