1. Google’s Liquid Cooling
Total comment counts : 6
Summary
Liquid cooling is expanding from PC enthusiasts to datacenters, driven by AI’s power demands. Google highlights a datacenter-scale water loop for TPUs: CDUs (Coolant Distribution Units) in racks, two non-mixing liquid circuits, heat transferred via split-flow cold plates; TPUv4 uses bare-die for higher heat transfer. Liquid cooling cuts cooling power consumption (pumps use <5% of air-based fan power). In datacenters, maintenance is managed with no downtime via extra CDUs, extensive leak testing, alerts, and scheduled checks. Enthusiast and datacenter approaches converge on efficiency but diverge in scale, reliability, and protocols.
Top 1 Comment Summary
The piece argues it’s odd to compare Google-scale data-center design with PC hobbyist rigs, noting that mainframes have heavily used water cooling for over 50 years and dense HPC centers have used liquid cooling for at least 20 years. It accuses the comparison of selective amnesia and being off-target, suggesting large-scale centers’ cooling practices are well established and should not be framed as novel or comparable to hobbyist setups.
Top 2 Comment Summary
TPU chips are cooled in a series loop, with cooling capacity allocated based on the last chip’s requirements. Regardless of series or parallel configuration, four 250W chips with 1 L/min flow will produce an outlet water temperature about 14°C hotter than the inlet due to water’s specific heat.
2. Show HN: Base, an SQLite database editor for macOS
Total comment counts : 44
Summary
Base is a compact SQLite editor for everyone. It includes a schema inspector to view table structures, types, constraints, and relationships, plus a visual table editor for creating or altering tables without SQL. A data browser lets you view, filter, and edit table data. An SQL editor offers autocomplete, syntax highlighting, and reusable snippets for quick queries. You can import/export CSV, SQL dumps, JSON, and Excel. The free version is feature-limited; Base 3 requires macOS 15 Sequoia or newer. © 2025 Menial Ltd.
Top 1 Comment Summary
A Mac-native SQLite browser search led me to “DB Browser” because it appeared in results. I checked GitHub and searched further but couldn’t find it. I’m glad to discover it now and plan to switch. It’s surprising the tool has existed for 15 years.
Top 2 Comment Summary
Long-time Base user (about 15 years) says it’s always been great, even while considering retirement, and notes it has continually improved over time.
3. A visual introduction to big O notation
Total comment counts : 15
Summary
Big O notation describes how a function’s running time grows with input size, not its exact timing. It helps compare performance across input scales. The article covers four common categories—constant, logarithmic, linear, and quadratic—and uses practical examples. It explains wall-clock time and shows a sum function whose time is proportional to n, i.e., O(n). It contrasts this with O(1) constant-time functions, which don’t depend on input size, though O(1) isn’t always instant. It notes that O notation captures growth in the smallest terms and mentions its origins and the meaning of the “O” symbol.
Top 1 Comment Summary
The article sits in the familiar space of Big-O notation explainers and the recurring debates over its precise technical meaning versus practical usage. It frames the discussion as a cyclical tradition likely to repeat, and points to two Ned Batchelder pieces—a concise bigo explanation and a piece on toxic experts—for context on the ongoing kerfuffle.
Top 2 Comment Summary
An electrical engineering graduate vents that Big O notation is rarely explained clearly in education, often being hand-waved as assumed knowledge. They wonder what level of math or computer science typically introduces Big O.
4. Launch HN: April (YC S25) – Voice AI to manage your email and calendar
Total comment counts : 22
Summary
April is a voice-driven AI assistant to tackle inbox and calendar overload during commutes. Using Deepgram for speech-to-text and ElevenLabs via LiveKit for text-to-speech, it lets you: summarize important emails and flag actions, dictate replies with formatting and tone, review your calendar and reschedule on the fly, pull context from email threads, and archive/organize messages. It runs on a custom Model Context Protocol (MCP) for Google authentication and thread context with low latency and natural interruption handling. Available on iPhone/iPad App Store; free 3-day trial, then $14.99/month. Feedback welcome.
Top 1 Comment Summary
While supportive of the idea, the author urges a pre-execution safety mechanism to catch adverse actions, noting emails can’t be unsent and rare miswordings would be unsettling. They also highlight risks from AI prompt injection and rising spam/phishing, and seek ideas for mitigating these issues.
Top 2 Comment Summary
User suspects this is a repost and recalls a past incident where the creators were slammed for urging people to drive while using it, an advice that allegedly caused crashes.
5. What are OKLCH colors?
Total comment counts : 37
Summary
OKLCH is a perceptually uniform color model (based on OKLab) with three components: Lightness (0–1), Chroma (saturation-like), and Hue (0–360). Unlike sRGB-based models like HSL, OKLCH preserves consistent brightness and hue across tones, enabling uniform palettes and predictable lightness changes. Gradients interpolate in OKLab, often smoother, though hue is circular and can detour without OKLAB gradient interpolation. It can describe colors beyond device gamuts (Display-P3/sRGB); such colors are clipped to the nearest representable gamut. Introduced in CSS Color Module Level.
Top 1 Comment Summary
Interpreting gradients in OKLCH by rotating the hue circle often yields colors outside sRGB and perceptible range, making gradients look strange. Clipping out-of-gamut colors back in can destroy perceptual uniformity, causing parts (like red) to darken. For better perceptual results, use Oklab interpolation, which draws a straight line across the circle (even through grey) and avoids those issues. Example: linear-gradient(in oklab, #f0f, #0f0) delivers a cleaner magenta-to-lime gradient. Tailwind v4 briefly considered OKLCH but ultimately defaulted to Oklab for safer, more uniform gradients.
