August 17, 2018 2:19 PM

LangSec and My Courses for the Year

As I a way to get into the right frame of mind for the new semester and the next iteration of my compiler course, I read Michael Hicks's Software Security is a Programming Languages Issue this morning. Hicks incorporates software security into his courses on the principles of programming languages, with two lectures on security before having students study and use Rust. The article has links to lecture slides and supporting material, which makes it a post worth bookmarking.

I started thinking about adding LangSec to my course late in the spring semester, as I brainstormed topics that might spice the rest of the course up for both me and my students. However, time was short, so I stuck with a couple of standalone sessions on topics outside the main outline: optimization and concatenative languages. They worked fine but left me with an itch for something new.

I think I'll use the course Hicks and his colleagues teach as a starting point for figuring out how I might add to next spring's course. Students are interested in security, it's undoubtedly an essential issue for today's grads, and it is a great way to demonstrate how the design of programming languages is more than just the syntax of a loop or the lambda calculus.

Hicks's discussion of Rust also connects with my fall course. Two years ago, an advanced undergrad used Rust as the implementation language for his compiler. He didn't know the language but wanted to pair it with Haskell in his toolbox. The first few weeks of the project were a struggle as he wrestled with mastering ownership and figuring out some new programming patterns. Eventually he hit a nice groove and produced a working compiler with only a couple of small holes.

I was surprised how easy it was for me install the tools I needed to compile, test, and explore his code. That experience increased my interest in learning the language, too. Adding it to my spring course would give me the last big push I need to buckle down.

This summer has been a blur of administrative stuff, expected and unexpected. The fall semester brings the respite of work I really enjoy: teaching compilers and writing some code. Hurray!


Posted by Eugene Wallingford | Permalink | Categories: Computing, Teaching and Learning

August 09, 2018 1:03 PM

Gerald Weinberg Has Passed Away

I just read on the old Agile/XP mailing list that Jerry Weinberg passed away on Tuesday, August 7. The message hailed Weinberg as "one of the finest thinkers on computer software development". I, like many, was a big fan of work.

My first encounter with Weinberg came in the mid-1990s when someone recommended The Psychology of Computer Programming to me. It was already over twenty years old, but it captivated me. It augmented years of experience in the trenches developing computer software with a deep understanding of psychology and anthropology and the firm but gentle mindset of a gifted teacher. I still refer back to it after all these years. Whenever I open it up to a random page, I learn something new again. If you've never read it, check it out now. You can buy the ebook -- along with many of Weinberg's books -- online through LeanPub.

After the first book, I was hooked. I never had the opportunity to attend one of Weinberg's workshops, but colleagues lavished them with praise. I should have made more of an effort to attend one. My memory is foggy now, but I do think I exchanged email messages with him once back in the late 1990s. I'll have to see if I can dig them up in one of my mail archives.

Fifteen years ago or so, I picked up a copy of Introduction to General Systems Thinking tossed out by a retiring colleague, and it became the first in a small collection of Weinberg books now on my shelf. As older colleagues retire in the coming years, I would be happy to salvage more titles and extend my collection. It won't be worth much on the open market, but perhaps I'll be able to share my love of Weinberg's work with students and younger colleagues. Books make great gifts, and more so a book by Gerald Weinberg.

Perhaps I'll share them with my non-CS friends and family, too. A couple of summers back, my wife saw a copy of Are Your Lights On?, a book Weinberg co-wrote with Donald Gause, sitting on the floor of my study at home. She read it and liked it a lot. "You get to read books like that for your work?" Yes.

I just read Weinberg's final blog entry earlier this week. He wasn't a prolific blogger, but he wrote a post every week or ten days, usually about consulting, managing, and career development. His final post touched on something that we professors experience at least occasionally: students sometimes solve the problems we et before them better than we expected, or better than we ourselves can do. He reminded people not to be defensive, even if it's hard, and to see the situation as an opportunity to learn:

When I was a little boy, my father challenged me to learn something new every day before allowing myself to go to bed. Learning new things all the time is perhaps the most important behavior in my life. It's certainly the most important behavior in our profession.

Weinberg was teaching us to the end, with grace and gratitude. I will miss him.

Oh, and one last personal note: I didn't know until after he passed that we shared the same birthday, a few years apart. A meaningless coincidence, of course, but it made me smile.


Posted by Eugene Wallingford | Permalink | Categories: General, Software Development, Teaching and Learning

August 07, 2018 3:04 PM

Too Bad Richard Feynman Didn't Have a Blog

There is a chapter in "Surely You're Joking, Mr. Feynman" about Feynman's work with biologists over summers and sabbaticals at Princeton and Cal Tech. He used a sabbatical year to work in a colleague's lab on bacteriophages, ribosomes, and RNA. After describing how he had ruined a potentially "fantastic and vital discovery" through sloppiness, he writes:

The other work on the phage I never wrote up -- Edgar kept asking me to write it up, but I never got around to it. That's the trouble with not being in your own field: You don't take it seriously.
I did write something informally on it. I sent it to Edgar, who laughed when he read it. It wasn't in the standard form that biologists use -- first, procedures, and so forth. I spent a lot of time explaining things that all the biologists knew. Edgar made a shortened version, but I couldn't understand it. I don't think they ever published it. I never published it directly.

