IBM OS/2 (Operating System/2) - an operating system developed by IBM and Microsoft, later developed exclusively by IBM. The name means that the system was developed for the second generation of IBM personal computers.
OS/2 1.0 was released in December 1987. It was a text-based system at the time, but already had a rich API for graphics control and mouse operation. The GUI was introduced with the November 1988 release of version 1.1. In 1990, Microsoft and IBM relaxed their collaboration on OS/2. The growing popularity of the Windows desktop environment prompted Microsoft to focus on its own system. This led to a division of work on OS/2 - IBM was supposed to focus on version 2.0, while Microsoft was supposed to focus on version 3.0, known as NT OS/2. Eventually, both companies' cooperation on OS/2 was broken and Microsoft released version 3.0 as Windows NT. IBM's 1992 release of OS/2 version 2.0 included a new graphical interface and 32-bit API. However, the real 32-bit system was only the Warp 3 version of OS/2 released in 1994, which also introduced better media and Internet support.
In early 1995, in connection with the introduction of new IBM Power Series personal supercomputers by IBM, work started on OS/2 Warp 3 for PowerPC. Unfortunately, the Power Series and ThinkPad Power Series computers were not commercially successful (the main reason was the price) and work on the system was suspended. Nevertheless, there are beta versions (unstable and unsuitable for use). IBM announced that it will withdraw OS/2 from sale on December 23, 2005, and on December 31, 2006 it will end its support for the system. However, supporters of the system tried to defend OS/2 by collecting signatures under the petition to release all or part of its source code, but it was rejected.