Top 2 Comment Summary
OKLCH in CSS is perceptually based; unlike HSL, hues differ and max chroma varies by hue and lightness, reflecting vision and screen limitations rather than a bug. It’s a formula you can use to generate colors (e.g., oklch(from var(–accent) calc(l + .1) c h)). It helps with dynamic colors but requires color theory or experimentation, since common assumptions (like shadows being just lightness shifts) can mislead. OKLCH gradients are consistently colorful, not necessarily the best for realistic light mixing—XYZ is better for that. Note: ‘ok’ is literally the word ‘ok’.
6. Building the mouse Logitech won’t make
Total comment counts : 58
Summary
Longtime MX Ergo user, the author loves it but notes issues after years. He DIYs two mods: 1) USB‑C port upgrade using a reverse‑engineered PCB design (via PCBWay); around $55 total and a hot‑air rework, with warranty and fire‑risk warnings. 2) Replaced noisy switches with Huano Silent (left/right) and alternatives (Omron B3F-1002 for the wheel, Alps SKQGABE010 for others), about $3 per switch; dramatically quieter. Recommends an iFixit desoldering guide. Also notes Logitech released MX Ergo S in 2024 with quieter switches and USB‑C at a higher price, aiming to reduce e‑waste.
Top 1 Comment Summary
Facing a $50+ turnkey assembly fee, the speaker chooses the financially prudent path and buys a $200+ hot-air rework station to solder the item themselves. A commenter echoes the sentiment.
Top 2 Comment Summary
The author loves the Logitech Anywhere MX for comfort, side back/forward buttons, long battery life, a small dongle, and flexible scrolling. Two main flaws: microswitches wear out after a few years (replacement is tedious and risks PCB damage), and the USB dongle is USB-A only—Logitech rejects USB-C/Unifying receivers. Newer MX models (MX 2S) add a built-in battery and changed features, with higher prices (~$90). The author plans to build an open-source Anywhere MX clone and wonders if a DIY mouse community exists.
7. Google to require developer verification for Android apps outside the Play Store
Total comment counts : 8
Summary
Google will require identity verification for all Android app developers, not just those on the Play Store. Beginning with early access in Oct 2025 and full verification in March 2026, rollout will be phased: by Sept 2026 in Brazil, Indonesia, Singapore, and Thailand, with global expansion by 2027. Developers must provide legal name, address, email, and phone number, which may push some independents to register as businesses. Sideloading and other app stores remain allowed, but anonymity is reduced to curb malware, fraud, and data theft. The move mirrors EU-style regulatory trends.
Top 1 Comment Summary
The article argues Google could arbitrarily approve or revoke apps, undermining an open platform. It suggests tolerance for unsigned apps if users see a warning or have a toggle to enable them. It notes Windows uses a similar approach, warning on unsigned binaries while allowing signed ones to run immediately.
Top 2 Comment Summary
The article argues that Google is aggressively pressuring the author to switch from Android to iPhone, using various tactics to push them toward Apple’s ecosystem.
8. How RubyGems.org protects OSS infrastructure
Total comment counts : 1
Summary
RubyGems.org operates a proactive, multi-layered security program: automated analysis (static/dynamic, behavior, metadata), risk scoring for escalation, retroactive scans, and external alerts. About 70-80% of malicious gems are stopped before reporting. Flagged gems are verified (≈95% prove legitimate), double-checked, removed, logged, and sometimes blocked by suspect-name filtering. In July–August 2025, a credential-stealing campaign was halted; Maciej Mensfeld and Josef Šimánek contributed to the response. Socket.dev later updated details; no widely trusted packages were affected. Community reporting is welcome; support funds security work.
Top 1 Comment Summary
Commenting on the Internet, the author notes that valuable content is hard to find today, contrasting it with a case where a dedicated team consistently improves their product’s quality. They also admit they should have switched to Ruby on Rails three years ago.
9. A small change to improve browsers for keyboard navigation
Total comment counts : 14
Summary
error
Top 1 Comment Summary
The snippet is a brief note titled “Link Hints, what else !!!!!!” that simply presents an HTML link to a Mozilla Add-ons image. The link is marked rel=“nofollow” and points to a PNG asset with a modified timestamp in its URL. There’s no additional content or context.
Top 2 Comment Summary
The author endorses Vimium, noting a months-long positive experience, and also recommends Mouseless for comprehensive keyboard-only navigation across the computer. Links: vimium.github.io and mouseless.click.
10. How to make things slower so they go faster
Total comment counts : 8
Summary
Synchronized demand occurs when many clients act together, overwhelming headroom H = μ − λ0 and causing queues, timeouts, and retries. Causes include natural clocks, deployments, cache/timer resets, and DDoS. The aim is to prevent peaks and drain safely with fair capacity discipline. Strategy: spread M actions over window W to minimize peak while obeying headroom (M/W ≤ H), service time, and spare concurrency, plus bounds on bucket counts. Server hints (Retry-After, Remaining, Reset) help set W. Pick the smallest W meeting bounds; if infeasible, add capacity or relax. To avoid cohorts, randomize TTLs and jitter; for backlog, drain safely.
Top 1 Comment Summary
Braess’s paradox is the counterintuitive idea that adding roads to a road network can slow down overall traffic flow through it.
Top 2 Comment Summary
Computations that can be expressed as a finite sequence of steps could be unwound and spread across a grid of FPGAs, though it would be large, expensive, and power-hungry. Such a setup could yield about a millisecond latency, giving next-token logits at roughly 1000 tokens per second. Adding latches for synchronization and pipelining may add ~10% latency but enables multiple independent streams. Instead of one customer at 1000 tokens/second, you could serve ten or more at ~900 tokens/second each. In short, parallelism and pipelining are the future of compute.