What was Microsoft’s best Windows operating system of all time ... the transition from the text-based world of MS-DOS into the visual world of the GUI, which had taken off with 1983’s release ...

To get the answer, just put a decimal point in the number "50"—my first Microsoft product was MS-DOS 5.0.

Apple's portable, 9-inch-screen computer was an exciting graphical leap ... was using an IBM PC (or a clone) and running MS-DOS, Microsoft's character-based operating system on which we ran everything ...