Windows 1.0 was the very first graphical operating system released by Microsoft back in 1985. Windows 1.0 was also known as Windows Premier Edition. It included a number of applications like Calculator, Calendar, Cardfile, Clipboard viewer, Clock, Control Panel, Notepad, Paint, Reversi, Terminal, and Write.
Windows 1.0 could run on a CGA/Hercules/EGA video card (producing either monochrome or 16 color output, as shown in the screenshot to the left), and support for VGA (with a 256 color output) was added in version 1.04.
Unlike modern versions of Windows, Windows 1.0 did not allow for overlapping application windows. Instead each window was tiled on the screen.