begin quoting Darren New as of Mon, Sep 29, 2008 at 08:49:59PM -0700: > SJS wrote: > >begin quoting Darren New as of Mon, Sep 29, 2008 at 05:48:36PM -0700: > >[snip] > >>Loose coupling: "Tell someone to go do something. Check with them later > >>to see if they finished it." > > > >That's not at ALL what I think of when I think of loose coupling. > > No, because you're thinking of it in CS terms, and I'm being a little > sloppier than I ought to. The point is that it's not at all difficult to > describe intuitively what "loose coupling" is. There are examples all over.
Actually, I was thinking of trailer hitches. And yes, there are examples all over, and it just seemed like you pulled the wrong metaphor out of your toolbox. Perhaps you misfiled asynchronous tasking. :-) [snip] > No, it's the people doing the work in parallel. (OK, I should have said > "do different pieces of work.") Anyone who has been in school or at work > knows what loose coupling and parallel execution are. Well... I dunno. I've met a few folks about whom I have my doubts. :) > >Well, yes. > > That's all I was saying. Parallelism and loose coupling are only hard in > the world of computer science, and only in detail. That's because handwaving doesn't work with computers. [snip - examples] > I'll tell you something else that's pretty intuitive: fault tolerance. > How do you get at least four truckloads of those pumpkins across the > country without spoiling if there are traffic jams? Did it take a lot of > time to figure out you can send different trucks on different routes? > Does anybody know why there's a thing called an "emergency brake" in > your car? I am routinely *amazed* at how many people fail to use the emergency brake. Oh, and it's called "parking brake" these days, and it's apparently supposed to be used for "drifting". > It's the details that kill you, and you're not going to be able to teach > the details of a distributed, fault-tolerant parallel system before you > know how one program works. Sure. You have to work your way up. We don't start off teaching kids to perform track-stands on their new bicycles, for example. > Heck, even Google gets it wrong. I read about the Map/Reduce stuff, and > how they'd run the map part on the same machine that's hosting the block > of data that it's mapping over, so it didn't have to go over the > network. And I thought "Wow, that's clever. I probably wouldn't have > thought of that at first." Then I read the history of the program, and > they were running it like six or nine months before they released the > version that did that, and I thought "Good, I'm not *too* stupid." Heh. -- I only had problems with loose coupling. Stewart Stremler -- KPLUG-LPSG@kernel-panic.org http://www.kernel-panic.org/cgi-bin/mailman/listinfo/kplug-lpsg
