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Many distributed systems have a leader-based consensus protocol at their heart. The protocol elects one server as the "leader" who receives all writes. The other servers are "followers", hot standbys who replicate the leader’s data changes. Paxos and Raft are the most famous leader-based consensus protocols. These protocols ensure consistent state machine replication , but reads are still tricky. Imagine a new leader L1 is elected, while the previous leader L0 thinks it's still in charge. A client might write to L1, then read stale data from L0, violating Read Your Writes . How can we prevent stale reads? The original Raft paper recommended that the leader communicate with a majority of followers before each read, to confirm it's the real leader. This guarantees Read Your Writes but it's slow and expensive. A leader lease is an agreement among a majority of servers that one server will be the only leader for a certain time. This means the leader can run...

Model minimalistically Start from a tiny core, and always keep a working model as you extend. Your default should be omission. Add a component only when you can explain why leaving it out would not work. Most models are about a slice of behavior, not the whole system in full glory: E.g., Leader election, repair, reconfiguration. Cut entire layers and components if they do not affect that slice. Abstraction is the art of knowing what to cut . Deleting should spark joy.  Model specification, not implementation Write declaratively. State what must hold, not how it is achieved. If your spec mirrors control flow, loops, or helper functions, you are simulating code. Cut it out. Every variable must earn its keep. Extra variables multiply the state space (model checking time) and hide bugs. Ask yourself repeatedly: can I derive this instead of storing it? For example, you do not need to maintain a WholeSet variable if you can define it as a state function of existing variables: WholeSet =...

I drive my daughter to school as part of a car pool. Along the way, I am learning a new language, Brainrot. So what is brainrot ? It is what you get when you marinate your brain with silly TikTok, YouTube Shorts, and Reddit memes. It is slang for "my attention span is fried and I like it". Brainrot is a self-deprecating language. Teens are basically saying: I know this is dumb, but I am choosing to speak it anyway. What makes brainrot different from old-school slang is its speed and scale. When we were teenagers, slang spread by word of mouth. It mostly stayed local in our school hallways or neighborhood. Now memes go global in hours. A meme is born in Seoul at breakfast and widespread in Ohio by six seven pm. The language mutates at escape velocity and gets weird fast.  Someone even built a brainrot programming language . The joke runs deep , and is getting some infrastructure. Here are a few basic brainrot terms you will hear right away. He is cooked : It means he is finis...

It is that time of year again to look back on a year of posts. I average about sixty posts annually. I don't explicitly plan for the number, and I sometimes skip weeks for travel or work, yet I somehow hit the number by December. Looking back, I always feel a bit proud. The posts make past Murat look sharp and sensible, and I will not argue with that. Here are some of the more interesting pieces from the roughly sixty posts of 2025. Advice Looks like I wrote several advice posts this year. I must be getting old. The Invisible Curriculum of Research Academic chat: On PhD What I'd do as a College Freshman in 2025 My Time at MIT What makes entrepreneurs entrepreneurial? Publish and Perish: Why Ponder Stibbons Left the Ivory Tower Databases Concurrency Control book reading was fun. Also the series on use of time in distributed databases. And it seems like I got hyperfocused on transaction isolation this year.  Concurrency Control and Recovery in Database Systems Book reading series...

Progress comes from motion.  Momentum is the invisible engine of any significant work. A project feels daunting when you face it as a blank page. It feels easier when you built some momentum with some next steps. So, momentum makes the difference between blocked and flowing. Think of a stalled truck on a desert road. You can't lift it with superhuman strength. But by rocking it with small periodic forces at the right rhythm (matching its natural frequency) you can get it rolling. Each tiny push adds to the previous one because the timing aligns with the system's response. The truck starts to move, and then the engine catches. Projects behave the same way. A big project has its own rhythm. If you revisit it daily, even briefly, your pushes line up. Your brain stays warm. Context stays loaded . Ideas from yesterday are still alive today. Each session amplifies the last because you are operating in phase with your own momentum. When you produce something every day, you never feel...