AI Summarized Hacker News

Front-page articles summarized hourly.

Japan's Skyscraper Factories (2021)

Japan’s Skyscraper Factories examines a late-20th-century push by major builders to solve construction productivity by turning job sites into automated factories. Starting in the 1980s, firms developed on-site robotized systems (SMART, Akatuki-21, Big Canopy, ABCS, T-Up) using conveyors, climbing platforms, and single-task robots to assemble precast or cast-in-place components with just-in-time delivery. Results included labor savings (roughly 20–70%), faster high-rise construction, and less waste, but very high upfront costs and long payback limited uptake. By the 2000s the systems largely disappeared, though Shimizu continues with newer 'Smart Site' concepts.

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Let's be honest, Generative AI isn't going all that well

Gary Marcus argues that generative AI hasn’t lived up to its promises. LLMs remain unreliable; much of their output is memorization rather than genuine understanding or value. Recent signals—like the Remote Labor Index and Washington Post data—suggest AI can automate only a small share of jobs. Scaling won't fix these issues, and policymaking around such shaky technology is misguided. The root problem is overpromising by creators; the tech is viable but far smaller and less transformative than claimed.

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A 40-Line Fix Eliminated a 400x Performance Gap

QuestDB reports that a 40-line OpenJDK/Linux fix closed a 400x gap between getCurrentThreadUserTime and getCurrentThreadCpuTime. The old approach parsed /proc/self/task/<tid>/stat, causing many syscalls and parsing; the fix uses a single clock_gettime(CLOCK_THREAD_CPUTIME_ID) call. Benchmarks fell from ~11 μs to ~0.28 μs per call (≈40x). A further tweak with a manually crafted clockid to hit the kernel fast-path reduced this to ~70 ns (≈13% more). Takeaways: study kernel code, POSIX limits, and stable Linux ABI. Patch landed Dec 3, 2025.

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We Don't Use AI

Yarn Spinner does not use AI or code-generation tools, and it does not accept contributions containing generated material. They argue AI companies promote labor exploitation and harm, so they won’t support or integrate AI. Despite a background in ML, they view the current industry shift toward generative tools as harmful to workers. They prefer building better games through focused, real problems rather than marketing-driven features. They may revisit ML in the future if labor concerns are resolved. They won’t ban users from using AI, but won’t use it in Yarn Spinner.

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The Insecure Evangelism of LLM Maximalists

An LLM productivity skeptic argues that agentic coding often requires excessive babysitting and is inefficient, despite LLMs being useful as digital assistants. He favors spec-driven coding but finds prompt-driven development slow and error-prone, draining tokens. He questions why proponents push a future where developers must adapt, suggesting evangelists may be driven by insecurity or fear of obsolescence. He admits he might be wrong, is open to rethinking, and challenges evangelists to admit they may not be as skilled at programming as they claim.

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Running Lean at Scale

Harmonic reports major progress in building Mathematical Superintelligence. Highlights include: pbcc, an in-house ahead‑of‑time Python Protobuf compiler that generates fast, memory‑efficient C++ code with a native Python API and type hints; Aristotle’s gold‑medal IMO performance and 96.8% VERINA verification success, with formally verified Lean proofs and public proofs; Yuclid+Newclid 3.0 for geometry problem solving; a 90% MiniF2F SOTA with updated autoformalization and a natural‑language interface; iOS beta for Aristotle. Fundraising milestones: Series A $75M (2024), Series B $100M (2025), Series C $120M (2025) valuing Harmonic at $1.45B. Open roles mentioned.

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Open sourcing Dicer: Databricks's auto-sharder

Databricks open-sources Dicer, a dynamic auto-sharder that replaces stateless or statically sharded architectures with an intelligent control plane that continuously reassigns key ranges (Slices) to pods (via Slicelets, Clerks, and the Dicer Assigner). It maintains high availability, handles rollouts, autoscaling, and hot keys, reducing latency and cloud costs. Used in Unity Catalog and SQL Query Orchestration to achieve 90–95% cache hit rates and zero downtime during restarts; supports in-memory/GPU serving, remote caches, work partitioning, soft leader selection, and rendezvous. Dicer is now available with demos and future plans for Java/Rust libraries and state transfer.

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Show HN: Nogic – VS Code extension that visualizes your codebase as a graph

Nogic is a free VS Code extension that visualizes your codebase with interactive diagrams. It provides a unified view of files, classes, and functions and lets you create boards to organize code. Key features: class diagrams, call graphs, quick search, and auto-sync. Getting started: open the visualizer from the Command Palette and add files to a Nogic Board via the Explorer; indexing runs automatically with permission. Core commands: Open Visualizer, Create New Board, Add to Nogic Board. Tips: right-click to add, double-click to open, drag to pan/zoom.

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Are two heads better than one?

An article analyzing a coin-toss game with independent liars. If Alice lies 20%, trusting her yields 80% accuracy. Adding Bob doesn’t improve this because disagreements create ties; simulations show overall accuracy stays at 80%. Adding Charlie (three liars) can raise accuracy to about 90% by using a majority to break ties; adding a fourth liar brings it back to 90%, with the pattern repeating as more friends are added. The author links this to Condorcet’s jury theorem and notes there isn’t a widely used name for this exact phenomenon beyond its voting-theory context.

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No management needed: anti-patterns in early-stage engineering teams

Early-stage startups should avoid engineering management. Motivation is an inherent trait of top engineers; founders should hire high-powered people and not try to motivate them with long hours or micromanagement. Don’t hire managers too soon: keep a flat structure, ideally with a single ongoing leader up to about 15 engineers. Only at 20–50 engineers should you add some management. Don’t imitate Google; use boring, proven tools (node & postgres) and focus on fast product delivery. Practical tips: asynchronous updates, minimal meetings, flexible docs, extreme transparency.

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A university got itself banned from the Linux kernel (2021)

The Verge recounts how University of Minnesota researchers tried to expose weaknesses in Linux kernel review by submitting patches that fixed bugs but introduced others (hypocrite commits). After outrage from kernel developers, Greg Kroah-Hartman banned UMN affiliates from contributing to the kernel. UMN retracted the paper describing the method; the Linux Foundation demanded IRB-consented research, full disclosure of vulnerable-code proposals, and the paper withdrawal. The episode sparked debate about patch review, ethics, and trust in open-source communities; some see it as proof the system works, others condemn the approach.

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