> Mechanical stuff somehow just magically work without proof whereas it's still debatable if proven software works (did we prove the software that proved it?).
It might seem like magic, but, of course, there is actually a science to it. Depending on the situation, a part can work if a certain length is 10.000 or if it's 10.001. In software, that is never the case: a value that should be 10 but is actualy 10.001 can stop everything. In engineering, there is a limited amount of leeway at every step of the process, and everything is slightly overengineered by some factor of safety to ensure that this is the case. For example, if an elevator cable is rated to hold 10,000lbs, the elevator will be sold as having a maximum capacity of 8,000lbs. In correct usage, (weight less than 8,000lbs), there is a sufficient factor of safety on the cable so that it won't break even if the cable is cracked, worn, etc.
I mean, we have that kind of thing in software too, when it comes to e.g. memory usage or runtime (in a sense, anywhere we start hitting physical reality, really).
What should we make these buffer sizes? There's not really a right answer, but there are definitely some wrong ones. Make it big enough to handle the expected use cases and pad a bit extra. Works exactly like a tolerance in physical engineering.
It might seem like magic, but, of course, there is actually a science to it. Depending on the situation, a part can work if a certain length is 10.000 or if it's 10.001. In software, that is never the case: a value that should be 10 but is actualy 10.001 can stop everything. In engineering, there is a limited amount of leeway at every step of the process, and everything is slightly overengineered by some factor of safety to ensure that this is the case. For example, if an elevator cable is rated to hold 10,000lbs, the elevator will be sold as having a maximum capacity of 8,000lbs. In correct usage, (weight less than 8,000lbs), there is a sufficient factor of safety on the cable so that it won't break even if the cable is cracked, worn, etc.