Joel Spolsky

This is part one of the text of a talk delivered to the Yale Computer Science department on November 28. The rest of the talk will be published tomorrow and Wednesday.

I graduated with a B.S. in Computer Science in 1991. Sixteen years ago. What I’m going to try to do today is relate my undergraduate years in the CS department to my career, which consists of developing software, writing about software, and starting a software company. And of course that’s a little bit absurd; there’s a famous part at the beginning of MIT’s Introduction to Computer Science where Hal Abelson gets up and explains that Computer Science isn’t about computers and it isn’t a science, so it’s a little bit presumptuous of me to imply that CS is supposed to be training for a career in software development, any more than, say, Media Studies or Cultural Anthropology would be.

I’ll press ahead anyway. One of the most useful classes I took was a course that I dropped after the first lecture. Another one was a class given by Roger Schank that was so disdained by the CS faculty that it was not allowed to count towards a degree in computer science. But I’ll get to that in a minute.

The third was this little gut called CS 322, which you know of as CS 323. Back in my day, CS 322 took so much work that it was a 1½ credit class. And Yale’s rule is, that extra half credit could only be combined with other half credits from the same department. Apparently there were two other 1½ credit courses, but they could only be taken together. So through that clever trickery, the half credit was therefore completely useless, but it did justify those weekly problem sets that took 40 hours to complete. After years of students’ complaining, the course was adjusted to be a 1 credit class, it was renumbered CS 323, and still had weekly 40 hour problem sets. Other than that, it’s pretty much the same thing. I loved it, because I love programming. The best thing about CS323 is it teaches a lot of people that they just ain’t never gonna be programmers. This is a good thing. People that don’t have the benefit of Stan teaching them that they can’t be programmers have miserable careers cutting and pasting a lot of Java. By the way, if you took CS 323 and got an A, we have great summer internships at Fog Creek. See me afterwards.

As far as I can tell, the core curriculum hasn’t changed at all. 201, 223, 240, 323, 365, 421, 422, 424, 429 appear to be almost the same courses we took 16 years ago. The number of CS majors is actually up since I went to Yale, although a temporary peak during the dotcom days makes it look like it’s down. And there are a lot more interesting electives now than there were in my time. So: progress.

For a moment there, I actually thought I’d get a PhD. Both my parents are professors. So many of their friends were academics that I grew up assuming that all adults eventually got PhDs. In any case, I was thinking pretty seriously of going on to graduate school in Computer Science. Until I tried to take a class in Dynamic Logic right here in this very department. It was taught by Lenore Zuck, who is now at UIC.

I didn’t last very long, nor did I understand much of anything that was going on. From what I gather, Dynamic Logic is just like formal logic: Socrates is a man, all men are mortal, therefore Socrates is mortal. The difference is that in Dynamic Logic truth values can change over time. Socrates was a man, now he’s a cat, etc. In theory this should be an interesting way to prove things about computer programs, in which state, i.e., truth values, change over time.

In the first lecture Dr. Zuck presented a few axioms and some transformation rules and set about trying to prove a very simple thing. She had a computer program “f := not f,” f is a Boolean, that simply flipped a bit, and the goal was to prove that if you ran this program an even number of times, f would finish with the same value as it started out with.

The proof went on and on. It was in this very room, if I remember correctly, it looks like the carpet hasn’t been changed since then, and all of these blackboards were completely covered in the steps of the proof. Dr. Zuck used proof by induction, proof by reductio ad absurdum, proof by exhaustion—the class was late in the day and we were already running forty minutes over—and, in desperation, proof by graduate student, whereby, she says, “I can’t really remember how to prove this step,” and a graduate student in the front row says, “yes, yes, professor, that’s right.”

And when all was said and done, she got to the end of the proof, and somehow was getting exactly the opposite result of the one that made sense, until that same graduate student pointed out where, 63 steps earlier, some bit had been accidentally flipped due to a little bit of dirt on the board, and all was well.

For our homework, she told us to prove the converse: that if you run the program “f := not f” n times, and the bit is in the same state as it started, that n must be even.

