6 ms·

For those who are reading this and are new to software development, please don't let these questions put you off or take them as some sort of test of your skill

For those who are reading this and are new to software development, please don't let these questions put you off or take them as some sort of test of your skills. The questions pertain only to the poster's particular CS degree and to his particular experience, which for some reason he thinks is the only CS degree and experience that is valid. Also note that you will come across people like this quite a lot in the software industry and you have to be careful not to let them get under your skin. They can be very difficult to work with. If you are a team lead and identify someone like this on your team then it can be very difficult to place them and you often have to gently coerce them into their own "special" area where they feel their talents are best used.

arethuza 14y ago
"They can be very difficult to work with." Don't you think that is a bit harsh? From what I have seen of Colin's work and contributions here on HN he seems like a pretty knowledgeable and decent chap to me. I rather enjoyed myself contemplating these questions - although I haven't had the nerve to submit completed answers!
- philbarr 14y ago
  The red flag was this line in the blog that led to the questions: "If you can't answer the majority of the questions on these four papers, and you're working or intend to work as a software developer, you should ask yourself why". This assumes an air of authority that the poster clearly cannot posses; that is, he does not have the right to judge whether someone is a valid software developer or not. Someone claiming this level of superiority seems to fit the personality type I described. Of course - I could well be wrong but that's what it sounded like to me.
  - ygra 14y ago
    Note that this refers to all four parts, not just the second. In this case one might lack detailed low-level knowledge of threading and a particular library used to do so on POSIX systems which may have no relation to performance in the other parts.
    - deleted 14y ago
      [deleted]
  - thaumaturgy 14y ago
    I liked the part of your comment where you cropped the rest of his sentence: "— most likely you're either you're missing something you really should know, or you're lucky enough to be working within a narrow area where your deficit doesn't matter."
    - philbarr 14y ago
      I didn't crop that so as to take it out of context, I cropped it to keep the quote short. I don't agree with the bit you added either.
  - sgift 14y ago
    The author never judges whether someone is a valid software developer or not. He ASKS why people who work as software developers don't know the answer to (in his opinion) basic questions. Obviously, you would have to read the whole sentence and not just a part of it to understand the question asked here. For your convenience: "If you can't answer the majority of the questions on these four papers, and you're working or intend to work as a software developer, you should ask yourself why — most likely you're either you're missing something you really should know, or you're lucky enough to be working within a narrow area where your deficit doesn't matter."
    - lolcraft 14y ago
      Not judging? "... most likely you're either missing something you really should know, or you're lucky enough to be working within a narrow area where your deficit doesn't matter." Talk about reading just part of the sentence.
      - sgift 14y ago
        "not judging whether someone is a valid software developer or not" :) I didn't write that he wasn't judging.
        taybin 14y ago
        "The author never judges" yes you did...
    - deleted 14y ago
      [deleted]
  - CodeMage 14y ago
    Okay, so I agree that Colin's exam might be a bit too specific and that he might have phrased certain things poorly, i.e. "lucky enough to be working within a narrow area where your deficit doesn't matter". I think either his experiment will help him discover that "luck" (i.e. statistical distribution) doesn't lean the way he assumed or -- and this is more likely -- he'll obtain biased results because a lot of people will refrain from sending bad results. That being said, I honestly prefer being judged by someone as accomplished as Colin Percival than hiding behind the attitude that we should not judge other people's abilities. Let's face it, there's an abundance of downright bad and mediocre programmers. There aren't that many top-notch programmers, although each of us would love to think we're among that small group. This is what motivates us to speak out against any attempt to measure and assess abilities, especially if such an attempt is likely to rank us low. I'm not ashamed to admit that, so far, I haven't been able to formulate an answer to more than 5 questions out of 10 he posted so far. While I freely admit that I don't consider myself to be a programmer in Colin's league, I think that's really beside the point here. My knowledge is cached: what I work with all the time is easier to recall; what I've worked with or read about, but I'm not using all the time is not as easy; and, of course, there's a ton of things I don't know, have never worked with or read about. This means that I don't feel confident talking about B-trees without consulting Internet, but since I read about them previously, I do remember that they're a form of search trees and that databases use them (or their variations) a lot. What's the point of this whole rant? Let's bottom-line it. I'm probably not as good as Colin overall and I'm definitely not as good as he is at what he, specifically, does. That doesn't mean I should feel threatened by his exam. Nor does it mean it has no validity whatsoever. Nor does it mean that Colin is "difficult to work with" or fits any specific personality type. Those two claims about Colin's personality and intentions are what really bothered me about your reaction. I'm not a fan of straightforward ad-hominems, but I detest veiled ones even more.
    - taybin 14y ago
      Well said, but I'm still not inclined to send him my non-answers so that I can deliberately enjoy the feeling of inadequacy.
ilcavero 14y ago
great conextualization philbarr, also I would add that CS is just one of the foundations of software engineering but certainly not the only one and many would think not even the most important one. Having said that if these questions tickle your intellectual curiosity go ahead and figure out their answers, just throw away the belief that you can become a valid/invalid software developer just because you can/cannot answer some questions.
ww520 14y ago
The questions are actually quite basic. It has nothing to do with CS degree. Anyone desires to learn would have learnt them. It just makes you a better developer. And people who know them are not difficult to work with. If you as a team lead feels threaten by people who posses basic CS knowledge, you don't qualify to be a team lead. Is this what we are coming to? The dumbing down of software development? Have the mainstream anti-intellectualism been spilled over into software development?
- philbarr 14y ago
  The point is that you can be a software developer without knowing this stuff off the top of your head. Naturally I would encourage anyone who doesn't know the answers to these questions to go ahead and learn them if they want to, but you're probably not going to need them day to day, so his assertion that you're not a software developer unless you can answer his "final exam" is incorrect and demonstrates a certain level of ego I find unsettling. I didn't say "people who know the answers to these questions are difficult to work with", I said, "people who declare their knowledge as an absolute requirement are difficult to work with".
- dagw 14y ago
  There is a huge difference between not knowing the answers off the top of your head and not being able to learn and understand the answers given 30 minutes and access to Google. If you fail the former that's fine in my book, if on the other hand you fail the latter then that might be reason for concern.
mjwalshe 14y ago
Yep we passed on a cat 1 from Martelsham(the place that built the colossus) for this very reason.
jaimzob 14y ago
Hear, hear. Obsession with trivia and a supercilious tone are sure signals of a B-player in my experience. "Name and describe the four states in MESI cache coherence"? Sorry, memorising an algorithm for determining if a graph is bipartite pushed that knowledge clean out of my head...no doubt I'm very stupid.
- jules 14y ago
  I thought that the bipartite graph algorithm question was the best so far. It was a question that, in addition to remembering what a bipartite graph is, required a little bit of thinking instead of just rote memorization (if you know what a bipartite graph is you can come up with the algorithm on your own -- no need to memorize that). Question #2 in this set is also pretty good.
  - ygra 14y ago
    Remembering the relation of a bipartite graph to graph coloring helped me coming up with an algorithm fairly quickly. Although that might in fact require a little familiarity with graphs and the associated terms. I guess most of my former fellow students who didn't hear a graph theory lecture won't really remember that.
- dfox 14y ago
  "Name and describe the four states in MESI cache coherence" is mostly about having at least basic idea of how multiprocessor systems work that is pretty crucial to any seriously meant multi-threaded programming. It's something that anyone who wants to call himself a programmer has to know (or at least have some idea that something like that is happening, which is almost equivalent to knowing how it works, because it's really straightforward).
  - jsnell 14y ago
    I don't think the question as phrased is about having a basic idea of how multiprocessor systems work. It's a question about naming(!) of the component parts of a specific protocol. That's trivia. It's as if the question about the TLB was about the acronym rather than the function. (So what's a good question to see if somebody understands cache coherency? Maybe describing a problem caused by cache-line contention, and asking for an explanation and fix to it?)

