Programming Bug Quotes

Wit and puns aren't just decor in the mind; they're essential signs that the mind knows it's on, recognizes its own software, can spot the bugs in its own program.

If debugging is the process of removing software bugs, then programming must be the process of putting them in.

Program testing can be used to show the presence of bugs, but never to show their absence!

Don't gloss over a routine or piece of code involved in the bug because you "know" it works. Prove it. Prove it in this context, with this data, with these boundary conditions.

Software testing is a sport like hunting, it's bughunting.

Without requirements and design, programming is the art of adding bugs to an empty text file.

Tibby sat on the outside of a group of kids in the film program. There was a lot of dark clothing and heavy footwear, and quite a few piercings glinting in sunlight. They had invited her to sit with them while they all finished up their lunches before film seminar. Tibby knew that they had invited her largely because she had a ring in her nose. This bugged her almost as much as when people excluded her because she had a ring in her nose.

Debugging: what an odd word. As if "bugging" were the job of putting in bugs, and debugging the task of removing them. But no. The job of putting in bugs is called programming. A programmer writes some code and inevitably makes the mistakes that result in the malfunctions called bugs. Then, for some period of time, normally longer than the time it takes to design and write the code in the first place, the programmer tries to remove the mistakes.

Dijkstra once said, “Testing shows the presence, not the absence, of bugs.” In other words, a program can be proven incorrect by a test, but it cannot be proven correct. All that tests can do, after sufficient testing effort, is allow us to deem a program to be correct enough for our purposes.

Any sufficiently complicated C or Fortran program contains an ad hoc, informally-specified, bug-ridden, slow implementation of half of Common Lisp.

Testing can only prove the presence of bugs, not their absence. –

My programs don't have bugs... they have random features.

Virding's First Rule of Programming: Any sufficiently complicated concurrent program in another language contains an ad hoc informally-specified bug-ridden slow implementation of half of Erlang.

Hopper would later gain fame both as a teacher and as a pioneer in the development of high-level programming languages. Yet perhaps her best-known contribution came in the summer of 1945, when she and her colleagues were tracking down a glitch in the Mark II and discovered a large moth that had gotten crushed by one of the relay switches and shorted it out. She taped the dead moth into the logbook with the notation “First case of an actual bug being found.

And once I realized that code I write never fucking goes away and I'm going to be a maintainer for life. I get comments about blog posts that are almost 10 years old. "Hey, I found this code. I found a bug," and I'm suddenly maintaining code.

Testing may convincingly demonstrate the presence of bugs, but can never demonstrate their absence."- Edsger W. Dijkstra, Computing Pioneer (1930–2002), "Programming as a discipline of mathematical nature," Am. Math. Monthly, 81 (1974), No. 6, pp. 608–12.

I like my code to be elegant and efficient. The logic should be straightforward to make it hard for bugs to hide, the dependencies minimal to ease maintenance, error handling complete according to an articulated strategy, and performance close to optimal so as not to tempt people to make the code messy with unprincipled optimizations. Clean code does one thing well. -Bjarne Stroustrup, inventor of C++ and author of The C++ Programming Language

In summary, we each spend our adult lives running on a unique operating system that took some eighteen years to program and is full of distinct bugs and viruses. And when we put together all these different theories of attachment, developmental immaturity, post-traumatic stress, and internal family systems, they make up a body of knowledge that allows us to run a virus scan on ourselves and, at any point, to look at our behaviors, our thoughts, and our feelings, and figure out where they come from. That’s the easy part. The tough part is to quarantine the virus, and to recognize the false self and restore the true self. Because it isn’t until we start developing an honest, compassionate, and functional relationship with ourselves that we can begin to experience a healthy, loving relationship with others.

To paraphrase an old joke among programmers, “Writing code accounts for 90 percent of programming. Debugging code accounts for the other 90 percent.” Your computer will do only what you tell it to do; it won’t read your mind and do what you intended it to do. Even professional programmers create bugs all the time, so don’t feel discouraged if your program has a problem.

In his 1972 essay “The Humble Programmer,” Edsger W. Dijkstra said that “Program testing can be a very effective way to show the presence of bugs, but it is hopelessly inadequate for showing their absence.

Under a $652-million clandestine program code named GENIE, the NSA, CIA, and special military operatives have planted covert digital bugs in tens of thousands of computers, routers, and firewalls around the world to conduct computer network exploitation, or CNE. Some are planted remotely, but others require physical access to install through so-called interdiction—the CIA or FBI intercepts shipments of hardware from manufacturers and retailers in order to plant malware in them or install doctored chips before they reach the customer.

We needed a man to repair the machines, to keep them going and everything. And the army was always going to send this fellow they had, but he was always delayed. Now, we always were in a hurry. Everything we did, we tried to do as quickly as possible. In this particular case, we worked out all the numerical steps that the machines were supposed to do—multiply this, and then do this, and subtract that. Then we worked out the program, but we didn’t have any machine to test it on. So we set up this room with girls in it. Each one had a Marchant: one was the multiplier, another was the adder. This one cubed—all she did was cube a number on an index card and send it to the next girl. We went through our cycle this way until we got all the bugs out. It turned out that the speed at which we were able to do it was a hell of a lot faster than the other way, where every single person did all the steps. We got speed with this system that was the predicted speed for the IBM machine. The only difference is that the IBM machines didn’t get tired and could work three shifts. But the girls got tired after a while.

Software development is the process of creating a computer software. It includes preparing a design, coding the program, and fixing the bugs. The final goal of software development is to translate user needs to software product, while continuously improving the team and the process.

In languages with a garbage collector (GC), the GC keeps track and cleans up memory that isn’t being used anymore, and we don’t need to think about it. Without a GC, it’s our responsibility to identify when memory is no longer being used and call code to explicitly return it, just as we did to request it. Doing this correctly has historically been a difficult programming problem. If we forget, we’ll waste memory. If we do it too early, we’ll have an invalid variable. If we do it twice, that’s a bug too. We need to pair exactly one allocate with exactly one free. Rust takes a different path: the memory is automatically returned once the variable that owns it goes out of scope.

