Linux uses every byte of free RAM as a disk cache. The first time you read a file, it's slow. The second time, it's instant -- not because the file got faster, but because the kernel kept it in memory. This invisible cache explains why your benchmarks lie, why 'free memory' is 200 MB on a 64 GB box, and why a fresh server feels slower than a warmed-up one.
Engineering Craft
TypeScript, CI/CD, databases, observability -- the skills that make code production-ready.
