zlacker

Software does not wear out like most physical components, but they often cause failure in interaction/coordinating between subsystems.

As the amount of coordination increases, the number of failure modes tends to grow quite fast. That's why software failures in physical, safety-critical systems are not trivially corrected. There are a lot of second order effects that need to be considered.

>>bumby+(OP)
> Software does not wear out like most physical components.

It fails like buildings near fault lines, because the ground moves under them. Think broken dependencies, operating system obsolescence, et cetera.

>>Qem+i7
I like this analogy. Although your example focused on software-centric coordination, I think it's important to also extend it to non-software systems.

An apropos and famous example is the Ariane 5 rocket mishap. The same validated software from the Ariane 4 was used, but the hardware design changed. Specifically, the velocity of the Ariane 5 exceeded that of its predecessor and exceeded the 16-bit variable used.