Recently, the oldest known versions of DOS were uploaded to the internet, and Michal Necasek dove into the floppy images. Even after more than 40 years(!), old software releases and pre-releases can still surface. In the case of 86-DOS 0.11 and 0.34 it’s practically a miracle, since there were probably never very many copies in existence. For the first time since the early 1980s, FAT formatted floppies with the primordial 16-byte directory entry format have come to light. The old 16-byte directory entries were gone by 86-DOS 1.0 in April 1981 and of course never appeared in any public PC DOS release. These prehistoric versions of 86-DOS allow us to fill in further missing pieces in the puzzle of DOS origins. It is fascinating to follow how DOS developed from almost nothing to a multi-million dollar business in the course of just a few years. ↫ Michal Necasek It started out so humbly. Yet, here we are, in 2024, and variants of DOS still have their uses in certain niches. An incredible legacy, for sure.