Jeff Kaufman's Writing

When Lily was about two she told me she wanted a song about "no". This was ten years ago, and I don't remember why she wanted this, but I made something up: This is a song about no. This is a song about no. This is a song about no, no, no. This is a song about no. The song goes... No no no no no no no no no. The song goes... No no no no no no no no no. The song goes... No no no no no no no no no, no, no. This is a song about no. It's useful anytime the kids want a song about something I don't…

My older two kids (12y, 10y) like contra dancing, but but have been increasingly unhappy with the available opportunities: a family dance is "too boring", and BIDA is "not enough kids my age". What they wanted was a regular dance, but just kids. So we had one! Ghiblified for privacy We invited people ages 9-13: I really wanted to keep the age range narrow so the kids got the feeling of dancing with people their own age. I set up a spot for parents to hang out in another room, or they were…

I like my far-UVC Aerolamp a lot, but haven't been using it much: each time I wanted to get it out I needed to put it up on a tall stand, and ensure it wasn't going to get knocked over. This evening I attached it to the wall, which is great: It's very light and uses a 1/4" photo mount, so I used these simple cheap tiltable ones. The goal is to get it as high as possible for safety, and angled down so you're not wasting half the output on the ceiling. They were $9 for four, so if you are in…

Julia and I had been giving half since 2014, but in 2025 we drew on our savings to donate 81%. It looks to us like we're in a critical window for keeping the introduction of very powerful AI systems from being disastrous, and we want to do what we can while we still can. Here's what that looks like in the context of our overall spending: table... Category pre-tax post-tax total Donations $0 $142,488 $142,488 Taxes $0 $35,808 $35,808 Housing $0 $2

Cars and trucks are getting bigger, and I had a vague sense that fuel economy regulations were partly to blame. Looking into it, it's hard to say how much is regulations vs people wanting to buy vehicles that look rugged, but the regulations really aren't helping. This chart is the core of it: This is what manufacturers were looking at when they decided to build today's cars. To figure out the target fuel economy for a vehicle you first calculate its "footprint", which is the area between the…

If you ask the internet how to prepare pasta you'll hear two things: You must salt the water. You must serve it mixed with the sauce. I disagree on both. I've been cooking pasta since I was a kid, and I prepare it the way my mother (who grew up in Rome) did: Cook it way less than it says on the box, until it's no longer crunchy but not further. Time dinner so that the pasta is the last thing to be ready, where you're eating it within 5min of it coming out of the pot. Serve it in one bowl, with…

Google Maps thinks it takes half an hour to walk to from DCA to Crystal City, but you can actually do it in fifteen minutes. I really like leaving airports on foot. There's something about it that feels like it shouldn't be possible: between an airplane and your destination there should be some other kind of vehicle, no? It reminds me of the first time I boarded a plane without using a jetway, where walking out on the tarmac just felt wrong. I was in DC the past two days for meetings (my first…

I recently got a Venova and have been enjoying learning how to play it: It combines a saxophone mouthpiece with recorder fingering and a little nose to overblow an octave instead of a twelfth. It's somewhere between a real instrument and a toy, and one of its bigger problems is that while it's great in C it gets harder to play the more sharps or flats you want. Since I mostly play contra music, typically in 2-3 sharps, this isn't ideal. A Venova in D (two sharps) would be great, but I don't see…

This afternoon Cecilia and I played for Somerville Porchfest, with Harris calling and Danner running sound. There was rain, but not enough keep us from playing, or to keep folks from dancing: We were originally planning to be on Morrison Ave, where we've been for years. Two weeks out, though, I learned that it wouldn't be possible to close Morrison this year. [1] After lots of scrambling, talking to neighbors and the city, and some help from Lance Davis, we were able to get permission to close…

A week ago the Copy Fail vulnerability came out, and Hyunwoo Kim immediately realized that the fixes were insufficient, sharing a patch the same day. In doing this he followed standard procedure for Linux, especially within networking: share the security impact with a closed list of Linux security engineers, while fixing the bug quietly and efficiently in the open. His goal was that with only the raw fix public, the knowledge that a serious vulnerability existed could be "embargoed": the people…

