From his own blog, John writes:
"Latest news on my debilitating health issues. I’ve suffered some major health issues, and discovered I have degenerative spine disease which is the root of most of my spine problems which started in or around 2004. My first surgery was in Dec of 2009, a year later, suffered trauma from a sudden pressure on the back of my neck thanx to some dude at Defcon party, you know who you are. Everything was ok until early in 2014, I started feeling that same back pain I was suffering from back in 1009, but it progressed much further, starting early march, About the time I was invited to the home brew computer club reunion, in the Bay Area. A few weeks later, was invited to speak at the hacker hostel, when at that time the pain was getting horribly bad." Read more ....