Too bad Feynman didn't have a blog. I'll bet I could have learned something from his write-up. Not being a biologist, I generally can use some explanation intended for a lay reader, and Feynman's relaxed style might pull me through a biology paper. (Of all the sciences, biology is usually the biggest chore for me to learn.)

These days, scientists can post their informal writings on their blogs with little or no fuss. Standard form and formal style are for journals and conferences. Blog readers prefer relaxed writing and, for the most part, whatever form works best for the writer in order to get the ideas out to the world.

Imagine what a trove of stories Feynman could have told on his blog! He did tell them, of course, but in books like "Surely You're Joking, Mr. Feynman". But not everyone is going to write books, or have books written for them, so I'm glad to have the blogs of scientists, economists, and writers from many disciplines in my newsreader. For those who want something more formal before, or instead of, taking on the journal grind, we have arXiv.org. What a time to be alive.

Of course, when you read on in the chapter, you learn that James Watson (of Watson & Crick fame) heard about Feynman's work, thought it was interesting, invited Feynman to give a seminar talk at Harvard, and then went into the lab with him to conduct an experiment that very same week. I guess it all worked out for Feynman in the end.


Posted by Eugene Wallingford | Permalink | Categories: General

August 05, 2018 10:21 AM

Three Uses of the Knife

I just finished David Mamet's Three Uses of the Knife, a wide-ranging short book with the subtitle: "on the nature and purpose of drama". It is an extended essay on how we create and experience drama -- and how these are, in the case of great drama, the same journey.

Even though the book is only eighty or so pages, Mamet characterizes drama in so many ways that you'll have to either assemble a definition yourself or accept the ambiguity. Among them, he says that the job of drama and art is to "delight" us and that "the cleansing lesson of the drama is, at its highest, the worthlessness of reason."

Mamet clearly believes that drama is central to other parts of life. Here's a cynical example, about politics:

The vote is our ticket to the drama, and the politician's quest to eradicate "fill in the blank", is no different from the promise of the superstar of the summer movie to subdue the villain -- both promise us diversion for the price of a ticket and a suspension of disbelief.

As reader, I found myself using the book's points to ruminate about other parts of life, too. Consider the first line of the second essay:

The problems of the second half are not the problems of the first half.

Mamet uses this to launch into a consideration of the second act of a drama, which he holds equally to be a consideration of writing the second act of a drama. But with fall semester almost upon us, my thoughts jumped immediately to teaching a class. The problems of teaching the second half of a class are quite different from the problems of teaching the first half. The start of a course requires the instructor to lay the foundation of a topic while often convincing students that they are capable of learning it. By midterm, the problems include maintaining the students' interest as their energy flags and the work of the semester begins to overwhelm them. The instructor's energy -- my energy -- begins to flag, too, which echoes Mamet's claim that the journey of the creator and the audience are often substantially the same.

A theme throughout the book is how people immerse themselves in story, suspending their disbelief, even creating story when they need it to soothe their unease. Late in the book, he connects this theme to religious experience as well. Here's one example:

In suspending their disbelief -- in suspending their reason, if you will -- for a moment, the viewers [of a magic show] were rewarded. They committed an act of faith, or of submission. And like those who rise refreshed from prayers, their prayers were answered. For the purpose of the prayer was not, finally, to bring about intercession in the material world, but to lay down, for the time of the prayer, one's confusion and rage and sorrow at one's own powerlessness.

This all makes the book sound pretty serious. It's a quick read, though, and Mamet writes with humor, too. It feels light even as it seems to be a philosophical work.

The following paragraph wasn't intended as humorous but made me, a computer scientist, chuckle:

The human mind cannot create a progression of random numbers. Years ago computer programs were created to do so; recently it has been discovered that they were flawed -- the numbers were not truly random. Our intelligence was incapable of creating a random progression and therefore of programming a computer to do so.

This reminded me of a comment that my cognitive psychology prof left on the back of an essay I wrote in class. He wrote something to the effect, "This paper gets several of the particulars incorrect, but then that wasn't the point. It tells the right story well." That's how I felt about this paragraph: it is wrong on a couple of important facts, but it advances the important story Mamet is telling ... about the human propensity to tell stories, and especially to create order out of our experiences.

Oh, and thanks to Anna Gát for bringing the book to my attention, in a tweet to Michael Nielsen. Gát has been one of my favorite new follows on Twitter in the last few months. She seems to read a variety of cool stuff and tweet about it. I like that.


Posted by Eugene Wallingford | Permalink | Categories: Computing, General, Personal