You Don't Want to Think Like a Programmer
prog21.dadgum.com
prog21.dadgum.com
I think this is a false dichotomy -- developing a masterful understanding of what things cost must be coupled with a masterful understanding of what makes things valuable.
If OP shared what caused him to think this thought perhaps a good conversation would happen. I could see myself write something similar about CFOs after encountering one at a past startup who kept turning the air conditioning off to the point where coding in the office was a sweaty experience.
I think the title of the correct article is "You want to think like a programmer and a customer" or "You don't want to thin like a bad programmer"
Regardless of whether what is proposed is a false dichotomy, I think the post The Recovering Programmer [1] offers some explanation for what motivates the author of this blog, as does Don't Fall in Love With Your Technology [2].
The key quote from the latter would be
>Slowly, not in a grand epiphany, I realized that there was something missing from the discussions in [comp.lang.forth]. There was talk of tiny Forths, of redesigning control structures, of ways of getting by with fewer features, and of course endless philosophical debates, but no one was actually doing anything with the language, at least nothing that was in line with all the excitement about the language itself.
I understand the whole series as intended to correct the reader's not caring enough about their problem domain (or, in the worst case, not having a problem domain at all). As such, it may overemphasize the importance of the problem domain to the exclusion of everything else for pedagogical reasons.
Overall, I agree though with your comment about the Forth community in general.
It might be a false dichotomy in theory ("well, no reason why these two concept should not be orthogonal") but it sure is a real dichotomy for very many developers.
People lost in the details of coding, best practices, new fancy languages, monads et al, while not producing anything of substance for real users -- or getting lost in the process and not getting anything released.
There's even a kind of term for these people "architecture astronauts" (coind by Joel Spolsky IIRC). And the even older, "worse is better" notion is also related to the same issue.
They've never written a line of code and yet somehow are dictating spaghetti enterprise architecture. Their business requirements are things like "must comply with all applicable standards" (isn't it your job to at least work out which ones, or are you above that?) and they never actually stop to think whether any of this will actually work.
I'll take a language hipster and a clueless business user who just wants it done any day.
I was saying much better advice to programmers is "remember to think about what makes software valuable" rather than "you don't want to think like a programmer"
At the end of the day you have to learn to make compromises, and that you can't always have "both".
No, I'm saying that what's merely possible doesn't matter, it's whats possible AND probable that's important.
That is, don't aspire to be THE exception that's excellent at both, first try to be adequate at both. This way, excellence at either or both, if it ever cames, won't have left you crippled at the other skill. Plus, it might never come anyway, in which case being adequate can get you a long way itself.
Also, my dichotomy (and what the original article talks about) doesn't concern merely "being good at programming", but about being preoccupied with excellence at programming -- the perfect architecture, masterful application of design patterns etc.
So it's simply not a problem I encounter, but maybe your experience is different.
But it's hard to remember all of that when you're in the middle of writing some C code so that it can be optimized with vectorized instructions when targeting newer chips.
Hacking is great, but engineering can inspire and enable hacking. How many of these cool startups would be around without gnu/linux/freebsd?
I think the trick is to go to a higher level once a day, or spend more time at a higher level once a week. What is value you will deliver to at least one other person? Are you making real progress getting there; or are you building an endless series of platforms on top of each other without ever having a clear application in mind?
Even if you are working on a generic performance improvement you can still do that. If 10,000 servers are running your software, and you improve performance by 2.5%, then you can measure the value you delivered in terms of power saved per year and it would be a real accomplishment. That will be motivational, and it will also help you choose a better follow-up project to deliver even more.
The main advantage, to me, is being able to collapse layers of abstraction. We've done that at one of the startup's I CTO for.
On the backend, we eliminated the entire multi-tier stack we've come to know and love from the late 90s. The database, application server, caching server, and authentication server were collapsed down into a single executable.
We dropped TCP, and went to UDP + NaCl-based crypto. This in turn changed how we did session management and logins (we only target mobile devices), and allowed us to gain further performance by bypassing the Linux kernel entirely, and talking directly to the Ethernet hardware. Our wire-to-wire latency for a UDP packet (without any processing, just heading through the LuaJIT app framework) is ~26 nanoseconds. We measure the entire request/response time in less than 10,000 nanoseconds for updates, and frequently, less than 3000 nanoseconds for reads.
