Microsoft threw its hat into the Graphical User Interface ring with the beginning of their “interface manage” project. And that ring was quite well established already: earliest GUIs came out with the Alto computer (named for Palo Alto, where it was developed) and was popularized by the Apple I. Microsoft introduced it to the public first in 1983, but its design was so similar to the Macintosh, they were forced to take two additional years to redesign it.

On this day, November 20, in 1985, after a long delay, Microsoft released its Windows version 1.0 on the market.

This time instead of the overlapping windows, Microsoft tiled them – a concept that remains in the current versions. But the windows could not be resized, only hidden, in which case an icon would appear on the taskbar representing the program. The entire operating system came on two 5.25″ floppy disks and required a minimum of 192 KB of RAM.