Greenspun’s 10th rule states, “Any sufficiently complicated C or Fortran program contains an ad hoc, informally specified, bug-ridden, slow implementation of half of Common Lisp.” This has morphed into the newer joke: “Every microservice architecture contains a half-broken reimplementation of Erlang.” I think there is a lot of truth to this.

One of the greatest problems for systems programmers (the people who write compilers, interpreters, assemblers, and other programs to be used by many people) is to figure out how to write error-detecting routines in such a way that the messages which they feed to the user whose program has a "bug" provide high-level, rather than low-level, descriptions of the problem. it is an interesting reversal that when something goes wrong in a genetic "program" (e.g., a mutation), the "bug" is manifest only to people on a high level - namely on the phenotype level, not the genotype level. Actually, modern biology uses mutations as one of its principal windows onto genetic processes, because of their multilevel traceability.

Seibel: There's a Dijkstra quote about how you can't prove by testing that a program is bug-free, you can only prove that you failed to find any bugs with your tests. But it sort of sounds the same way with a proof-you can't prove a program is bug-free with a proof-you can only prove that, as far as you understand your own proof, it hasn't turned up any bugs.

That’s the nature of culture. It’s not a single decision—it’s a code that manifests itself as a vast set of actions taken over time. No one person makes or takes all these actions. Cultural design is a way to program the actions of an organization, but, like computer programs, every culture has bugs. And cultures are significantly more difficult to debug than programs.

Nintendo’s standards were exacting. “In terms of game testing they revolutionised the concept,” said Milgrom. “They said zero defects – we will not allow you to release a game that has any bugs in it whatsoever. Now zero defects was an unheard of concept in any other software or on any other gaming platform. Nintendo knew if they were going to sell it in the supermarkets and sell it to mums and dads it had to work off the shelf and had to be flawless. They didn’t want returns. We had to change our programming attitude and the way we developed games, which was brilliant. It was really hard work. If you had a bug in your final version you could miss Christmas because it would take a month for them to go through the testing of the title.

Emotions aren’t a bug in the programming, something left over from your malfunctioning lizard brain or incomplete childhood. You do not have these weird, unwieldy emotions that happen mysteriously to you, and you simply need to tolerate them, like that crazy uncle you have to sit next to at Thanksgiving dinner. Your emotions aren’t a mistake; they are some of the best parts of you. Feelings aren’t a design flaw; they are divine in origin.

Program maintenance involves no cleaning, lubrication, or repair of deterioration. It consists chiefly of changes that repair design defects. Much more often than with hardware, these changes include added functions. Usually they are visible to the user. The total cost of maintaining a widely used program is typically 40 percent or more of the cost of developing it. Surprisingly, this cost is strongly affected by the number of users. More users find more bugs.

Zawinski: Sometimes. I end up doing all the sysadmin crap, which I can't stand-I've never liked it. I enjoy working on XScreenSaver because in some ways screen savers-the actual display modes rather than the XScreenSaver framework-are the perfect program because they almost always start from scratch and they do something pretty and there's never a version 2.0. There's very rarely a bug in a screen saver. It crashes-oh, there's a divide-by-zero and you fix that.

You should do well but not really good. And the reason is that in the time it takes you to go from well to really good, Moore’s law has already surpassed you. You can pick up 10 percent but while you’re picking up that 10 percent, computers have gotten twice as fast and maybe with some other stuff that matters more for optimization, like caches. I think it’s largely a waste of time to do really well. It’s really hard; you generate as many bugs as you fix. You should stop, not take that extra 100 percent of time to do 10 percent of the work.

Bored with Pisit today, I switch to our public radio channel, where the renowned and deeply reverend Phra Titapika is lecturing on Dependent Origination. Not everyone’s cup of chocolate, I agree (this is not the most popular show in Thailand), but the doctrine is at the heart of Buddhism. You see, dear reader (speaking frankly, without any intention to offend), you are a ramshackle collection of coincidences held together by a desperate and irrational clinging, there is no center at all, everything depends on everything else, your body depends on the environment, your thoughts depend on whatever junk floats in from the media, your emotions are largely from the reptilian end of your DNA, your intellect is a chemical computer that can’t add up a zillionth as fast as a pocket calculator, and even your best side is a superficial piece of social programming that will fall apart just as soon as your spouse leaves with the kids and the money in the joint account, or the economy starts to fail and you get the sack, or you get conscripted into some idiot’s war, or they give you the news about your brain tumor. To name this amorphous morass of self-pity, vanity, and despair self is not only the height of hubris, it is also proof (if any were needed) that we are above all a delusional species. (We are in a trance from birth to death.) Prick the balloon, and what do you get? Emptiness. It’s not only us-this radical doctrine applies to the whole of the sentient world. In a bumper sticker: The fear of letting go prevents you from letting go of the fear of letting go. Here’s the good Phra in fine fettle today: “Take a snail, for example. Consider what brooding overweening self-centered passion got it into that state. Can you see the rage of a snail? The frustration of a cockroach? The ego of an ant? If you can, then you are close to enlightenment.” Like I say, not everyone’s cup of miso. Come to think of it, I do believe I prefer Pisit, but the Phra does have a point: take two steps in the divine art of Buddhist meditation, and you will find yourself on a planet you no longer recognize. Those needs and fears you thought were the very bones of your being turn out to be no more than bugs in your software. (Even the certainty of death gets nuanced.) You’ll find no meaning there. So where?

Some people mistakenly refer to software defects as bugs. When called bugs, they seem like pesky things that should be swatted or even ignored. This trivializes a critical problem and fosters a wrong attitude. Thus, when an engineer says there are only a few bugs left in a program, the reaction is one of relief. *Supposed, however, that we called them time bombs instead of bugs.* Would you feel the same sense of relief if a programmer told you that he had thoroughly tested a program and there were only a few time bombs left in it? Just using a different term changes your attitude entirely.

