[stevefan1999]

> A chain is only as strong as its weakest link

wow, when I read this, it is actually much cleaner than what I would use as in the past: the overall system strength is min {i in 0...m} subsystem[i] where m is the total number of subsystems

[DmitryOlshansky]

Rather reliability of sum is a product of reliabilty of constituents (unless redundancy was applied) where reliability is in [0,1.0] range.

[contravariant]

This is extreme nitpicking but I'd recommend seeing it as a reliability of a product of constituents.

A sum of constituents is more likely to be a situation where you're fine if at least one of the options works (e.g. a cluster with redundancy).

This will actually get you a semiring (easy to check), although whether that is really useful remains to be seen. It's nice to have anyway.