Before Blockchains, There Was State Machine Replication

Every blockchain today relies on replication techniques first developed in the 1980s by researchers who weren't thinking about cryptocurrencies at all. In this episode, Tim Roughgarden speaks with MIT professor and Turing Award winner Barbara Liskov, one of the pioneers of programming languages, fault tolerance, and distributed systems. Joined by a16z crypto research partner Ittai Abraham, they trace the evolution of ideas that now underpin modern blockchain networks. The conversation explores viewstamped replication, Practical Byzantine Fault Tolerance (PBFT), state machine replication, and why concepts developed decades before Bitcoin became the foundation for today's blockchain protocols. Along the way, Liskov reflects on the relationship between theory and practice, the importance of modularity and formal reasoning, and why AI is creating a new generation of systems research.