Nanoseconds! Today's hardware is crazy efficient, but yesterdays software architectures waste it all.
For caching, we employ a database library (lmdb) that uses the file system and memory mapping for all data, a lot like Varnish Cache does. We can service reads without a single malloc() call. No more memcached.
Finally, the entire system is built around an event streaming approach (see Disruptor/LMAX). For that to work, we wrote our own cross-platform Core Data alternative on the client, and for this particular application (a social network), the end result is that the user experiences ZERO network latency for everything but search.
Everything is local by the time the user is made aware of it. For updates like making a post, we make it happen instantly on the client, speculatively, and eventually the update makes it's way to the server and back, and then on to everyone else. The user doesn't even need a live network connection to post, and "offline" usage works as expected.
And also (since this is a speciality of mine), our object graph syncing is multi-device from day one. Lots of projects (e.g. Vesper) struggle with that one. We didn't bolt it on, it's a fundamental property of our data model and overall system.
After collapsing the crypto, database, and authentication, we were able to introduce object capabilities that requires zero memory lookups, instead of the usual RBAC, which in my experience is difficult to implement efficiently and hard for people to manage.
And because we have our own network protocol, and are targeting native clients we control, we can easily do client-side load balancing. We use consistent hashing to contact read-only servers (that also handle crypto), mostly so we can spread out the bandwidth without having a crazy expensive load balancer. Thanks to our custom database/app server, we can service all writes on a single machine, although like LMAX, it's designed to run three in parallel, discarding the results of two of them at any given time.
Point is, there are HUGE gains to be made when you (a) understand the whole stack, (b) have the skills and understanding to rewrite any part as you need to, and (c) have the guts to ignore 15 years of received wisdom on how to scale an app and are willing to collapse layers down in pursuit of speed and simplicity.
It may be harder, but the payoff is enormous. I did all of the above myself in just over four months, including building a cross-platform app framework for iOS (porting to Android in March), and the app itself.
Think accounting systems on a mainframe talking to inventory systems written in C talking to HR systems provided by the consultantware flavor of the month. In those kinds of environments it made a ton of sense to break up the various functional tiers so that you could attach to the appropriate one with minimal translation layers.
Having worked on systems like that in the past, you'd never go in thinking that it is the lowest latency way to do it. Latency wasn't typically a major design driver.
That said, I work on low latency message systems now and the architecture your describing is very typical in that space.
Totally, and whatever innovation I actually produce is mainly putting together cool stuff other people have done in a novel way (which at times, hardly seems innovative). I'm hugely indebted to all of the research and pioneers in production in our industry.
One of the things I love about CS is how easy it is to take cool shit from one subfield and apply it to another. There's just so many smart people figuring stuff out that to a guy like me, that's like Christmas every week. :)
This is also my way of thinking and the way we are doing things in Snabb Switch. I'm influenced by my brief time working with Mitch Bradley on firmware hacking at OLPC. Linux would never get the same performance out of hardware as his seemingly toy little Forth drivers.
luke@snabb.co if you fancy a chat some time :-)
P.S. Thanks for the generous link-plug that landed on highscalability.com. I look forward to hearing more about your systems in the future.
Did I understand that correctly? You're the CTO of multiple startups? How's that working out?
The first I worked on for a year straight starting fall 2012, it launched, we got our first customer which exceeded our year-one goal in revenue by 2-3x, and was too big for us to handle anyone else without raising funds. We're replacing a Lotus Notes system for a $100 million/year company with 800+ employees.
My dev partner in Australia has been handling that account ever since (it's an Australian company, and I'm in the US), and as we've been working together for almost 8 years, there's not a lot of back and forth needed at this point. Mostly just weekly meetings and the occasional Skype call. My plan is to pick development back up again on that startup mid-Summer in preparation for expanding beyond that first company.
The other startup I began immediately after the first launched, and I've been designing and coding basically non-stop for 4 months. So there's hasn't been much overlap for me, and so far, it's worked out okay.
In my experience, I'm most useful launching projects. I can do the architecture, code up the initial design, and then at that point, other (better) programmers can see what it is I'm trying to do, and buckle in for the long haul.