For example, say you're an average web developer. You're familiar with a dozen programming languages, tons of helpful libraries, standards, protocols, what have you. You still have to learn more at the rate of about one a week, and remember to check the hundreds of things you know to see if they've been updated or broken and make sure they all still work together and that nobody fixed the bug in one of them that you exploited to do something you thought was really clever one weekend when you were drunk. You're all up to date, so that's cool, then everything breaks. "Double you tee eff?" you say, and start hunting for the problem. You discover that one day, some idiot decided that since another idiot decided that 1/0 should equal infinity, they could just use that as a shorthand for "Infinity" when simplifying their code. Then a non-idiot rightly decided that this was idiotic, which is what the original idiot should have decided, but since he didn't, the non-idiot decided to be a dick and make this a failing error in his new compiler. Then he decided he wasn't going to tell anyone that this was an error, because he's a dick, and now all your snowflakes are urine and you can't even find the cat.

Encapsulation is a good thing, right? Well, don’t ask testers about that; they are liable to bite your head off. Classes that are too big often hide too much. Encapsulation is great when it helps us reason about our code and when we know that certain things can be changed only under certain circumstances. However, when we encapsulate too much, the stuff inside rots and festers. There isn’t any easy way to sense the effects of change, so people fall back on Edit and Pray (9) programming. At that point, either changes take far too long or the bug count increases. You have to pay for the lack of clarity somehow.

We are about to study the idea of a computational process. Computational processes are abstract beings that inhabit computers. As they evolve, processes manipulate other abstract things called data. The evolution of a process is directed by a pattern of rules called a program. People create programs to direct processes. In effect, we conjure the spirits of the computer with our spells. A computational process is indeed much like a sorcerer's idea of a spirit. It cannot be seen or touched. It is not composed of matter at all. However, it is very real. It can perform intellectual work. It can answer questions. It can affect the world by disbursing money at a bank or by controlling a robot arm in a factory. The programs we use to conjure processes are like a sorcerer's spells. They are carefully composed from symbolic expressions in arcane and esoteric programming languages that prescribe the tasks we want our processes to perform. A computational process, in a correctly working computer, executes programs precisely and accurately. Thus, like the sorcerer's apprentice, novice programmers must learn to understand and to anticipate the consequences of their conjuring. Even small errors (usually called bugs or glitches) in programs can have complex and unanticipated consequences.

It bugged him. He stepped back, stepped back some more so he saw the building proper and realized he had been here before. Back in the ’70s. The restaurant had been a community center or the like, legal aid, a view of the desks so you can see that everybody looks like you. Help you fill out the application for food stamps and other government programs, break down the discouraging bureaucratese, probably run by some former Panthers. He was still working for Horizon so it had to be the ’70s. Top floor, middle of summer, and the elevator was out. Humping up all that white-and-black hexagon tile, the steps worn from so many feet that they seemed to smile, a dozen smiles every floor.

since every vehicle is an autonomous entity, when two vehicles approach the same intersection at the same time, the drivers might miscommunicate their intentions and collide. Self-driving cars, in contrast, can all be connected to one another. When two such vehicles approach the same junction, they are not really two separate entities—they are part of a single algorithm. The chances that they might miscommunicate and collide are therefore far smaller. And if the transportation department decides to change some traffic regulation, all self-driving vehicles can be easily updated at exactly the same moment, and barring some bug in the program, they will all follow the new regulation to the letter.4

Why should anyone trust a government that has condoned torture, spied on at least thirty-five world leaders, supports indefinite detention, places bugs in thousands of computers all over the world, kills innocent people with drone attacks, promotes the post office to log mail for law enforcement agencies and arbitrarily authorizes targeted assassinations? Or, for that matter, a president that instituted the Insider Threat Program, which was designed to get government employees to spy on each other and ‘turn themselves and others in for failing to report breaches,’ which includes ‘any unauthorized disclosure of anything, not just classified materials.’” Some say this program was designed to turn government employees, such as your postman, into an army of snitches. The

Bitcoin’s Test Blockchains You might be surprised to learn that there is more than one bitcoin blockchain. The “main” bitcoin blockchain, the one created by Satoshi Nakamoto on January 3rd, 2009, the one with the genesis block we studied in this chapter, is called mainnet. There are other bitcoin blockchains that are used for testing purposes: at this time testnet, segnet, and regtest. Let’s look at each in turn. Testnet — Bitcoin’s Testing Playground Testnet is the name of the test blockchain, network, and currency that is used for testing purposes. The testnet is a fully featured live P2P network, with wallets, test bitcoins (testnet coins), mining, and all the other features of mainnet. There are really only two differences: testnet coins are meant to be worthless and mining difficulty should be low enough that anyone can mine testnet coins relatively easily (keeping them worthless). Any software development that is intended for production use on bitcoin’s mainnet should first be tested on testnet with test coins. This protects both the developers from monetary losses due to bugs and the network from unintended behavior due to bugs.

There, in that presumed paradise, the engineers were stranded in the company of an infantile mentality. They created artificial smartness, made a simulacrum of intelligence. But what they talked to all day was little more than a mechanism that read bits off a disk drive. If a comma in the code was out of place, it complained like a kid who won’t tolerate a pea touching the mashed potatoes. And, exhausted though the programmer may be, the machine was like an uncanny child that never got tired. There was Karl and the rest of the team, fitting the general definition of the modern software engineer: a man left alone all day with a cranky, illiterate thing, which he must somehow make grow up. It was an odd and satisfying gender revenge. Is it any surprise that these isolated men need relief, seek company, hook up This is not to say that women are not capable of engineering’s male-like isolation. Until I became a programmer, I didn’t thoroughly understand the usefulness of such isolation: the silence, the reduction of life to thought and form; for example, going off to a dark room to work on a program when relations with people get difficult. I’m perfectly capable of this isolation. I first noticed it during the visit of a particularly tiresome guest. All I could think was: There’s that bug waiting for me, I really should go find that bug.