arethuza 14y ago

"They can be very difficult to work with." Don't you think that is a bit harsh? From what I have seen of Colin's work and contributions here on HN he seems like a pretty knowledgeable and decent chap to me. I rather enjoyed myself contemplating these questions - although I haven't had the nerve to submit completed answers!

philbarr 14y ago
The red flag was this line in the blog that led to the questions: "If you can't answer the majority of the questions on these four papers, and you're working or intend to work as a software developer, you should ask yourself why". This assumes an air of authority that the poster clearly cannot posses; that is, he does not have the right to judge whether someone is a valid software developer or not. Someone claiming this level of superiority seems to fit the personality type I described. Of course - I could well be wrong but that's what it sounded like to me.
- ygra 14y ago
  Note that this refers to all four parts, not just the second. In this case one might lack detailed low-level knowledge of threading and a particular library used to do so on POSIX systems which may have no relation to performance in the other parts.
  - deleted 14y ago
    [deleted]
- thaumaturgy 14y ago
  I liked the part of your comment where you cropped the rest of his sentence: "— most likely you're either you're missing something you really should know, or you're lucky enough to be working within a narrow area where your deficit doesn't matter."
  - philbarr 14y ago
    I didn't crop that so as to take it out of context, I cropped it to keep the quote short. I don't agree with the bit you added either.
- sgift 14y ago
  The author never judges whether someone is a valid software developer or not. He ASKS why people who work as software developers don't know the answer to (in his opinion) basic questions. Obviously, you would have to read the whole sentence and not just a part of it to understand the question asked here. For your convenience: "If you can't answer the majority of the questions on these four papers, and you're working or intend to work as a software developer, you should ask yourself why — most likely you're either you're missing something you really should know, or you're lucky enough to be working within a narrow area where your deficit doesn't matter."
  - lolcraft 14y ago
    Not judging? "... most likely you're either missing something you really should know, or you're lucky enough to be working within a narrow area where your deficit doesn't matter." Talk about reading just part of the sentence.
    - sgift 14y ago
      "not judging whether someone is a valid software developer or not" :) I didn't write that he wasn't judging.
      - taybin 14y ago
        "The author never judges" yes you did...
  - deleted 14y ago
    [deleted]
- CodeMage 14y ago
  Okay, so I agree that Colin's exam might be a bit too specific and that he might have phrased certain things poorly, i.e. "lucky enough to be working within a narrow area where your deficit doesn't matter". I think either his experiment will help him discover that "luck" (i.e. statistical distribution) doesn't lean the way he assumed or -- and this is more likely -- he'll obtain biased results because a lot of people will refrain from sending bad results. That being said, I honestly prefer being judged by someone as accomplished as Colin Percival than hiding behind the attitude that we should not judge other people's abilities. Let's face it, there's an abundance of downright bad and mediocre programmers. There aren't that many top-notch programmers, although each of us would love to think we're among that small group. This is what motivates us to speak out against any attempt to measure and assess abilities, especially if such an attempt is likely to rank us low. I'm not ashamed to admit that, so far, I haven't been able to formulate an answer to more than 5 questions out of 10 he posted so far. While I freely admit that I don't consider myself to be a programmer in Colin's league, I think that's really beside the point here. My knowledge is cached: what I work with all the time is easier to recall; what I've worked with or read about, but I'm not using all the time is not as easy; and, of course, there's a ton of things I don't know, have never worked with or read about. This means that I don't feel confident talking about B-trees without consulting Internet, but since I read about them previously, I do remember that they're a form of search trees and that databases use them (or their variations) a lot. What's the point of this whole rant? Let's bottom-line it. I'm probably not as good as Colin overall and I'm definitely not as good as he is at what he, specifically, does. That doesn't mean I should feel threatened by his exam. Nor does it mean it has no validity whatsoever. Nor does it mean that Colin is "difficult to work with" or fits any specific personality type. Those two claims about Colin's personality and intentions are what really bothered me about your reaction. I'm not a fan of straightforward ad-hominems, but I detest veiled ones even more.
  - taybin 14y ago
    Well said, but I'm still not inclined to send him my non-answers so that I can deliberately enjoy the feeling of inadequacy.

