3 ms·

Various impossibility theorems say otherwise, eg. the CAP theorem for distributed computing, the scalability trilemma for blockchains, Arrow's impossibility the

Various impossibility theorems say otherwise, eg. the CAP theorem for distributed computing, the scalability trilemma for blockchains, Arrow's impossibility theorem for voting systems. Many times you have mutually incompatible constraints that are both desirable, and the best you can do is pick a point on the continuum that's satisfactory to the particular subset of users you wish to serve.

inimino 7y ago
> Various impossibility theorems say otherwise No, they say that the naïve "right thing" is actually not possible, and the right thing is something else, that is possible, but may be unknown.
a1369209993 7y ago
> the CAP theorem for distributed computing The (highly cost-ineffective) Right Thing is to invest enough in network infrastructure that there are no network partitions. I don't know about the other examples off the top of my head, but they're probably similar (and similarly impractical). Anyone can design a bridge that won't fall down; engineering is the process of figuring out which corners you can cut and still have the bridge just barely not fall down.
- heavenlyblue 7y ago
  >> The (highly cost-ineffective) Right Thing is to invest enough in network infrastructure that there are no network partitions. And... It’s no longer a distributed system.
  - inimino 7y ago
    Something can still be distributed in space without us having to assume that the network can fail.
  - wolf550e 7y ago
    It's still a distributed system if clients connect to the closest server, speed of light latency between servers exists, and the system deals with consensus between servers, even if the design assumes network partitions never happen.
vvanders 7y ago
My favorite one of these is metastability[1]. Any time you have a crossing clock domain the fact that your ASIC works is based on statistics and not hard guarantee. [1] http://www.asic-world.com/tidbits/metastablity.html http://www.asic-world.com/tidbits/metastablity.html

inimino 7y ago

> Various impossibility theorems say otherwise No, they say that the naïve "right thing" is actually not possible, and the right thing is something else, that is possible, but may be unknown.

a1369209993 7y ago

> the CAP theorem for distributed computing The (highly cost-ineffective) Right Thing is to invest enough in network infrastructure that there are no network partitions. I don't know about the other examples off the top of my head, but they're probably similar (and similarly impractical). Anyone can design a bridge that won't fall down; engineering is the process of figuring out which corners you can cut and still have the bridge just barely not fall down.

heavenlyblue 7y ago
>> The (highly cost-ineffective) Right Thing is to invest enough in network infrastructure that there are no network partitions. And... It’s no longer a distributed system.
- inimino 7y ago
  Something can still be distributed in space without us having to assume that the network can fail.
- wolf550e 7y ago
  It's still a distributed system if clients connect to the closest server, speed of light latency between servers exists, and the system deals with consensus between servers, even if the design assumes network partitions never happen.

vvanders 7y ago

My favorite one of these is metastability[1]. Any time you have a crossing clock domain the fact that your ASIC works is based on statistics and not hard guarantee. [1] http://www.asic-world.com/tidbits/metastablity.html http://www.asic-world.com/tidbits/metastablity.html