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All I really want is to spend my life learning new things and sharing them with others.
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Teiva Harsanyi retweeted
The breakthrough that let us crush Dragon's Lair and Starcraft also makes it *much* easier to set up Antithesis. So we're launching a simpler offering for startups and small teams. DM us for early access, brutal honesty required.
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Teiva Harsanyi retweeted
okay so, @Revolut is running on a single Google Cloud region?
The most innovative fintech in the world is single cloud, single region, with no failover?
maybe "dinosaur banks" are not that bad huh
The most innovative fintech in the world is single cloud, single region, with no failover?
maybe "dinosaur banks" are not that bad huh
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Teiva Harsanyi retweeted
If anyone has used the monorepo in Google and Meta they know what this is. There is no point pulling the entire repo down like Git because by the time your git fetch completes, a few dozen/hundred diffs get merged
Best to make shallow copy-on-write file system level pull of the monorepo of the files you are working on.
Any company which had tens of thousands of engineers working on a monorepo have had to do this already. I do not know how it works in Amazon/MSFT but I suspect similar things there too.
When you use Agents, you reach the 10k "agents" working on the same repo very quickly even with ~100 engineers. You need the same primitives that these large companies have.
Best to make shallow copy-on-write file system level pull of the monorepo of the files you are working on.
Any company which had tens of thousands of engineers working on a monorepo have had to do this already. I do not know how it works in Amazon/MSFT but I suspect similar things there too.
When you use Agents, you reach the 10k "agents" working on the same repo very quickly even with ~100 engineers. You need the same primitives that these large companies have.
RIP Git
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Teiva Harsanyi retweeted
@JackEllisl@satyanadellaat i would never presume what the problems are. i have not seen the inside of github's architecture since 2019. i know they have good folks working there. i know that type of scale coming so quickly is very hard to react to when you run at the scale GiHub runs at. nothing is really that elastic, and orders of magnitudes more traffic showing up very quickly is hard to get in front of. I've worked at extreme scale before and seen companies spend three months just preparing for events that will increase their traffic by 10% or 20% percent, which is nothing compared to what GitHub's facing now.
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Teiva Harsanyi retweeted
🥳 Google is donating Agent Substrate to CNCF, and our submissions is accepted today! This effort has now the full potential to become the underlying compute runtime layer for all agentic systems. github.com/cncf/sandbox/i…
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Teiva Harsanyi retweeted
THE ANNOUNCEMENT: We’re going to make the prophecy of The Year of Linux on the Desktop come true. All the pieces are now in place. Time to go all in! omarchy.org/news/2026/08/o…
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Teiva Harsanyi retweeted
August has been a weird month for iximiuz Labs so far. Signups and playground usage are up compared to June and July. But the revenue is significantly down - way below the sustainability level.
To stimulate things a bit, I'm running the Fair Pricing pilot - you can pick your asked. If you've been considering upgrading your membership, now is a good time to both support the labs and get a good deal: labs.iximiuz.com/pricing
Reposts are much appreciated, too!
And if you don't know what iximiuz Labs is, it's an indie learning-by-doing platform where you can master Linux, networking, containers, and Kubernetes in interactive VM-based playgrounds.
To stimulate things a bit, I'm running the Fair Pricing pilot - you can pick your asked. If you've been considering upgrading your membership, now is a good time to both support the labs and get a good deal: labs.iximiuz.com/pricing
Reposts are much appreciated, too!
And if you don't know what iximiuz Labs is, it's an indie learning-by-doing platform where you can master Linux, networking, containers, and Kubernetes in interactive VM-based playgrounds.
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Systems Thinking Explained: From Events to Systemic Structures
read.thecoder.cafe/p/systems-thin…
read.thecoder.cafe/p/systems-thin…
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Teiva Harsanyi retweeted
In 2022, as a Google intern, I sent a random calendar invite to Jeff Dean.
He accepted.
