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> physical engineering they don't have to Totally agree with what you wrote but in any well run engineering organization one has to consider the cost/benefit o

> physical engineering they don't have to Totally agree with what you wrote but in any well run engineering organization one has to consider the cost/benefit of extra testing and engineering. If you're making a USB powered LED desk lamp, you get into diminishing returns fairly quickly. If you're making basically anything on JWST, less so.

kevin_thibedeau 2y ago
There is no excuse for making defective products, no matter how low the profit margins are. The key why properly engineered anything works is that safety margins are baked into the design. Every real engineering field uses repeatable processes with known likelihood of success. Software "engineering" doesn't do that.
- hn367621 2y ago
  Defective means a product doesn’t deliver on its specifications. For example if my LED desk lamp doesn’t promise to last any time at all, it’s not defective if it fails inside a month. If you want one that lasts longer, you pay more and can have that. Same for software. But most software basically promises nothing…
- jandrewrogers 2y ago
  The concept of "safety margins" in physical engineering are largely nonsensical in a software context. In physical systems, correctness is a bulk statistical property of the design, an aggregate of probability distributions, which makes safety simple. If you are uncertain, add a bit more steel just in case, it is very cheap insurance. Physical systems are defect tolerant, they aren't even close to defect-free. In software systems, correctness is binary, so they actually have to be defect-free. Defects don't manifest gradually and gracefully like they often do in physical systems.
- datadrivenangel 2y ago
  Much better to think about low-quality products instead of defective. Junk can still be useful, and just good enough is definitionally good enough (most of the time). Also, most real engineering fields are full of projects that are done in non-repeatable ways and go horribly over budget. You're correct that for implementation you can get repeatable processes, but for process improvement you don't have anywhere near the level of repeatability.

kevin_thibedeau 2y ago

There is no excuse for making defective products, no matter how low the profit margins are. The key why properly engineered anything works is that safety margins are baked into the design. Every real engineering field uses repeatable processes with known likelihood of success. Software "engineering" doesn't do that.

hn367621 2y ago
Defective means a product doesn’t deliver on its specifications. For example if my LED desk lamp doesn’t promise to last any time at all, it’s not defective if it fails inside a month. If you want one that lasts longer, you pay more and can have that. Same for software. But most software basically promises nothing…
jandrewrogers 2y ago
The concept of "safety margins" in physical engineering are largely nonsensical in a software context. In physical systems, correctness is a bulk statistical property of the design, an aggregate of probability distributions, which makes safety simple. If you are uncertain, add a bit more steel just in case, it is very cheap insurance. Physical systems are defect tolerant, they aren't even close to defect-free. In software systems, correctness is binary, so they actually have to be defect-free. Defects don't manifest gradually and gracefully like they often do in physical systems.
datadrivenangel 2y ago
Much better to think about low-quality products instead of defective. Junk can still be useful, and just good enough is definitionally good enough (most of the time). Also, most real engineering fields are full of projects that are done in non-repeatable ways and go horribly over budget. You're correct that for implementation you can get repeatable processes, but for process improvement you don't have anywhere near the level of repeatability.