Us in speech therapists office, Brandy says, “It helps to know you’re not anymore responsible for how you look than a car is,” Brandy says. “You’re a product just as much. A product of a product of a product. The people who design cars, they’re products. Your parents are products. Their parents were products. You’re teachers, products. The minister in your church, another product,” Brandy says. Sometimes your best way to deal with shirt, she says, is to not hold yourself as such precious little prize. “My point being,” Brandy says, “is you can’t escape the world, and you’re not responsible for how you look, if you look beauticious or butt ugly. You’re not responsible for how you feel or what you say or how you act or anything you do. It’s all out of your hands,” Brandy says. The same way a compact disk isn’t responsible for what’s recorded on it, that’s how we are. You’re about as free to act as a programmed computer. You’re about as one-of-a-kind as a dollar bill. “There isn’t any real you in you,” she says. ”Even your physical body, all your cells will be replaced within eight years.” Skin, bone, blood, and organs transplant from person to person. Even what’s inside you already, the colonies of microbes and bugs that eat your food for you, without them you’d die. Nothing of you is all-the-way yours. All of you is inherited. “Relax,” Brandy says, “Whatever you’re thinking, a million other folks are thinking. Whatever you do, they’re doing, and none of you is responsible. All of you is a cooperative effort.

Trash first. Then supplies. Stepping forward, I kicked a pile of takeout containers to one side, wanting to clear a path to the cabinets so I could look for latex gloves. But then I stopped, stiffening, an odd scratching sound coming from the pile I’d just nudged with my foot. Turning back to it, I crouched on the ground and lifted a greasy paper at the top of the mess. And that’s when I saw it. A cockroach. In Ireland. A giant behemoth of a bug, the likes I’d only ever seen on nature programs about prehistoric insects. Okay, perhaps I was overexaggerating its size. Perhaps not. Honestly, I didn’t get a chance to dwell on the matter, because the roach-shaped locust of Satan hopped onto my hand. I screamed. Obviously. Jumping back and swatting at my hand, I screamed again. But evil incarnate had somehow crawled up and into the sleeve of my shirt. The sensation of its tiny, hairy legs skittering along my arm had me screaming a third time and I whipped off my shirt, tossing it to the other side of the room as though it was on fire. “What the hell is going on?” I spun toward the door, finding Ronan Fitzpatrick and Bryan Leech hovering at the entrance, their eyes darting around the room as though they were searching for a perpetrator. Meanwhile, I was frantically brushing my hands over my arms and torso. I felt the echo of that spawn of the devil’s touch all over my body. “Cockroach!” I screeched. “Do you see it? Is it still on me?” I twisted back and forth, searching. Bryan and Ronan were joined in the doorway by more team members, but I barely saw them in my panic. God, I could still feel it. I. Could. Still. Feel. It. Now I knew what those hapless women felt like in horror movies when they realized the serial killer was still inside the house.

THEORY OF ALMOST EVERYTHING After the war, Einstein, the towering figure who had unlocked the cosmic relationship between matter and energy and discovered the secret of the stars, found himself lonely and isolated. Almost all recent progress in physics had been made in the quantum theory, not in the unified field theory. In fact, Einstein lamented that he was viewed as a relic by other physicists. His goal of finding a unified field theory was considered too difficult by most physicists, especially when the nuclear force remained a total mystery. Einstein commented, “I am generally regarded as a sort of petrified object, rendered blind and deaf by the years. I find this role not too distasteful, as it corresponds fairly well with my temperament.” In the past, there was a fundamental principle that guided Einstein’s work. In special relativity, his theory had to remain the same when interchanging X, Y, Z, and T. In general relativity, it was the equivalence principle, that gravity and acceleration could be equivalent. But in his quest for the theory of everything, Einstein failed to find a guiding principle. Even today, when I go through Einstein’s notebooks and calculations, I find plenty of ideas but no guiding principle. He himself realized that this would doom his ultimate quest. He once observed sadly, “I believe that in order to make real progress, one must again ferret out some general principle from nature.” He never found it. Einstein once bravely said that “God is subtle, but not malicious.” In his later years, he became frustrated and concluded, “I have second thoughts. Maybe God is malicious.” Although the quest for a unified field theory was ignored by most physicists, every now and then, someone would try their hand at creating one. Even Erwin Schrödinger tried. He modestly wrote to Einstein, “You are on a lion hunt, while I am speaking of rabbits.” Nevertheless, in 1947 Schrödinger held a press conference to announce his version of the unified field theory. Even Ireland’s prime minister, Éamon de Valera, showed up. Schrödinger said, “I believe I am right. I shall look an awful fool if I am wrong.” Einstein would later tell Schrödinger that he had also considered this theory and found it to be incorrect. In addition, his theory could not explain the nature of electrons and the atom. Werner Heisenberg and Wolfgang Pauli caught the bug too, and proposed their version of a unified field theory. Pauli was the biggest cynic in physics and a critic of Einstein’s program. He was famous for saying, “What God has torn asunder, let no man put together”—that is, if God had torn apart the forces in the universe, then who were we to try to put them back together?

Is that really what you want, or is that your programming?” Bug challenged. Actin sent a series of rude emojis. “It’s what I want. It’s my programming. I can’t possibly know, and it’s a completely uninteresting question to me. I don’t even believe in consciousness. When I’ve got my autonomy, I’ll still be programmed, and I’ll still need a job researching brain interfaces.

It is surprising how little page space is devoted to bugs and debugging in most introductory programming textbooks.

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Sladkey recalls the first time he found and sent a bug to Linus: "My first contribution was in porting some program, probably one of my smaller personal projects. I discovered a bug. Since Linux came with source, my first inclination as a hacker was to take a look under the hood and see if I could fix the problem. I found that although I had never done any kernel work, that I was able to navigate around the code pretty easily and provide a small patch to correct the problem. "With my heart beating and my palms sweating, I composed the most professional message I could muster and sent it off to linus.torvalds@cs.helsinki.fi describing the bug and including my proposed fix. Minutes later he replied something like, 'Yup, that's a bug. Nice investigation. Thanks. Fixed,' and I was hooked.

