We on Team DTrace knew John to be a remarkably talented and determined software engineer. As those who have attempted ports can attest, DTrace passes through rough country, and a port to a foreign system is a significant undertaking that requires mastery of both DTrace and (particularly) the target system. And in being the first to attempt a port, John's challenge was that much greater -- and his success in the endeavor a tribute to both his ability and (especially) his tenacity. For example, in performing the port, John decided that DTrace's dependency on the cyclic subsystem was such that it, too, needed to be ported. He didn't need to do this (and indeed, other ports have decided that an arbitrary resolution profile provider is not worth the significant trouble), but that he undertook this additional technical challenge anyway -- even when any victory would remain hidden to all but the most expert eye -- says a lot about John as both an engineer and a man. Later, when the port ran into some frustrating licensing issues, John once again did not give up. Rather, he backed up, and found a path forward that would satisfy all parties -- even though it required significant technical reworking on his part. I have long believed that the mark of a great engineer is not how frequently they get knocked down, but rather how quickly they get back up -- and in this regard, John was indisputably a giant.
John, you will be missed -- not only by the FreeBSD community upon which you made an indelible mark, but by those of us in the DTrace community who only had the opportunity to work with you more recently. And while your legacy might remain anonymous to the future generations that will benefit from the fruits of your long labor, we will always know that it never would have happened without you. Thank you, and farewell.
(Those who wish to memorialize John may want to do as I did and make a donation in his memory to the FreeBSD Foundation.)