OS/2

OS/2 was IBM's proposed replacement for DOS as the primary operating system for its personal computer lines. Co-developed with Microsoft, OS/2 was intended to run in the protected mode of the Intel x86 family, which offered memory virtualization and multitasking. It was announced in the spring of 1987 at the same time as the PS/2 line of PCs, but wasn't delivered until December of the same year

Due to rapid adoption of Microsoft's Windows 3, and major differences in focus between the two companies, Microsoft stopped participation in OS/2 by 1990. IBM would gradually move OS/2 to a full 32-bit architecture which allowed it to run virtual machines that could run both DOS and Windows 3 software. Unfortunately, 3rd party adoption of OS/2 was not strong and the system often lacked in hardware drivers compared to DOS which limited both its adoption and applicability as a game platform. Later versions of OS/2 adopted a fully object oriented graphical interface called the Workplace Shell.

A few game developers did target OS/2 such as Stardock with its popular Galactic Civilizations line of games. Otherwise, most commercially released OS/2 games were ports of games already released for DOS or Unix systems.

IBM finally discontinued development on OS/2 in 2001 after years of only doing maintenance releases and stopped selling it in 2005. As late as 2016, installations of OS/2 still were in use, often using licensed third party versions such as eComStation or ArcaOS which were tweaked versions of OS/2 with minor fixes and enhancements beyond the base IBM product.