This has been a busy week, I had no time to read with attention and write notes as I read. I'm compiling what I remember now.

Chapter 17 is about standards.

It begins with the history of C standards, from early C to K&R C, to C89 and C99.
Then comes the history of UNIX standards, from the early UNIX wars to POSIX, XPG and SUS
The chapter continues with the standards-as-DNA attitude and how UNIX programs are durable through time as they are portable through hardwares.
It ends with the portability of each language.

Quote:Linux changes so fast that any given release of a distribution would probably be obsolete by the time it could get certified.

And that's probably one reason why so few Linuxes are certified as UNIX.

Chapter 18 is about documentation.

The author enumerates the available zoo of documentation formats and the styles of documentation.
WYSIWYG and hyperlinking are explored. Traditional UNIX documentation lacks both, and also lacks online/on-program documentation, except for some programs such as vim.
WYSIWYG is something I do not care for writing documentation, but TROFF syntax does not resamble at all what you get in the end.

Hyperlinking is good, but can be abused. When the user come across a lot of hyperlinks, both through the document itself and to other documents, it may give the false impression that all of them are important. I call this “hyperlink hell”. It can be solved with a good index and a SEE ALSO/REFERENCES section.