I went to this school – only for one year (1993) – where I became friends with a boy named "Mark Williams".
And he had a DOS floppy disk from the Mark Williams Company entitled "Mark Williams Utilities". We tried running some of the programs on it, and whatever they actually did went over both our heads, but he was just amused to have come across programs that had his name on them.
In hindsight, I'm guessing it was probably the utilities that came with their DOS C compiler, but I don't really know.
I remember their Coherent UNIX-like OS for PCs that they were selling for $99 in the early 1990s which was mentioned in the article. It came with an excellent paper manual which was like a thousand pages. If it had come out five years earlier than it did it would have been a huge success. But in the early 1990s it soon faced competition from Linux and the various BSDs.
The article gives the wrong version of Coherent for the CBM 900 -- it was way too early for Coherent 2.x. It came with 0.7, some sources say 0.72 and some 0.73.
The manuals for the utilities like awk etc. are still very helpful and clear, a bit dated but can help you learn the basics. I remember the ads and now wish I had bought Coherent back in the day as it would have accelerated my Unix learning.
And he had a DOS floppy disk from the Mark Williams Company entitled "Mark Williams Utilities". We tried running some of the programs on it, and whatever they actually did went over both our heads, but he was just amused to have come across programs that had his name on them.
In hindsight, I'm guessing it was probably the utilities that came with their DOS C compiler, but I don't really know.