Back in 1995 I bought this rather expensive, and ambitious book simply called: Developing Your Own 32-Bit Operating
And while it is a LONG read, it really is the embodiment of Apple pie from scratch. Rather than rely on open and available tools, the author Richard Burgess instead goes on to write his own assembler, compiler, and then onward to a simple message passing RTOS.
No doubt the price he paid for eschewing popular GNU tools, and having a non BSD/GPL license for the time is that it was quickly relegated to history as the inevitable rise of Linux took place.
Recently while reading a comment about PC-MOS/386 v5.01 final, I came back to MMURTL, which is now in the public domain.
For those wishing to look, not only is the source code and a few patches available on the site ipdatacorp.com, but so is a PDF of the 1st edition of the book.
While MMURTL may not have caught on in the marketplace of ideas, it’s still astounding to look at the volume of work produced, that even though open source tools and starting points were available (The book easily could have been using CMU Mach 3.0) instead it’s all written from scratch by a single person.