[notarealllama]

One of my favorite tech interview questions for any position is, "Describe in excruciating detail, everything that happens when you request and load a website in your browser."

You learn a LOT about how a candidate thinks and the depth of their knowledge.

[spps11]

i feel this question correlates more with the generation of the SWE more than anything.

expecting current gen SWEs to talk about network layer protocols while answering this is kinda the same as expecting 1990s SWEs to include wire physics and dispersion statistics in their answer to this question.

Depth alone isn't always a good indicator. We have to move on from some of the low level stuff at some point and it is okay for engineers to know in detail about things that have been solved long back.

[Swizec]

Surely that depends what your hiring them for?

The nice thing about the website load question is that it touches every part of the stack. You could talk for an hour about rendering on screen at the OS level, or network protocols, or server stuff, or web client stuff, or data center stuff, or …

Really to answer the question in its full entirety would be the equivalent of that “Everything that goes into a pencil” essay. You could build an entire college curriculum just out of that question.

[LoganDark]

> that “Everything that goes into a pencil” essay

which one! I tried googling this but without quotes it gives me clickbait and with quotes it only points to this comment. :(

[baggy_trough]

I, Pencil

[LoganDark]

thank you!!

[panza]

I think it's fine to ask a web developer how web pages are served.

If they can talk about network layer protocols, then that tells you something. If the next candidate's understanding stops at knitting libraries together, then that's also notable.

Even if it's not a discriminating factor in hiring, it still helps you flesh out the candidate.

[notarealllama]

That's the beauty. I could care less if my backend JS candidate knows anything about Ethernet frames, but I damn well expect h3 and async discussion.

But my devops guy? He better be talking about CDN, cavhing, WAF.

[rendaw]

Do you prompt them? Expecting them to talk about CDN and WAF seems unfair, those go beyond the definition of the web.

[hadlock]

For a senior role? no. They should be asking you how deep you want to go. And you should be the one stopping them for time. If your SRE/DevOps can't wax poetic about the deep deep details, how are they going to get you out of the ditch when production goes down at 11am on a Tuesday, or 11pm on a Saturday

[miyuru]

> CDN and WAF seems unfair, those go beyond the definition of the web

Current web is full of WAFs and CDNs, devops should know that they exist at the very least.

[dartos]

I’d expect an SRE to know about all that.

[fud101]

what is h3?

[theandrewbailey]

HTTP/3

[spankalee]

Why should "current generation" SWEs know about network protocols? We live in a more networked world, not less.

[spankalee]

Oops! Bad, meaning-reversing omission: I mean "not know".

[tabony]

100% a generation thing.

Been around long enough so I've written my own CSS framework, server-side framework, web browser, web server, sent bits over Ethernet, written assembler, programmed a FPGA, built circuits, AND have a electrical engineering degree... and YET, _ABSOLUTELY NONE_ of this is useful _99%_ of the time.

So meh. If I want you to do frontend, I will ask you frontend questions. Hopefully you can go deep on a11y and that's what I care about.

(But the 1% of the time when I can precisely step through a whole stack is also fun.)

[notarealllama]

Exactly, someone who can answer where media queries fall in terms of loading priorities for FE (when hiring for that.)

Electrical engineering is a whole nother thing!

[dylan604]

Hence the differences in the level of schooling. Graduating a coding boot camp for using React vs years of engineering school. Why are the interviewers are confused on this is the unsane thing.

[layer8]

Yes, I would drop the “in excruciating detail” and “everything”. The level of detail the interviewee starts at or goes down to by default is also informative.

[groby_b]

The only good answer here is "breadth first, or depth first"?

If they say "depth first", go all the way down to electrons bumping into each other on the wire.

It's an "I'm so smart, are you so smart" question, the only right approach is a smart aleck approach.

I work on web browsers for a decade+ now, and worked on network protocols for a decade+, and it's not a question I'd consider in any way high signal. If this particular area matters to you, ask a problem in the space. "Web page X doesn't load, figure out why". It shows you way more than "please regurgitate every detail"

[notarealllama]

That's exactly the point - sometimes too much detail or focused on wrong thing can ve distracting.

