OS/2 is a series of computer operating systems, initially created by Microsoft and IBM, then later developed by IBM exclusively. The name stands for ""Operating System/2"", because it was introduced as part of the same generation change release as IBM's ""Personal System/2 (PS/2)"" line of second-generation personal computers. The first version of OS/2 was released in December 1987 and newer versions were released until December 2001.OS/2 was intended as a protected mode successor of PC DOS. Notably, basic system calls were modeled after MS-DOS calls; their names even started with ""Dos"" and it was possible to create ""Family Mode"" applications: text mode applications that could work on both systems. Because of this heritage, OS/2 shares similarities with Unix, Xenix, and Windows NT in many ways.OS/2 is no longer marketed by IBM, and IBM standard support for OS/2 was discontinued on 31 December 2006. It has been since maintained with relatively few new features under the name of eComStation.