Holding a large program in your head is like holding a city in your head. You can't entirely do it. What you can do is to know broad outlines and principles, so you can navigate to the relevant points and negotiate difficult parts. When you see the details at the relevant places, then you can deal with them. It's like being a cab driver. You don't memorize every cobblestone and pothole, but you know how to get where you need to go you can deal with them as you're driving.
Holding a Program in One's Head (2007)
71–80 of 104 posts
Re: Holding a Program in One's Head (2007)
#72I find it interesting to read this again after a few years only to realize that Paul is in direct contradiction of those who would have us take a break every 25 minutes with his second point. It's kinda refreshing to hear this point of view again. I worked 5 solid hours last night, starting that particular stretch around 7pm and got around 3-4 normal work days worth of work done.
Re: Holding a Program in One's Head (2007)
#73It's actually an indictment of our programming tools that they require one to hold so much of the design context in one's head. If they were better (more expressive, easier to interact with) they would help to solve the problems rather than require superhuman feats of endurance. pg does mention that succinct programming languages help, which is true, but they don't go nearly as far as they could. Like him, I use Lisp…
> It's actually an indictment of our programming tools that they require one to hold so much of the design context in one's head.
Reminds me of a misconception a vocal student I met had about math. She thought she could understand the attraction of math because the symbols and equations could look pretty. I had to explain that the beauty was not in the symbols, but in the pictures and concepts they could evoke in your mind, much as the beauty of music wasn't in notes on a page, but the sounds they represent.
Feynman once said something about how equations evoked animations in his mind.
This is the value of things like Lisp, Python, Ruby, Smalltalk, Light Table -- by interacting with systems in a tight feedback loop, you can start to form pictures and understandings in your mind. It also shows where those environments and other current tools are lacking. Instead of having to reconstruct relationships in our minds, we should have a way of navigating an explicit diagram of them. Even IDEs like Eclipse, for all their complexity, still require you to read then form relationships in your mind. (It's like we're all still doing word processing with non WYSIWYG word processors.)
Re: Holding a Program in One's Head (2007)
#74Holding a large program in your head is like holding a city in your head. You can't entirely do it. What you can do is to know broad outlines and principles, so you can navigate to the relevant points and negotiate difficult parts. When you see the details at the relevant places, then you can deal with them. It's like being a cab driver. You don't memorize every cobblestone and pothole, but you know how to get where…
You can visit the neighborhoods often enough that they are quickly familiar when you happen upon them again. That's called a domain expert.
In fact, London cab drivers DO hold the city in their head. They are required to, before they get their license.
Re: Holding a Program in One's Head (2007)
#75Holding a large program in your head is like holding a city in your head. You can't entirely do it. What you can do is to know broad outlines and principles, so you can navigate to the relevant points and negotiate difficult parts. When you see the details at the relevant places, then you can deal with them. It's like being a cab driver. You don't memorize every cobblestone and pothole, but you know how to get where…
You can visit the neighborhoods often enough that they are quickly familiar when you happen upon them again. That's called a domain expert. In fact, London cab drivers DO hold the city in their head. They are required to, before they get their license.
Yes, I was thinking about what I read about London cabbies. However, they don't necessarily have recall of every pothole and cobblestone. They remember enough of a map so they can get to where they need to be, and deal with what's there on the way.
Re: Holding a Program in One's Head (2007)
#76For years now I have been arguing with other programmers on the merits of IDE features such as intellisense. My position has always been that they are completely unnecessary. Autocomplete is useful, sure, since it saves some typing, but that is it's primary goal - to save keystrokes, not to help you remember what a class is capable of doing. Many programmers appear to get caught up in the small picture way of thinkin…
>>>> "The answer is diet, nootropics, meditation, exercise and knowledge of techniques (e.g. how to memorise facts rapidly). I won't go into specifics but suffice it to say that most people are undernourished and are mentally impaired because of it." Dude, if you have some concrete insights in these areas, you definitely should go into specifics . A lot of us would be very interested.
