MS-DOS 4.0 (multitasking)

MS-DOS 4.0 was a multitasking release of MS-DOS developed by Microsoft based on MS-DOS 2.0. A lack of interest from OEMs, particularly IBM, led to it being released only in a scaled-back form, and it is sometimes called European MS-DOS 4.0 because it was primarily used there; it should not be confused with the unrelated PC DOS 4.00 or MS-DOS 4.01 and later, which did not carry its multitasking features. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/