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Colm MacCarthaigh

@colmmacc.bsky.social
1.9K followers 352 following 221 posts

VP / Distinguished Engineer at Amazon Web Services. Also: Open Source and Apache, Cryptography, Irish Music, mediocre Photography.

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Colm MacCarthaigh @colmmacc.bsky.social · 07/10/2026
In Margaret Hamilton's honor, @awscloud.bsky.social gives a "Hamilton Award" at our weekly ops meeting to builders whose curiosity and foresight prevented operational issues before they could happen. RIP. news.mit.edu/2026/margare...
news.mit.edu
Margaret Hamilton, computing pioneer who led software development for the Apollo program, dies at 90
Margaret H. Hamilton, a profoundly influential computer scientist best known for leading the software engineering team at MIT’s Instrumentation Lab during NASA’s Apollo program, died at age 90.
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Colm MacCarthaigh @colmmacc.bsky.social · 06/10/2026
"I guess I had nothing to do that weekend, so I decided to fall in love."
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Colm MacCarthaigh @colmmacc.bsky.social · 04/10/2026
Congrats! that's huge.
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Colm MacCarthaigh @colmmacc.bsky.social · 03/10/2026
Consciousness is a story we tell ourselves. It's the only pure truth we are objectively certain of, but paradoxically and definitionally, it is totally subjective. Any determinations about AI consciousness will always be a matter of belief.
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Colm MacCarthaigh @colmmacc.bsky.social · 29/09/2026
AI safety talk fixates on stopping rogue superintelligence. We should talk far more about building solid, benevolent assistants that help people flourish. Automation is always coming ... how lucky are we that AI can even recognize evil?
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Colm MacCarthaigh @colmmacc.bsky.social · 24/09/2026
For a show I always wonder if they tailor to the model, or tailor the model to the cloths. They have so many models to choose from that finding the person it fits perfectly with small adjustments is viable. In this case though, who else could dance like that!
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Colm MacCarthaigh @colmmacc.bsky.social · 21/09/2026
We pay the highest tier specifically to avoid ads. If we see an ad, we'll just cancel. Simple as that. For us, ads are non-negotiable. We can spend it on blu-ray box-sets for our kid if it comes to it.
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Colm MacCarthaigh @colmmacc.bsky.social · 18/09/2026
I had a fun time putting on my ridiculous hard hat and talking about how we build datacentres and AI with Ella. datacentremagazine.com/podcasts/ep-...
datacentremagazine.com
Ep. 15: Why AI Infrastructure Must Stay Agile
AWS’s Colm MacCárthaigh explores cloud infrastructure, edge computing, AI demand, power constraints and why agility is critical at scale.
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Colm MacCarthaigh @colmmacc.bsky.social · 15/09/2026
This was one of the reasons we went with a HMAC based derivation scheme for AWS SIGv4. I hope more copy it!
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Colm MacCarthaigh @colmmacc.bsky.social · 15/09/2026
A spreadsheet. No joke. Used for my basement 10U, and for hyperscale compute clusters.
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Colm MacCarthaigh @colmmacc.bsky.social · 09/09/2026
O.k. but hear me out, iPhone Duo FaceTime looks perfect for chasing our toddler around while keeping him on camera with his grandparents. This could be a killer feature.
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Colm MacCarthaigh @colmmacc.bsky.social · 08/09/2026
If it were about decelerating that growth alone, wouldn't it target say ... Americans with lucky grandparents?
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Colm MacCarthaigh @colmmacc.bsky.social · 07/09/2026
Cape Town vibes
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Colm MacCarthaigh @colmmacc.bsky.social · 29/08/2026
It also has big mountains, a big lake, everything is very expensive, is a liberal dot surrounded by classical conservatism, and the people can be quite aloof! But also Dublin is the San Francisco of Europe.
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Colm MacCarthaigh @colmmacc.bsky.social · 25/08/2026
I'm kinda love/hate that Dolly Parton locked away one last single not to be heard until 2045. Sure would like to hear it now. That's all I got.
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Colm MacCarthaigh @colmmacc.bsky.social · 19/08/2026
CIS person here. I believe that we as a society can afford it, that it's good for us all to take care of one another, and that we will all be enriched by giving each other the best life that they can have. That it is good for its own sake. But for me it's not about "deserves".