My apologies, I thought that it was outside of the context of the conversation.
A surprisingly high percentage of people have nutritional deficiencies. For example, an alarmingly high percentage of people in the US are deficient in Magnesium, an essential nutrient (meaning that your body cannot manufacture it).
http://en.wikipedia.org/wiki/Magnesium_deficiency_%28medicin...
> 57% of the US population does not meet the US RDA for levels of magnesium
And we're talking about a first-world country here! Magnesium is essential for a healthy stress response, and, as we probably know from experience, many people struggle with the stresses of day to day life. Anybody who regularly consumes alcohol, tobacco or caffeine is likely to be deficient as those drugs rapidly deplete Mg reserves in the body.
That is just one example. Another is Calcium, which 75% of people have deficiency of (http://www.livestrong.com/article/365193-heart-disease-cause...).
The body also becomes less efficient as time goes on. Have you ever wondered by old people tend to be more grumpy than everybody else? Because our serotonin (a neurotransmitter which is implicated in mood and irritability) levels fall as we age - http://www.pslgroup.com/dg/4098E.htm
One way to offset the brain's natural decline of neurotransmitters is to supplement with the precursor amino acids which are used to manufacture those neurotransmitters. For example, L-Tryptophan, an essential (again, meaning that you cannot make it) amino acid is rapidly absorbed by the body and is used to make more serotonin (among other things). The difference between protein and straight amino acids is that the latter are ready for use, whereas proteins, which are composed of amino acids, need to be broken down to their constituent parts before the body can use them.
Another age-related neurotransmitter decline - dopamine. A lot of older people have had some success with using D,L-Phenylalanine and L-Tyrosine to boost dopamine levels and reclaim their sex drive.
Healthy acetylcholine levels are also essential for cognition and can be boosted with things containing Choline (eggs are an excellent source).
GABA levels are very important for short term memory and focus. For example, anyone who drinks coffee will have experienced that overexcited state where you have a mountain of motivation but lack proper focus. Taking L-Theanine (Green Tea also contains this), an amino acid which causes increases GABA levels will restore the focus. I never drink coffee without L-Theanine for this reason.
Taking L-Glutamine prior to drinking alcohol will prevent a hangover. It will also stop alcohol and sugar cravings. This is because the body is capable of using L-Glutamine as a source of energy.
But the most important thing is how all of these neurotransmitters interact with each other. Some of them are polar opposites, some modulate the release/inhibition of others. The brain is always striving for balance (homeostasis). All of these neurotransmitters, nutrients and minerals are vectors which pull it in one direction or another. Keeping them in balance is the key to feeling good. Having a model of their interactions makes it considerably easier to debug problems and fix them. This comes with experimenting with your body and gaining an intuitive understanding of what's what. I think that it would be difficult to come up with a generalised approach due to people's baseline levels of each neurotransmitter being different.
Note that even popular multivitamin brands sometimes contain too little of a given nutrient. I recently bought a doctor-recommended one and it barely contains and magnesium or calcium. It pays to educate yourself and not to completely defer your health to someone else. It's your body and it's essentially your problem.
After addressing deficiencies, I found that I felt a lot better and that my rate of recovery from stress, a night of drinking or strenuous physical activity had improved considerably.
Another important factor is removing things which cause harm. E.g. alcohol, in sufficiently high doses (high enough to be drunk), is neurotoxic, meaning that it directly harms the brain. One of the primary mechanisms of alcoholism is that the damage caused by alcohol directly contributes to future alcohol cravings. A lot of people have problems with anxiety - they would be wise to discontinue caffeine intake altogether as it is a major risk factor in anxiety disorders.
Meditation has a host of benefits and structural changes have been observed in the brains of practitioners - http://www.scientificamerican.com/podcast/episode.cfm?id=med...
Exercise is absolutely essential and, frankly, should be a first-line treatment for things such as depression.
There are also a few new and interesting nootropic substances such as Piracetam, Aniracetam and Noopept, the last one being the most effective for me personally.
