Programming

IM IN YR LOOP, INCRMENTNG YR VRS (OK, as a bone to my non-programming readers, consider the natural evolution of pet pictures on the web. It actually seems to have a consistent, emergent grammar. It doesn't meet the technical requirements of a Pidgin language, but it bears a certain resemblance; call it a faked pidgin. Gaim (open source IM client) recently renamed itself to Pidgin, and despite using a pigeon as a logo, pidgin is where the name came from.

I want to be clear about my purpose here. My point is not to claim that the uniqueness of programming is itself unique. Every interesting field is unique in its own special way. For each field, it is helpful to understand why it is unique if you wish to truly excel, or you may bring inappropriate concepts from other domains in, or export inappropriate programming concepts to other domains. I say that programming has several unique aspects and that these aspects are worth thinking about, but this does not mean that programming is privileged somehow.

The most common complaint about software is that it is "too buggy". The question is, "What does too buggy mean?" People making this complaint are often holding software to absurdly high standards, even when making comparisions to other engineering disciplines. In fact, bridges do fall down. Architects fail; often the designs can be seen to fail and corrected or maintained before catastrophic collapse, but it happens. Software is no more likely to be absolutely perfect than any other human endeavor.

Software is an engineering concern, and one of the things that means is that you can't have anything for free. If faced with the choice between a $100 piece of buggy or incomplete software, and a $50,000 piece of production-quality bullet-proof highly-tested quality software, it's unfair to complain that the $100 piece of software is buggy and incomplete.

Some guy took a crack at answering that question. Or more accurately, he claimed to take a crack at it; he never actually got around to answering it. It occurred to me the questioner does have a point, though.

What is computer science, anyhow?

In my continuing series on why software is special, motivating writing a book about it, this post discusses how software is chaotic.

Here I refer to the mathematical definition of chaos, which I will define as: "A chaotic system is one in which small changes in the initial conditions can cause large and unpredictable changes in the system's iterated state." This is based on the mathematical definition(s), but simplified for our purposes. It's not just a word, it's a quasi-formal concept.

In 2007, with a well-loaded Linux desktop installation, my /usr/bin is 257 megabytes, with debugging off and dynamically-linked libraries not contributing to that count. My particular copy of the Linux kernel 2.6.19 with certain Gentoo patches has 202,381,268 bytes of C code alone. If I'm computing this correctly, at a constant 100 words per minute (5 chars/word), that's 281 24-hour days just to re-type the C code in the kernel.

I've gone on before about how distrustful of metaphors I am, and it seems like every year I'm getting more distrustful of them. Either deal with the thing as it is, or just give up understanding it. Metaphors lead to the beginning of understanding, but no farther.

Programmers aren't immune to the metaphor sickness, and if there's one metaphor you can expect to see trotted out at the earliest available opportunity, it's the "programming as construction" metaphor. This metaphor has been skillfully deconstructed many many times before, but I'm going to deconstruct it from the opposite angle... what if construction was like software engineering?

Engineers of other disciplines often take offense at the claim that software is uniquely difficult. They do have a point. As pointed out by Fred Brooks in hyper-classic The Mythical Man Month, one reason software is hard because software is so uniquely easy. We fundamentally built on top of components that have reliability literally in the 99.999999999% range and beyond; a slow 2GHz CPU that "merely" failed once every trillion operations would still fail on average in eight hours at full load, which would be considered highly unreliable in a server room.

The first step to attaining wisdom is to understand why special "programming wisdom" is needed in the first place. It's easy to get the idea that software is easy to create, because it is partially true. Computers get more powerful every year, and we trade in on that power to make programming easier. Every year results in more and better libraries. Changing software is very easy, and it's relatively easy to test compared to an equivalently-complex real-world object.

This is the first post of my new BlogBook, Programming Wisdom.

This initial post starts off by discussing exactly what I mean by "wisdom" in the context of programming. Non-programmers may still be interested as it is more about wisdom than programming.