But having a frontend engineer aware of Safari on iOS or macOS vs assuming chrome compatibility, or a SRE aware of abusive UDP http2 / h3 stuff...

Again the beauty is in the flexibility and scope of something normies take for granted, and this video delves into some of the esoterics of this topic!

[groby_b]

Yep, having a video explaining it in detail is great. It's absolutely interesting. (I mean, I would say that, wouldn't I ;)

My objection was to using it as an interview question. An broad open-ended question like that without any guidance what the interviewer cares about is a signal of either copy-pasted hiring practices, or a working culture that doesn't know what it wants. It's also a question with little signal in the noise if you don't give a bit more clarity.

I mean, fundamentally I'm happy if other companies use the question, more good hires for me, but in terms of "we should really raise the bar on this interviewing thing" I still object :)

[fc417fc802]

It's only low signal if you directly score the answer based on presence or correctness of specific details.

Forget about that. The question is an open ended and adaptable tool to get a huge amount of information about knowledge, verbal ability, audience awareness, and all sorts of other directly relevant skills. No trick questions just "teach me everything you know about this subject" and then work with the other party.

That said I suppose there's no reasonable expectation that (for example) most firmware developers necessarily know anything whatsoever about loading a web page. But anyone whose touches network (ie most) should know something.

[what]

I assume we have to start with the physical action of typing in a url and everything involved in that? Then how the physical keyboard works? Then how the OS handles the input from the keyboard? Then…

[mburns]

For a relatively in-depth take on this question: https://github.com/alex/what-happens-when

[jiveturkey]

too outdated. even at the time of last commit (3y ago), lots is missing.

[buzer]

I mean yeah, it doesn't even touch what is happening inside your body in order to actually press those buttons. Or what forces are being converted and how they affect the surroundings.

[nosianu]

You may say that as a joke, but looking back at my education, this is in part what I did later, after uni, when I thought about things to learn next. In my mind, I started explaining stuff in depth, and found the many many many holes in my apparently quite superficial school knowledge.

I think this would be excellent as a once-in-a-while exercise to teach the complexity of it all, after we went the other way to abstract the hell out of everything to make it more palatable. A reality check, so to speak, and as a check for everyone about the many holes in their understanding. Basically, in support of something that has been posted here more than once, this blog post: http://johnsalvatier.org/blog/2017/reality-has-a-surprising-...

In the last few years I read a lot of easily digestible progression fantasy on RoyalRoad. One frequent theme is rebirth or isekai on another world, one that's usually much more primitive. Often the main character starts bringing earth technology ideas into the new world. And every single time it is obvious that the authors very, VERY severely the complexity and difficulty of even the smallest thing that we take for granted. My favorite blog post describing an extremely simple product, and how large and sophisticated its supply chain is: https://medium.com/@kevin_ashton/what-coke-contains-221d4499...

To me, this shows that some more awareness of how much complexity there is in things might be valuable.

Being more aware of the connections across our abstractions also helps finding what's missing. It could also help to find optimizations across abstraction borders, instead of limiting oneself to only looking within ones favorite abstraction layer.

[LoganDark]

> My favorite blog post describing an extremely simple product, and how large and sophisticated its supply chain is: https://medium.com/@kevin_ashton/what-coke-contains-221d4499...

is walled. Is there a way to read the article without extra steps?

[fc417fc802]

This would be an interesting way to frame an entire series of textbooks covering pretty much all of science, electrical engineering, and CS. The entire premise being "you type a URL into your browser and it loads the requested webpage".

Each textbook in the series at the depth of a bachelors degree, split by relevant subject including physics, chemistry, biology, neuroscience, materials science, electrical engineering, hardware design, kernel and device driver design, systems level networking, and all the remaining browser engine, VM, security, and webdev stuff.

To keep the task at least theoretically tractable cut off at the NIC in the local box.

Who knew you could premise a textbook on protein folding on "how a web page is loaded"?

[jiveturkey]

great idea! i knew a physics professor once who developed an entire semester using "how racecars work" as his guiding light. i think he wrote a textbook, but i can't find it.

not: the physics of racecars, that is explaining racecar dynamics given physics fundamentals, rather explaining the fundamentals using racecars instead of spherical cows. i think not very different to first semester analog ee courses using hifi audio as the basis.

