I mean no offense, but honestly I'm a bit flabbergasted that anyone who has worked in programming computers for over a decade wouldn't have acquired this exceptionally basic bit of computing knowledge.
Being a "software engineer" who doesn't understand this seems to me like being an architect who doesn't understand trigonometry or something.
But really, there are people doing software engineering who have never thought about this, and while I agree that any blind spot in knowledge is detrimental (and everyone has some blind spots), it's condescending to suggest that this specific blind spot is noteworthy to the point of lacking foundational knowledge. Your software engineering isn't the only type of software engineering.
> the only time I think about the bit position of something is when setting/viewing file permissions, or reading source code for a library which does deal with this (there are legitimate reasons to use bitwise operators in JS for things like hashing, cryptography, secure string generation, etc.)
People should understand how the libraries they use work. Not necessarily in detail, but they shouldn't be a magic box they're helpless to understand if it isn't working right.
> it's condescending to suggest that this specific blind spot is noteworthy to the point of lacking foundational knowledge.
Possibly. I'll admit that though it seems foundationally important to my understanding of computing it may not necessarily be foundational to understanding of computing in a conceptual sense. However, it is so basic, and follows so naturally from boolean logic (which is foundational), that it is quite surprising it never came up for someone in this profession. I mean, if you already know how logic gates work it is trivial to leverage that into understanding bitwise operations.
What I'm saying is that 'should' is unfairly prescriptive. There are things I don't understand that would be massively beneficial such as being able to understand drivers and driver code, C (we didn't learn it to any meaningful capacity in my program), and many other skills.
Fortunately, I've managed to take what I do know about computing, software, and programming, and find places I can apply that knowledge in a software engineering discipline that utilizes the knowledge I do have most effectively. Would I be able to write a driver if I was being paid to do it? Probably; there would be some learning required, maybe not even that much, but someone would be paying me to learn things outside of my general experience. I'd welcome it as well, but it just hasn't happened.
Similarly, there are people whose knowledge encompasses a subset of what I know (but possibly excluding binary and bitwise operations in totality) who are also very effective software engineers.
If you can think about browser state, reactivity, CSS specificity, the DOM, and git, you can be a very effective front-end engineer, and you never have to know much about how computers work. There are absolute wizards with 'front-of-front-end' who will be much more effective at animations, effects, device breakpoints, and visually pleasing layouts than I will ever be, who will never think about binary. And it will never be remotely relevant to them.
You don't need to be an expert at bitwise operations to grok these important concepts.
Yeah, I've learned all of this stuff ~10 years ago (in compsci also) and forgotten a lot of it due to never using it. Should I learn it again? To be honest, I'd like to, but I haven't taken the time either. I contemplated doing a deep dive the one time I've had to interview recently, but then didn't end up needing it. I'm sure if I wanted to move to a FAANG I'd need to brush up, but in the mean time I'm bombarded with plenty of things I need to learn on a regular basis to keep up with the actual technologies I work with
> but this is still kind of basic second-year compsci, right?
To be honest, I find I have a very hard time really integrating knowledge of something until I've had ample opportunity to apply it in different ways over some extended period of time. I think this was why the knowledge never stuck when I learned it in CS. There were so many things I'd cram before the test and then never need to think about again.
If I don't have the opportunity to apply these concepts, trying to really 'learn' them is a Sisyphean task for me. With enough effort and repetition I'm sure I could, but I don't agree that I should. I think your attitude really overlooks the variance in learning styles and capabilities. Not everyone can remember things they don't apply for 10 years.
Mostly what I'm doing currently is defending my level of surprise.
When you look at the number of programming languages and how different "idiomatic code" can be for the same task, I think it's a proof that different people think in a different way. For some low-level stuff will be very intuitive, for some it'll be functional programming, for others OO, etc.
As some other people said, CS/SWE is very wide, it's hard to know everything at any point. Add to that that for most people working with high level software, knowing more about the business gives more leverage than learning more about CS fundamentals, you end up with people knowing widely different things.
I think that in general, what's important is having a basic idea about most thing (known unknowns instead of unknown unknowns) so that you can look into stuff deeper if you need it.
....how in the world can that be? Bitwise operations are just the application of boolean logic to each pair of bits in the arguments. If you know what "exclusive or" means, XOR should be perfectly comfortable to you no matter how many bits are involved.
That's the same whether it's decimal (n=10) or binary (n=2).
For what it’s worth, I think most people consider me a competent software engineer. I have a degree in computational mathematics from a good school.
Can you clarify what you mean by this? Because the concept of shifting bits to the left or right is so simple that I don't see how it could possibly strike you as unintuitive unless you are completely unfamiliar with the idea of data being represented by a string of contiguous binary digits.
