Getting Things Right: A Look at Centralized vs Decentralized Systems Through the Eyes of Instant Replay
Three baseball umpires were sitting around a bar, talking about how they make calls on each pitch: First umpire: Some are balls and some are strikes, and I call them as they are. Second umpire: Some are balls and some are strikes, and I call them as I see 'em. Third umpire: Some are balls and some are strikes, but they ain’t nothin' until I call 'em.
It’s fun to look at how concepts we think of as belonging primarily to the domain of computer science play out in other fields. One intriguing example is how Instant Replay reflects and even helps shape the culture of a sport by how replay is implemented: decentralized or centralized.
Lucrative TV deals have pumped huge sums of money into professional sports. With so much money in play, sports have shifted from being pure entertainment to wanting to get things right. The price of making a bad call is just too high to let the human element decide the fate of titans.
Getting things right is also a much talked about subject in computer science. In CS the language of getting things right uses terms like transaction, rollback, quorum, optimistic replication, linearizability, synchronization, lock, eventually consistent, compensating transaction, and so on.
In sports to get things right referees use terms like flag, penalty, by rule, ruling stands, reset the clock, down and distance, line to gain, the whistle blew, ruling confirmed, and ruling overturned.
Though the vocabulary is different, the intent is much the same. Correctness.
Intent is not all tech and sports have in common. As technology evolves we are seeing sports change to take advantage of the new capabilities technology offers. And those changes should be familiar to anyone in software. Sports have gone from a completely decentralized system of officiating to where we now see the NBA, NFL, MLB, and NHL, all converging on some form of a centralized system.
The NHL were the innovators, starting their centralized instant replay system in 2011. It works something like this...officials sit in a war room located in Toronto that looks a lot like every network operations center ever built. Video feeds from all games flow into the room. When there is a controversy or an obvious review-worthy play, Toronto is contacted for a quick review and judgement on the correct call. Every sport will implement their own centralized replay system in their own way, but that's the gist of it.
We’ve seen the exact same transformation as federated services like email have been replaced with centralized services like Twitter and Facebook. It turns out sports and computer science have some deeper similarities. What might those be?