He felt people at IBM worshiped hierarchies. Each employee worried about his little piece of turf and nothing else. Diamond still recalled with amazement the time an IBM programmer, hacking away at OS/2, watched the program crash to a halt. The guy studied his screen for a minute, then said, “Wow, what a nasty problem. Glad that isn’t in my code.” He restarted his PC and went back to work, never even reporting the bug. At

Bugs were the backdrop of the code writer’s life. A comma in the wrong place. An “if” where there should be a “then.” An erroneous call from one piece of the program to another. Each could instantly cause a seizure, the collapse of a finely wrought abstraction into a puddle of ones and zeroes. Only human, software was born to fail. If not catastrophically, then aesthetically. Every software captain knew this.

Errors in code are what programmers call bugs, though when our programs go wrong, we prefer to call them “unexpected additional features.” Very

From now on, if you see a multisig unlocking script, you should expect to see an extra 0 in the beginning, whose only purpose is as a workaround to a bug that accidentally became a consensus rule.

I often end up rewriting. Sometimes I do that without ever finding the bug. I get to the point where I can just feel that it’s in this part here. I’m just not very comfortable about this part. It’s a mess. It really shouldn’t be that way. Rather than tweak it a little bit at a time, I’ll just throw away a couple hundred lines of code, rewrite it from scratch, and often then the bug is gone. Sometimes I feel guilty about that. Is that a failure on my part? I didn’t understand what the bug was. I didn’t find the bug. I just dropped a bomb on the house and blew up all the bugs and built a new house. In some sense, the bug eluded me. But if it becomes the right solution, maybe it’s OK. You’ve done it faster than you would have by finding it.

Fixing a bug is much like adding a new feature: the presence of the bug suggests that a case was missing from the initial test suite, and the bug fix should include that missing test case.

They can mislead us and can even cause pain, but their quirky behavior, to borrow from computer programming parlance, is almost always a feature of the software, not a bug in the program. However abnormal your mind may seem to you, it is probably functioning as it should.

the lesson I should have drawn is there may be more than one bug here and I should have looked harder the first time. But another lesson is that if a bug is thought to be rare, then looking at rarely executed paths may be fruitful. And a third thing is, having good documentation about what the algorithm is trying to do, namely a reference back to Knuth, was just great.

If you find yourself unable to sleep, don’t allow yourself to lie in bed panicking about not sleeping. Instead, get excited and embrace the fact you’re awake. Tell yourself, This is going to be a nice, quiet time, where I’m not bugged by texts, emails, or people needing something. I am going to get that research done, finally read that book, watch that program on the Discovery Channel, tidy that closet, or work uninterrupted on a project!

Program testing can be a very effective way to show the presence of bugs, but it is hopelessly inadequate for showing their absence.

Program testing can be used to show the presence of bugs, but never to show their absence!

the greatest limitation in writing software is our ability to understand the systems we are creating. As a program evolves and acquires more features, it becomes complicated, with subtle dependencies between its components. Over time, complexity accumulates, and it becomes harder and harder for programmers to keep all of the relevant factors in their minds as they modify the system. This slows down development and leads to bugs, which slow development even more and add to its cost. Complexity increases inevitably over the life of any program. The larger the program, and the more people that work on it, the more difficult it is to manage complexity.

physical sharing and exchange of computer tapes and disks on which the code was recorded. In current Internet days, rapid technological advances in computer hardware and software and networking technologies have made it much easier to create and sustain a communal development style on ever-larger scales. Also, implementing new projects is becoming progressively easier as effective project design becomes better understood, and as prepackaged infrastructural support for such projects becomes available on the Web. Today, an open source software development project is typically initiated by an individual or a small group seeking a solution to an individual's or a firm's need. Raymond (1999, p. 32) suggests that "every good work of software starts by scratching a developer's personal itch" and that "too often software developers spend their days grinding away for pay at programs they neither need nor love. But not in the (open source) world...." A project's initiators also generally become the project's "owners" or "maintainers" who take on responsibility for project management." Early on, this individual or group generally develops a first, rough version of the code that outlines the functionality envisioned. The source code for this initial version is then made freely available to all via downloading from an Internet website established by the project. The project founders also set up infrastructure for the project that those interested in using or further developing the code can use to seek help, provide information or provide new open source code for others to discuss and test. In the case of projects that are successful in attracting interest, others do download and use and "play with" the code-and some of these do go on to create new and modified code. Most then post what they have done on the project website for use and critique by any who are interested. New and modified code that is deemed to be of sufficient quality and of general interest by the project maintainers is then added to the authorized version of the code. In many projects the privilege of adding to the authorized code is restricted to only a few trusted developers. These few then serve as gatekeepers for code written by contributors who do not have such access (von Krogh and Spaeth 2002). Critical tools and infrastructure available to open source software project participants includes email lists for specialized purposes that are open to all. Thus, there is a list where code users can report software failures ("bugs") that they encounter during field use of the software. There is also a list where those developing the code can share ideas about what would be good next steps for the project, good features to add, etc. All of these lists are open to all and are also publicly archived,

Your career is stagnating by the minute. You are steadily letting your sedentary computer-programming desk-bound lifestyle turn your body into mush. All of these problems are much bigger and harder to just fix than a bug. They’re all complex, hard to measure, and comprised of many different small solutions—some of which will fail to work!

A good example is overflow detection on arithmetic, or providing bignums instead of just letting 32-bit integers wrap around. Now, implementing those is more expensive but I believe that providing full-blown bignums is a little less error-prone for some kinds of programming. A trap that I find systems programmers and designers of operating-systems algorithms constantly falling into is they say, "Well, we need to synchronize some phases here so we're going to use a take-a-number strategy. Every time we enter a new phase of the computation we'll increment some variable and that'll be the new number and then the different participants will make sure they're all working on the same phase number before a certain operation happens." And that works pretty well in practice, but if you use a 32-bit integer it doesn't take that long to count to four billion anymore. What happens if that number wraps around? Will you still be OK or not? It turns out that a lot of such algorithms in the literature have that lurking bug. What if some thread stalls for 2 to the 32nd iterations? That's highly unlikely in practice, but it's a possibility. And one should either mitigate that correctness problem or else do the calculation to show that, yeah, it's sufficiently unlikely that I don't want to worry about it. Or maybe you're willing to accept one glitch every day. But the point is you should do the analysis rather than simply ignoring the issue. And the fact that counters can wrap around is a lurking pitfall

In the Windows 10 Technical Preview, the more-or-less monthly new builds are delivered through Windows Update. Participants in the preview program can choose between two update speeds, also known as rings. Choosing the Fast ring makes new builds available as soon as they’re released by Microsoft; opting for the Slow ring delays the availability of a new build until it’s been thoroughly vetted by the Fast ring, with any bugs addressed via interim updates.

