Windows 1.0 was the first release of what eventually made it onto almost every desktop computer in the entire world. Many of you are probably unaware of this release from 1985; conceived from ideas found in the original Lisa/Macintosh and Xerox Star system, Windows 1.0 was Microsoft's attempt at a graphical multitasking operating environment for the IBM PC.
The earliest known appearance of "Microsoft Windows" was in a 1983 Byte Magazine, and it was heavily promoted at the Fall 1983 Comdex. It was marketed as a response to GUI environments such as Digital Research GSX, VisiCorp Visi On, and Apple Macintosh, although the first completed release was not until late 1985.
Windows 1.0x features co-operative multitasking, tiled windows, ability to launch and integrate with DOS programs, runs on top of existing DOS, supports 8088 based PCs with IBM CGA, Hercules Monochrome, and IBM EGA video.
It was followed up by Windows 2.x.ScreenshotsRelease notes
The IBM PS/2 disks contain support for the IBM PS/2 Model 30, 50, 60, 80 and were distributed using 3.5" 720k media. They include drivers for the IBM PS/2 mouse interface, IBM MCGA video (monochrome VGA), IBM VGA video, and IBM 8514/A video. Because these standards were adopted on PC clones, these disks will work on many other computers and emulators.
The IBM version of Windows 1.04 was used as the runtime in the "IBM PS/2 Collegiate Kit".