Behind The Scenes of Bun Install

Bun's package manager achieves 7x faster installs than npm by treating package installation as a systems programming problem rather than a JavaScript one. Key optimizations include direct system calls in Zig (eliminating Node.js overhead), binary manifest caching, optimized tarball extraction with pre-allocation, cache-friendly data layouts using Structure of Arrays, OS-native file copying (clonefile on macOS, hardlinks on Linux), and lock-free multi-core parallelism. These techniques minimize expensive system calls and leverage modern hardware capabilities that traditional package managers don't fully utilize.