DR-DOS 6.0

Faced with substantial competition in the DOS arena, Microsoft released MS-DOS 5.0 in June 1991, which included advanced features similar to those of DR-DOS 5.0. forcing Digital Research to responde with DR-DOS 6.0. in September 1991.

DR-DOS 6.0 bundled in SuperStor - on-the-fly disk compression, to maximize available hard disk space. It also included an API for multitasking on CPUs capable of memory protection, namely the Intel 80286 and newer. The API was available only to DR-DOS aware applications, but well-behaved ordinary DOS applications can also be pre-emptively multitasked by the bundled task-switcher, TaskMax. On 286-based systems, allowing only one process to execute at a time, DOS applications are suspended to the background to allow others to run.

Microsoft responded with
MS-DOS 6.0, which again matched some features of DR-DOS 6.0.