weichi

Could you be more specific?

"If I could prove to you a fact that disagreed with the big bang, would you then abandon the theory"

Sure I would! What are some of your facts?

Funniest line:

"CEOs are highly skilled in a special form of lying called leadership"

The only decision to be made right now is whether to continue talking to them until you get an offer (or until one or both sides decide it isn't a good fit after all). There are no downsides to doing this, so you might as well do it.

Once you have a specific offer, then you have a decision to make.

I think there's a lot of truth here.

I would also point out that for a lot of programming tasks, particularly in a corporate IT environment, "thinking like the customer" can be a good thing: it helps you make sure that you are building something that truly helps the customer do their job.

The risk is that no matter how much "domain experience" you have, the customer has more, and you can fool yourself into thinking that you understand what they need better than they do.

How do NoSQL databases allow you to do a better job at "secondary data reuse" than a traditional RDBMS? Is it just a matter of (1) Denormalization (2) performance gains from not needing to worry about transactions?

I don't really get this article. Dennehy writes:

However, while Dyer was making a point based on insufficient reliability and robustness in the available tools, Spolsky is making the same assertion purely on the basis that it takes more time to produce a good design than to use a simpler tool and “duct tape” a solution.

This is not an accurate reflection of Spolsky's article. In particular there is this paragraph:

One principle duct tape programmers understand well is that any kind of coding technique that’s even slightly complicated is going to doom your project. Duct tape programmers tend to avoid C++, templates, multiple inheritance, multithreading, COM, CORBA, and a host of other technologies that are all totally reasonable, when you think long and hard about them, but are, honestly, just a little bit too hard for the human brain.

Added: Spolsky is not claiming that these techniques take too much time. He is claiming that it is very hard to use these techniques to make a product that is reliable and robust.

My reading of Spolsky is that he is making the claim that is it a good idea to have programmers on your team who are very focussed on shipping product, and don't really care whether the technology being used is particularly advanced or popular. They just want to do whatever it takes to ship.

I think he's right; it's good to have these people around. Programmers love learning about new technologies and programming techniques, and when we learn about them we want to apply them. Our enthusiasm can push us to use technology that isn't really required for the problem at hand, and when that technology is difficult to use correctly, this can cause big problems. Having someone around keep you focussed on what matters - shipping a working product - is very helpful.

Not relevant to the "hiring process" discussion, but I think the idea that:

Claude Shannon didn't have to satisfy any customers. He could spend years developing a theory, whose practical value was only clear after it was sufficiently developed

is historically wrong; certainly reading the wikipedia page on Shannon makes it sound like he developed his ideas while doing quite practical work during WW II.

Someone please correct me if my impression is incorrect.

I've never written any Ruby, but I refuse to believe that Ruby cares about which line has the comma. Am I misunderstanding something?

It's true that s-expressions don't give you a literal syntax for hashmaps or arrays, but note that some lisps (e.g. Clojure) do support these natively … and in a syntax that's better than JSON since you don't have to type all those annoying commas ;-)

1. Where will you get the $5k? Your own pocket? Are you charging people $1? But it says free ...

2. Are sure you aren't going to get into legal trouble? IANAL, and I know nothing at all about the relevant laws, but still ...

3. Contest Rules and Terms don't mention the required tweet anywhere.

Axler and Strang are really very different books with very different intents. The most striking example is that Gaussian elimination is practically the first thing that Strang covers, but Axler doesn't cover it at all.

I can't speak in general because I've only skimmed Strang, whereas I worked through nearly all of Axler. But if your interest in Linear Algebra is as preparation for quantum mechanics, then Axler is a great choice, perhaps even for a novice (though it does require a bit of mathematical maturity). Axler really hammers you with the idea that a matrix is just a way to represent a linear transformation, and that the numbers in the matrix depend on the basis you choose for the underlying vector space. This way of thinking is very helpful when you learn quantum mechanics.

EDIT: Axler also has the advantage that it is short. Personally, I find it much easier to work independently through short math/physics books than long books.

Can you be more specific? What parts of the "hot big bang, cold dark matter, accelerating expansion, geometrically flat, ~14 billion years old" model will be shown to be "deeply wrong"? Do you think that discovering, say, the nature of dark energy, is going to demonstrate that the universe isn't really expanding? That we are going to discover that the universe is really 100 billion years old? That the universe was actually colder and larger in the past?

waterlesscloud is not saying that there is lots we still don't understand. He is saying that much, perhaps most of what we currently believe is "deeply wrong". This is of course possible, but I think it is very unlikely.

Seriously, what are you talking about?

We know a lot about cosmology. In particular there is very good evidence for for the basic model: hot big bang, cold dark matter, accelerating expansion, geometrically flat, ~14 billions years old (see http://www.astro.ucla.edu/~wright/cosmology_faq.html for more).

Granted we don't know what the dark matter is, and we don't know what's causing the acceleration. Those are big unknowns! But the basic picture is pretty well understood. And I think it's very unlikely that much of this picture is "deeply wrong".

I mean, what do you think? Some day we are going to discover that the universe wasn't really denser and hotter in the past? That the universe isn't really expanding? That baryonic matter makes up all of the mass of the universe?

Someone twittered "Did Scala influence Erlang?". Since Erlang development started 17 years before Scala appeared, this seems unlikely. The blog post was a deadpan attempt at a humorous response. My comment was hoping to generate more humorous responses on HN, but alas …

Another little-known fact: that JVM that Erlang was originally written on? It was coded by Scott McNealy! It was a side project of his to prove to Bill Joy that he wasn't just a suit.

It's great, and I use it all the time because it handles units properly, but once things get complicated, it's a pain (you can't define variables or easily use results of previous calculations).

Since we're on the topic of calculators ...

Is there something like Soulver or Speedcrunch, but also handles unit conversions a la google calculator?

instacalc is OK, but doesn't handle units properly either.

edit: www.encalc.com seems to do units right, but allowing only one expression at a time is limiting.

On the high school level, perhaps jr high as well, if you could replace the 5th day at school with a day in a workplace - some kind of internship - then I think you would end up with a better system. Perhaps vastly better.

An interesting thing about the Casimir force is that there is a derivation due to Lifshitz that doesn't use the concept of a quantized electromagnetic field; it uses zero-point fluctuations of the charge distribution in the plates to get the same result. So it's not clear that the casimir force is direct evidence for zero-point field fluctuations.

There was a nice paper a few years ago deriving a casimir-like force between (if I'm recalling correctly) a pair of coupled resistors/inductors. I can't find the reference right now, I'll post it later if I can.

No. The energy you get out when the plates would repel will be equal to the energy required to push the plates together in the first place. No free lunch!

Whether or not "don't spend your families life savings on your startup" is good advice or not really depends on the amount of the savings, the age of the individual/family, and the family's earning potential, etc.

Losing all of your $20k savings at age 25, DINK family: hurts, but not life-changing in any way (as long as your spouse is OK with it, and you'd better be damn sure they aren't lying to you when if they say it's OK)

Losing all of you $200k savings at age 35, two small children and stay-at-home spouse: extraordinarily painful and will impact every decision you make for a long time.