Long ago (1988) I moved to Berkeley and started sending a monthly "newsletter" to my Boston friends. When I returned to Boston (1993), I continued the tradition for about five more years (or until I had kids). Looking back, I realize that I was actually blogging. Each newsletter contained anywhere from a few to several blog posts. Having been silent for the past decade or so, I've decided to resume these activities. Don't expect anything profound -- I tend to focus on what I find entertaining or amusing and perhaps sometimes informative. We shall see!

Wednesday, September 2, 2015

At it again ....

About three years ago I did a series of posts reporting on my experience flipping my operating systems class. Well, I'm baaaaack.

Whereas the big challenge I experienced last time was avoiding overloading the students with pre-class preparation while they were in the midst of implementing large, complex, challenging assignments, this time the key challenge is scale. CS61 is one of our introductory courses and has been running about 150 students. And, just in case that didn't pose enough of a challenge, it's also been part of the certificate program offered through the extension school -- so I have students flung around the globe taking this same class I'm trying to flip. Well, I do hope you'll join me on this adventure. As I did before, I will try very hard to write weekly posts, revealing the good, the bad, and the ugly -- all in the service of education science!

Let me launch the series with a little bit of what's been happening behind the scenes.

Hiring Staff

Having taught large introductory courses before, I knew that I was going to have to start early recruiting teaching fellows (TFs) (teaching assistants in other schools). I got started a bit later than I intended, but I did manage to advertise for TFs and interview people last spring. There were, however, a few obstacles.

  1. Most of our students have never taken a flipped class, so while I can tell them all about it and point them to my blog, they don't really know what they are getting into. Maybe this is good.
  2. Now that CS50 is the largest course in the college, a very large number of our undergraduates (who often make outstanding teaching fellows for introductory courses) are already involved in CS50.
  3. I did not realize how much attrition there would be over the summer. This is perhaps fodder for another post, but I have had more students this summer consider taking a year off to join a startup than ever before.
  4. I didn't realize that I could have hired a teaching fellow for the entire spring semester to help me prepare. That would have been amazingly helpful.

Enough whining -- I am happy to report that I have assembled an awesome collection of teaching fellows. They are sharp, enthusiastic, and best of all, they seem to have bought into my vision of the course and the idea that we're going to support our students in learning a bunch of really cool stuff!


It might not be the final frontier, but where the heck do you flip a class of 150 students? The beautiful classroom we have that is used for flipping holds about 60 officially and perhaps 75 in a pinch. That's way shy of 150.

I had my eyes on a large open space in the basement of one of our newish buildings (amusingly, this is called the Northwest building and while it is, in fact, north of most of campus, it's actually not west of much). The space was officially event space, but it looked just about the right size to fill with tables and white boards and hold a humungous flipped classroom.

It took the better part of the summer, but I am pleased to report that pedagogy won out and I was given the space, the school purchased new furniture, and they replaced doors on the adjacent rooms to help with soundproofing. In fact, everyone was terrific about making this happen. It took while to all come together though, and so I put off preparing materials until I knew that this fantasy of mine was going to come to fruition. That made for a rather hectic end of August and will make for a pretty frantic semester, but c'est la vie.


In my OS course, I kept things very low tech: audio annotated powerpoint. I recorded individual slide clips using Audacity, converted to video using moyea and then made the videos smaller using handbrake. It was a bit of a nuisance, because Moyea only runs on Windows and I do everything else on my Mac. In February, I was in a Microsoft store and saw Office Mix -- a way to incorporate Q&A, screen shot, recording, etc into a nice powerpoint video. I thought this would be the ideal tool to prepare my video clips, so I wanted to test it. Alas, it doesn't run on Mac. It also doesn't run on my ThinkPad Tablet II. So I contacted IT to see if I could borrow a machine (for just a few hours) to give the thing a run before buying a machine. After multiple weeks of being told "any day now" I was informed that they could get me a machine one week before classes started. I freaked. I ordered a Surface 3.

I am happy to report that it was worth it. I really like the capabilities that Mix provides. There are, however, a few things that I would love to see fixed:

  1. If you want the interactive Q&A, you have to run it on Microsoft's servers. Sad. I want to host everything locally.
  2. If I want identified per-student data on the questions, I have to have students create Microsoft accounts. I'm not excited about requiring that.
  3. You can really only fit one question on a slide -- I'd really like a more compact presentation so I could have a list of questions on a slide.
  4. I would love some global operators (make all my audio clips start automatically).

After bugging my teaching fellows and trying all sorts of different ways of presenting material, I decided that I would embed some Q&A in the videos, but not the "pre-class work" that I keep track of as part of participation. Instead, I would continue to use google forms for that (even though the Mix analytics are much better). In this way, I can host the videos on the MS servers, but do not need to require a login. If you're interested in the technology, you can check it out here. (Select any of the pre-class videos.)

Extension School

Here's the real conundrum: how do you teach a flipped class via distance learning? The students are used to watching videos of live lecture and then having sections, but recording a live flipped classroom doesn't actually make all that much sense now does it?

Fortunately, my colleague, Harry Lewis, has been offering his flipped class via extension. One of our former graduates has been his teaching assistant and is regarded as the guru of flipped distance ed. So, I lured her over to the house one weekend (since I still couldn't drive; see previous blog series on total hip replacement) to talk flipping and eat homemade biscotti. She assured me that you could run good interactive sessions using the extension school's web conferencing software. So, that's what we're doing.

We will try to record some of the class time and make it available, but the extension students can tune in for a live, instructor guided, web conference to go through the in-class exercises. We will have live streaming of section, but I'm not going to require attendance there, since I think the web conferences will be more important and I didn't want to ask them to do three days per week. We'll have to see how this all works out.

Off and Running

Other than the hours I've spent watching last year's lectures, making pre-class materials, developing in-class exercises, and figuring out the infrastructure that the previous instructor developed, that's about it! Tomorrow is our first class -- our goal: make sure students understand what they are getting themselves into!

Until next week!

Find all posts about flipping this course here.


  1. I couldn't access the link in your technology section: http://cs61.seas.harvard.edu/2015/Schedule. It gives me an error.

    1. Apologies for the delay -- should be all fixed now.

  2. Do you have pictures of the awesome new gigantic flipped classroom??

  3. This comment has been removed by the author.

  4. Glad to hear faculty take the summer off... not

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