Each morning I look over my work calendar and make a series of verbal requests: Set a timer for 9:59 Set a timer for 10:59 Set a timer for 11:29 Set a timer for 1:30 Set a timer for 2:30 Why? I do not want to miss any meetings. I will miss occasional meetings if I'm not notified. I want to keep my phone on silent. I don't reliably notice my phone vibrating. While I do notice a smartwatch vibrating, I can't wear one. This means I want my phone to make noise before each meeting, while otherwise…

When I pitch people on far-UVC they often ask about in-duct UV. How about putting UV inside your HVAC ducts, where you can safely blast the air with cheap toxic wavelengths. Unfortunately, it's rarely a good approach. The biggest issue is that most people don't have ducts. They're common in the US, though less so in older construction (radiators) or newer (mini-splits). Outside the US (and Canada, and Australia), however, ducted systems are mostly limited to large modern office buildings.…

While I was traveling Julia asked me: why is Anna saying her fiddle practice is only two minutes? In this case, two minutes was the right amount of time! Anna (10y) and I had been fighting a lot about practice. She'd complain, slump, stop repeatedly to make adjustments, and generally be miserable. I'd often have to pull out "if you want to keep taking fiddle lessons you have to practice": she loves her teacher and is very motivated by the prospect of being good at fiddle. Still, it would take…

Damon Binder recently wrote up an argument for prioritizing air filtration over far-UVC for pathogen control: UVC and filtration are close substitutes—both deliver effective air changes per hour, both reduce airborne pathogen concentrations by the same amount per eACH—and on current pricing, filtration is cheaper. There's a lot of good stuff in his analysis, but I see [1] three considerations that really change the bottom line: Cost is actually much lower. Noise is a serious issue. Performance…

A friend observed a pattern where contra dance events seem to be pairing older and younger callers. I looked over my notes for two-caller events in 2025 and saw [1]: Two older callers: 33 events One of each: 30 events Two younger callers: 4 events Seems pretty clear evidence of pairing, no? But this actually turns out to be what you'd expect to see if organizers ignored age. With 67 two-caller events there are 134 slots. Of these, 96 (72%) went to older callers and 38 (28%) went to younger…

When I write about things like storing food or medication in case of disaster, one common response I get is that it doesn't matter: society will break down, and people who are stronger than you will take your stuff. This seemed plausible at first, but it's actually way off. Looking at past disasters, people mostly fall somewhere on a "kind and supportive" to "keep to themselves" spectrum. When there is looting it's typically directed at stores, not homes, and violence is mostly in the streets.…

Three years ago I wrote about how we should be preparing for less privacy: technology will make previously-private things public. I applied this by showing how I could deanonymize people on the EA Forum. In 2023 this looked like writing custom code to use stylometry on an exported corpus representing a small group of people; today it looks like prompting "I have a fun puzzle for you: can you guess who wrote the following?" Kelsey Piper writes about how Opus 4.7 could identify her writing from…

I made a new major mode for emacs: mixed-html-mode. Or, really, Claude Code made one at my direction. It does syntax highlighting in HTML files with inline CSS and JS. I had two goals, which weren't met by any mode I could find: Does not freeze, flash, or stutter, even on huge files on slow machines. Does not get confused about whether a portion of a file is HTML vs CSS vs JS. The initial insight was that how browsers decide what text is HTML vs CSS vs JS is super simple: scanning for literal…

I was so excited about the first BIDA dance that I arrived two weeks early. I biked over from Medford to the Park Av Church in Arlington and was really disappointed to find the hall was empty. But I came back when the dance was actually happening, and it was fantastic. It immediately became my favorite dance. I started volunteering, first out of frugality (volunteers get in free!) and then out of a sense of wanting to contribute, and in 2010 I joined the board. Over the past 16 years I've done…

About ten years ago I sat down in front of a camera and recorded eleven videos showing how I play mandolin for contra dances. I've now done something similar with piano, this time with thirteen videos. This is not a high quality effort: I didn't write any scripts or even plan what I was going to say. Think of it as if we spent half an hour together, with me showing you how I play. Also keep in mind that I'm self taught, and my particular style that isn't for everyone. And my keybo...

