2h 57m total
The computer-science fundamentals every technical interview probes, taught from the ground up and kept language-agnostic. You'll learn what an operating system actually does — the kernel/user-mode split, system calls, and the abstractions it sells you (processes, files, virtual memory) — then go deep on processes versus threads and the cost of a context switch, CPU scheduling (FCFS, round-robin, priority, MLFQ) and the throughput/latency/fairness tradeoffs, and memory management: physical versus virtual memory, paging, page tables, the TLB, page faults, and the stack versus the heap. From there you tackle concurrency: concurrency versus parallelism, shared state and race conditions, critical sections, mutexes, semaphores and atomicity, then deadlocks — the four Coffman conditions and how to prevent, avoid, or detect them — plus the producer-consumer and readers-writers patterns. The networking half builds the stack from the wire up: the layered model, IP addressing, TCP versus UDP, the three-way handshake and reliability, ports and sockets, then DNS resolution, HTTP/HTTPS, the TLS handshake, and load balancing. It closes with a capstone that traces exactly what happens when you type a URL and press Enter, and a small threaded producer-consumer project you reason about end to end. Short illustrative snippets (C, Python, shell) make the ideas concrete; no single language is assumed.
