Systems Programming

Build a complete data compressor from first principles. You'll compute Shannon entropy, build Huffman trees, implement LZ77 sliding-window matching with hash chains, and combine them into a DEFLATE-style compressor with CRC checksums. By the end you'll deeply understand what gzip, zstd, brotli, and every modern compressor actually do.

Build a fully-featured cron daemon from the ground up. You'll parse cron expressions, compute next firing times across timezones, schedule jobs with a min-heap, and handle real-world concerns like missed jobs, overlapping runs, and timezone DST. By the end you'll deeply understand the scheduler behind every "do this on a schedule" system you've ever used.

Build a production-grade L7 load balancer from scratch. You'll implement round-robin, weighted, and least-connection selection; active and passive health checks; circuit breakers; consistent hashing; sticky sessions; rate limiting; TLS termination (SNI); and Prometheus metrics. By the end you'll deeply understand what NGINX, HAProxy, Envoy, and AWS ALB actually do.

Build a complete package manager from scratch — semver parsing, constraint matching, dependency tree expansion, deduplication, backtracking SAT-style resolution, lockfile generation, hash verification, lifecycle scripts, and vulnerability auditing. By the end you'll deeply understand what npm, yarn, pnpm, cargo, and pip actually do.

Build a CI/CD runner like GitHub Actions: parse YAML workflows, expand build matrices, topologically sort job DAGs, execute steps with logs, manage artifacts and caches, handle self-hosted runners, and protect secrets. Used by every modern engineering team.

Build a container runtime from scratch using Linux namespaces, cgroups, and overlayfs. You'll implement PID/mount/network namespace isolation, memory and CPU resource limits, layered image storage with copy-on-write, and the full container lifecycle. By the end you'll deeply understand what Docker, Podman, runc, and containerd actually do.

Build a fully functional Redis clone from the ground up. You'll implement the RESP protocol, key-value storage, expiry, lists, hashes, sets, sorted sets, and transactions — all through test-driven exercises. By the end, you'll deeply understand how one of the world's most popular databases works internally.