If your problem is merely that knowing what bit-shifting is does not present any obvious use cases to you, that isn't the same as finding the underlying concept unintuitive.
If I had more experience with lower level languages and / or dealing with raw binary data formats, I probably would have internalized it better by now.
I'd say to most people raised on "ordinary" maths they follow more naturally from quite a different concept: Moving the decimal point.
To me it sounds like very productive work and a progression of technology. It's 2021, where 99.99% of us don't have to implement our own binary protocols, and work with computers rather than microcontrollers. If you're bit shifting, then it's most likely extremely low level work, which, as is the point of advancements in technology, is necessarily becoming more and more rare, or some case of NIH.
I do work with binary protocols, so I'm very familiar with bit shifting, but I also realize this is all grunt work that I'm having to implement due to poor vendor support of usable/no libraries.
Instead the person clearly was motivated only by some specific application of computing or by making money.
You don’t get to decree what genuine interest in computing looks like for all of humanity.
There's a reason Randall Munroe draw that butterflies xkcd comics.
Stop gatekeeping there’s going to be someone smarter than you.
People work at different levels.
The logic of how a huge program works can be abstracted above bit shifting. It is still computation.
Maybe try be more understanding.
I know that computers store data in binary digits but it has absolutely no impact on how I do my job. I'm vaguely aware of how bitwise operators work but have never had to use them in my work, only in random hacky side projects.
> like being an architect who doesn't understand trigonometry or something
I'd equate it with a an architect that doesn't know where the brick supplier they are working with sources their bricks from. It's absolute essential to the project, nothing is going to get built without the bricks. But the architect can still plan the use of those bricks and the project can be entirely successful without them needing that knowledge.
Sure, you can learn the habits just fine, and maybe go your entire career without knowing what goes on under the hood. But sooner or later you're going to get stuck on the side of the road waiting for someone else to come out and fix something trivial.
I actually think this is a pretty good analogy. A truck driver does not need to know how to fix their truck to do their job. A web developer does not need to know how to bitshift. For mechanics or low level programmers it is a different story.
I know about them because I had to. My first computer had 4K of RAM. When I hit the limits of Applesoft BASIC, which didn't take long, I had to learn 6502 assembler. Later, I've done things like writing protocol decoders, so I've also learned them in Python.
But I think it's perfectly reasonable to have a solid career and never use these. To forget that they ever existed, because one is solving problems where they're just not relevant anymore. Our field is too big to know everything, so I think it's fine that people focus on different aspects of the work.
I'm sure there are plenty of use cases out there, I just haven't worked on them.
Sometimes when we learn a new technique we suddenly see all the places it can be used that we didn't know about before. There's the old (probably apocryphal) story about the landscaper who was able to fire one of his staff when a customer told him he can calculate the side of a right-angled triangle without measuring all 3 sides. What he did worked for him, he just didn't know there was a better way.
Anyway I do agree in this case you are probably correct. I think most programmers these days use bitwise logical operators for flags and rarely if ever bit shift outside of system code.
And on the other side L+1 would be databases, L+2 would be system architecture / systems design, L+3 would be user experience and communication, L+4 organisation and team design, L+5 would be LISP?
How many levels would someone have to straddle to meet the higher standard? And does it matter which level their midpoint is?
There's no way your ordinary programmer would have done memory management better than the GC options available with something like the JVM.
This is in fact Java/Python/Perl exist in the first place.
Slow software is better than software that crashes often.
I read about bit-shifting operations but never, ever had the need to use them. So I did not push further and just know that they exist and that they look like <<.
I hope I did not made your flabbergastering worse.
Ah, I also wrote a (tiny) bit of the Linux kernel in ~1994 (what today would be modules).
And still survived without <<
It does unnerve me as well, since it is so fundamental in my mind. But hey, maybe there is just so much to learn there's no time to teach computer architecture anymore?
If you want to feel humbled, read the book "Hackers Delight". It is about 300 pages of mostly bitwise algorithms and operations. I thought I knew a thing or two from decades coding, but this book goes so deep that my brain just shut off.
https://www.powells.com/book/hackers-delight-1st-edition-978...
EDIT: Upon further pondering, bitwise operations make certain assumptions about machine word size for that context. It could be dangerous for higher level languages to allow bitwise ops if the # of bits isn't known, as this context of instructions is generally tied to the hardware: the opposite of high level languages!
I think I've bit-shifted in anger, like... twice.
I 1000% could not do anything useful with them without consulting a reference, as with most anything else I don't do on an ~weekly basis.
[EDIT] rather, that's all bitwise operators. I know I've used them once (in a "write it once, never touch it again" kind of context) and maybe one other time but recollection's hazy. Just a basic bit-packing thing IIRC, for the one I recall.
If you are truly flabbergasted by this you need to try to find a way out of your bubble so you can understand reality better.