https://archive.org/details/byte-magazine-1981-06 https://archive.org/details/byte-magazine-1981-06 has a very good description of Xenix starting on page 248. T

https://archive.org/details/byte-magazine-1981-06 https://archive.org/details/byte-magazine-1981-06 has a very good description of Xenix starting on page 248. This was just before the IBM PC was announced. In page 286 of https://archive.org/details/byte-magazine-1983-11-rescan https://archive.org/details/byte-magazine-1983-11-rescan one of the main advantages of MS-DOS 2.0 is supposed to be its Xenix compatibility. That is why MS-DOS 1 had CP/M style system calls while MS-DOS 2 added Unix style ones. At that time Microsoft was thinking that eventually MS-DOS and Xenix would be merged into a single operating system (I read it in yet another Byte article but can't look for it right now) but things ended up going in a different direction.