ilcavero 14y ago

great conextualization philbarr, also I would add that CS is just one of the foundations of software engineering but certainly not the only one and many would think not even the most important one. Having said that if these questions tickle your intellectual curiosity go ahead and figure out their answers, just throw away the belief that you can become a valid/invalid software developer just because you can/cannot answer some questions.

ww520 14y ago

The questions are actually quite basic. It has nothing to do with CS degree. Anyone desires to learn would have learnt them. It just makes you a better developer. And people who know them are not difficult to work with. If you as a team lead feels threaten by people who posses basic CS knowledge, you don't qualify to be a team lead. Is this what we are coming to? The dumbing down of software development? Have the mainstream anti-intellectualism been spilled over into software development?

philbarr 14y ago
The point is that you can be a software developer without knowing this stuff off the top of your head. Naturally I would encourage anyone who doesn't know the answers to these questions to go ahead and learn them if they want to, but you're probably not going to need them day to day, so his assertion that you're not a software developer unless you can answer his "final exam" is incorrect and demonstrates a certain level of ego I find unsettling. I didn't say "people who know the answers to these questions are difficult to work with", I said, "people who declare their knowledge as an absolute requirement are difficult to work with".
dagw 14y ago
There is a huge difference between not knowing the answers off the top of your head and not being able to learn and understand the answers given 30 minutes and access to Google. If you fail the former that's fine in my book, if on the other hand you fail the latter then that might be reason for concern.

mjwalshe 14y ago

Yep we passed on a cat 1 from Martelsham(the place that built the colossus) for this very reason.

jaimzob 14y ago

Hear, hear. Obsession with trivia and a supercilious tone are sure signals of a B-player in my experience. "Name and describe the four states in MESI cache coherence"? Sorry, memorising an algorithm for determining if a graph is bipartite pushed that knowledge clean out of my head...no doubt I'm very stupid.

jules 14y ago
I thought that the bipartite graph algorithm question was the best so far. It was a question that, in addition to remembering what a bipartite graph is, required a little bit of thinking instead of just rote memorization (if you know what a bipartite graph is you can come up with the algorithm on your own -- no need to memorize that). Question #2 in this set is also pretty good.
- ygra 14y ago
  Remembering the relation of a bipartite graph to graph coloring helped me coming up with an algorithm fairly quickly. Although that might in fact require a little familiarity with graphs and the associated terms. I guess most of my former fellow students who didn't hear a graph theory lecture won't really remember that.
dfox 14y ago
"Name and describe the four states in MESI cache coherence" is mostly about having at least basic idea of how multiprocessor systems work that is pretty crucial to any seriously meant multi-threaded programming. It's something that anyone who wants to call himself a programmer has to know (or at least have some idea that something like that is happening, which is almost equivalent to knowing how it works, because it's really straightforward).
- jsnell 14y ago
  I don't think the question as phrased is about having a basic idea of how multiprocessor systems work. It's a question about naming(!) of the component parts of a specific protocol. That's trivia. It's as if the question about the TLB was about the acronym rather than the function. (So what's a good question to see if somebody understands cache coherency? Maybe describing a problem caused by cache-line contention, and asking for an explanation and fix to it?)