MS-DOS Version 4.0 introduced a menu-driven DOS shell to ease users’ interaction with the system, but it was not widely accepted. When Version 5.0 was released, IBM and Microsoft also released a new operating system, OS/2, which was designed to replace MS-DOS. Although OS/2 offered several advantages over MS-DOS, such as using all available memory and supporting multiprogramming, it failed to generate the interest that both companies expected.