I worked on that problem for hours and hours. I had her original proof in front of me, going in one direction, which, upon closer examination, turned out to have all kinds of missing steps that were “trivial,” but not to me. I read every word about Dynamic Logic that I could find in Becton, and I struggled with the problem late into the night. I was getting absolutely nowhere, and increasingly despairing of theoretical computer science. It occurred to me that when you have a proof that goes on for pages and pages, it’s far more likely to contain errors in the proof as our own intuition about the trivial statements that it’s trying to prove, and I decided that this Dynamic Logic stuff was really not a fruitful way of proving things about actual, interesting computer programs, because you’re more likely to make a mistake in the proof than you are to make a mistake in your own intuition about what the program “f := not f” is going to do. So I dropped the course, thank God for shopping period, but not only that, I decided on the spot that graduate school in Computer Science was just not for me, which made this the single most useful course I ever took.

Now this brings me to one of the important themes that I’ve learned in my career. Time and time again, you’ll see programmers redefining problems so that they can be solved algorithmically. By redefining the problem, it often happens that they’re left with something that can be solved, but which is actually a trivial problem. They don’t solve the real problem, because that’s intractable. I’ll give you an example.

You will frequently hear the claim that software engineering is facing a quality crisis of some sort. I don’t happen to agree with that claim—the computer software most people use most of the time is of ridiculously high quality compared to everything else in their lives—but that’s beside the point. This claim about the “quality crisis” leads to a lot of proposals and research about making higher quality software. And at this point, the world divides into the geeks and the suits.

The geeks want to solve the problem automatically, using software. They propose things like unit tests, test driven development, automated testing, dynamic logic and other ways to “prove” that a program is bug-free.

The suits aren’t really aware of the problem. They couldn’t care less if the software is buggy, as long as people are buying it.

Currently, in the battle between the geeks and the suits, the suits are winning, because they control the budget, and honestly, I don’t know if that’s such a bad thing. The suits recognize that there are diminishing returns to fixing bugs. Once the software hits a certain level of quality that allows it to solve someone’s problem, that person will pay for it and derive benefit out of it.

The suits also have a broader definition of “quality.” Their definition is about as mercenary as you can imagine: the quality of software is defined by how much it increases my bonus this year. Accidentally, this definition of quality incorporates a lot more than just making the software bug-free. For example, it places a lot of value on adding more features to solve more problems for more people, which the geeks tend to deride by calling it “bloatware.” It places value on aesthetics: a cool-looking program sells more copies than an ugly program. It places value on how happy a program makes its users feel. Fundamentally, it lets the users define their own concept of quality, and decide on their own if a given program meets their needs.

Now, the geeks are interested in the narrowly technical aspects of quality. They focus on things they can see in the code, rather than waiting for the users to judge. They’re programmers, so they try to automate everything in their life, and of course they try to automate the QA process. This is how you get unit testing, which is not a bad thing, don’t get me wrong, and it’s how you get all these attempts to mechanically “prove” that a program is “correct.” The trouble is that anything that can’t be automated has to be thrown out of the definition of quality. Even though we know that users prefer software that looks cooler, there’s no automated way to measure how cool looking a program is, so that gets left out of the automated QA process.

In fact what you’ll see is that the hard-core geeks tend to give up on all kinds of useful measures of quality, and basically they get left with the only one they can prove mechanically, which is, does the program behave according to specification. And so we get a very narrow, geeky definition of quality: how closely does the program correspond to the spec. Does it produce the defined outputs given the defined inputs.

The problem, here, is very fundamental. In order to mechanically prove that a program corresponds to some spec, the spec itself needs to be extremely detailed. In fact the spec has to define everything about the program, otherwise, nothing can be proven automatically and mechanically. Now, if the spec does define everything about how the program is going to behave, then, lo and behold, it contains all the information necessary to generate the program! And now certain geeks go off to a very dark place where they start thinking about automatically compiling specs into programs, and they start to think that they’ve just invented a way to program computers without programming.