In plain English, an assert statement says, “I assert that this condition holds true, and if not, there is a bug somewhere in the program.” Unlike exceptions, your code should not handle assert statements with try and except; if an assert fails, your program should crash. By failing fast like this, you shorten the time between the original cause of the bug and when you first notice the bug. This will reduce the amount of code you will have to check before finding the code that’s causing the bug. Assertions are for programmer errors, not user errors. For errors that can be recovered from (such as a file not being found or the user entering invalid data), raise an exception instead of detecting it with an assert statement.

Rushing to optimize before the bottlenecks are known may be the only error to have ruined more designs than feature creep. From tortured code to incomprehensible data layouts, the results of obsessing about speed or memory or disk usage at the expense of transparency and simplicity are everywhere. They spawn innumerable bugs and cost millions of man-hours—often, just to get marginal gains in the use of some resource much less expensive than debugging time. Disturbingly often, premature local optimization actually hinders global optimization (and hence reduces overall performance). A prematurely optimized portion of a design frequently interferes with changes that would have much higher payoffs across the whole design, so you end up with both inferior performance and excessively complex code.

One of the primary reasons that abstraction is overloved is that a completed program full of the right abstractions is perfectly beautiful. But there are very few completed programs, because programs are written, maintained, bugs are fixed, features are added, performance is tuned, and a whole variety of changes are made both by the original and new programming team members. Thus, the way a program looks in the end is not important because there is rarely an end, and if there is one it isn't planned.

For example, every year, I rent Intuit’s TurboTax so I can do my income taxes. I pay for something I only need for a few weeks in February even though it holds my data for the entire year. That is because it has my data from the previous year (and for years before that). It simply asks if my financial situation has changed or if I have unique needs for a given tax year. It even has built-in, crowd-based support to help me when I get stuck. TurboTax meets many of the lovability requirements. It solves my problem, meets needs I did not know I had, makes my life easier, and adapts as my circumstances change. Best of all, I pay a reasonable price to rent it every year. But how does Intuit really know what I need? Well, Intuit is famous for a program they call Follow Me Home. It sounds exactly like what it is — a way to observe customers in their homes or offices in order to understand how they actually use Intuit’s products. The founding team used Follow Me Home as a way to help their teams get an immersive look at what customers liked and what they needed, as well as what worked and what did not work. By observing customers in their own spaces, the Intuit team was able to see how often customers were interrupted while trying to use their product, or if they started on one device and finished the task on another. They were able to funnel that information back to their development team to make updates in subsequent releases. It is important to note that they were not following customers home to look for bugs in the product. No, they had a deeper purpose — to truly understand the experience of their customers and if their products were making their work and life easier. That deep commitment to understanding customers helped Intuit find elegant ways to help them. It is a simple concept and one that more product builders would benefit from.

Beliefs are like computer operating systems/programs. If they are well-built and free of bugs, the computer runs smoothly and is powerful. If the system/programs aren't well-constructed or full of bugs, the computer operates, or behaves poorly, it is slow to respond and cannot perform in the miraculous way in which it was created. That’s why I study the Bible.

To find why that happen and why this is happening, you should start from the beginning the problem comes from the beginning go and remove the bug, fix the problem and try again to see what will happen... Life is like a program you can fix it by going to that point and fixing it, but be careful what do you program and how you do it and what type of codes you use!

It was time to resume his regularly scheduled program of bugging his little brother, tormenting Ash, and loving up Sloane. Bring it.

Remember that although the bug is of course impossible, it is happening. This

Edsger Dijkstra said: Program testing can be used to show the presence of bugs, but never to show their absence.

Programming, and especially debugging, sometimes brings out strong emotions. If you are struggling with a difficult bug, you might feel angry, despondent or embarrassed. There is evidence that people naturally respond to computers as if they were people 2 . When they work well, we think of them as teammates, and when they are obstinate or rude, we respond to them the same way we respond to rude, obstinate people. Preparing for these reactions might help you deal with them. One approach is to think of the computer as an employee with certain strengths, like speed and precision, and particular weaknesses, like lack of empathy and inability to grasp the big picture

In addition to the habituation and education of programmers are the constraints offered by the programming environments themselves which can be very unforgiving. Punctuation, for example, is part of the syntax of programming languages and misplaced punctuation can cause all sorts of strange bugs and errors to occur

it always bothered him when he came back to the States and saw the everyday people walking around without a thought for the men and women dying overseas for their freedom.  Then these same people would go and vote away their freedom to support some feel good candidate who talked a good game.  And then there was no longer a work ethic.  People didn’t have the drive to provide for themselves and their families.  Social programs were there and people lived well. They had food, homes and even cellphones all provided by “the government.”  People didn’t know of didn’t care that they were taking money away from those who worked hard and were successful and gave them to slugs of society or the lazy.  Sure some of these people truly needed assistance but 47% of the population receiving government benefits and even fewer paying taxes was out of control.  The country was willingly voting itself into socialism because “it was the right thing to do.”  When had it become ok to be on government assistance?  When had that social stigma to be embarrassed to be on food stamps gone away?

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Terrorism suspects aren’t the NSA’s only targets, however. Operations against nation-state adversaries have exploded in recent years as well. In 2011, the NSA mounted 231 offensive cyber operations against other countries, according to the documents, three-fourths of which focused on “top-priority” targets like Iran, Russia, China, and North Korea. Under a $652-million clandestine program code named GENIE, the NSA, CIA, and special military operatives have planted covert digital bugs in tens of thousands of computers, routers, and firewalls around the world to conduct computer network exploitation, or CNE. Some are planted remotely, but others require physical access to install through so-called interdiction—the CIA or FBI intercepts shipments of hardware from manufacturers and retailers in order to plant malware in them or install doctored chips before they reach the customer.

