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Comment by yusina | Hacker News Reader

Real world example. You go sit in your ICE car. You press the gas pedal and the car starts moving. And that's your mental model. Depressing pedal = car moves. You do not think "depress pedal" = "more gasoline to the engine" = stronger combustion" = "higher rpm" = "higher speed". But that's the level those C and C-like language discussions are always on. The consequence of you using this abstraction in your car is that switching to a hybrid or lately an EV is seemless for most people. Depress pedal, vehicle moves faster. Whether there is a battery involved or some hydrogen magic or an ICE is insubstantial. Most of the time. Exceptions are race track drivers. But even those drop off their kids at school during which they don't really care what's under the hood as long as "depress pedal" = "vehicle moves faster".

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This may be true, but it's also false. Many regular drivers have an understanding of how the machine they're driving works. Mechanical sympathy is one of the most important things I've ever learnt. It applies to software as well. Knowing how the data structures are laid out in memory, knowing how the cache works, knowing how the compiler messes with the loops and the variables. These aren't necessarily vital information, and good compilers mean that you can comfortably ignore much of these things, but this knowledge definitely makes you a better developer. Same as knowing how the fuel injection system or the aspiration of your ICE will make you a better driver.

I'm totally with you that it's useful knowledge. One of the main differences between a Youtube/bootcamp trained programmer and a university-CS-educated software engineer, though either "side" has outliers too.

But there is a fine line between having general understanding of the details of what's going on inside your system and using that knowledge to do very much premature optimizations and getting stuck in a corner that is hard to get out of. Large parts of our industry are in such a corner.

It's fun to nerd out about memory allocators, but that's not contributing to overall improvements of software engineering as a craft which is still too much ad hoc hacking and hoping for the best.

> It's fun to nerd out about memory allocators, but that's not contributing to overall improvements of software engineering as a craft which is still too much ad hoc hacking and hoping for the best.

I'm sorry, but it is. Understanding memory layout and (sometimes) using custom allocators can improve performance in ways that no compiler cannot do automatically. And when used correctly they contribute to code correctness too. This is the reason they are used in projects like Chromium.

Regarding your car analogy, you have to remember that developers here are not driving the car: they're building the car. Understanding the differences between and ICE engine and an electric motor are very salient to designing a good car.

The perfect analogy, because sometimes people want to drive a manual car, and sometimes people aren't American and it's the default.

PRESS PEDAL CAR STOPS

DIDNT SHIFT UP

> You do not think

Actually I do, and I include the inertia and momentum of every piece of the drive-train as well, and the current location of the center of gravity. I'm thinking about all of these things through the next predicted 5 seconds or so at any given time. It comes naturally and subconsciously. To say nothing of how you really aren't going to be driving a standard transmission without that mental model.

Your analogy is appropriate for your standard American whose only experience with driving a car is the 20 minute commute to work in an automatic, and thus more like a hobbyist programmer or a sysadmin than someone whose actual craft is programming. Do you really think truckers don't know in their gut what their fuel burn rate is based on how far they've depressed the pedal?

Uhhhhh that's kind of how I think about the gas pedal though. There's some lag. The engine might stall a bit if you try to accelerate uphill in a wrong way. There's ideal RPM range. Etc.

And you were perhaps asking about programming languages. Python does not model objects as bytes in physical memory. Functional languages normally don't. That all has consequences, some of which the "close to the metal" folks don't like. But throwing the "but performance" argument at anyhing that moves us beyond the 80s is really getting old.

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