Now, this is the software engineering equivalent of a perpetual motion machine. It’s one of those things that crackpots keep trying to do, no matter how much you tell them it could never work. If the spec defines precisely what a program will do, with enough detail that it can be used to generate the program itself, this just begs the question: how do you write the spec? Such a complete spec is just as hard to write as the underlying computer program, because just as many details have to be answered by spec writer as the programmer. To use terminology from information theory: the spec needs just as many bits of Shannon entropy as the computer program itself would have. Each bit of entropy is a decision taken by the spec-writer or the programmer.

So, the bottom line is that if there really were a mechanical way to prove things about the correctness of a program, all you’d be able to prove is whether that program is identical to some other program that must contain the same amount of entropy as the first program, otherwise some of the behaviors are going to be undefined, and thus unproven. So now the spec writing is just as hard as writing a program, and all you’ve done is moved one problem from over here to over there, and accomplished nothing whatsoever.

This seems like a kind of brutal example, but nonetheless, this search for the holy grail of program quality is leading a lot of people to a lot of dead ends. The Windows Vista team at Microsoft is a case in point. Apparently—and this is all based on blog rumors and innuendo—Microsoft has had a long term policy of eliminating all software testers who don’t know how to write code, replacing them with what they call SDETs, Software Development Engineers in Test, programmers who write automated testing scripts.

The old testers at Microsoft checked lots of things: they checked if fonts were consistent and legible, they checked that the location of controls on dialog boxes was reasonable and neatly aligned, they checked whether the screen flickered when you did things, they looked at how the UI flowed, they considered how easy the software was to use, how consistent the wording was, they worried about performance, they checked the spelling and grammar of all the error messages, and they spent a lot of time making sure that the user interface was consistent from one part of the product to another, because a consistent user interface is easier to use than an inconsistent one.

None of those things could be checked by automated scripts. And so one result of the new emphasis on automated testing was that the Vista release of Windows was extremely inconsistent and unpolished. Lots of obvious problems got through in the final product… none of which was a “bug” by the definition of the automated scripts, but every one of which contributed to the general feeling that Vista was a downgrade from XP. The geeky definition of quality won out over the suit’s definition; I’m sure the automated scripts for Windows Vista are running at 100% success right now at Microsoft, but it doesn’t help when just about every tech reviewer is advising people to stick with XP for as long as humanly possible. It turns out that nobody wrote the automated test to check if Vista provided users with a compelling reason to upgrade from XP.

I don’t hate Microsoft, really I don’t. In fact, my first job out of school was actually at Microsoft. In those days it was not really a respectable place to work. Sort of like taking a job in the circus. People looked at you funny. Really? Microsoft? On campus, in particular, it was perceived as corporate, boring, buttoned-down, making inferior software so that accountants can do, oh I don’t know, spreadsheets or whatever it is that accountants do. Perfectly miserable. And it all ran on a pathetic single-tasking operating system called MS-DOS full of arbitrary stupid limitations like 8-character file names and no email and no telnet and no Usenet. Well, MS-DOS is long gone, but the cultural gap between the Unixheads and the Windows users has never been wider. This is a culture war. The disagreements are very byzantine but very fundamental. To Yale, Microsoft was this place that made toy business operating systems using three-decades-old computer science. To Microsoft, “computer sciency” was a bad word used to make fun of new hires with their bizarre hypotheses about how Haskell is the next major programming language.

Just to give you one tiny example of the Unix-Windows cultural war. Unix has this cultural value of separating user interface from functionality. A righteous Unix program starts out with a command-line interface, and if you’re lucky, someone else will come along and write a pretty front end for it, with shading and transparency and 3D effects, and this pretty front end just launches the command-line interface in the background, which then fails in mysterious ways, which are then not reflected properly in the pretty front end which is now hung waiting for some input that it’s never going to get.

But the good news is that you can use the command line interface from a script.

Whereas the Windows culture would be to write a GUI app in the first place, and all the core functionality would be tangled up hopelessly with the user interface code, so you could have this gigantic application like Photoshop that’s absolutely brilliant for editing photos, but if you’re a programmer, and you want to use Photoshop to resize a folder of 1000 pictures so that each one fits in a 200 pixel box, you just can’t write that code, because it’s all very tightly bound to a particular user interface.

