Subject: Re: garnet performance issues From: Erik Naggum <email@example.com> Date: 1999/02/12 Newsgroups: comp.lang.lisp Message-ID: <firstname.lastname@example.org> * Duane Rettig <email@example.com> | Your arguments sound like the "quality" argument (i.e. "do it right the | first time", "strive for zero defects"), and mine comes from a slightly | different point of view that I believe is in harmony with the quality | perspective, but which is often forgotten. um, no, not quite. I don't believe it is possible to do anything right until you know what "right" means, and this is not available a priori, despite what all the lectures in programming methodology and systems design would have poor students believe. (if it was, we would have had a perfect society, too -- law is nothing more than programming society, so if it were possible to plan for everything, it would have been worked out many millenia ago. I'm amazed that people think large-scale experiments in top-down design like dictatorships and planned economies would fare any better in any other endeavor involving creative people.) therefore, you have to go through various iterations, and your design must be prepared for this, but that is not to say that you should _not_ expect success, or actively prohibit it. the issue I want to raise is whether people should approach the first version with "let's try to get this right" vs "we're going to throw this one out, so let's not waste too much resources on it". the whole point with wasting the first version is to waste _only_ the first version, at worst. people who set out to do something that will be a waste in the eyes of managers who cannot understand why their employees do not know enough to get it right the first time, will _not_ learn all there is to learn and will _not_ ensure that only the first version gets wasted, but will waste version after version. now, if they do get he first version right, and don't need to waste it at all, that's a very commendable result, but if you only set out to "prototype", this is no longer an option, either by choice of language or tools or something else that everyone knows was intended to be wasted, and would feel bad if it were to go into production. that's what I think is wrong about using specific languages to prototype things and talk about a language as "good for prototyping". it is invariably understood as "not good for production code". I have to fight this impression. in conclusion, it is hard enough work to it right the second time when you have all the data from the first try available if you should not also have to do it a third time because you weren't _allowed_ to go all the way in the first attempt. | Another way to put it is "Don't hang on to the first thing you did." my argument is that the reverse is equally valid: don't _always_ throw out the first thing you did. | However, I submit that lispers prototype constantly, and that every time | you type "(defun foo () ...)" to the prompt, you are prototyping | something that you _intend_ to throw away (otherwise you would have put | it into a file!). ok, that's the gist of your disagreement. I think intent to throw away is the bad part about prototyping. throwing away is something you should be prepared to do without much concern, but you should strive to make it usable, too. if you intend to throw it away, the threshold to keep it is set too high. now, what if it actually does work the way you wanted it to? do you still throw it away? if you prototype in Lisp and write production code in C, you would have to, right? that's bad. not only because doing something you have already done over again is stifling, the problems in C are different from the problems in Lisp and you have to do a lot of redundant work. | The world is full of programmers stuck on their own dinosaurs because | they won't let go. well, letting go is as much a part of caring about something as not letting go. sadly, our cultures are built by people who couldn't let go, so everything around us is shaped by an unhealthy conservatism, and because people are afraid of having to suffer as much pain every time they manage to get something to work somewhat right, we have a lot of stuff that were shaped by a trial-and-error process that stopped as soon as the errors were tolerably small. had people been able to let go, and use their knowledge from what failed, perhaps we could move on. in my view, the patent system was supposed to let inventors capitalize on the works of others and make _significant_ improvements, while the patent effectively forbade the meager insignificant improvements. a wonderful mechanism that should be applauded and made much stronger, it has turned into a monster that stifles innovation by admitting overly broad and senseless patents, instead because the wrong kind of people approve patents. this is just another example of how society is shaped by conservatives who have no clue _what_ they are conserving, only that change is bad. | In which case you have already rewritten (at least parts of) your | application several times over. But to be free to do this rewriting, you | have to have made a correct estimate of how long the project will take. | If you factor in the prototyping (call it "learning curve", or "concept | development") time, you will have the time to do this. ironically, you always have time to do that, despite what everyone says. the key is to get something to the point where it does not fail, and then you can change everything as long as it continues not to fail. people always have time to improve things, and they embrace things get improved in oh so minor ways. | But if they hear bad news from someone they know can and has done the job | on time in the past, they tend to be much happier than when they hear | good news from someone that they know they are going to have to plan | "slop" time for. And for those programmers who gain the reputation of | getting work done on time, the subject of prototyping should rarely even | come up. well, there's often a "fuzz factor" you can add to or multiply with what people say. a good manager learns the fuzz factor and doesn't want to change it. some programmers get all the big work done in the first few days and then spends a lot of time fixing minor bugs, while others tinker with fundamentals 95% of the time and whip up a marvelous piece of art in the last few days. the key to managing is to understand what you deal with, and programmers are predictable _one_ at a time, even when they are (supposedly) part of a team. incidentally, getting something to work is child's play. where you need the expertise is in not making it fail, or fail gracefully. and I don't think a prototype that only shows how it works is useful at all, since you learn nothing about surviving the failure modes by having something that only "works". anyway, I like Common Lisp because I can write enough serious code in it to watch how it actually deals with a hostile world (specifically, socket code that distributes functionality across hundreds of computers over thousands of little stretches of cable and routers that people upgrade and add bogus routes to and all kinds of shit) and then rewrite it before the hostilities resulted in harming anything. also, Allegro CL is the first environment I have used which allows me to use all I know and learn about the hostile world without writing tons and tons of code. when something causes a crash only once a year, you ignore it in C because it might change your whole design and basically send you back to the drawing board for a year to deal with it, and then you suffer a crash once a year, so it isn't worth the costs. it might take a week or a month to redesign to survive such a problem in Common Lisp, but you can actually offord to take care of it. this means that the next time you have to deal with this kind of problem, the competent Common Lisp programmer gets it right, while the competent C programmer still doesn't know what it would take to solve that particular problem because he hasn't been there. #:Erik -- Y2K conversion simplified: Januark, Februark, March, April, Mak, June, Julk, August, September, October, November, December.