Craig Ulmer

Revisiting my Dissertation

2020-06-12 net

Recently, I needed to dig up some references to papers I either read or wrote back in the 1990s about programmable network interface cards. Out of curiosity, I did a search for my own dissertation on the web to see if it's floating around somewhere, 17 years after I published it. It didn't surprise me that some of the slide-scraping sites had copies of my defense presentation slides (I made these available on my Ga Tech website). However, I was surprised to find two sites that claimed to have an electronic copy of the actual dissertation since I had never made it available. As it turns out, the Georgia Tech library scanned in the paper version a few years after I graduated (cool!). The other place was some scraper site in China (maybe not so surprising).

The GT Library webpage said they didn't have permission to share the dissertation with people outside GT, so I contacted them and submitted the paperwork to make it world readable. The pdf download was disappointing though- it was 40MB in size (!) and had scanner burn on several of the pages. It occured to me that I could generate a better version, resurrected from my old files. That snowballed into a lot more work than I wanted, but I finally finished it and have added it to this website. Wading through it has given me an opportunity to reflect on what I wrote.

Converting to LaTeX

Resurrecting my dissertation was an absolute chore. At the time, my advisor was curious as to whether modern WYSIWYG editors were solid enough for a dissertation, so he suggested that we buck the time-honored trend of usng LaTeX and have me write it in MS Word 2000. It seemed like a valid, harmless decision when I started, but by the end of the writing it was a constant battle to get the document done before word corrupted it in some unfixable way. To this day, I still have a fear that I'll open a word document and all my section headers will have a mysterious "Char Char Char" phrase prepended to the section title. It was handy to be able to use Power Point and Excel to do my figures and plots, though. Plus, my advisor did periodically use the Track Changes feature to get me comments and corrections. It just would have been nicer to have something in between Word (hard to precisely control) and LaTeX (hard to view while writing).

For the conversion proces, I loaded each chapter into Libre Office and then exported to either text or LaTeX depending on how complicated the text was (the LaTeX output always seemed to spew a lot of extra junk that needed to be filtered out). GT had a standard thesis/dissertation template available that did most of the document boilerplate work for me. The hard part about this process was writing a bunch of one-off awk/grep scripts to correct all the formatting mistakes that happened during export. Importing all the figures was nother problem, but I found the modern version of word let me save my Power Points/plots to pdf, which I could then trim with Linux tools. Done. The last chore was proofreading the text and fixing the bibliography. 17 years is a long time for references to stay valid and many of the product white papers simply disappeared. In the end I think I produced a pretty decent spin of my dissertation that's only 1.6MB in size. I've added a post with the dissertation back on 11/19/2002 when it happened.

Better Material than Expected

I'll admit that when I started reading my dissertation I had low expectations about the content. While I put a lot of work into my research topic, I've always felt like it was a 5% research / 95% development effort. Everyone that starts grad school thinks they'll hit some keen idea that will come up with a new way to do things that will beat quicksort, get around the Nyquist sampling rate limits (compressed sensing kinda did!), or cure cancer. Over time, most people realize that the idea tree was picked clean by the 1960's, and that most of what we've been doing since then is reacting to improvements in technology. Still, there's a lot of snobbery among researchers that if you're not writing a lot of theorems, lemmas, and QEDs in your papers, you're not doing research. My dissertation had zero proofs so I've always felt like I messed up somewhere.

Reading the text again though, I realized I explored a lot of ideas that people hadn't dug into much at the time, and that some of those ideas were things that have only become important to others in the last decade. My thesis was about how you could design a message layer that ran on a programmable NIC and managed all the gritty details about communication so that both host CPUs and peripheral devices could access the network. My word did all the things other people did at the time (low-latency, high-bandwidth messages between hosts, RDMAs to physical and virtual memory, network-interface based multicast!), plus it let you steer data to multimedia cards (video capture/display, FPGA accelerators, and storage cards). In retrospect, this kind of thing became a lot more important 5 years later when people needed a way to route data between GPUs, or more recently when vendors returned to building Smart NICs so people could embed operations in the fabric. While my dissertation had zero impact on any of this, it at least feels good to look back on it and see that I was on the right track.

The Negatives

The main negatives I had about my dissertation was that it was simply too long and filled with details that nobody would care about. After five years of Ph.D. work, I had a chip on my shoulder and wanted to write about every single aspect of what I had done, no matter how boring it was. I understand now that conciseness is the key to good writing, and that giant chunks of text could have been moved to an appendix or dropped entirely. When profs commented about how much text there was, I remember telling them I wanted it there so I'd have it for myself to read later. Well, grad-school-Craig, mid-career-Craig wants you to know he appreciates the sentiment, but he doesn't want to read all of that either. As they say out here in future land, ain't nobody got time for that.

Remembering Sudha

Reading my dissertation reminded me of all the great conversations I had with my advisor, Sudha Yalamanchili, during those years (and in later work visits). Last year Sudha passed away after a long, quiet fight with cancer. GT was not exactly a friendly school, but Sudha always had an optimism to him that made me want to stay longer and try out new ideas. While I made grad school go on longer than it should have, I'm proud of the work I did with this dissertation and am glad that I had Sudha to guide me through the whole process.