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Reposted by Colm MacCarthaigh
Tommaso Gagliardoni @tomgag.infosec.exchange.ap.brid.gy · 06/08/2026
Uh-oh... eprint.iacr.org/2026/1591 Potentially worrying. Has anyone looked into it already? #cryptography #pqc #crypto #quantum #quantsec #postquantum #lattice
eprint.iacr.org
A Polynomial-Time Quantum Algorithm for the Dihedral Coset Problem
We present a polynomial-time quantum algorithm for the Dihedral Coset Problem (DCP). The algorithm is based on Regev's polynomial-time reduction of the Dihedral Subgroup Problem (DSP) to the modular subset sum problem, but uses a different technique to erase sample bits without use of a subset sum oracle. The algorithm can thus combine with Regev's reduction of lattice problems to DCP, improved by Brakerski, Kirshanova, Stehl{\'e} and Wen, to yield polynomial-time quantum algorithms for various lattice problems, such as finding a polynomial-factor approximation to the shortest vector in an $n$-dimensional lattice (SVP), and the ``learning with errors'' problem (LWE). The algorithm can tolerate a faulty sample rate as high as $1/O(\log{n})$, allowing the algorithm-reduction combination to efficiently solve, for example, SVP with a $\sqrt{n}$ polylog($n$) approximation factor, or LWE instances with $\alpha=\sqrt{n}$ polylog($n$).
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Colm MacCarthaigh @colmmacc.bsky.social · 02/08/2026
What a Ms. Take
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Colm MacCarthaigh @colmmacc.bsky.social · 29/07/2026
That's actually how the unit is defined.
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Colm MacCarthaigh @colmmacc.bsky.social · 24/07/2026
static.klipy.com
DeLorean Time Travel Vanish
ALT: DeLorean Time Travel Vanish
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Colm MacCarthaigh @colmmacc.bsky.social · 16/07/2026
You were! It was fun and we did have volleyball :)
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Colm MacCarthaigh @colmmacc.bsky.social · 16/07/2026
At my last gig we had a company summer party planned. A big party on a Dutch beach. The time and location were fixed, but one of the notes in the invite was that there may or may not be beach volleyball because it depended on the tide. As if it were like weather.
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Colm MacCarthaigh @colmmacc.bsky.social · 07/07/2026
Meanwhile you've been bought off with cricket food trucks!!
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Colm MacCarthaigh @colmmacc.bsky.social · 07/07/2026
But by the teen years, soccer isn't a dominant or valorized sport in the US for boys. The most athletic boys gravitate elsewhere. In Ireland, GAA and Rugby have a very similar effect. To a larger degree than similarly sized countries like Scotland or Norway.
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Colm MacCarthaigh @colmmacc.bsky.social · 07/07/2026
In Seattle, our nearly-three-year-old boy has been in two different lil' kickers soccer programs. One indoors, and one in a nearby park. Cheap and coached by teenagers. In Maine, our nephew has the same. It's much more accessible than baseball, softball, hockey, basketball, or American football.
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Colm MacCarthaigh @colmmacc.bsky.social · 09/06/2026
They say it's better to clean and tidy as you go, but if you put off cleaning and tidying until it just can't wait any more then you might die before that happens and just think you could have been wasting some of your final moments cleaning and tidying.
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Colm MacCarthaigh @colmmacc.bsky.social · 15/05/2026
Why divide, when you can multiply?
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Reposted by Colm MacCarthaigh
LRB Bookshop @londonreviewbookshop.co.uk · 13/04/2026
samuel beckett was born on this day 120 years ago. astonishing to think that if he had survived, and could run 100m in 9.57 seconds, he would be not only the oldest but also the fastest man in the world - together with his nobel prize for literature, an astonishing trifecta
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Colm MacCarthaigh @colmmacc.bsky.social · 10/04/2026
Last year at a security review of a particular thing I brought out some pens and just kept writing the alphabet on paper until someone caught the visual metaphor. More pen testing. It amused me at least.
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Colm MacCarthaigh @colmmacc.bsky.social · 21/03/2026
The cycle is complete. If 'Rock and Roll Kids' were written today — with the same 32-year nostalgia as when it won Eurovision in 1994 — it'd be about Kurt Cobain, Riverdance, and ... Rock and Roll Kids. www.youtube.com/watch?v=ohBO...
youtube.com
Paul Harrington & Charlie McGettigan - Rock 'n' Roll Kids | Ireland 🇮🇪 | Winner of Eurovision 1994
YouTube video by Eurovision Song Contest
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Colm MacCarthaigh @colmmacc.bsky.social · 16/03/2026
Last year, Jessica Lee Gagné was the first woman to win the Cinematography Emmy too. The best known photographer in the world is also a woman. This is a field that could be dominated by women within a decade or two. For our collective enrichment!
