TLA+: Modeling Beyond the Code Level

TLA+ is a language for modeling software above the code level and hardware above the circuit level. It features an IDE and tools for model checking, most notably the TLC model checker. Based on mathematics, it differs significantly from programming languages. PlusCal, a simpler algorithm language, translates to TLA+ for verification. TLA+ models system behavior as sequences of states, emphasizing the importance of high-level modeling to prevent design flaws and enhance system simplicity. One industrial project demonstrated a tenfold reduction in real-time operating system code size using TLA+, highlighting its power in improving design before coding.