His calendar was accessible even to interns, so I figured I had nothing to lose.
The next day, I sent this photo to my team. Everyone was shocked.
It’s hard to imagine Google without Jeff. gest inspirations.
Thank you for everything, Jeff.
He accepted.
His calendar was accessible even to interns, so I figured I had nothing to lose.
The next day, I sent this photo to my team. Everyone was shocked.
It’s hard to imagine Google without Jeff. gest inspirations.
Thank you for everything, Jeff.
Tomorrow will be my last day at Google after 27 years, and watching it grow from 25 people to 190,000+ has been an amazing journey. Below is a note I shared with many people internally at Google today. An excerpt is:
It has been an absolute pleasure to work with you and to help widely used and impactful products of all time. As a kid, I dreamed of helping build software that would be used by many people, and Google now has thirteen products used by more than a billion people (amazing!). Our work has had a tremendous impact in the world, and I have been lucky enough to collaborate and form friendships with many colleagues that I deeply admire, respect, and enjoy. It still brings me joy every time I see people out in the world using our products to find information, handle email, translate documents, watch videos, learn new things, navigate and understand the physical world, browse the web, use their phone, run large-scale computations on our infrastructure, ride in an autonomous vehicle, or perform complex tasks with the help of our AI systems. I hope you all share this sense of joy, because it is a shared accomplishment! Thank you to all of my colleagues at Google over many years!
Now I'm excited to go start @DiscoLoopAI with my longtime friends and colleagues @Sanjay_Ghemawat, @OriolVinyalsML, and @quocleix.
(Updated post: slightly redacted to not have some personal info)
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Teiva Harsanyi retweeted
At least I don't have to hear about how great pair programming is anymore
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Teiva Harsanyi retweeted
My Go Concurrency book is now available on Amazon:
amazon.com/dp/B0H94S2G4K
And, of course, it's still free to read on my website:
antonz.org/go-concurrency
With interactive examples!
amazon.com/dp/B0H94S2G4K
And, of course, it's still free to read on my website:
antonz.org/go-concurrency
With interactive examples!
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Did my book create a series? Yes, it did.
One of the fastest ways to learn isn't avoiding mistakes. It's understanding why they happen.
That's what makes "mistakes to avoid" books so effective. They expose the common traps that trip people up, helping you build stronger intuition instead of just memorizing the right
• 100 Go Mistakes and How To Avoid Them by @teivah
• 100 C++ Mistakes and How to Avoid Them
• 100 Java Mistakes and How to Avoid Them by @tagir_valeev
• 100 SQL Server Mistakes and How to Avoid Them
Browse today's Deal of the Day: hubs.la/Q04nRn2h0
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Teiva Harsanyi retweeted
A French engineer who lives quietly in Paris has spent 30 years writing software that the entire internet now runs on without knowing his name.
He wrote the code that streams every YouTube video, every Netflix show, every TikTok clip. He wrote the code that runs the virtual Google Cloud, and Microsoft Azure. He calculated more digits of pi than anyone in history. He has no Twitter. He has no marketing. He just keeps shipping.
His name is Fabrice Bellard.
Here is the story, because almost nobody outside the systems programming world knows what one man has built.
Fabrice was born in 1972 in Grenoble, France. He studied at École Polytechnique, the top French engineering school. He never went to Silicon Valley. He never built a startup empire. He just wrote code.
In 2000 he started a project called FFmpeg, an open-source multimedia framework for encoding, decoding, and streaming video. He was 28. The project did one thing nobody else had done well. It handled every video and audio format that existed, in one library, on every operating system. He led it himself for years.
Today FFmpeg is the invisible engine of the internet. YouTube uses it. Netflix uses it. VLC uses it. Chrome and Firefox use parts of it. Every Android phone, every iPhone, every smart TV, every video editing tool you have ever touched runs FFmpeg somewhere underneath. If you have watched a video on a screen in the last 20 years, Fabrice's code processed it.
He was not done.
