Tangential, but it's wild to me to see a vector PDF (as opposed to a scan) for a book from 1994!
Adobe Acrobat came out in 1993 but it's not like 800-page books were being distributed for it by the following year, at least not that I remember. It's really cool that whatever program that manual was typeset in, someone eventually went back and managed to export the manuscript to PDF.
Or, of course, maybe it was output in PostScript originally and they saved that and so a later conversion to PDF was trivial.
A lot of documents like that were typeset in DTP applications like FrameMaker. FrameMaker et al were sort of like WYSIWYG takes on TeX, you'd lay out template-like design elements and the input text would have markup that put the text in the elements.
Most such applications would directly spit out PostScript, enabling PDF export was straight forward. Also as you mentioned converting PostScript to a PDF was straight forward as well.
Adobe Acrobat came out in 1993 but it's not like 800-page books were being distributed for it by the following year, at least not that I remember. It's really cool that whatever program that manual was typeset in, someone eventually went back and managed to export the manuscript to PDF.
Or, of course, maybe it was output in PostScript originally and they saved that and so a later conversion to PDF was trivial.