(BTW I'm contemplating CTOing a third company, if anyone has one they'd like to pitch me (erich.ocean@me.com). I've got 3-4 months of time available to work on something new. If you project can be launched in that amount of time, I might be able to help.)
(Of course, I don't presume to know your situation.)
That's actually my favorite part about this particular company. Normally, it's a bunch of tech and business guys trying to "get traction". This business already had traction, and just needed a better app and infrastructure.
So I took four months and solved that problem for good. :)
I would love to hear more about this. I was looking for a way to send UDP that is encrypted and authenticated, with private contents and no replay attacks. The best option I could find is DTLS, but that has spotty support on Windows and no API in common scripting languages. Can you say more about your approach? If it is roll-your-own, what makes you confident it is secure?
And because of my playing around with NaCL, I've come to the conclusion that encryption isn't the hard problem---key management is the hard problem.
I use crypto_box/unbox as is, although we do do the crypto_beforenm()/crypto_afternm() as (a) our clients are known, and (b) it's ridiculously faster. The docs on NaCl mention it, sort of, but it's much, much, faster. If you can do it, you always should do it.
As for replay attacks, we use what I'll call "hash chaining" (if someone knows the real name, I'd like to know). We have two kinds of messages, ordered and unordered. Unordered messages can be replayed at any time, as they are read-only, or some other kind of status messages, such as a heartbeat.
For ordered messages, we hash the previous message and use it as input for the next message when it is hashed. Both hashes are sent with each message (we use Sip-Hash 2-4, highly recommended BTW). (One analogy would be how git works, where the previous commit's hash is hashed as part of the new commit's hash.)
The chain of messages from the device to the server is called the "device stream", and we have a second chain going back to the device, the "update stream". The system supports multiple device streams for a single users (e.g. an iPhone and an iPad), but there's only one update stream for all devices, so they stay in sync.
Both ends of the connection test the hashes before applying, which trivially prevents replay attacks, since every ordered message can only be "played" once. We store the current device stream hash when the database is updated, in the same transaction, on both the client and the server. This provides resiliency in the face of crashes.
We also use the hash chain to detect out-of-order messages. In our application, they're pretty rare, so I simply drop out-of-order messages and request the correct one from the client.
This could be bad, because playing back old messages would illicit a response. For that reason, and also because I don't want to store update streams in the database permanently, the messages include their offset in the stream. The in-memory, wire format, and on-disk format of each messages is identical, so we can lay them end-to-end on disk. When a messages comes in, we can trivially determine if it is old, and drop it that way, too. If we need to write an update stream to disk, because the client hasn't connected in a while and we want to free up space, it's a single sendfile() + known offset call, conceptually, to send the update stream since they last signed back on. That way, we don't need a separate index for streams on disk.
Hope that helps!
Also for anyone that got this far without realising, this NaCl is not NaCl the google chrome "native client".
I'm going to go out on a limb and say that:
1. Ditching TCP for a social network app is insane.
2. Bypassing standard POSIX sockets for a social network app is insane.
3. Writing a custom database server for a social network app is insane.
4. There's no way you did that in four months, especially if you were CTO for multiple startups.
Even if you're the greatest developer alive on Earth today and you really did all that, think of how many amazing features you could have developed in that time to differentiate your product, instead of obsessing over insignificant nanosecond latency gains.
They would be using Solaris, Aix, HP-UX, Tru64, VMS, Windows instead.
Remember how expensive it was to start an internet company in the 90s when you had to run Sun hardware, Oracle databases...Even developer hardware was expensive. $3,000 laptops vs today's $1,000 machines.
The ideal is to cycle. Focus on the problem domain. Get something working. Come back, look at the software engineering domain. Obsess about that for a while. Then move on to the next project. The cycle itself means you get to be productive, get to focus on solving real problems, and get a chance to evaluate your code style and experience, improving it along the way too.
I have maintained 200k line Perl programs written by someone who never stopped to ponder anything outside the problem domain. It was a total mess. The program was basically a textbook in how not to program, particularly how not to write Perl. Matt Trout said it was "written by the programmer that Matt's Scripting Archive would have fired for writing bad code."
If you want your software to last, then software engineering has to be an aspect of it. But the author is also right that you can't let this detract from solving the problems at hand. Consequently you have to be able to really focus on learning each side in cycles.