Anyway, the two cultures roughly correspond to highbrow vs. lowbrow, and in fact, it’s reflected accurately in the curriculum of computer science departments throughout the country. At Ivy League institutions, everything is Unix, functional programming, and theoretical stuff about state machines. As you move down the chain to less and less selective schools Java starts to appear. Move even lower and you literally start to see classes in topics like Microsoft Visual Studio 2005 101, three credits. By the time you get to the 2 year institutions, you see the same kind of SQL-Server-in-21-days “certification” courses you see advertised on the weekends on cable TV. Isn’t it time to start your career in (different voice) Java Enterprise Beans!

Part 2

After a few years in Redmond, Washington, during which I completely failed to adapt to my environment, I beat a hasty retreat to New York City. I stayed on with Microsoft in New York for a few months, where I was a complete and utter failure as a consultant at Microsoft Consulting, and then I spent a few years in the mid-90s, when the Internet was first starting to happen, at Viacom. That’s this big corporate conglomerate which owned MTV, VH1, Nickelodeon, Blockbuster, Paramount Studios, Comedy Central, CBS, and a bunch of other entertainment companies. New York was the first place I got to see what most computer programmers do for a living. It’s this scary thing called “in house software.” It’s terrifying. You never want to do in house software. You’re a programmer for a big corporation that makes, oh, I don’t know, aluminum cans, and there’s nothing quite available off the shelf which does the exact kind of aluminum can processing that they need, so they have these in-house programmers, or they hire companies like Accenture and IBM to send them overpriced programmers, to write this software. And there are two reasons this is so frightening: one, because it’s not a very fulfilling career if you’re a programmer, for a list of reasons which I’ll enumerate in a moment, but two, it’s frightening because this is what probably 80% of programming jobs are like, and if you’re not very, very careful when you graduate, you might find yourself working on in-house software, by accident, and let me tell you, it can drain the life out of you.

OK, so, why does it suck to be an in house programmer.

Number one. You never get to do things the right way. You always have to do things the expedient way. It costs so much money to hire these programmers—typically a company like Accenture or IBM would charge $300 an hour for the services of some recent Yale PoliSci grad who took a 6 week course in dot net programming, and who is earning $47,000 a year and hoping that it’ll provide enough experience to get into business school—anyway, it costs so much to hire these programmers that you’re not going to allowed to build things with Ruby on Rails no matter how cool Ruby is and no matter how spiffy the Ajax is going to be. You’re going into Visual Studio, you’re going to click on the wizard, you’re going to drag the little Grid control onto the page, you’re going to hook it up to the database, and presto, you’re done. It’s good enough. Get out of there and onto the next thing. That’s the second reason these jobs suck: as soon as your program gets good enough, you have to stop working on it. Once the core functionality is there, the main problem is solved, there is absolutely no return-on-investment, no business reason to make the software any better. So all of these in house programs look like a dog’s breakfast: because it’s just not worth a penny to make them look nice. Forget any pride in workmanship or craftsmanship you learned in CS323. You’re going to churn out embarrassing junk, and then, you’re going to rush off to patch up last year’s embarrassing junk which is starting to break down because it wasn’t done right in the first place, twenty-seven years of that and you get a gold watch. Oh, and they don’t give gold watches any more. 27 years and you get carpal tunnel syndrome. Now, at a product company, for example, if you’re a software developer working on a software product or even an online product like Google or Facebook, the better you make the product, the better it sells. The key point about in-house development is that once it’s “good enough,” you stop. When you’re working on products, you can keep refining and polishing and refactoring and improving, and if you work for Facebook, you can spend a whole month optimizing the Ajax name-choosing gizmo so that it’s really fast and really cool, and all that effort is worthwhile because it makes your product better than the competition. So, the number two reason product work is better than in-house work is that you get to make beautiful things.

Number three: when you’re a programmer at a software company, the work you’re doing is directly related to the way the company makes money. That means, for one thing, that management cares about you. It means you get the best benefits and the nicest offices and the best chances for promotion. A programmer is never going to rise to become CEO of Viacom, but you might well rise to become CEO of a tech company.

