CS Fundamentals
DBMS, OS, networking and security — tied to how you actually implemented them.
- DBMS — Transactions, Isolation & Indexes
ACID, the isolation levels and the anomalies they prevent, how B-tree indexes really work (and when they hurt), and normalization vs denormalization.
DBMStransactionsisolationindexes - Concurrency — Threads, Races & Deadlock
Processes vs threads, what creates a race condition, the four deadlock conditions and how to break them, and optimistic vs pessimistic locking — grounded in the StockStump double-spend.
concurrencythreadsdeadlocklocking - Networking — HTTP, TCP, TLS & WebSockets
TCP vs UDP, what a TLS handshake buys you, how DNS resolves, and when to use WebSockets vs SSE vs polling for real-time.
networkingTCPTLSwebsocket - Security — Auth, Hashing & OWASP
Authentication vs authorization, sessions vs JWT, hashing vs encryption (bcrypt vs Fernet), and the OWASP bugs (XSS, CSRF, SQLi) with their mitigations — grounded in StockVision.
securityauthOWASPencryption