A Tale of Three Talks

Continuing my commentary1 on HotOS

Like my advisor, I share a fondness for the non-non-interactive talks (i.e., hold the “hold your questions until the end”, thanks). It’s unclear whether or not people really understand the value of the back-and-forth that occurs, how to steer it, or how exciting it seems to those present. Take the opening session of HotOS’09 as an illustrative example. A tale of three talks, if you will.

Margo kicked it off with a great talk2 claiming hierarchical file systems are dead[3. Interesting to look up the Urban Dictionary definition of "hFAD": "hot from a distance." Any reflection on the work? Beats me.]. Most of the 30 minutes was spent in a rolling back-and-forth that really got things off on the right foot. To my mind, a great example of a confident researcher able and willing to roll with the punches facing, what was at that point a very punchy audience.

Colin went next, presenting a paper that claimed that middleboxes are dead. 3 Coming on the heels of Margo’s talk, Colin’s got a rise from the already fairly well-stirred room, and I think he thought that things got off the rails a bit. Completing the triple feature was Mike Walfish claiming that asynchrony, too, was awaiting reaping. (Ahh, Rushdie: “Hierarchical filesystems are dead! Middleboxes are dead! Asynchrony is dead! Aargh, they’re all alive, and they’re coming after us!”4) In contrast to the prior two talks, Professor Walfish asked us to hold our questions to the end. It was amazing how quickly the audience went limp, how fast the air rushed out of the balloon. Twenty minutes later, at the close of his talk, he couldn’t even get a rise out of the crowd with the (fairly apropos, to be fair) bad pun that closed out the deck.

Now there was probably a certain degree to which a fair amount of nervous, excited energy had been pent up and was waiting to leave the room during the first couple of talks. (Remind me to beg for an early slot at HotOS-XIII.) That said, after the excited discussions that accompanied the first two talks, slamming the door on the audience was probably not the wisest move. To me it seemed like, “OK, that was fun for a bit, but now back to normal conference mode, open laptop, begin email…” (Actually I was good about staying away from my laptop throughout. It helps to have read the papers beforehand.) Interestingly enough, while I didn’t talk to Professor Walfish afterwards I did see Colin who seemed a bit shaken up, and I got the impression he didn’t think that his talk had gone that well. Au contraire, mon amis! The talks where people opened up and let the audience participate stand out in my mind as the best. Something worth thinking about when you’re hiking back into town after being tarred and feathered by a technological lynch mob. At least that’s exciting!

For me, that sort of back-and-forth produces multiple concrete benefits (besides being pulse-raising):

  • It’s a test of character. Working with someone who is so defensive that they can’t even internalize any criticism of their work is really, really hard and rarely worth the effort (IMHO). Being on the spot in front of an audience is tough. It tends to favor those that are quick-witted, able to dismiss questioners with a joke, a bit of self-deprecation, acknowledgement, or (on the rare occasion) a succinct, intelligent answer. For the rest of us, the majority that can’t answer questions on the spot without relying on some form of pattern matching (see next), our best hope is to allow the questions to steer us without giving away too much ground (see below).
  • It shows how well you understand your own work. If you’re really thought through multiple aspects of a project you can let the questions lead you and further focus the talk. It’s hard to know what a particular audience will be curious about, or what objections they’ll have. Most slide decks take a particularly safe path through the material, doing their best to obscure, minimize, or skirt dangerous territory, i.e. limitations, drawbacks, etc. And in the typical conference format with large number of attendees and limited question time, many questions are dealt with by “pattern matching”, essentially picking the answer out of my pre-determined deck of question answers that seems to address your question. It probably doesn’t, but you won’t follow up, will you? Oh, all right, let’s take the whole thing offline!
  • It lets the audience guide the talk. Interfacing with the crown means that the vulnerable points mentioned above get noticed and commented on. This might lead you towards things you might not have wanted to talk about. It also allows the audience to feel out where your Alamos are. What intellectual or design territory will you abandon if faced with even a modest assault, and where are you really going to dig in and protect this house? Finally, it lets the audience lead you toward what interest them. This is good for them, and good for you. Even if it doesn’t feel good.

I would love to see what would happen to slide decks for HotOS-XIII if the conference organizers decide to dictate that presenters must handle questions during the talk. Maybe instead of trying to steer away from tender spots you just get right to them, let it all hang out, practice intelligent and pithy justifications, and thereby avoid becoming bogged down in sniping caused by those who see through overly-rosy claims. I don’t know. A middle-ground approach would be to hold questions for the first 5 or 10 minutes of the talk, to let people get their one point across, then let the next 10-15 be more interactive and then open up for full-on Q&A.

  1. 1 []
  2. 2. The talk was great. I'm less sure about the idea, which seemed, at least based on the comments in the room, to have been rolled multiple times before. []
  3. 4. Actually, the session would have been much funnier/more interesting had the authors had to argue about which, of the three papers, had identified the thing that was really did, maybe finishing with an audience vote. Idea for HotOS-XIII: every session ends with a vote, of some kind. []
  4. 5. From "The Ground Beneath Her Feet". []


I returned last Thursday from HotOS’09, held in Monte Verita, Switzerland. It took me a few days to recover on the tail end. Staying up for the Eliot Senior Dinner Thursday night (and the drinking that ensued), and then the reopening of the NS Beer Club on Friday (more drinking) probably didn’t help my readjustment, but flying West is supposed to be easier, right?

I had a blast at the conference and thoroughly enjoyed the talks. Coming from the states, journeying out there, the stimulating talks and between- and after-talk conversation, it all made for a very intense experience. Having never been to HotOS before I can’t comment on the relative strength or weakness of the conference as a whole, but I have to say that I really enjoyed the many meta-technology discussions that I overheard and participated in, particularly the ones that happened on the terrace, overlooking the lake, punctuated by continuations of the little mini-debate about “Is this the clearest it’s been?” that percolated throughout the three days we were there. Subject included the aesthetics of technology v the desire for “truth”, anonymity and the review process, the role of computer scientists in society, and cycles of innovation and forgetfulness. 1 Maybe it was the distance up the hill, the overall sense of being “away”, or the small group of engaging, thoughtful participants. I don’t know. The alchemy escapes me, finally. It was awesome.

  1. 1. A lot of these topics were presaged, eerily, by a great conversation Colin Dixon and I had walking along the shore of Lake Zurich waiting for the train to leave Sunday. []