Ditto, though I think I have a unique element to my story.
I spent a week deleting code I couldn't detect a use for. I nuked nearly 40,000 lines and could not discern a difference in functionality (though, couldn't be certain since I hadn't completed the test suite.)
Writing a test suite for software with no spec and only others' vague recollections of meetings to go on (Agile!) is fun - it basically ends up a regression suite enforcing current broken behaviour.
Perl takes no part of the blame for this, some of the Rails code needs to be seen to be believed - looked like an early PHP tutorial in places.
What was great was, the Perl was full of comments about how much easier it would have been in Ruby/Rails because he never bothered to read the docs on references.
I don't think we deleted 20k lines. Probably more like 5k.
However the kicker was when deleting something that seemed harmless enough broke something. In that case, it was a comment. We're not talking about smart comments here. We are talking about comments that are parsed and used by the application at run-time for actual logic :-P.
Oh, and when we added test cases for rounding numbers.... the test cases failed....
Regarding the role of language, I would much rather be maintaining bad Perl code than bad PHP code.....
The problem is that there is so much cargo cult junk in programming as a field that it's impossible for a novice to discern the pseudo-engineering crap from the truly beneficial concepts. Beyond the core algorithms and data structures whose mastery should be kinda obligatory if you want to implement anything in production, it is impossible for a novice to tell what he should ingrain in his daily work and what he should not.
The advice given here is therefore is very good. Get practical experience in building things, so you identify the beneficial abstractions when you learn of them, and have courage abandon those that do not provide value.
The downside is the "expert beginner" who learns a one way to do a thing and thinks it's well and good to do it that way for all eternity. Higher level languages are fantastic because they offer efficient and practical abstractions out of the box for the "patterns" you would implement yourself in a half-assed way in a lower level language like c.
People infatuated with solutions finding a problem are kinda bad from a communication point of view. They are so a plenty that when one tries to offer practical higher level solutions to existing problems the listener often thinks this is motivated out of love for the solution and not out of love for the problem.
They are there to optimize the use of the mental energy of the programmer.
Const correctness makes it much easier to read and reason code someone else has written. Or myself, months from now on.
Standardized code layout should be strict enough that you can identify scope at a glance when browsing through a 10 MLOC engineering CAD application and hunting for that one bug or strange call path.
But - these are necessary features for _production_ code. For _prototyping_ code you should optimize for maximal mutation rate and not necessarily legibility rate. Although the code should not be garbage (if you can't read it it's kinda worthless) strict conventions often hinder fast iteration and you should really figure out which ones are necessary constraints for the problem at hand and which are not.
I imagine someone will protest this idea, saying that there's already enough crappy software out there, that the world doesn't need any more technical debt. But this fails to realize that technical debt is a good thing in someways- it's a by-product of learning and crashing through boundaries.
In a way, technical debt is analogous to carbon emissions- yes, by itself it's a bad thing. But in the larger scope, carbon emissions are a by-product of industrialization, a process which has vastly improved our quality of life. Technical debt, like carbon emissions, is a sign of progress.
So the solution was to basically rebuild this web service from scratch. This decision also came with business logic simplifications - as we realized that certain features were unfeasible at that scale, so many features ended up being dropped based on technical considerations. Which IMHO was OK, because the best way to approach problem solving is to build less and sometimes we end up building features instead of solving the problem that we set out to solve in the first place.
I wish I could say that our initial approach allowed us to iterate fast. But it didn't. I was there from the start, I've built the prototypes, I did the pivots, I made all the wrong choices, I managed the team that came after and I could've made all the right choices without sacrificing fast iterations. All it takes is experience and tools that do "the right thing" in regards to your problem, without sacrificing productivity - being able to recognize the best tool for the job, being able to simplify problems, being able to tell the cost of something - now those are traits of good software developers.
The article does have a point though - you can learn all day about tools, best practices, algorithms, paradigms or whatnot, but in the end the goal isn't and shouldn't be to write "beautiful code", but rather to produce artifacts for solving problems that people have.
As long as you learned a lot from it.... We all make architectural errors. One can't learn without making mistakes though.
Mate, I agree PHP sucks (aside from the legions of maschochists who do useful stuff with it), but a lot of perl (when used in a disciplined manner in communication with ones peers) is a useful and productive orthogonal take on computer science.
