Released in 1985 by Microsoft, this was their first attempt at implementing a graphical user interface that could multitask on a personal computer. Microsoft sent kits to industry executives and press containing a cryptic squeegee and washcloth along with an invitation to the unveiling of their new software.
Regarded mostly as a front end interface to MS-DOS, it included it’s own memory management system and device drivers for common hardware. Originally little interest was shown in the software, as the market was currently happy with other offerings. This version of the operating system ran a shell known as the MS-DOS Executive. Modern Windows users would be surprised to find that it didn’t allow overlapping windows, instead it tiled them! The only thing allowed to be over one was a dialog box. It was later replaced by Windows 2.0 in Nov., 1987.