OS/2 started as an effort between Microsoft and IBM in the mid-80s when the two industry giants were looking for an alternative OS to beat Apple's Mac OS. OS/2 version 1.0 was text-mode only with a graphical user interface added to version 1.1. Windows 3.0 and OS/2 shared common APIs and source code back in the beginning of the '90s, but Microsoft was playing a double game regarding their partnership with IBM. When they realized that they could continue developing Windows 3.1 without the help of IBM, they put an end to that relationship. IBM continued developing OS/2 alone and even tried to port it to the PPC platform.
The OS had its highest success in 1994 with the release of OS/2 Warp 3. I remember that in 1995 demo CDs of Warp 3 were bundled with RAM Magazine in Greece, a country not too hot for computers at the time. Warp 4 was released in 1996, but soon after IBM stated that they would be limiting support for the OS. This was due to Windows 95 taking the desktop market by storm.
Die-hard advocates and developers asked IBM to license Warp to them so they could continue supporting the community. Aurora was born, but supporting a full blown OS was proved difficult to the organize. The community started to shrink dangerously, but Serenity Systems managed to convince IBM to let them give it a go and continue develop OS/2. So, just some months ago, eComStation OS/2 1.0 was released, and this is the version I will review today.
To read more about OS/2 history, here are two articles: The story from a cold & objective point of view, and the moving story from the eyes of an OS/2 (ex-fanatic) developer (not by just any developer, but the person who released the best selling OS/2 application ever).