Question: What is a good non-CS analogy for the cache coherence problem?
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jhhardin
I've been trying to think of a good one, but this is the best I've come up with (really it's only one value rather than a cache): Consider a scenario where there is a central bank in the city and a bunch of villages with banks, and we're still on the gold standard. All of the villages should have the same price of gold to avoid rich people from exploiting the differences and becoming richer (because we are democratic and whatnot). The price of gold depends on the amount in the bank and in circulation, so it changes when gold discoveries are made and when bank robberies occur by outlaws (who remove the gold from circulation) (note that discoveries are only made in rural places, and security of the central bank is too high for robberies to occur). Each local bank is aware of these changes, and updates the price accordingly. The central bank should always be up to date with these changes, as well as each other village, so that the exchange price is equal everywhere. Communication requires someone physically delivering the message though, so coherence isn't trivial.
Hoping to see someone else give a stab at it!
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benchoi
A team is playing a basketball game. When the opponent takes possession of the ball, the game state changes from OFFENSE to DEFENSE (and vice versa when the team gets the ball). Each player caches the game state in order to focus on what they are doing, but need to know when the game state changes, so the player who changes the game state (for example by losing the ball to an opponent) shouts to let his team know, and they drop their own cached state and reorient to figure out what is going on.
Question: What is a good non-CS analogy for the cache coherence problem?
This comment was marked helpful 0 times.
I've been trying to think of a good one, but this is the best I've come up with (really it's only one value rather than a cache): Consider a scenario where there is a central bank in the city and a bunch of villages with banks, and we're still on the gold standard. All of the villages should have the same price of gold to avoid rich people from exploiting the differences and becoming richer (because we are democratic and whatnot). The price of gold depends on the amount in the bank and in circulation, so it changes when gold discoveries are made and when bank robberies occur by outlaws (who remove the gold from circulation) (note that discoveries are only made in rural places, and security of the central bank is too high for robberies to occur). Each local bank is aware of these changes, and updates the price accordingly. The central bank should always be up to date with these changes, as well as each other village, so that the exchange price is equal everywhere. Communication requires someone physically delivering the message though, so coherence isn't trivial.
Hoping to see someone else give a stab at it!
This comment was marked helpful 0 times.
A team is playing a basketball game. When the opponent takes possession of the ball, the game state changes from OFFENSE to DEFENSE (and vice versa when the team gets the ball). Each player caches the game state in order to focus on what they are doing, but need to know when the game state changes, so the player who changes the game state (for example by losing the ball to an opponent) shouts to let his team know, and they drop their own cached state and reorient to figure out what is going on.
This comment was marked helpful 0 times.