[jamiek88]

Or the decision to do it, the neurons involved, free will or otherwise.

Basically to load a web page you must first invent the universe.

[user432678]

Went for an interview, ended up with the existential dread.

[genewitch]

And entropy when your browser garbage collects and free()

[notarealllama]

That's the beauty... Sometimes too much detail can be distracting, so knowing what to mention/omit is part of it too.

As CTO for multiple companies and hiring across multiple competencies for 10 years... This is the question that keeps on giving!

[masfuerte]

> too much detail can be distracting

I don't get it. You ask for excruciating detail. But you want candidates to intuit what to leave out? Eh?

[emmelaich]

You guide them a little. No point spending most of an hour describing keyboard technology.

[notarealllama]

Consider, do you type or paste the url? With or wothout http/s? Or www? Does it matter? What if you typo wwww.domain.com?

And what do you mean physical keyboard, the virtual one on my phone works fine ;) (also preconceived notions)

[rovr138]

Which branch, physical or virtual. How does the virtual one work?

[nill0]

"All of the amazing things that modern computers do, are based on just ability to compute any computable function." - Ben Eater

source: https://youtu.be/AqNDk_UJW4k?list=PLowKtXNTBypGqImE405J2565d...

at 13:44s

[layer8]

In former times, this used to be “Describe what happens between pressing a key on the keyboard and the corresponding letter appearing on the screen”. You can go into all sorts of interesting tangents with that topic.

[remram]

"excruciating details"? I don't think I would ever get to the network if you asked that. I would have to cover how you pressing "enter" gets encoded by the keyboard, how the USB bus works, the interrupt processed by the processor, how that context switch happens, how the next instruction is fetched and decoded by the CPU, how the code for the interrupt gets read, TLB, L1/L2 cache, pipelined execution, microinstructions, transistors, ...

Depth-first doesn't work when the depth of reality is basically unlimited.

[LoganDark]

How are you requesting the website? Are you typing into the address bar? Of which browser (and what version)? On which operating system (and what version)? On which hardware platform? Have you configured the address bar to also work as a search bar ("omnibox")? Are you typing a domain name or an IP address? Do you have any entries in your hosts file for the domain name? Is the machine configured to resolve hostnames on the local network? Is the domain name one of those? Are you connected to a network? Is your network connection over Wi-Fi or Ethernet? (or something else?) What is your network card and how is it connected? (If USB, which port? If PCIe, which slot?) What other network interfaces do you have? What access point are you using? Do you have a network switch, and if so, which one? Is your internet service over fiber or cable? Which ISP are you using? Gimme a second to look up their peering...

I could go on but :)

[hydrogen7800]

Is there an "explain like I'm 5" version of the answer to this question? I have read "The Internet explained from first principles" [0], and while I think I understood most of it in theory but, it didn't help me understand in practice.

[0]https://explained-from-first-principles.com/internet/#prefac...

[gamedever]

It depends on the role. I suspect the majority of software developers have no clue. The majority of C, C++, C#, Rust, Java, Python people, really don't know, unless their job deals with the browser. Most game devs don't know.

[jiveturkey]

i literally am the inventor of this question.

it's an awful question.

[gnabgib]

You are! Amazing, I was asking it before you were a on HN. I guess I would have though you'd mention it before? https://hn.algolia.com/?&query=Describe%20user%3Ajiveturkey&...

[youngtaff]

I started asking it over 25yrs ago…

Never specified the level of detail I wanted but left it open to the candidate…depending on where they went it leaves plenty of room for follow on questions to probe their knowledge

[jiveturkey]

Yes. I invented this question approx 25-26 years ago. At the time it was a pretty fair question. Today it's a trivia knowledge kind of question. You will be "impressed" by a candidate that can use up the entire interview (very possible) answering it, but that proves nothing about the candidate. Unless of course the job is writing system documentation based on personal knowledge only.

[jiveturkey]

i change my HN identity once in a while. this is the longest run for me.

[hoten]

would be fun to do this while stepping through chromium w/ a debugger.

[hinkley]

The button on your keyboard is depressed, making a connection between two wires. The circuit is made and interpreted by a microcontroller, which differentiates which key press was made based upon…

What? You said excruciating…