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Colm MacCarthaigh @colmmacc.bsky.social · 16/03/2026
Blursed. 4 leaves is always a tell to Irish people. In the 10 minutes I spent at the Disney store in Dublin, 5 different Irish people must have remarked on their "Irish" Mickey having the wrong number of leaves.
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Colm MacCarthaigh @colmmacc.bsky.social · 15/03/2026
Of course in reality, politics would react to the change in constituency formation, and so applying polls from geographic based voting is kind of garbage, but it's interesting to see how polarized the results still come out. Elections seem a good bit more competitive under this model though.
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Colm MacCarthaigh @colmmacc.bsky.social · 15/03/2026
It used to take me a few days to do these kind of cross-tabulated experiments, and I could never get the charting that good on my own. Pretty cool.
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Colm MacCarthaigh @colmmacc.bsky.social · 15/03/2026
I asked Kiro to use that table to figure out the lean for each age-range, and to make the chart. Finally, a few tweaks to make the chart more readable. About 30 minutes work. I then asked Claude and ChatGPT each to red team it and find flaws, and I did re-check using different polls.
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Colm MacCarthaigh @colmmacc.bsky.social · 15/03/2026
Then, I asked it to create a table of political leaning by age in each state, using curve fitting. It chose to use the National age-bracket Democratic two-party vote shares from the 2024 AP VoteCast, and piecewise-linear interpolation between bracket midpoints.
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Colm MacCarthaigh @colmmacc.bsky.social · 15/03/2026
Next up; I asked it to divide each states age groups, starting from age 18, into "N" equally sized groups, where N is the number of US representatives in that state. It chose to do a least mean squares regression using dynamic programming.
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Colm MacCarthaigh @colmmacc.bsky.social · 15/03/2026
Next, I asked it to adjust the size of each group to count the children of parents or caregivers against that group. Kiro chose the Census Bureau American Community Survey and its Number of Own Children (NOC) data.
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Colm MacCarthaigh @colmmacc.bsky.social · 15/03/2026
I asked Kiro to find demographic data for each US state and build population pyramids. It chose the US Census Bureau Population Estimates Program (PEP) and fetched the data.
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Colm MacCarthaigh @colmmacc.bsky.social · 15/03/2026
I vibed this whole chart in about 30 minutes using Kiro, reviewed it myself, and then pressure tested it with Claude Code and ChatGPT. Here's the general approach ...
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Colm MacCarthaigh @colmmacc.bsky.social · 15/03/2026
What if instead of geographic constituencies for the House of Representatives, we had demographic constituencies? Each representative elected by roughly equally-sized age groups, counting children with their parents or carers. Wonder no more ...
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Colm MacCarthaigh @colmmacc.bsky.social · 15/03/2026
Here for this 1000%
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Colm MacCarthaigh @colmmacc.bsky.social · 10/03/2026
Cherry blossoms fall before anyone could say what they meant to say
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Colm MacCarthaigh @colmmacc.bsky.social · 04/03/2026
Been like this for me for months. I'm on Safari and use a Google Apps domain identity which might contribute, but that can't be that unusual.
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Colm MacCarthaigh @colmmacc.bsky.social · 04/03/2026
What is with YouTube these days? I pay for YT Premium, but there are so many bugs. It wants me to sign in again every day, yet somehow the sidebar is still personalized with my subscriptions and history. Trying to play a short in browser never works the first time, I get the next in the roll.
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Colm MacCarthaigh @colmmacc.bsky.social · 09/02/2026
Just some frequentists waiting on a few more samples.
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Colm MacCarthaigh @colmmacc.bsky.social · 09/02/2026
Who would ever name a stout that? what? I can't even ... wait, is it because it's loaded full of Iron?
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Colm MacCarthaigh @colmmacc.bsky.social · 09/02/2026
Costco was packed today during Super Bowl - busier than previous years, even when Seattle played. Our traditional hack is losing its clout.
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Colm MacCarthaigh @colmmacc.bsky.social · 06/02/2026
It used to cost half a penny to cross the Liffey, but a quarter of panti could get you a whole new perspective on life.
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Colm MacCarthaigh @colmmacc.bsky.social · 05/02/2026
This ... x.com/timbray/stat...
x.com
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