In 2003 he started QEMU, a machine emulator and virtualizer. He wrote it solo until version 0.7.1 in 2005. QEMU lets you run any operating system on any other operating system. It became the foundation of modern virtualization. KVM, the Linux kernel hypervisor, runs on top of QEMU. Every major cloud provider, AWS, Google Cloud, Microsoft Azure, IBM Cloud, runs virtual machines on infrastructure built around it. The Quick Emulator is the most cited piece of cloud infrastructure code on Earth.
He kept going.
In 2001 he won the International Obfuscated C Code Contest with a small C compiler that grew into TCC, the Tiny C Compiler. TCC can compile and boot a Linux kernel from source in under 15 seconds. In 2004 he calculated the most digits of pi ever computed at the time, using a personal desktop computer and an algorithm he derived himself called Bellard's formula. In 2011 he wrote a complete PC emulator in pure JavaScript that runs Linux in your browser, a project called JSLinux that engineers still cannot believe is real.
In 2019 he released QuickJS, a small but complete JavaScript engine that fits where V8 cannot. In 2021 he released NNCP, a neural network based lossless data compressor that immediately took the lead on the Large Text Compression Benchmark.
Then he turned his attention to large language models. He built TextSynth Server, a web server with a REST API for running LLMs locally. He released ts_zip and ts_sms, compression utilities that use language models to compress text and short messages at ratios traditional algorithms cannot reach. He released TSAC, a very low bitrate audio compression system. In December 2025 he released Micro QuickJS, a new JavaScript engine for microcontrollers, separate from QuickJS, designed for environments with almost no memory.
Fabrice co-founded a telecom company called Amarisoft in 2012, where he serves as CTO. Amarisoft builds 4G and 5G base station software used by carriers and labs around the world. He has been running it for over a decade while continuing to ship personal projects from his own home page at bellard dot org
He has no Twitter. He has no Instagram. He gives almost no interviews. His personal website is a flat list of projects with no styling, no fonts, no marketing copy. Just titles and links.
A quiet French engineer who never moved to Silicon Valley wrote the code that quietly runs the internet.
He is still shipping.
He wrote the code that streams every YouTube video, every Netflix show, every TikTok clip. He wrote the code that runs the virtual Google Cloud, and Microsoft Azure. He calculated more digits of pi than anyone in history. He has no Twitter. He has no marketing. He just keeps shipping.
His name is Fabrice Bellard.
Here is the story, because almost nobody outside the systems programming world knows what one man has built.
Fabrice was born in 1972 in Grenoble, France. He studied at École Polytechnique, the top French engineering school. He never went to Silicon Valley. He never built a startup empire. He just wrote code.
In 2000 he started a project called FFmpeg, an open-source multimedia framework for encoding, decoding, and streaming video. He was 28. The project did one thing nobody else had done well. It handled every video and audio format that existed, in one library, on every operating system. He led it himself for years.
Today FFmpeg is the invisible engine of the internet. YouTube uses it. Netflix uses it. VLC uses it. Chrome and Firefox use parts of it. Every Android phone, every iPhone, every smart TV, every video editing tool you have ever touched runs FFmpeg somewhere underneath. If you have watched a video on a screen in the last 20 years, Fabrice's code processed it.
He was not done.
In 2003 he started QEMU, a machine emulator and virtualizer. He wrote it solo until version 0.7.1 in 2005. QEMU lets you run any operating system on any other operating system. It became the foundation of modern virtualization. KVM, the Linux kernel hypervisor, runs on top of QEMU. Every major cloud provider, AWS, Google Cloud, Microsoft Azure, IBM Cloud, runs virtual machines on infrastructure built around it. The Quick Emulator is the most cited piece of cloud infrastructure code on Earth.
He kept going.