Anyway. After Microsoft I took a job at Viacom, because I wanted to learn something about the internet and Microsoft was willfully ignoring it in those days. But at Viacom, I was just an in-house programmer, several layers removed from anybody who did anything that made Viacom money in any way.

And I could tell that no matter how critical it was for Viacom to get this internet thing right, when it came time to assign people to desks, the in-house programmers were stuck with 3 people per cubicle in a dark part of the office with no line-of-sight to a window, and the “producers,” I don’t know what they did exactly but they were sort of the equivalent of Turtle on Entourage, the producers had their own big windowed offices overlooking the Hudson River. Once at a Viacom Christmas party I was introduced to the executive in charge of interactive strategy or something. A very lofty position. He said something vague and inept about how interactivity was very important. It was the future. It convinced me that he had no flipping idea whatsoever what it was that was happening and what the internet meant or what I did as a programmer, and he was a little bit scared of it all, but who cares, because he’s making 2 million dollars a year and I’m just a typist or “HTML operator” or whatever it is that I did, how hard can it be, his teenage daughter can do that.

So I moved across the street to Juno Online Services. This was an early internet provider that gave people free dial-up accounts that could only be use for email. It wasn’t like Hotmail or Gmail, which didn’t exist yet, because you didn’t need internet access to begin with, so it was really free.

Juno was, allegedly, supported by advertising. It turned out that advertising to the kinds of people who won’t pay $20 a month for AOL is not exactly the most lucrative business in the world, so in reality, Juno was supported by rich investors. But at least Juno was a product company where programmers were held in high regard, and I felt good about their mission to provide email to everyone. And indeed I worked there happily for about three years as a C++ programmer. Eventually, though, I started to discover that the management philosophy at Juno was old fashioned. The assumption there was that managers exist to tell people what to do. This is quite upside-down from the way management worked in typical west-coast high tech companies. What I was used to from the west coast was an attitude that management is just an annoying, mundane chore someone has to do so that the smart people can get their work done. Think of an academic department at a university, where being the chairperson of the department is actually something of a burden that nobody really wants to do; they’d much rather be doing research. That’s the Silicon Valley style of management. Managers exist to get furniture out of the way so the real talent can do brilliant work.

Juno was founded by very young, very inexperienced people—the president of the company was 24 years old and it was his first job, not just his first management job—and somewhere in a book or a movie or a TV show he had gotten the idea that managers exist to DECIDE.

If there’s one thing I know, it’s that managers have the least information about every technical issue, and they are the last people who should be deciding anything. When I was at Microsoft, Mike Maples, the head of the applications division, used to have people come to him to resolve some technical debate they were having. And he would juggle some bowling pins, tell a joke, and tell them to get the hell out of his office and solve their own damned problems instead of coming to him, the least qualified person to make a technical decision on its merits. That was, I thought, the only way to manage smart, highly qualified people. But the Juno managers, like George Bush, were the deciders, and there were too many decisions to be made, so they practiced something I started calling hit-and-run micromanagement: they dive in from nowhere, micromanage some tiny little issue, like how dates should be entered in a dialog box, overriding the opinions of all the highly qualified technical people on the team who had been working on that problem for weeks, and then they disappeared, so that’s the hit-and-run part, because there’s some other little brush fire elsewhere that needs micromanagement.

So, I quit, without a real plan.

Part 3

I despaired of finding a company to work for where programmers were treated like talent and not like typists, and decided I would have to start my own. In those days, I was seeing lots of really dumb people with really dumb business plans making internet companies, and I thought, hey, if I can be, say, 10% less dumb than them, that should be easy, maybe I can make a company too, and in my company, we’d do things right for a change. We’d treat programmers with respect, we’d make high quality products, we wouldn’t take any shit from VCs or 24-year-olds playing President, we’d care about our customers and solve their problems when they called, instead of blaming everything on Microsoft, and we’d let our customers decide whether or not to pay us. At Fog Creek we’ll give anyone their money back with no questions asked under any circumstances whatsoever. Keeps us honest.

