The first software system that I worked on was the operator consoles for a nuclear power plant. A two year long dev project. We used Framemaker (1990, before Adobe purchased them). Was an awesome tool for technical documentation. Our documentation when printed and bound was three feet wide on a shelf. I think I contributed two inches. It's been all downhill since - both in terms of the tools and the quality of the documentation. Now days it's the typical - auto-gen from code plus markdown for narrative.