Table of contents 📻 Network OSI 7 Layer TCP Congestion Control UDP HTTP HTTPS, TLS, SSL HTTP Request & Response URL vs URI vs URN Load Balancing DNS NAT DHCP MAC ARP REST Cookie, Session, JWT Socket, WebSocket , Socket IO CORS CDN PDU gRPC vs tRPC 🔧 Operating System Process vs Thread File Descriptor Thread-Safe System Call Context Switch Signal Deadlock Mutex & Semaphore Race Condition Memory Management Scheduler CPU Scheduler Memory Hierarchy Cache Locality Interrupt IPC Virtual Memory Thrashing Synchronous vs Asynchronous RAID CISC vs RISC Byte Order ☕ JavaScript 💾 Database Index Transaction ACID Normalization 📑 Web XSS, CSRF, SQL Injection