Thinking like a programmer is really near to mathematical thinking, just the basic stuff: logic, invariants and program correctness, in paper, and using pseudo-code. After a year one will be ready to throw that stuff through the window, not because it is not useful, but because it is already engraved on your brain and somehow, even if you do not use assertions at the start of your functions or do not write an invariant down for each loop, it will be there and will make your code cleaner and free of copy-pasted code.
But the real truth is that people are different. Some people are mechanics in the head, they like to optimize small functions and break systems and loved the assembly c time. Some people see the world as states and attribute facts to static objects, these people love OO, its an entire paradigm that complies to their though process! Some people are rigours about how the world moves, they like Haskell and logic programming and always bring these aspects to their code base.
Some people are dynamic and see the world as a continuous flow of time (not pinning attributes to things, seance a thing can change along its time line, thus brining focus on the core of things and ones purpose), they like languages like lisp where transformations of data is the center, not classes with fixed static attributes, that is contrary to their irl thought processes. These are the people who develops non-deterministic programming, because the focus is on time not space. They like macros and other efficient expressive tools because it allows you to express your solution in a better language and automate transformations.
tl;dr / Summary People think differently and programming is merely a means to express yourself, ergo your view of programming will be a view of how you like to think and function, and to say that your own definition is the universal truth is arrogant, narrow-minded and wrong.
http://wikisocion.org/en/index.php?title=Statics_and_dynamic...
As a note, maths are not a field I am really strong on, and had a hard time with them at the university. But, even when it was hard, it helped wrap my brain around programming and provided me with elemental tools. Yes, programming might be drawing pixels in a grid, or could be just throwing words at the computer until the output is what you want.
I do not consider myself a proficient programmer and yet, I pity the programmers that look confused at a chunk of code in Eclipse and just add whatever a set of libraries provide to get something to work, which often ends up with larger chunks of code that basically do nothing, but are there just because (with an special guest, more chunks of commented code that are waiting for someone to delete them). I experienced this feeling the first time I programmed something for Android. And no, in this case there's no 'some people might have a different view on the issue'. There's people who code that have no clue of what is happening, and that is saddening (and I guess, stressful to them).
As an exercise on what I am referring with basic tools let's see the simplest example I can think of: define a function that returns the factorial of a number. We know the answer already, but instead of doing that, let's think first, and generate the code later [∗]
What defines a factorial?
n! = 1 * 2 * 3 * ... * n-1 * n
0! = 1
- At each iteration, we will mantain that f = i!
- For all iterations, i ≤ n
Ok, now code
// Pre: n ≤ 0
// Post: returns n!
int factorial(int n):
int i = 0
int f = 1
// inv: f = i! and 0 ≤ i ≤ n
while(i < n):
i = i + 1
f = f * i
return f
It is not "the universal truth of programming", and there are many many different "states of mind" that one will need to learn in order to do something (OpenGL and state machines, SQL and declarative languages, etc). But before learning something (unless you are really talented, I guess), one must learn to learn.
I really can't see the point of your third paragraph, what are you arguing for? That the people who threw code was people who didn't share your view on programming? Or is the paragraf to be interpreted that anyone who try to use leverage in code is a fool? And also how are inexperienced untrained programmers skill really relevant to different views on programming?
Let me give an exercise in return. Add to the code base a module that allows the skin of the site to be changed depending on the users device in a way that it is easy to add skins and also capability to random give users different skins. How much math do you really need beyond Math.rand(0,100)?
This instead is task that is solved by being able to formulate an expression that is general enough and can communicate with the existing system and fit the existing organization without breaking the big structure. No computations is really taking place ( in the seance we want to get some mathematical result from different values ) it's only flag checking at the bottom line.
You learn to learn when you grow up. The things you mention are different ways to look at problem and thus different ways to express solutions.
Maths may not relate on how you structure code, but (as I see it) an early start with a little dose of maths on understanding algorithms, may make your brain understand the elementary stuff easily, and make you think like a programmer. Are there any other introductory ways to get there? Sure, why not.
My third paragraph was referring to what I have seen on the people that do not think as programmers. Not as a matter on how they got there, but as how they never got there.