So, it was the summer of 2000, and I had taken some time off from work while I hatched the plans for Fog Creek Software and went to the beach a lot. During that period I started writing up some of the things I had learned over the course of my career on a website called Joel on Software. In those early days before blogs were invented, a programmer named Dave Winer had set up a system called where anyone could post things to the web in a sort-of blog like format. Joel on Software grew quickly and gave me a pulpit where I could write about software development and actually get some people to pay attention to what I was saying. The site consists of fairly unoriginal thoughts, combined with jokes. It was successful because I used a slightly larger font than the average website, making it easy to read. It’s always hard to figure out how many people read the site, especially when you don’t bother counting them, but typical articles on that site get read by somewhere between 100,000 and a million people, depending on how popular the topic is.

What I do on Joel on Software—writing articles about somewhat technical topics—is something I learned here in the CS department, too. Here’s the story behind that. In 1989 Yale was pretty good at AI, and one of the big name professors, Roger Schank, came and gave a little talk at Hillel about some of his AI theories about scripts and schemas and slots and all that kind of stuff. Now essentially, I suspect from reading his work that it was the same speech he’d been giving for twenty years, and he had spent twenty years of his career writing little programs using these theories, presumably to test them, and they didn’t work, but somehow the theories never got discarded. He did seem like a brilliant man, and I wanted to take a course with him, but he was well known for hating undergraduates, so the only option was to take this course called Algorithmic Thinking—CS115—basically, a watered-down gut group IV class designed for poets. It was technically in the CS department, but the faculty was so completely unimpressed that you were not allowed to count it towards a CS major. Although it was the largest class by enrollment in the CS department, I cringed every time I heard my history-major friends referring to the class as “computer science.” A typical assignment was to write an essay on whether machines can think or not. You can see why we weren’t allowed to count it towards a CS degree. In fact, I would not be entirely surprised if you revoke my degree today, retroactively, upon learning that I took this class.

The best thing about Algorithmic Thinking was that you had to write a lot. There were 13 papers—one every week. You didn’t get grades. Well, you did. Well, ok, there’s a story there. One of the reasons Schank hated undergrads so much was that they were obsessed with grades. He wanted to talk about whether computers could think and all undergrads wanted to talk about was why their paper got a B instead of an A. At the beginning of the term, he made a big speech about how grades are evil, and decided that the only grade you could get on a paper was a little check mark to signify that some grad student read it. Over time, he wanted to recognize the really good papers, so he added check-PLUS, and then there were some really lame papers, so he started giving out check-minuses, and I think I got a check-plus-plus once. But grades: never.

And despite the fact that CS115 didn’t count towards the major, all this experience writing about slightly technical topics turned out to be the most useful thing I got out of the CS department. Being able to write clearly on technical topics is the difference between being a grunt individual contributor programmer and being a leader. My first job at Microsoft was as a program manager on the Excel team, writing the technical specification for this huge programming system called Visual Basic for Applications. This document was something like 500 pages long, and every morning literally hundreds of people came into work and read my spec to figure out what to do next. That included programmers, testers, marketing people, documentation writers, and localizers around the world. I noticed that the really good program managers at Microsoft were the ones who could write really well. Microsoft flipped its corporate strategy 180 degrees based on a single compelling email that Steve Sinofsky wrote called Cornell is Wired. The people who get to decide the terms of the debate are the ones who can write. The C programming language took over because The C Programming Language was such a great book.

So anyway, those were the highlights of CS. CS 115, in which I learned to write, one lecture in Dynamic Logic, in which I learned not to go to graduate school, and CS 322, in which I learned the rites and rituals of the Unix church and had a good time writing a lot of code. The main thing you don’t learn with a CS degree is how to develop software, although you will probably build up certain muscles in your brain that may help you later if you decide that developing software is what you want to do. The other thing you can do, if you want to learn how to develop software, is send your resume to, and apply for a summer internship, and we’ll teach you a thing or two about the subject.

Thank you very much for your time.