July 16, 2020 10:47 AM

Dreaming in Git

I recently read a Five Books interview about the best books on philosophical wonder. One of the books recommended by philosopher Eric Schwitzgebel was Diaspora, a science fiction novel by Greg Egan I've never read. The story unfolds in a world where people are able to destroy their physical bodies to upload themselves into computers. Unsurprisingly, this leads to some fascinating philosophical possibilities:

Well, for one thing you could duplicate yourself. You could back yourself up. Multiple times.
And then have divergent lives, as it were, in parallel but diverging.
Yes, and then there'd be the question, "do you want to merge back together with the person you diverged from?"

Egan wrote Diaspora before the heyday of distributed version control, before darcs and mercurial and git. With distributed VCS, a person could checkout a new personality, or change branches and be a different person every day. We could run diffs to figure out what makes one version of a self so different from another. If things start going too wrong, we could always revert to an earlier version of ourselves and try again. And all of this could happen with copies of the software -- ourselves -- running in parallel somewhere in the world.

And then there's Git. Imagine writing such a story now, with Git's complex model of versioning and prodigious set of commands and flags. Not only could people branch and merge, checkout and diff... A person could try something new without ever committing changes to the repository. We'd have to figure out what it means to push origin or reset --hard HEAD. We'd be able to rewrite history by rebasing, amending, and squashing. A Git guru can surely explain why we'd need to --force-with-lease or --unset-upstream, but even I can imagine the delightful possibilities of git stash in my personal improvement plan.

Perhaps the final complication in our novel would involve a merge so complex that we need a third-party diff tool to help us put our desired self back together. Alas, a Python library or Ruby gem required by the tool has gone stale and breaks an upgrade. Our hero must find a solution somewhere in her tree of blobs, or be doomed to live a forever splintered life.

If you ever see a book named Dreaming in Git or Bug Report on an airport bookstore's shelves, take a look. Perhaps I will have written the first of my Git fantasies.


Posted by Eugene Wallingford | Permalink | Categories: Computing, General, Software Development

July 07, 2020 2:42 PM

Spurious Precision

When I pestered Conway for more details regarding the seminal Moscow meeting that inspired his triumphant half-day of discovery, he begged off. He was loath to add any "spurious precision", as he came to refer to his embellishments, advertent or accidental. "My memory. My memory is a liar," he said. "It's a good liar. It deceives even me."

I love the phrase "spurious precision". It's a great name for something I see in the world -- and, all too often, in my own mind. I should be as careful with my own memory as Conway tried to be in this instance.

(From a 2015 profile in The Guardian.)


Posted by Eugene Wallingford | Permalink | Categories: General

July 01, 2020 3:19 PM

Feeling Unstuck Amid the Pandemic

Rands recently wrote about his work-from-home routine. I love the idea of walking around a large wooded yard while doing audio meetings... One of his reasons for feeling so at ease struck a chord with me:

Everyone desperately wants to return to normality. I am a professional optimist, but we are not returning to normal. Ever. This is a different forever situation, and the sooner we realize that and start to plan accordingly, the sooner we will feel unstuck.

I have written or spoken a variation of this advice so many times over my fifteen years as department head, most often in the context of state funding and our university budget.

Almost every year for my first decade as head, we faced a flat or reduced budget, and every time several university colleagues expressed a desire to ride the storm out: make temporary changes to how we operate and wait for our budgets to return to normal. This was usually accompanied by a wistful desire that we could somehow persuade legislators of our deep, abiding value and thus convince them to allocate more dollars to the university or, failing that, that new legislators some future legislature would have different priorities.

Needless to say, the good old days never returned, and our budget remained on a downward slide that began in the late 1990s. This particular form of optimism was really avoidance of reality, and it led to many people living in a state of disappointment and discomfort for years. Fortunately, over the last five or ten years, most everyone has come to realize that what we have now is normal and has begun to plan accordingly. It is psychologically powerful to accept reality and begin acting with agency.

As for the changes brought on by the pandemic, I must admit that I am undecided about how much of what has changed over the last few months will be the normal way of the university going forward.

My department colleagues and I have been discussing how the need for separation among students in the classroom affects how we teach. Our campus doesn't have enough big rooms for everyone to move each class into a room with twice the capacity, so most of us are looking at ways to teach hybrid classes, with only half of our students in the classroom with us on any given day. This makes most of us sad and even a little depressed: how can we teach our courses as well as we always have in the past when new constraints don't allow us to do what we have optimized our teaching to do?

I have started thinking of the coming year in terms of hill climbing, an old idea from AI. After years of hard work and practice, most of us are at a local maximum in our teaching. The pandemic has disoriented us by dropping us at a random point in the environment. The downside of change in position is that we are no longer at our locally-optimal point for teaching our courses. The upside is that we get to search again under new conditions. Perhaps we can find a new local maximum, perhaps even one higher than our old max. If not, at least we have conducted a valuable experiment under trying conditions and can use what we learn going forward.

This analogy helps me approach my new course with more positive energy. A couple of my colleagues tell me it has helped them, too.

As many others have noted, the COVID-19 crisis has accelerated a few changes that were already taking place in our universities, in particular in the use of digital technology to engage students and to replace older processes. Of the other changes we've seen, some will certainly stick, but I'm not sure anyone really knows which ones. Part of the key to living with the uncertainty is not to tie ourselves too closely to what we did before.


Posted by Eugene Wallingford | Permalink | Categories: General, Managing and Leading, Teaching and Learning