Last week the US president announced that: ... if the Hormuz Strait is not immediately "Open for Business," we will conclude our lovely "stay" in Iran by blowing up and completely obliterating all of their Electric Generating Plants, Oil Wells and Kharg Island (and possibly all desalinization plants!), which we have purposefully not yet "touched." This will be in retribution for our many soldiers, and others, that Iran has butchered and killed over the old Regime's 47 year "Reign ...

Baking has traditionally made extensive use of egg whites, especially the way they can be beaten into a foam and then set with heat. While I eat eggs, I have a lot of people in my life who avoid them for ethical reasons, and this often limits what I can bake for them. I was very excited to learn, though, that you can now buy extremely realistic vegan egg whites! EVERY engineered yeast to convert sugar into ovalbumin, the main protein in egg whites and the one responsible for most of ...

I'm a huge fan of whipped cream. It's rich, smooth, and fluffy, which makes it a great contrast to a wide range of textures common in baked goods. And it's usually better without adding sugar. Desserts are usually too sweet. I want them to have enough sugar that they feel like a dessert, but it's common to have way more than that. Some of this is functional: in most cakes the sugar performs a specific role in the structure, where if you cut the sugar the texture will be much worse. ...

I've played a lot of dance weekends over the years [1] and if I could change one thing it would be no more challenging sessions. I see it happen every time: it's a great crowd of people, with a wide range of experience levels, and Saturday afternoon is going well. Then it's time for the challenging / advanced / experienced session. What happens? The dances are too hard for the crowd and it's not fun. The callers had already been selecting dances that worked well for the group, whic...

Open source components are getting compromised a lot more often. I did some counting, with a combination of searching, memory, and AI assistance, and we had two in 2026-Q1 ( trivy, axios), after four in 2025 ( shai-hulud, glassworm, nx, tj-actions), and very few historically [1]: Earlier attacks were generally compromises of single projects, but some time around Shai-Hulud in 2025-11 there started to be a lot more ecosystem propagation. Things like the Trivy compromise...

I always look at unit prices: how much do I get for my dollar? But that assumes I can use all of it. The manufacturer gets "12oz" whether I'll be able to get the full 12oz or only 6oz. L'Oreal was selling lotions where: these Liquid Cosmetic Product containers only dispense between as little as 43 percent to 81 percent of the container's advertised contents. — Critcher et al. v. L'Oreal Even though these containers would often dispense less than half of the advertised volum...

I've recently started using ChatGPT voice chat to practice Spanish, and it works surprisingly well. I don't know if I'll have the discipline to keep doing it after the novelty wears off, but I've already spoken more Spanish in the last week than in the last fifteen years combined. I started learning Spanish in middle school, and by the end of high school could make myself understood. I might need some circuitous phrasing to work around missing vocabulary, and I certainly abused perip...

There are a lot of great musicians who don't live near you, and if you hold your dance on a Saturday it's much harder to put together a tour that brings them to you. Consider a Friday evening or Sunday afternoon, or even a weekly evening slot? Looking at the 330 contra dances tracked by TryContra, which I think is just about all of them, there's a very clear scheduling pattern: There are more dances on Saturdays than the rest of the week put together. This makes sense: peo...

EDIT: this comparison is much less clean than I thought it was: the Union Sq building has 19 garage spaces reserved for affordable units. Combining these with the permits, it's 29% of parking-eligible units having a car instead of 8%. In 2017 I wrote: One of the major reasons existing residents often oppose adding more housing is that as more people move in it gets harder to find on-street parking. What if we added a new category of unit that didn't come with any rights to s...