HN

A developer debugging a bare-metal ARM64 hypervisor chased random lockups caused by enabling CTR_EL0 intercepts, using tracing, kernel logs, and QEMU single-stepping to isolate the problem. The root causes included ARM icache/dcache incoherence when executing modified data and subtle code-generation/relocation differences that made semantically equivalent C constructs fail on real hardware, forcing assembly workarounds and binary bisecting to diagnose.

arm aarch64 hypervisor debugging low-level
55 pts 34 comments
bzip3 (github.com)

bzip3 is an open-source LGPLv3 successor to BZip2 that uses an order-0 context-mixing entropy coder, a suffix-array-based Burrows–Wheeler transform, and LZP/PPM-style passes to deliver much higher compression ratios and competitive speeds (including parallelism), especially on text/code. The repo includes build instructions, architecture support, and benchmarks showing dramatically smaller outputs than bzip2, xz and zstd on a large Perl source corpus.

compression bzip2 benchmarks open-source
35 pts 4 comments

Off-topic items

Live map of public transport in Belgium (openbaarvervoerbelgie.be)

Interactive live map that shows every bus, tram, metro and train in Belgium (De Lijn, STIB-MIVB, TEC, NMBS) with real-time delays, stops and departure times. Covers all Belgian regions and provides sources, FAQ, and privacy/terms information.

public-transport belgium realtime map
43 pts 17 comments

Researchers report an experimental observation of effects predicted by Einstein's general relativity within a quantum system, showing gravitational influence at quantum scales. The result bridges tests of general relativity and quantum mechanics and has implications for understanding the interface between the two theories.

quantum-gravity general-relativity experimental-physics fundamental-physics
182 pts 44 comments
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