MS didn't use / for directory separators before. They wanted to in DOS 2.0, but that would mean they had to change / in front of options to something else. So t

MS didn't use / for directory separators before. They wanted to in DOS 2.0, but that would mean they had to change / in front of options to something else. So to keep backwards compatibility they used \ instead. It's true that they were ok with breaking that backwards compatibility, but IBM convinced them not to