In 1988, Microsoft released MS-DOS 4.0.
MS-DOS 4.0 provided XMS support, support for partitions on hard disks up to 2 GB and a graphical shell. Compatability issues and bugs were addressed in MS-DOS 4.01 later that year.
Learn more at http://en.wikipedia.org/wiki/MS-DOS
Wasn’t MS-DOS 4.0 the “NAFF” one? Much like Win Vista, everybody hated it!!
Absolutely. It was pretty much disliked across the board. The 4.0 version was very buggy. But the time 4.01 was released, the damage was done.