Some people say that but I've never understood it myself. To me, programming is nothing like mathematical thinking, especially at an intro level. It's more about giving super precise instructions to a stupid machine that has to be told every little thing. There are lots and lots of successful, competent programmer who don't know much math or logic as academic fields.
Edit; maybe a more relevant discussion would be talk about what is meant by 'mathematical thinking'.
2*3=(1+1)*3 | Definition of 2
2*3=1*3+1*3 | Distributive property
2*3=3+1*3 | Identity of Multiplication
2*3=3+3 | Identity of Multiplication
2*3=3+(2+1) | Definition of 3
2*3=3+(1+2) | Commutativity of Addition
2*3=3+1+2 | Associativity of Addition
2*3=(3+1)+2 | Associativity of Addition
2*3=4+2 | Associativity of Addition
2*3=4+(1+1) | Definition of 2
2*3=4+1+1 | Associativity of Addition
2*3=(4+1)+1 | Associativity of Addition
2*3=5+1 | Definition of 5
2*3=6 | Definition of 6
I agree with him that working on a project is often the best ways to learn a new skill. But for heaven sake, heed to what the experienced folk say and deliberate on whether to follow them or not.
This is a truism, but I don't think it's all that applicable to everything.
There are lots of musicians who paved their own way, breaking the rules, without first having "mastered" the previous ruleset. Same for painters (there are pioneer modern painters who could not paint anything Renaissance style for example).
And, yes, there are programmers who created succesful software, even multi-million businesses, without really knowing the whole craft of software engineering.
Isn't, for example, Derek Shivers (who frequents HN from time to time) a classic example of "fake it till you make it"?
Or even this Zuckenberg guy. I don't think Facebook was the result of a master software craftsman.
While some people see that middle bit where you teeter on the precipice of becoming a full blown architecture astronaut as wasted time or effort I see it as a Journeyman phase that most people need to go through to become true masters.
Sort of like photographers should fully understand the rule of thirds and other classic rules of composition because really understanding them gives them better insight into when and why they are better off breaking them.
Part of the problem is that human language is by nature imprecise as is human knowledge. The rules have very fuzzy edges and people need to be introspective about these sometimes. But you can't be introspective about the rules if you aren't pushing the limits. Otherwise you are in safe territory and there's nothing to be introspective about.
It's a little like saying don't think like an English speaker or you're going to pedantically correct everything. Sure it happens, but it's not a lot of people that do it and among those its 1 in a million that actually do it to a point where it gets in their own way.
"Don't think like a programmer, think like a developer"
"Learn to code, not to program"
Most of the cases we have words that mean basically the same, and we almost randomly say, more or less, that X means "a good Y".
What matters at the end of the day is delivering working solutions to a problem, not how beautiful such solutions are.
The foundation for these abilities comes from habits this OP encourages you to avoid
Or it could result in you getting lost in its minutiae and losing the big picture.
After a while you might not even care to improve it at all, just end happily exploring niche advanced areas.
Anyone else have a gag reflex when they see code like this?
var firstVar = "one";
var secondVar = "two";
var thirdVar = "three";
var firstVar = "one";
var secondVar = "two";
var thirdVar = "three";
var firstVar = "one";
var secondVar = "two";
var thirdVar = "three";
var thisVarHasAReallyLongName = "four";
var thisIsAnotherVarWithALongerName = "five";
var firstVar = "one";
var secondVar = "two";
var thirdVar = "three";
var thisVarHasAReallyLongName = "four";
var thisIsAnotherVarWithALongerName = "five";
I also think that it's at least a little bit harder to consistently enforce a convention of this kind. If a variable name gets too long, and you're not using some sort of auto-formatting, you have to manually space-out the variables to a new name length every time you introduce a newer, longer-named variable.
I think the real impulse people have for this kind of convention is that it actually just looks a little bit neater, because things are aligned in columns. In reality I think it's much more difficult to parse and maintain.
var firstVar = "one";
var secondVar = "two";
var thirdVar = "three";
var thisVarHasAReallyLongName = "four";
var thisIsAnotherVarWithALongerName = "five"; var firstVar = "one";
var secondVar = "two";
var thirdVar = "three";
var thisVarHasAReallyLongName = "four";
var thisIsAnotherVarWithALongerName = "five";