Back in the day there was also DR-DOS which was very similar and to some extent, compatible and in some aspects, better. Until the arrival of Windows, that is.

Back in the day there was also DR-DOS which was very similar and to some extent, compatible and in some aspects, better. Until the arrival of Windows, that is. Have not used it in decades, though, so I couldn't really provide details about it. In fact, back then a lot of people still used monochrome displays.