PDF was extracted from an archive on <a href="http://www.collyer.net/who/geoff/9/" rel="nofollow">http://www.collyer.net/who/geoff/9/</a>, that's why it's hosted on my web site.
Interesting that there's no discussion of 9front, probably some of the most fanatical lovers of plan9.<p>It is worth buying their copy of the programmer's manual for how good it is.