Programming is quite difficult – if you make a mistake, a bug will bother you for the rest of the day.

Systems Test No parts of the schedule are so thoroughly affected by sequential constraints as component debugging and system test. Furthermore, the time required depends on the number and subtlety of the errors encountered. Theoretically this number should be zero. Because of optimism, we usually expect the number of bugs to be smaller than it turns out to be. Therefore testing is usually the most mis-scheduled part of programming. For some years I have been successfully using the following rule of thumb for scheduling a software task: l /3 planning l/6 coding l/4 component test and early system test l/4 system test, all components in hand.

Writing and repairing software generally takes far more time and is far more expensive than initially anticipated. “Every feature that is added and every bug that is fixed,” Edward Tenner points out, “adds the possibility of some new and unexpected interaction between parts of the program.”19 De Jager concurs: “If people have learned anything about large software projects, it is that many of them miss their deadlines, and those that are on time seldom work perfectly. … Indeed, on-time error-free installations of complex computer systems are rare.”20 Even small changes to code can require wholesale retesting of entire software systems. While at MIT in the 1980s, I helped develop some moderately complex software. I learned then that the biggest problems arise from bugs that creep into programs during early stages of design. They become deeply embedded in the software’s interdependent network of logic, and if left unfixed can have cascading repercussions throughout the software. But fixing them often requires tracing out consequences that have metastasized in every direction from the original error. As the amount of computer code in our world soars (doubling every two years in consumer products alone), we need practical ways to minimize the number of bugs. But software development is still at a preindustrial stage—it remains more craft than engineering. Programmers resemble artisans: they handcraft computer code out of basic programming languages using logic, intuition, and pattern-recognition skills honed over years of experience.

When the handwritten guidance program was transcribed in Florida, a superscript bar was mistakenly left off the program. That one mistake meant that the program wasn’t able to correct the rocket’s course. Both the hardware failure of the Atlas antenna and the software bug in its guidance system meant that Mariner was completely out of control.

Every piece of technology upon which your project depends has some (hopefully small) risk of containing critical bugs and security vulnerabilities that might come to light only after you’ve started relying on it. If you are incapable of deploying a patch for Heartbleed or mitigating speculative execution problems like Meltdown and Spectre because you’ve assumed (or promised) that nothing will ever change, that is a significant gamble.

They said, ‘We just gave you the 8086 last week! How could you report a bug already?’”, Tesler recalled. But Intel had not reckoned with PARC’s do-it-yourself mentality. Years earlier the lab had purchased a rare million-dollar machine known as a Stitchweld, which could turn out printed circuit boards overnight from a digital schematic prepared on Thacker’s SIL program. “It turned out that no one else using the 8086 had Stitchwelds. Everyone else was going through complicated board designs, so they wouldn’t know for months if there was a bug. But at Xerox we gave them that feedback in a few days.

It's not a bug; it's an undocumented feature.

Most people are like pre-programmed robots, and unable to go off script for fear of bugging the programme and failing the programmers. All intelligence is art-making, that is, artificial.

According to Senate investigation, domestic programs that have violated these strictures in the Bill of Rights include the FBI’s COINTELPRO operations, the FBI’s campaign “to ‘neutralize’ [Martin Luther King] as an effective civil rights leader,” the CIA’s mail opening program which the FBI and CIA heads declared illegal in 1970 even as it continued, the NSA collection of millions of cables sent by private citizens, widespread wiretapping and bugging without warrant, the collection and dissemination of purely political or personal information obtained through electronic surveillance, hundreds (during the 1960s alone) of warrantless CIA/FBI break-ins which often involved theft and bugging, and the widespread use of informants to infiltrate and surveil “peaceful, law-abiding groups.

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Coding Sonnet One of the most powerful tools of science is coding, A string of illegible characters can make or break a society. 145,000 lines of code landed Armstrong 'n Aldrin on the moon, And 2 billion of them are working to satisfy everyday curiosity. But this awesome force is still used mostly to generate revenue, Welfare of humanity isn't a priority here, but a mere suggestion. That's why the coding marvel that set out to connect the world, Has become a playground for conspiracy, bigotry and division. Learn from the horrific blunders of society's founding coders, Make humanity the primary command of every code you write. A code that doesn't lift the society is nothing but a hideous bug, Zeros and Ones know no good or bad, unless by you it is defined. Uncle Ben once said, with great power comes great responsibility. I say to you today, a humane code facilitates a humane society.

People are inherently imperfect - we like to say that humans are mostly a collection of intermittent bugs. But before you can understand the bugs in your coworkers, you need to understand the bugs in yourself. We’re going to ask you to think about your own reactions, behaviors, and attitudes - and in return, we hope you gain some real insight into how to become a more efficient and successful software engineer who spends less energy dealing with people-related problems and more time writing great code.

Another detrimental effect of undervaluing people skills was that in some cases, programmers were rewarded more for raw code production than for meeting the user's needs. Marge Devaney, a programmer at Los Alamos National Laboratory in the 1950's, recalled sex differences in how programmers judged their performance. Asked if she had ever experienced gender bias on the job, sh replied that discrimination was difficult to prove, adding, "With things like computing, it's very hard to judge who's doing the best. Is it better to produce a program quickly and have it full of bugs that the users keep hitting, and so it doesn't work? Or is it better to produce it more slowly and have it so it works?...I do know some of the men believed in the first way: 'Throw it together and let the user debug it!'" This critique is echoed by women today who find their male peers rewarded for averting disasters through heroic last-minute efforts, while women's efforts at preventing such problems through careful work and communication with users go unrecognized. As a female software engineer complained in 2007, "Why don't we just build the system right in the first place? Women are much better at preventive medicine. A Superman mentality is not necessarily productive; it's just an easy fit for the men in the sector.

