A 32 bit operating system from IBM. In the early 1990ís OS/2 gave a serious competition to Windows, which many people (like this author) believed in.
Originally Microsoft was co-working with IBM on deleopment of OS/2. As Windows became successfull and popular, Microsoft left the project to go for Windows 95 and Windows NT (now Windows 2000) instead. IBM continued the development of OS/2 until 1998.
OS/2 was from a technological point of view an excellent program. The user interface was a slightly different from Windows. Right from the beginning the the 32 bits OS/2 could multitask - something Windows 98 never learned.
Looking back, OS/2 could just as well as Windows have become the standard OS for all of us. However Microsoft had much better marketing and devotion than IBM did.
Today we find OS/2 within certain branches. In this country (Denmark) some banks still use OS/2.