All the wise folk say that the body should be treated like a temple. I completely agree with them since the mind and the body are but one and the same. Treat the body right and the mind will follow. Treat the mind right and you will feel right.
Re: Holding a Program in One's Head (2007)
#77I do it. I build mockups in my mind, run through clicks and interactions and finally the code flows.
Re: Holding a Program in One's Head (2007)
#78Earlier quoted context omitted.
The "whole problem" is simply a process. Processes in the real world are composed of 1-* sub-processes, and ultimately distill down into transformations (input -> transformation -> output). You don't need to understand every low-level process to make a start. You raise two interesting points though. Yes, revisiting an architecture is required when you've not solved a similar problem before. Consider though that in th…
> Consider though that in this community 99.9% of the time others have solved your problem before. You could reinvent the wheel (which is arrogant), or you could do some research to see which architecture has been successful for others. The best way to learn something is to come up with it yourself. If you base your architecture on what you read in books or elsewhere, you probably only have a limited understanding of…
The best way to learn something is to come up with it yourself.
That's been bugging me, and it's been bugging me because it's not entirely right. It's not entirely wrong either, though.
Given an undirected graph, in which you need to calculate the shortest path between two vertices, would you slog it out or would you just find a shortest path algorithm?
Now move that up a level, from feature implementation to feature design -
If you had to federate identities between two directories, would you hack something together, or would you have a look to see if someone else has done that before? Assuming the latter, you'd probably discover OpenId, OAuth, WS-Federation, and SAML. Would you then use one of these or try to roll something that models their behaviour?
Take that up all the way until you reach the age-old build vs. buy debate, and the connected enterprise and so on. Building something just to understand it is not making much sense to me.
Re: Holding a Program in One's Head (2007)
#79In my experience, this is PG's most helpful/ reassuring technical essay. Recently I was working on/ creating pretty complex algorithms with gargantuan cobweb of edge cases. Not only did I had to work for 15+ straight hours, but in order to maintain productivity fasted (bar caffeine, few nuts & water) every alternate day to keep the steam going. Incredible times, and rather close to reaping the fruits now, but there i…
i'm not bashing you - i've been there myself. but that same shared experience requires me to ask: dude, how are you going to maintain that? you need to find a simpler way... if that's how you feel now, a year down the line you're going to hate that code.
dude, how are you going to maintain that?
Depends on why it took 15 hours to figure out the problem and make it work. I would presume he (you) learned something during the process, so if it had to be repeated you wouldn't have the same false starts and understand the general solution much quicker. After that, comments should help the coder understand the details like edge cases and non-obvious decisions.
I speak from a recent similar experience where I had to build a fairly complex piece of multi-threaded image processing code on Android. Starting out there was a lot of knowledge about image processing and Android that I simply did not know. Learning and internalizing that information took a significant chunk of time reading the docs and other peoples code. Only then could I fully understand my particular problem and implement a solution.
Re: Holding a Program in One's Head (2007)
#80I find it interesting to read this again after a few years only to realize that Paul is in direct contradiction of those who would have us take a break every 25 minutes with his second point. It's kinda refreshing to hear this point of view again. I worked 5 solid hours last night, starting that particular stretch around 7pm and got around 3-4 normal work days worth of work done.
Yesterday a friend explained the physiological reasons behind 25 minute breaks: basically the muscles (including eye muscles) go into a different state of relaxed-tension and its generally not good for them to be in that state while the body is sitting-looking.
There's also the issue of the effort required to concentrate on a task, which gives diminishing returns as you extend it beyond ~25 minutes without break.
However a mental flow state (what you seem to describe) requires little to no concentration effort and so can yield great returns over the time spent. The tradeoff is that the body is in a less-than-desirable muscular situation for a prolonged time - but I'm guessing the damage there is not so significant if 8 hour flow sessions are not a daily habit.
tl;dr: the 25 minute break thing is probably a good general guide, but shouldn't stop you pulling an 8 hour session if you are absorbed and productive