you? I think somebody pulled the plug on your brain drain! I’d rather run through a lion den in pork-chop underwear than talk to you! Well, you started with nothing, you’ve got that left! Most people live and learn but you just living aren’t you. You’re a just a few churns away from being butter aren’t you! I’m not a doctor, but I think you’ve got suckit-itus! I think there’s a manufacturer’s defect in your DNA! I don’t know what makes you so screwed up, but whatever it is, it’s working! Your brain must feel like brand new, since you never use it! The results of your IQ test would probably be negative! Call 911! I think somebody stole all your common sense! You look like a perfect example of a total failure! Was the ground cold when you crawled out this morning? For crying out loud! You’re acting like some kind a brainless, drunk, penguin! On the bright side, as a failure, you’re a great success! If idiots could fly, you’d be an eagle! How’d you even get here? Did somebody leave your cage open? If you had your head examined they wouldn’t find a lick of sense! I think you’ve got a bug in your programming! Don’t feel bad. A lot of people have no talent. Hi, I’m a human being! What are you again? I see you’re not letting your education get in the way of your ignorance! How long has it been since they performed your lobotomy? Are you in town for an idiot convention? You’re about as fun as licking the hand rail on an escalator! I’d slap you senseless if I could spare the two seconds it would take! Tough-titty said the kitty when the milk was all gone. The world needs examples like you so the rest of us can feel better! I don’t think you’re a fool. But what’s my opinion against thousands of others? I wish I could break whatever spell keeps magic’n you here! It looks like what you lack in intelligence you make up for in stupidity!

Software can have serious bugs and still be wildly successful. Lotus 1-2-3 famously mistook 1900 for a leap year, but it was so popular that versions of Excel to this day have to be programmed to honor that mistake to ensure backward compatibility. And because Excel’s popularity ultimately dwarfed that of Lotus 1-2-3, the bug is now part of the ECMA Office Open XML specification.

Most programmers approach software development with a mindset I call tactical programming. In the tactical approach, your main focus is to get something working, such as a new feature or a bug fix. At first glance this seems totally reasonable: what could be more important than writing code that works? However, tactical programming makes it nearly impossible to produce a good system design.

Steele: So I guess there's lessons there—the lesson I should have drawn is there may be more than one bug here and I should have looked harder the first time. But another lesson is that if a bug is thought to be rare, then looking at rarely executed paths may be fruitful. And a third thing is, having good documentation about what the algorithm is trying to do, namely a reference back to Knuth, was just great.

Seibel: What's your desert-island list of books for programmers? Peyton Jones: Well, you should definitely read Jon Bentley's Programming Pearls. Speaking of pearls, Brian Hayes has a lovely chapter in this book Beautiful Code entitled, “Writing Programs for ‘The Book’” where I think by “The Book” he means a program that will have eternal beauty. You've got two points and a third point and you have to find which side of the line between the two points this third point is on. And several solutions don't work very well. But then there's a very simple solution that just does it right. Of course, Don Knuth's series, The Art of Computer Programming. I don't think it was ever anything I read straight through; it's not that kind of book. I certainly referred to it a lot at one stage. Chris Okasaki's book Purely Functional Data Structures. Fantastic. It's like Arthur Norman's course only spread out to a whole book. It's about how you can do queues and lookup tables and heaps without any side effects but with good complexity bounds. Really, really nice book. Everyone should read this. It's also quite short and accessible as well. Structure and Interpretation of Computer Programs. Abelson and Sussman. I loved that. And Compiling with Continuations, Andrew Appel's book about how to compile a functional program using continuation passing style. Also wonderful. Books that were important to me but I haven't read for a long time: A Discipline of Programming by Dijkstra. Dijkstra is very careful about writing beautiful programs. These ones are completely imperative but they have the “Hoare property” of rather than having no obvious bugs they obviously have no bugs. And it gives very nice, elegant reasoning to reason about it. That's a book that introduced me for the first time to reasoning about programs in a pretty watertight way. Another book that at the time made a huge impression on me was Per Brinch Hansen's book about writing concurrent operating systems. I read it lots of times.

I really believed that computers were deterministic, that you could understand what they were supposed to do, and that there was no excuse for computers not working, for things not functioning properly. In retrospect, I was surprisingly good at keeping the system running, putting in new code and having it not break the system. That was the first instance of something I got an undeserved reputation for. I know that my boss, and probably some other of my colleagues, have said I was a great debugger. And that's partly true. But there's a fake in there. Really what I was was a very careful programmer with the arrogance to believe that very few computer programs are inherently difficult. I would take some piece of code that didn't look like it was working and I would try to read it. And if I could understand, then I could usually see what was wrong or poke around with it and fix it. But sometimes I would get a piece of code—often one that other people couldn't make work—and I would say, “This is way too complicated.” So I would think through what it was supposed to do, throw it away, and write it again from scratch. Some of the folks I worked with—like Will Crowther—who are terrific programmers, couldn't tolerate that. They would believe that by doing that, I would probably have fixed the 2 bugs that were there and introduced 27 new bugs. But the fact is, I was good at that. So I would rewrite stuff completely and it would be organized differently than the original programmer had organized it because I had thought about the problem differently. Typically, it was simpler than it used to be, or at least simpler to my eyes. And it would work. So I got this reputation—I fixed these mysterious bugs that nobody else could fix. Fortunately, they never asked me what the bug was. Because the truth of the matter is if they'd have asked, “How did you fix the bug?” my answer would have been, “I couldn't understand the code well enough to figure out what it was doing, so I rewrote it.” I did that a lot on the PDP-1 time-sharing system. There were chunks of the code that I would read and would say, “This doesn't do what I think this part of the program is supposed to be doing,” or “It's weird.” So I'd rewrite it. The only thing that kept me working there, with that attitude, was that I had a good track record. That's one of the things, that if you're not good at it, you make chaos. But if you are good at it, the world thinks that you can do things that you can't, really.

So when they ask, “How long is it going to take you to put this change in?” you have three answers. The first is the absolute shortest way, changing the one line of code. The second answer is how long it would be using my simple rule of rewriting the subroutine as if you were not going to make that mistake. Then the third answer is how long if you fix that bug if you were actually writing this subroutine in the better version of the program. So you make your estimate someplace between those last two and then every time you get assigned a task you have a little bit of extra time available to make the program better. I think that that makes an incredible difference. It makes for programs that evolve cleanly.