Random Dennis Ritchie story: my high school principal was Dennis' brother, John, and had a "UNIX Magic" poster (<a href="https://i.imgur.com/aqg21UI.jpg" rel="nofollow">https://i.imgur.com/aqg21UI.jpg</a>) hanging in his office.<p>I asked him what that was about and he dismissed it with a wave of his hand, as if annoyed: "oh, just something my brother did".
I didn't read the thesis itself yet but I feel like some key point must be missing from the article. The "loop programs" described are nearly identical to the "abacus machine" presented in the textbook <i>Computability and Logic</i> (pp. 55-56 3rd ed.) which cites Joachim Lambek who published "How to Program an Infinite Abacus" in 1961 which seems to also be trivially close in structure (not merely equivalent).<p>Lambek in turn cites Melzak's "An Informal Arithmetical Approach to Computability and Computation" which not identical - it has transfer and arbitrary compare branch instructions - but that seems a compromise for pedagogical purposes as deriving both from the "abacus" seems fairly trivial to me.
I am not surprised about the effort it took to find a copy of Ritchie's dissertation. Dissertations tend to be difficult to find if they are not already listed on WorldCat or in ProQuest. But the museum used the best method in this case: talk to people close to people who had a copy at one point. In my experience when all else fails, this strategy is the primary one that ends up working. It doesn't work all the time, and I still am looking for a few "ancient" technical reports despite some sustained effort on my part, but I have been able to find several documents/reports just by asking the right people.<p>Does anybody else have similar experiences? I'm interested if there are other avenues that somebody could try as well.
So after reading this, is it correct to say that Ritchie basically showed in his thesis the application of the for loop for recursive prime number computation and also its application to computational complexity? AFAIK for loops where already known at the time since they first appeared in ALGOL a little earlier?
When I was a teen, K&R The C Programming Language changed my life. Years later I shared an elevator with him at Usenix. I always regretted not saying something to him, but I didn't have the words.<p>Kids: If you meet your heroes, say something. "Thank you" is good if you don't have the words.
"he shows that assessing loop programs by their depth of loops is exactly equivalent to Grzegorczyk’s hierarchy. The rate of growth of primitive recursive functions is indeed related to their computational complexity, in fact, they are identical."<p>"I would have loved to collaborate with him, because he seemed like a smart, nice guy who’d be fun to work with, but yeah, you know, he was already doing other things. He was staying up all night playing Spacewar!”
> <i>My graduate school experience convinced me that I was not smart enough to be an expert in the theory of algorithms and also that I liked procedural languages better than functional ones.</i><p>I wonder if that last bit was as unfashionable a statement when he made it as it would be now.
> He already had a coveted job as a researcher at Bell Labs, and “never really loved taking care of the details of living.”<p>I love reading things like this. It reminds me that I'm not alone (although, yes, I realise Ritchie is dead). I find it very hard to participate in these kind of trivialities even though many other people seem to value them so much that it mean the difference between a PhD and no PhD. But I'll often kick myself later for not bothering. I wonder if Ritchie did.