In 2001 he won the International Obfuscated C Code Contest with a small C compiler that grew into TCC, the Tiny C Compiler. TCC can compile and boot a Linux kernel from source in under 15 seconds. In 2004 he calculated the most digits of pi ever computed at the time, using a personal desktop computer and an algorithm he derived himself called Bellard's formula. In 2011 he wrote a complete PC emulator in pure JavaScript that runs Linux in your browser, a project called JSLinux that engineers still cannot believe is real.
In 2019 he released QuickJS, a small but complete JavaScript engine that fits where V8 cannot. In 2021 he released NNCP, a neural network based lossless data compressor that immediately took the lead on the Large Text Compression Benchmark.
Then he turned his attention to large language models. He built TextSynth Server, a web server with a REST API for running LLMs locally. He released ts_zip and ts_sms, compression utilities that use language models to compress text and short messages at ratios traditional algorithms cannot reach. He released TSAC, a very low bitrate audio compression system. In December 2025 he released Micro QuickJS, a new JavaScript engine for microcontrollers, separate from QuickJS, designed for environments with almost no memory.
Fabrice co-founded a telecom company called Amarisoft in 2012, where he serves as CTO. Amarisoft builds 4G and 5G base station software used by carriers and labs around the world. He has been running it for over a decade while continuing to ship personal projects from his own home page at bellard dot org
He has no Twitter. He has no Instagram. He gives almost no interviews. His personal website is a flat list of projects with no styling, no fonts, no marketing copy. Just titles and links.
A quiet French engineer who never moved to Silicon Valley wrote the code that quietly runs the internet.
He is still shipping.
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Teiva Harsanyi retweeted
LeetCode but for Linux, Docker, Kubernetes, and Networking problems? 🤔
245 hands-on challenges (over half are free) based on real-world scenarios that come with:
- Preconfigured environments
- Automated verification
- Hints and editorial solutions
labs.iximiuz.com/challenges
245 hands-on challenges (over half are free) based on real-world scenarios that come with:
- Preconfigured environments
- Automated verification
- Hints and editorial solutions
labs.iximiuz.com/challenges
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Teiva Harsanyi retweeted
RAM exists as a 1-dimensional space. For programming…that’s kind of irritating.
All the important math happens in 2D arrays.
It’s simple(ish) to compress a higher level space into a single dimension (most languages today are row-major), but there’s a funny quirk.
At the the actual bits *are* stored in a 2D array, rows and columns. (…well, when you add up all the layers, it’s more like a hierarchy of 2D arrays, but you get my point).
If this information was directly exposed to you…gosh there are all sorts of neat tricks you can get away with!
Unfortunately, keeping memory addresses in a 1-D space makes things much simpler from the OS perspective for memory management, not to mention code portability. There are nasty security problems too...certainly some valid reasons for keeping physical structure hidden.
Yet, think of how much of performance engineering / memory locality work could be shortcutted if it were trivial to understand the exact physical layout of how your arrays were stored!
All the important math happens in 2D arrays.
It’s simple(ish) to compress a higher level space into a single dimension (most languages today are row-major), but there’s a funny quirk.
At the the actual bits *are* stored in a 2D array, rows and columns. (…well, when you add up all the layers, it’s more like a hierarchy of 2D arrays, but you get my point).
If this information was directly exposed to you…gosh there are all sorts of neat tricks you can get away with!
Unfortunately, keeping memory addresses in a 1-D space makes things much simpler from the OS perspective for memory management, not to mention code portability. There are nasty security problems too...certainly some valid reasons for keeping physical structure hidden.
Yet, think of how much of performance engineering / memory locality work could be shortcutted if it were trivial to understand the exact physical layout of how your arrays were stored!
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Teiva Harsanyi retweeted
This is such a great example of theory vs practice. In theory, UUIDv4 collisions don't happen (generating one million per second, probability of seeing one collision in a year is ~10^-8).
But they have been observed to happen in practice, especially in distributed systems. Why?
But they have been observed to happen in practice, especially in distributed systems. Why?
UUID v4 collisions are less rare than you think 💣
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